Effect of film thickness on the optical and electrical properties of TiO2 thin films was studied. Thin films of different thicknesses were deposited by screen printing method on fluorine doped tin oxide coated on glass substrate. The film thickness was determined by surface profile measurement. The thicknesses were 3.2, 8.2, 13.5 and 18.9 µm. Transmittance, reflectance and absorbance spectra were studied using UV-VIS-NIR spectrophotometer in the photon wavelength range of 200-2500 nm for transmittance and reflectance and 200-1200 nm for absorbance. Band gap and refractive index of the films were determined using these spectra. It was found that reflectance, absorbance, band gap and refractive index increase with film thickness while transmittance decreases with increase in thickness. I-V characteristics of the films were also measured by a 4- point probe. Electrical resistivity (

This research is an experimental design which came up with the optical and electrical properties of magnesium doped zinc oxide for photovoltaic applications. The specific objectives are to determine the Optical properties, and electrical properties of Magnesium doped ZnO of Magnesium doped ZnO. These objectives are to be achieved by sputtering three types of targets on to glass slides. The targets that will be used are two targets of magnesium doped ZnO with compositions of ZnO: Mg being 95:5 wt% and 90:10 wt%, both with a purity of 99.99% and a third target of un-doped ZnO with a purity of 99.99% . The optical properties will be determined using a double beam spectrophotometer in the UV/VIS/NIR regions. Thus the absorption, transmission and reflection properties will be focused on. The electrical properties will be determined using four point probe and the film resistance, sheet resistance and film conductivity will be looked at.

— Cu2O thin films have been deposited using reactive dc magnetron sputtering technique using an Edward Auto 306 Magnetron Sputtering System. Transmittance and reflectance data in the range 300 nm-2500 nm were obtained using UV-VIS NIR Spectrophotometer Solid State 3700 DUV for all the thin films samples that were prepared. Transmittance values of above 70% were observed. The optical measurements were simulated using SCOUT 98 software to determine optical constants and optical bad gap of the thin. The optical properties in these films were varied by varying oxygen flow rate at constant powerof 200 W. Optical studies show a direct allowed transition and a shift in the optical absorption edge as the oxygen flow rate varies at constant argon flow rate and other deposition parameters. These results show that single phase Cu2O thin films can be synthesized at a relatively low substrate temperature using the reactive dc magnetron sputtering technique. Band gap values of 1.62 eV –2.54 eV is observed. The surface sheet resistivities at room temperature of 298 K were found to vary with the deposition parameters and film thickness. Urbach energy varied between 0.6 ×10-4 to 1.92 ×104

800x600 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";}

A composite thin film consisting of TiO2 (binder), uniformly mixed CuFeMnO4 paint (solar absorber) was coated on textured aluminum sheets by dip coating. The film’s elemental analysis was done using energy dispersive x-ray (EDX) and the surface of the film characterized using scanning electron microscope (SEM). Optical properties of the TiO2/CuFeMnO4 composite film were also studied using computerized double beam solid-spec 3700 DUV Shimadzu Spectrophotometer. Reflectance was obtained by spectrophotometric measurements, and thermal emmittance was determined using heat flux- based technique respectively. Reflectance measurement values less than 0.03 in the solar wavelength (290 nm < λ < 2500 nm) and low thermal emmittance less than 0.016 for temperatures between 24°C and 100°C were obtained.

A composite thin film consisting of TiO2 (binder), uniformly mixed CuFeMnO4 paint (solar absorber)
was coated on textured aluminum sheets by dip coating. The film’s elemental analysis was done using energy
dispersive x-ray (EDX) and the surface of the film characterized using scanning electron microscope (SEM). Optical
properties of the TiO2/CuFeMnO4 composite film were also studied using computerized double beam solid-spec
3700 DUV Shimadzu Spectrophotometer. Reflectance was obtained by spectrophotometric measurements, and
thermal emmittance was determined using heat flux- based technique respectively. Reflectance measurement values
less than 0.03 in the solar wavelength (290 nm < λ < 2500 nm) and low thermal emmittance less than 0.016 for
temperatures between 24°C and 100°C were obtained.
Keywords: CuFeMnO4 paint, TiO2- bound, reflectance, thermal emmittance, solar thermal

The responses of cells in the visual cortex to stimulation of the two eyes changes dramatically following a period of monocular visual deprivation (MD) during a critical period in early life. This phenomenon, referred to as ocular dominance (OD) plasticity, is a widespread model for understanding cortical plasticity. In this study, we designed stimulus patterns and quantification methods to analyze OD in the mouse visual cortex using optical imaging of intrinsic signals. Using periodically drifting bars restricted to the binocular portion of the visual field, we obtained cortical maps for both contralateral (C) and ipsilateral (I) eyes and computed OD maps as (C - I)/(C + I). We defined the OD index (ODI) for individual animals as the mean of the OD map. The ODI obtained from an imaging session of less than 30 min gives reliable measures of OD for both normal and monocularly deprived mice under Nembutal anesthesia. Surprisingly, urethane anesthesia, which yields excellent topographic maps, did not produce consistent OD findings. Normal Nembutal-anesthetized mice have positive ODI (0.22 +/- 0.01), confirming a contralateral bias in the binocular zone. For mice monocularly deprived during the critical period, the ODI of the cortex contralateral to the deprived eye shifted negatively towards the nondeprived, ipsilateral eye (ODI after 2-day MD: 0.12 +/- 0.02, 4-day: 0.03 +/- 0.03, and 6- to 7-day MD: -0.01 +/- 0.04). The ODI shift induced by 4-day MD appeared to be near maximal, consistent with previous findings using single-unit recordings. We have thus established optical imaging of intrinsic signals as a fast and reliable screening method to study OD plasticity in the mouse.

The responses of cells in the visual cortex to stimulation of the two eyes changes dramatically following a period of monocular visual deprivation (MD) during a critical period in early life. This phenomenon, referred to as ocular dominance (OD) plasticity, is a widespread model for understanding cortical plasticity. In this study, we designed stimulus patterns and quantification methods to analyze OD in the mouse visual cortex using optical imaging of intrinsic signals. Using periodically drifting bars restricted to the binocular portion of the visual field, we obtained cortical maps for both contralateral (C) and ipsilateral (I) eyes and computed OD maps as (C - I)/(C + I). We defined the OD index (ODI) for individual animals as the mean of the OD map. The ODI obtained from an imaging session of less than 30 min gives reliable measures of OD for both normal and monocularly deprived mice under Nembutal anesthesia. Surprisingly, urethane anesthesia, which yields excellent topographic maps, did not produce consistent OD findings. Normal Nembutal-anesthetized mice have positive ODI (0.22 +/- 0.01), confirming a contralateral bias in the binocular zone. For mice monocularly deprived during the critical period, the ODI of the cortex contralateral to the deprived eye shifted negatively towards the nondeprived, ipsilateral eye (ODI after 2-day MD: 0.12 +/- 0.02, 4-day: 0.03 +/- 0.03, and 6- to 7-day MD: -0.01 +/- 0.04). The ODI shift induced by 4-day MD appeared to be near maximal, consistent with previous findings using single-unit recordings. We have thus established optical imaging of intrinsic signals as a fast and reliable screening method to study OD plasticity in the mouse.

An optical immunosensor (AQUA-OPTOSENSOR) and ELISA (enzyme-linked immunosorbent assay) for the analysis of pyrethroids and DDT in river water and/or sediment, are described. The optical immunosensor consists of a bench-top optical read-out-device and disposable single-use sensor chips. ELISA was carried out in the coating antigen format. As examples, phenothrin (pyrethroid) and p,p'-DDT were chosen. Herein we describe the overall strategy, the set-up and principle of the immunosensor platform, and show representative results for immunosensor and ELISA analysis. The immunosensor employs fluorophore (Oyster®-645)-labeled monoclonal antibodies (mouse mAb Py-1 and rat mAb DDT 7C12), and makes use of the evanescent field, thus operating without washing steps. ELISA in the coating antigen format uses a second antibody labeled with peroxidase. Both, phenothrin and p,p'-DDT can be analyzed with these immunochemical techniques in the low ppb levels. Advantages and drawbacks of both immunochemical platforms are discussed.

An optical immunosensor (AQUA-OPTOSENSOR) and ELISA (enzyme-linked immunosorbent assay) for the analysis of pyrethroids and DDT in river water and/or sediment, are described. The optical immunosensor consists of a bench-top optical read-out-device and disposable single-use sensor chips. ELISA was carried out in the coating antigen format. As examples, phenothrin (pyrethroid) and p,p'-DDT were chosen. Herein we describe the overall strategy, the set-up and principle of the immunosensor platform, and show representative results for immunosensor and ELISA analysis. The immunosensor employs fluorophore (Oyster®-645)-labeled monoclonal antibodies (mouse mAb Py-1 and rat mAb DDT 7C12), and makes use of the evanescent field, thus operating without washing steps. ELISA in the coating antigen format uses a second antibody labeled with peroxidase. Both, phenothrin and p,p'-DDT can be analyzed with these immunochemical techniques in the low ppb levels. Advantages and drawbacks of both immunochemical platforms are discussed.

Ternary thin film alloys of Se90-XIn10SbX (x = 1, 4, 10, 15 and 20) were synthesised by flash evaporation of the pre-melt quenched bulk samples under a vacuum of 10−5 Torr. Optical absorption analysis pointed to indirect allowed transitions as the mechanism of excitation across the energy gap. The optical band gap (Eg) was evaluated on the basis of Wemple-Didomenico single oscillator model and Tauc's extrapolation method in the spectral region where the absorption coefficient, α ≥ 104 cm−1. The refractive index (n), complex dielectric constant (ε), band tailing parameter (B), plasma frequency (ωp), single oscillator parameters (Eo and Ed) and lattice dielectric constant (εL) were deduced for each alloy. The compositional dependence of optical and dielectric parameters was explained on the basis of chemical bond approach. The observed shift in the trends of Eg, Ed, εL and ωp values at the composition where Sb = 4 at% was correlated to the usual chemical threshold at this composition.

Thin films of 〖 Se〗_(100-x) 〖Bi〗_x (x=0.0,1.5,3.0,4.5 and 6.0 at.%) deposited by flash evaporation technique, have been investigated in the wavelength range of 500nm-1000nm. It is found that the effect of increasing bismuth content on the as deposited films led to increase in the absorption coefficient, reflectance, refractive index, extinction coefficient, real and imaginary parts of dielectric constant while transmittance and optical band gap energy decreased. On the other hand, reflectance, absorption coefficient, extinction coefficient, refractive index, band gap energy, real and imaginary parts of dielectric constant increased with increase in film thickness but transmittance decreased.

The current study optimised breeding schemes for litter size (LS), lambing interval (LI), body weight (BW) and gastrointestinal parasite resistance for sheep in Kenya. Selection for the breeding goal traits was performed in a conventional way using information on phenotypes only. For gastrointestinal parasite resistance, information on genetic makers was used, with faecal egg count (FEC) as an indicator trait. Selection for parasite resistance was partly based on field measurements and the possibilities for marker-assisted selection (MAS) were explored. Several selection schemes were defined based on whether a classical selection only was used (Latin number 1), a quantitative trait loci (QTL) for FEC was assumed to be available (2), that the correlation between FEC and BW was assumed to be positive (unfavourable-Roman I) or negative (favourable- II) and finally how FEC was included in the index (i.e., no inclusion (A), with FEC (B) or with FEC QTL (C-F)). The schemes with overlapping generations were evaluated using the computer program SelAction. Rams, ewes and total selection responses in US dollars ($) per animal, and rams’ and ewes’ accuracies for each scheme with a favourable or unfavourable correlation were estimated. The differences in total selection responses between schemes that did not include FEC in the selection index resulted in a response of $0.16 in scheme 1AI and $0.20 in scheme 1AII. In schemes 1BI and 1BII, FEC was included in the index. The responses in scheme 1BI and 1BII were $0.165 and $0.217, respectively. The increase in response in schemes II compared with schemes I was due to a favourable correlation between BW and FEC. The different FEC index traits had a different effect on economic response. It should be noted that increased emphasis on selection for FEC will reduce the relative responses to the breeding goal traits BW, LS and LI. Consequently, the goal of selection for FEC should be to maintain acceptable levels of gastro-intestinal parasite resistance as well as sufficient improvement of LS and BW.

Power utility companies are required to supply customers with power within specified voltage limits. Voltage rise in networks with distributed generators therefore poses a challenge. This paper presents a coordinated network controller whose objective is to maintain an optimal voltage profile across the power network. The operations of distributed generators, on-load tap-changing transformers and reactive power sources are controlled. The controller is modelled as an optimisation problem which is solved using Particle Swarm Optimisation. The IEEE 30-bus test network is then used to verify the effectiveness of the controller. The results obtained show that this controller can greatly improve the voltage profile of a power network by varying the parameters of existing generation and voltage control equipment.

Extensive work has been done on Anaerobic digestion of single substrates and using codigestion.
In a number of cultures around the world, the wastes that are discarded as
household waste may not easily fit in the biogas models that have been developed so far. It is
therefore necessary to analyse the biogas produced from food mixtures found in unique
settings and compare them with literature values of individual substrates. In the current study,
food mixture found at waste bin at a cafeteria used by StudentsofUniversity of Nairobiwas
analysed. The purposes of this study were to investigate adjusted modes of substrate pretreatment
(Mechanical, thermal and thermo-chemical) and their role in maximizing the
process of anaerobic digestion through speeding up hydrolysis. The experiments were carried
out on waste samples consisting of carbohydrate food waste (ugali+Rice),potato peels, banana
peels and a mixture of the substrates mixed with rumen slurry in the ratio 3:1 under controlled
mesophilic anaerobic conditionsin the lab scale digester. Thermo-chemical pre-treatment was
the most effective for speeding up hydrolysis with the co digested substrates producing
maximum biogas. The desired C:N ratio of 31 was obtained when all the four substrates were
combined. Similarly, the biogas produced from the mixture of the four substrates was higher
than from any of the substrates.

Recent statistics show a rise in the margin of consumption and utilization of essential oils. People
have turned their attention to traditional medicines, and so the demand for essential oils in the
international market has increased drastically. However, essential oil extraction processes have
been observed to suffer from minimum output levels. The purpose of this study was to
investigate the effects of changing the process parameters (time of extraction, leaf sizes and
leaves to water ratio) and their contribution to maximizing the process of extraction and also the
composition of Eucalyptus grandis oil to establish utility of the oil.The extracted oil’s refractive
index was determined and GC-MS analysis of the oil was also done to determine the
composition of the oil. There was an increase of %yield with increase in time up to 150
minutes.Quality of the oil extract was desirable from appearance and smell. Variation in oil yield
was also noted from varying the leaves to water ratio, with 1:12.5 (w/v) being optimal. The
adjustment of leaf sizes was found to be most effective with a very high increase in yield margin.
The whole leaves produced the highest amounts of oil. More than 20 compounds were identified
with many of them appearing in eucalyptus oil from other species seen in literature.
Key Words: Essential Oils, Eucalyptus grandis, Clevenger Distillation, Optimization, GC-MS

Description
The study aimed at optimizing the extraction conditions and establishing the physicochemical properties of the mucilage obtained from root bark of Malva verticillata. Effects of temperature, time, particle size and amount of water as a solvent on the yield and composition of mucilage were established. Micrometric, physical, chemical and structural properties were used to characterise the extracted mucilage. Result showed significant correlation between extraction conditions and mucilage yield. Low temperature and short extraction time results into pharmaceutically valuable mucilage with low protein content, high viscosity and good dispersion in aqueous solvent. Large and small size particles of the plant material results into low mucilage yield without significant difference (p= 0.054). The mucilage shows mixed cohesiveness with less tendencies to flow. It exhibits vibration bands in FTIR that are associated with the presence of polysaccharides and proteins. The mucilage contains 2.65% protein, 13.83% inorganics, 1.85% fats, and the rest carbohydrates. High extractive value˃ 80% and moisture content˃ 12% implies that mucilage has high tendency to microbial attack. Optimized extraction conditions results into high yield of the mucilage with the same physicochemical properties and mineral composition regardless of the plant material sampling sites.

This research paper focuses on the optimization of the input parameters used in the computer numerical controlled (CNC) milling of polypropylene + 60 wt% quarry dust composite. The efficiency and profitability of the cutting operation was assessed using the material removal rate (MRR). Finding the optimal and suitable parameters to use in the cutting of polypropylene + 60 wt% quarry dust composite is crucial when it comes to increasing productivity without increasing the cost of production and machining time. Therefore, the Taguchi technique was utilized to optimize the cutting speed, the feed rate and the depth of cut used while focusing on their effects on the material removal rate. The analysis of the input parameters was carried out using the L9 Taguchi orthogonal array, the signal-to-noise (S/N) ratio and the analysis of variance (ANOVA). The finding showed that the optimal milling parameters for efficient productivity were; the cutting speed of 600 rpm, a feed rate of 200 mm/min and depth of cut of 0.8 mm. Additionally, the feed rate is the most contributing factor in affecting the material removal rate, followed by the depth of cut and lastly the cutting speed at 53%, 17 and 10% respectively.

Among the several techniques for additive manufacturing (AM), fused deposition modelling (FDM) is widely used. Fused deposition modelling process uses a thermoplastic material, which is melted and then extruded layer by layer through a nozzle, in order to create a three-dimensional object. As a result of the default setting of process parameters provided by the manufacturers, produced parts normally have a poor surface finish, low mechanical properties, low dimensional accuracy, and increased residual stresses compared to the parts produced using conventional manufacturing processes like molding (casting). Qualities of fused deposition modelled (FDMed) parts are generally affected by process parameters including the layer thickness, extrusion temperature, build orientation, printing speed, raster angle, infill density, raster width, nozzle diameter, and air gap. Increasing infill density, printing temperature, and decreasing print speed and layer thickness lead to increase mechanical strength and improve the surface finish of the printed parts. The optimal process parameters are preferred to achieve superior properties of the parts. This paper reviews the optimal fused deposition modelling process parameters on part qualities for making the stability of used deposition modelled parts for use. Various process parameters are identified in order to obtain desirable qualities in the manufactured parts. Areas for future research are proposed.

This study is based on the optimization of the parameters that influence the computer numerical control (CNC) milling operation during the machining of polypropylene+60wt.% quarry dust composite. The input parameters studied are the cutting speed, the feed rate and the depth of cut. These input parameters were optimized using the Taguchi optimization technique with the output response taken into consideration was the surface roughness. An L9 orthogonal array (OA) was selected and formulated in a commercial software Minitab 19 based on three factors and three levels combination. The signal-to-noise (S/N) ratio was analysed to give a combination of values of the input parameters that produced optimum results for surface roughness. The analysis of variance (ANOVA) was then conducted to determine the significance and percentage contribution of each parameter. From the results, the optimum values obtained were cutting speed of 1000 rpm, feeding rate of 120 mm/min and depth of cut of either 0.5 mm or 0.8 mm. The cutting speed had the highest contribution towards the surface roughness at 81.98%, followed by the depth of cut at 7.43% and the feed rate having the least contribution at 3.69%.

Using students in the performance of industrial assessments is a cost-effective way to staff a team and is likely to increase in popularity. Students have always been an integral part of the process in DOE's Industrial Assessment Center program. In recent years, however, that process has been greatly enhanced, as the program developed from a simple energy audit to an integrated assessment, focusing on the "Industries of the Future" as defined by the Department of Energy. This paper investigates the nature of the student experience, and further looks to define what it can be in the future both from the aspect of improving the assessment product and the education of the student.

In this paper, emphasis has been given to both the expected number of runs and the expected number of incorrect decisions and two stage group-screening designs have been obtained which minimise one fixing the other or minimise some sort of cost function which connects the two. Some group-screening plans have been given at the end as illustrations.
Keywords: group-screening plans, orthogonal main-effect plans, group-factor

There are concerns that the evidence from studies showing noninferiority of oral amoxicillin to benzyl penicillin for severe pneumonia may not be generalizable to high-mortality settings.

There are concerns that the evidence from studies showing noninferiority of oral amoxicillin to benzyl penicillin for severe pneumonia may not be generalizable to high-mortality settings.

The article examines some preponderant elements that create an impression that Ngugi wa Thiong'o's novel, Devil on the Cross, is orally narrated. More often than not associated with oral discourse, these elements are the narrative voice, biblical allusions, oral literature and the confessional mode. As a result of preponderant oral elements in a form of written discourse, there is not only intersection between oral and written discourse but also an interface between the two modes of transmission of literary works, oral and written, in the novel. Consequently, the article calls for further research into the implications this interface has for the two modes of transmission of literary works.

There is limited research on oral health seeking behavior in the Sub- saharan Africa. The few existing reports show very low utilization of oral health care services. The objective of this study was to assess the oral health seeking behaviour of persons living with HIV. It was a cross¬sectional study conducted at the Kenyatta National Hospital and Mbagathi district hospital Comprehensive Care Centers (CCC). Two hundred and fifty two HIV sero-positive males and females age between 19-73 years who presented themselves at the two Ccc. About a third 67.5% of the respondents said they had ever visited a dental clinic. Only 6.9% were visiting a dental clinic regularly. Less than half of the respondents (43.5%) were satisfied with the treatment received in the clinics. The main reason for satisfaction was pain relief. For those who were not satisfied with the treatment, the main reason for dissatisfaction was the use of local anaesthesia. For the respondents who had never visited a dental clinic, the main reason (60%) was their HIV status. "ajority of persons living with HIV/AIDS do not seek dental treatment regularly. The main reason for not seeking treatment is their HIV status. Only less than a half of those who seek treatment are satisfied with treatment given.

Clefts of the lip and palate (CLP) are amongst the commonest craniofacial anomalies
encountered by clinicians. Compared to many other anomalies, CLP is easily diagnosed
and described. Due to this, it has been one of the most intensively studied congenital
malformation worldwide. Anomalies of the face give rise to considerable morbidity
which is psychologically traumatic to the parents. Thus the need to study the oral health
status of children with cleft lip/palate (CLP) in a section of a Kenyan population.
Type of study: A descriptive comparative cross-sectional study.
Methods: A total of 89 children were clinically examined, 49 formed the study group
(children with clefts) and 40 were the control group (children without clefts) ; age range,
2 to 15 years. Factors such as plaque, gingivitis, caries, missing teeth and stage of the
dentition were recorded.
Setting: Nairobi, Kenya.
Results: Out of the 49 children in the study group, 55% had CLP and 33% had CLA
while 6%had isolated CL. The prevalence of plaque was 96.27% in the 'study group while
among the control group this was lower at 89.5% (p<0.05). This was reflected by the
significant difference observed in the frequency of tooth brushing (x211.564 l df
p=O.OOI). Children with clefts had a significantly increased number of units with
gingivitis ranging from 79.2% for tooth 16 (p=0.04) to 51.6% for tooth 52 (p =0.264),
although not statistically significant in the latter.
The prevalence of caries in the study group was 11.8% (95% CI; 9.8%-13.8%) and the
control group was 8% (95% CI; 6.2%-9.8%). This difference was significant (p<0.05).
These children also showed an increased number of carious teeth in the posterior
segments ranging from 16.7% for tooth 16 (p>O.05) to 41.2% for tooth 46 (p>O.05),
while in the deciduous dentition it ranged from 22.6% for tooth 61 (p>O.05) to 36.7% for
tooth75 ( p>O.05)and was not significant. The children with clefts also showed generally
delayed eruption in both the permanent and the deciduous dentitions. This was significant
for the lateral incisors in the deciduous dentition (pO.05).
Conclusions: Children with clefts had generally poor oral hygiene and gingival health
with an increased number of carious teeth compared to children without clefts. These
children should be considered to have an increased risk of developing dental diseases and
therefore,will require stringent oral hygiene instructions and regular reviews by dental
professionals. Their treatment should involve preventive and curative services in order to
maintain healthy primary and permanent dentitions.

Department of Periodontology/ Community and Preventive Dentistry, School of Dental Sciences, University of Nairobi, P.O. Box 19676 - 00202, Nairobi, Kenya. OBJECTIVE: To determine the influence of oral hygiene habits and practices on the risk of developing oral leukoplakia. DESIGN: Case control study. SETTING: Githongo sublocation in Meru District. SUBJECTS: Eighty five cases and 141 controls identified in a house-to-house screening. RESULTS: The relative risk (RR) of oral leukoplakia increased gradually across the various brushing frequencies from the reference RR of 1.0 in those who brushed three times a day, to 7.6 in the "don't brush" group. The trend of increase was statistically significant (X2 for Trend : p = 0.001). The use of chewing stick as compared to conventional tooth brush had no significant influence on RR of oral leukoplakia. Non-users of toothpastes had a significantly higher risk of oral leukoplakia than users (RR = 1.8; 95% confidence levels (CI) = 1.4-2.5). Among tobacco smokers, the RR increased from 4.6 in those who brushed to 7.3 in those who did not brush. Among non-smokers, the RR of oral leukoplakia in those who did not brush (1.8) compared to those who brushed was also statistically significant (95% CL = 1.6-3.8). CONCLUSION: Failure to brush teeth and none use of toothpastes are significantly associated with the development of oral leukoplakia, while the choice of brushing tools between conventional toothbrush and chewing stick is not. In addition, failure to brush teeth appeared to potentiate the effect of smoking tobacco in the development of oral leukoplakia. Recommendations: Oral health education, instruction and motivation for the improvement of oral hygiene habits and practices; and therefore oral hygiene status, should be among the strategies used in oral leukoplakia preventive and control programmes.

Department of Periodontology/ Community and Preventive Dentistry, School of Dental Sciences, University of Nairobi, P.O. Box 19676 - 00202, Nairobi, Kenya. OBJECTIVE: To determine the influence of oral hygiene habits and practices on the risk of developing oral leukoplakia. DESIGN: Case control study. SETTING: Githongo sublocation in Meru District. SUBJECTS: Eighty five cases and 141 controls identified in a house-to-house screening. RESULTS: The relative risk (RR) of oral leukoplakia increased gradually across the various brushing frequencies from the reference RR of 1.0 in those who brushed three times a day, to 7.6 in the "don't brush" group. The trend of increase was statistically significant (X2 for Trend : p = 0.001). The use of chewing stick as compared to conventional tooth brush had no significant influence on RR of oral leukoplakia. Non-users of toothpastes had a significantly higher risk of oral leukoplakia than users (RR = 1.8; 95% confidence levels (CI) = 1.4-2.5). Among tobacco smokers, the RR increased from 4.6 in those who brushed to 7.3 in those who did not brush. Among non-smokers, the RR of oral leukoplakia in those who did not brush (1.8) compared to those who brushed was also statistically significant (95% CL = 1.6-3.8). CONCLUSION: Failure to brush teeth and none use of toothpastes are significantly associated with the development of oral leukoplakia, while the choice of brushing tools between conventional toothbrush and chewing stick is not. In addition, failure to brush teeth appeared to potentiate the effect of smoking tobacco in the development of oral leukoplakia. Recommendations: Oral health education, instruction and motivation for the improvement of oral hygiene habits and practices; and therefore oral hygiene status, should be among the strategies used in oral leukoplakia preventive and control programmes.

Department of Periodontology/ Community and Preventive Dentistry, School of Dental Sciences, University of Nairobi, P.O. Box 19676 - 00202, Nairobi, Kenya. OBJECTIVE: To determine the influence of oral hygiene habits and practices on the risk of developing oral leukoplakia. DESIGN: Case control study. SETTING: Githongo sublocation in Meru District. SUBJECTS: Eighty five cases and 141 controls identified in a house-to-house screening. RESULTS: The relative risk (RR) of oral leukoplakia increased gradually across the various brushing frequencies from the reference RR of 1.0 in those who brushed three times a day, to 7.6 in the "don't brush" group. The trend of increase was statistically significant (X2 for Trend : p = 0.001). The use of chewing stick as compared to conventional tooth brush had no significant influence on RR of oral leukoplakia. Non-users of toothpastes had a significantly higher risk of oral leukoplakia than users (RR = 1.8; 95% confidence levels (CI) = 1.4-2.5). Among tobacco smokers, the RR increased from 4.6 in those who brushed to 7.3 in those who did not brush. Among non-smokers, the RR of oral leukoplakia in those who did not brush (1.8) compared to those who brushed was also statistically significant (95% CL = 1.6-3.8). CONCLUSION: Failure to brush teeth and none use of toothpastes are significantly associated with the development of oral leukoplakia, while the choice of brushing tools between conventional toothbrush and chewing stick is not. In addition, failure to brush teeth appeared to potentiate the effect of smoking tobacco in the development of oral leukoplakia. Recommendations: Oral health education, instruction and motivation for the improvement of oral hygiene habits and practices; and therefore oral hygiene status, should be among the strategies used in oral leukoplakia preventive and control programmes.

Oral infection with Herpes Simplex Virus (HSV) is a frequent and well documented complication in immunosuppressed individuals including patients on immunosuppressive medication. We report the development of severe oral infection with HSV type 1 in a 34 year old woman with type 1 diabetes mellitus and end stage renal disease (ESRD) following cadaveric renal transplantation at the Western General Hospital, Edinburgh. The role of acyclovir in therapy and chemoprophylaxis is discussed.

Department of Periodontology/ Community and Preventive Dentistry, School of Dental Sciences, University of Nairobi, P.O. Box 19676 - 00202, Nairobi, Kenya. OBJECTIVE: To determine the influence of oral hygiene habits and practices on the risk of developing oral leukoplakia. DESIGN: Case control study. SETTING: Githongo sublocation in Meru District. SUBJECTS: Eighty five cases and 141 controls identified in a house-to-house screening. RESULTS: The relative risk (RR) of oral leukoplakia increased gradually across the various brushing frequencies from the reference RR of 1.0 in those who brushed three times a day, to 7.6 in the "don't brush" group. The trend of increase was statistically significant (X2 for Trend : p = 0.001). The use of chewing stick as compared to conventional tooth brush had no significant influence on RR of oral leukoplakia. Non-users of toothpastes had a significantly higher risk of oral leukoplakia than users (RR = 1.8; 95% confidence levels (CI) = 1.4-2.5). Among tobacco smokers, the RR increased from 4.6 in those who brushed to 7.3 in those who did not brush. Among non-smokers, the RR of oral leukoplakia in those who did not brush (1.8) compared to those who brushed was also statistically significant (95% CL = 1.6-3.8). CONCLUSION: Failure to brush teeth and none use of toothpastes are significantly associated with the development of oral leukoplakia, while the choice of brushing tools between conventional toothbrush and chewing stick is not. In addition, failure to brush teeth appeared to potentiate the effect of smoking tobacco in the development of oral leukoplakia. Recommendations: Oral health education, instruction and motivation for the improvement of oral hygiene habits and practices; and therefore oral hygiene status, should be among the strategies used in oral leukoplakia preventive and control programmes.

n/a

Orbital involvement in tuberculosis is rare even in areas where TB is endemic.1 Orbital TB is classified into five forms; classical periostitis, orbital soft tissue tuberculoma or cold abscess with no bone destruction, orbital TB with bone destruction, orbital TB spread from para-nasal sinuses and tuberculous dacryoadenitis2,3,4,5. We present a 17 year old patient who presented with a third recurrence of orbital and forehead abscesses. On orbital CT-scan, the patient had pan-sinusitis, right orbital and frontal abscesses, bilateral proptosis and frontal bone destruction. Initially the diagnosis of orbital TB was based on a good response to antituberculosis medications and it was later confirmed by histology showing caseating TB granulomas.

Socio-economic changes that have taken place in Africa have influenced people's eating habits in both rural and urban set-ups. Most people prefer introduced foods to traditional foods, including plant foods whose consumption is widely regarded as a primitive culture manifesting poor lifestyles. However, recent studies on traditional plant foods have shown that some are highly nutritious; containing high levels of both vitamins and minerals. They also have potential as a remedy to counter food insecurity since most are well adapted to the local environment, enabling them to resist pests, drought and diseases. This paper describes the mineral (calcium, iron and zinc) contents in some 54 traditional vegetable species collected from Nyang'oma area of Bondo district, western Kenya. Atomic absorption spectroscopy was used to determine the mineral content. We found that most traditional leafy vegetables, domesticated and wild, generally contain higher levels of calcium, iron and zinc compared with the introduced varieties such as spinach (Spanacia oleracea), kale (Brassica oleracea var. acephala) and cabbage (Brassica oleracea var. capitata). The results of this study could contribute towards identification, propagation and subsequent domestication and cultivation promotion of nutrient-rich and safe species within the farming systems of the local communities in Kenya, sub-Saharan Africa or elsewhere.

PURPOSE: To build capacity in the resource-poor setting to support the clinical investigation and treatment of AIDS-related malignancies in a region of the world hardest hit by the AIDS pandemic. METHODS: An initial MEDLINE database search for international collaborative partnerships dedicated to AIDS malignancies in developing countries failed to identify any leads. This search prompted us to report progress on our collaboration in this aspect of the epidemic. Building on the formal Uganda-Case Western Reserve University (Case) Research Collaboration dating back to 1987, established NIH-supported centers of research excellence at Case, and expanding activities in Kenya, scientific and training initiatives, research capital amongst our institutions are emerging to sustain a international research enterprise focused on AIDS and other viral-related malignancies. RESULTS: A platform of clinical research trials with pragmatic design has been developed to further enhance clinical care and sustain training initiatives with partners in East Africa and the United States. An oral chemotherapy feasibility trial in AIDS lymphoma is near completion; a second lymphoma trial of byrostatin and vincristine is anticipated and a feasibility trial of indinavir for endemic Kaposi's sarcoma is planned. CONCLUSIONS: In the absence of published reports of evolving international partnerships dedicated to AIDS malignancy in resource constrained settings, we feel it important for such progress on similar or related international collaborative pursuits to be published. The success of this effort is realized by the long-term international commitment of the collaborating investigators and institutions to sustain this effort in keeping with ethical and NIH standards for the conduct of research; the provision of formal training of investigators and research personnel on clinical problems our East African partners are faced with in practice and the development of pragmatic clinical trials and therapeutic intervention to facilitate technology transfer and enhance clinical practice.

PMID: 15829373 [PubMed - indexed for MEDLINE]

PURPOSE: To build capacity in the resource-poor setting to support the clinical investigation and treatment of AIDS-related malignancies in a region of the world hardest hit by the AIDS pandemic. METHODS: An initial MEDLINE database search for international collaborative partnerships dedicated to AIDS malignancies in developing countries failed to identify any leads. This search prompted us to report progress on our collaboration in this aspect of the epidemic. Building on the formal Uganda-Case Western Reserve University (Case) Research Collaboration dating back to 1987, established NIH-supported centers of research excellence at Case, and expanding activities in Kenya, scientific and training initiatives, research capital amongst our institutions are emerging to sustain a international research enterprise focused on AIDS and other viral-related malignancies. RESULTS: A platform of clinical research trials with pragmatic design has been developed to further enhance clinical care and sustain training initiatives with partners in East Africa and the United States. An oral chemotherapy feasibility trial in AIDS lymphoma is near completion; a second lymphoma trial of byrostatin and vincristine is anticipated and a feasibility trial of indinavir for endemic Kaposi's sarcoma is planned. CONCLUSIONS: In the absence of published reports of evolving international partnerships dedicated to AIDS malignancy in resource constrained settings, we feel it important for such progress on similar or related international collaborative pursuits to be published. The success of this effort is realized by the long-term international commitment of the collaborating investigators and institutions to sustain this effort in keeping with ethical and NIH standards for the conduct of research; the provision of formal training of investigators and research personnel on clinical problems our East African partners are faced with in practice and the development of pragmatic clinical trials and therapeutic intervention to facilitate technology transfer and enhance clinical practice.

PMID: 15829373 [PubMed - indexed for MEDLINE]

PURPOSE OF REVIEW: With the emergence of the highly active antiretroviral therapy era, it is apparent that the incidence of Kaposi sarcoma, in particular, and lymphoma in patients with AIDS is declining, especially in regions of the world where these regimens are routinely available. The burden of HIV infection and AIDS is greatest in the developing world, and no doubt neoplastic complications are increasingly encountered. The purpose of this review is to highlight recent developments of this aspect of the AIDS epidemic in the developing world. RECENT FINDINGS: It was readily apparent that the incidence of Kaposi sarcoma sharply increased after the onset of the AIDS epidemic in developing countries. By the end of the second decade of the epidemic, non-Hodgkin lymphoma is increasing in incidence and the natural history of Burkitt lymphoma is evolving in the backdrop of HIV infection as well. Cervical cancer is the most common cancer in women in many developing countries, yet the true impact of HIV infection on the development of this neoplasm is not fully understood. Squamous cell carcinoma of the conjunctiva appears to be a unique AIDS-associated neoplasm that is encountered in sub-Saharan Africa as well. Finally, although the epidemiologic and clinicopathologic features for many AIDS-associated neoplasms are well characterized in developing regions of the world, there is a paucity of data on the therapeutic approach to these tumors in this setting. SUMMARY: It is apparent that as the AIDS pandemic proceeds, the burden of neoplastic diseases is increasing in developing nations. Current therapeutic approaches are not well documented. Pragmatic prevention and therapeutic interventions suitable for the resource-constrained setting are clearly needed.

PURPOSE OF REVIEW: Following our review of AIDS-associated cancer in developing nations in 2004, we sought to update recent publications and review data on the challenges and opportunities for the treatment and research of AIDS malignancies in Africa. RECENT FINDINGS: It is apparent that the burden of AIDS-related malignancies and other virus-associated tumors is significant and increasing in Africa. Several recent studies report findings on conjunctival squamous cell carcinoma and there is a report that Hodgkin's disease, a non-AIDS-defining neoplasm, is increasing in incidence. International collaborative partnerships dedicated to AIDS malignancies in developing countries are feasible and invaluable for clinical strategies to address this aspect of the pandemic. A departure point is the ongoing work of the East Africa - Case Western Reserve University Collaboration in AIDS malignancies. SUMMARY: The burden of neoplastic complications of HIV infection and endemic virus-associated tumors are assuming increasing significance in Africa. There is a need to develop nonmyelotoxic therapies and approaches that are hypothesis-driven and pathogenesis-based. The scarcity and shortages in this region demand that our scientific and therapeutic strategies are both suitable and pragmatic for testing in this setting. It is also imperative that African investigators lead us in this important endeavor.

PURPOSE OF REVIEW: Following our review of AIDS-associated cancer in developing nations in 2004, we sought to update recent publications and review data on the challenges and opportunities for the treatment and research of AIDS malignancies in Africa. RECENT FINDINGS: It is apparent that the burden of AIDS-related malignancies and other virus-associated tumors is significant and increasing in Africa. Several recent studies report findings on conjunctival squamous cell carcinoma and there is a report that Hodgkin's disease, a non-AIDS-defining neoplasm, is increasing in incidence. International collaborative partnerships dedicated to AIDS malignancies in developing countries are feasible and invaluable for clinical strategies to address this aspect of the pandemic. A departure point is the ongoing work of the East Africa - Case Western Reserve University Collaboration in AIDS malignancies. SUMMARY: The burden of neoplastic complications of HIV infection and endemic virus-associated tumors are assuming increasing significance in Africa. There is a need to develop nonmyelotoxic therapies and approaches that are hypothesis-driven and pathogenesis-based. The scarcity and shortages in this region demand that our scientific and therapeutic strategies are both suitable and pragmatic for testing in this setting. It is also imperative that African investigators lead us in this important endeavor.

Studies were conducted to compare digestive functions in two species of sub-human primate, the bushbaby (Galago crassicaudatus) and the Vervet monkey (Cercopithecidae pygerythrus). Major differences were observed in the rate at which digesta markers moved through their respective gastrointestinal tracts, and in the concentration of lactic acid present in the gut. In both species, the caecum and colon were the principle sites of microbial activity and organic acid production.

Porous clay ceramics are used as thermal insulators in high temperature applications such as kins and chacoal stoves (Jikos).

The variations in the organic content of a sediment core from a pro-glacial lake, Hausberg Tarn, located on the NW slope of Mount Kenya has been determined. Two types of methods for determining organic content were compared using sediments from the same core. One type was direct measurement of organic carbon using a carbon analyser and the other was X-ray analysis. The results show that both techniques reveal changes in organic content, which are believed to reflect changes in the glacier size during the last 5700 years. However, the X-ray technique discloses a much more detailed view of the changes in the environment. In addition, the method is considerably faster than the methods of determining organic carbon content or weight loss on ignition.

Five organic resources commonly used for soil fertility maintenance in large parts of Kenya were selected for litter decay and nutrient mineralization studies that were conducted in three farms (Machakos, Kabete and Njabini) located at an elevational transect ranging from 1500 to 2800 m above sea level. These organic residues included: bean trash, maize stover, tree prunnings (Grevillea robusta), Senna spectabilis foliage, cow and poultry manures. Organic residues were either mulched or incorporated in the soil. Satellite experiments were also carried out in each of the three sites with one additional site at Maseno based in western Kenya. These experiments aimed at assessing the role of soil biota in the decomposition
and nutrient release. Soil fauna were excluded from control plots using 1-mm mesh litterbags. The organic residues were different in chemical composition i.e. nitrogen (N), phosphorus (P), potassium (K), carbon (C), lignin (L) and polyphenol (PP) contents, which in turn influenced their rate of decomposition and nutrient release patterns. Bean trash decomposed and released N and P faster than either the maize stover or Grevillea prunings. The slowest rate of decomposition observed for Grevillea prunings could be attributed to the high lignin content (24%). The N release was influenced by (L+PP):N ratio. Bean trash having a ratio of 10 released N faster than either maize stover or Grevillea prunings whose respective ratios of 20 and 13. P release was influenced by both C:P and N:P ratios. Maize stover with C:P and N:P ratios that were higher than the critical levels of 123 and 10 respectively, mineralized and released P more slowly than either bean trash or Grevillea prunings. Incorporated materials decomposed and released nutrients faster than surface applied materials. For surface applied organic materials, the delay in litter decay ranged from 4.1 to 4.4 days for every 100 m increase in altitude, while for incorporated materials the delay in litter decay ranged from 1 to 3 days per 100 m increase in elevation. This implies that farmers at higher elevations would benefit more by incorporating residues before planting, while at low elevations post emergence surface application would lead to improved nutrient availability. Njabini and Kabete recorded significantly higher microbial biomass (C, N and P) than Machakos. This could be linked to the higher organic C, higher total N, higher moisture content but lower temperatures reported for Njabini and Kabete than Machakos. Soil fauna enhanced decomposition of organic residues, although their role in influencing nutrient availability to crops from the organic residues may depend on the nature of the material. Fauna had no significant influence on nutrient release patterns of Senna possibly due to secondary compounds present in Senna, which were lower than the critical levels of 15 for lignin and 4 for polyphenol respectively.

Key words: Resource quality, placement, soil fauna, decomposition, nutrient release, microbial biomass