Investigating the electron tunneling effect on photovoltaic performance of almond (Prunus dulcis) dye-sensitized solar cell.

Dye-sensitized solar cells (DSSCs) are characterized by several special attributes such as low cost, ease of fabrication, all year availability of sunlight, and capacity to operate under diffuse lighting conditions. However, their universal adoption is still restricted by a low efficiency photovoltaic output. Thus, this research seeks to explore avenues of present photon mitigation which could be corrected in future DSSC technology in order to improve on existing efficiency records. A preliminary phytochemical screening of Prunus dulcis (P. dulcis) leaf extract revealed a variety of chromophores which renders high possibility for charge transport. UV/VIS spectroscopy showed P. dulcis with peak absorbance wavelength within the visible region of the electromagnetic spectrum of light. Fourier transform infrared spectroscopy specifically highlighted the fingerprint of the chromophores present in this organic extract. Photovoltaic parameters such as short circuit current (Isc), open circuit voltage (Voc), maximum power (Pmax), fill factor (ff) and efficiency (ƞ) were the factors taken into consideration for the determination of the photovoltaic outcome. In P. dulcis DSSCs, KBr electrolyte recorded the best ƞ of 10.18%. However, P. dulcis DSSC with electrolyte KI indicated the best Isc, Voc and Pmax of 0.135 mA, 280 mV and 34.2 mW respectively. The similarity of this photovoltaic result with previous DSSC results necessitated further analysis. Consequently, scanning electron micrograph (SEM) of P. dulcis was modelled first with Gwyddion software and this output was analyzed with Excel and Origin programs. The outcome is a scientific discovery of electron tunneling in the P. dulcis shells, effect of dopant ions boosting the electrolytic Fermi level and a high probability of influencing the future efficiency outcome in P. dulcis DSSCs. Using mathematical algorithms from the Origin and Excel software applications, a direct function of the impact of doping, relative speed of electrolyte molecules as they percolate P. dulcis framework was obtained. Thus, the significance of this work lies in the relationship of behavioral dynamics of dopants to photovoltaic performance of P. dulcis. This indicates that a vital optical tunable characteristic of DSSCs lies in electrodynamics of dopant ions, which presents a viable prospect for application in DSSC technology research.

Impact of red blood cell transfusions on intestinal barrier function in preterm infants.

OBJECTIVE: To determine the relationships of red blood cell (RBC) transfusion and enteral feeding to changes in intestinal permeability (IP) measured by the relative intestinal uptake of lactulose (La) and rhamnose (Rh) in preterm infants <33 wk gestation. DESIGN/METHODS: Infants 240-326wk gestation received La/Rh solution enterally on study days 1, 8 and 15.Urinary La/Rh ratio was measured by HPLC. Hematocrit preceding transfusion, total RBC transfusion volume, volume/kg, and feeding status during each study interval (birth-d1; d1-d8, and d8-d15) were determined. RESULTS: Of the seventeen (40.5%) subjects who received≥1 transfusion during the study period, 12 (70.6%) infants were <28 wk gestation and 5 (29.4%) infants were≥28 wk gestation, p < 0.0001. Lower pre-transfusion hematocrit was observed in intervals preceding high IP (La/Rh > 0.05) than in intervals preceding low IP (La/Rh≤0.05) measurements (33 vs 35.8, p = 0.1051). RBC transfusions occurred more frequently in intervals preceding high IP than in intervals preceding low IP (26.8%; vs 8.3%, p = 0.0275) with 5-fold higher total RBC volume and volume/kg in intervals preceding any time point with high IP. RBC transfusion during an interval was associated with a three-fold increased risk of high IP (aOR 2.7; 95% C.I 0.564-12.814; p = 0.2143). Exclusive breast milk exposure and post-menstrual age reduced the risk for high IP following RBC transfusion. CONCLUSIONS: Both RBC transfusion number and volume was associated with subsequent high IP measurements in preterm infants <33 weeks gestation and potentially may contribute to impairment of the preterm intestinal barrier.

An audit of the diagnosis and reporting of soft tissue sarcomas at the Lagos University Teaching Hospital.

BACKGROUND: : The effective management of patients with cancer is predicated on the right diagnoses and other relevant parameters included in the pathology report. This is particularly important in soft tissue pathology where arriving at the right diagnosis is often challenging. The aim of this study, therefore, was to perform an audit of sarcoma diagnosis and reporting in our institution. METHODS: Slides of soft tissue sarcomas diagnosed in our institution over a 5-year period were reviewed with specialist soft tissue pathologists. Ancillary immunohistochemistry and fluorescent in situ hybridization were performed where necessary. The contents of the reports were assessed using a diagnostic checklist developed by the Association of Directors of Anatomic and Surgical Pathology. RESULTS: Fifty-five of the 62 patients studied (88.7%) were correctly identified as sarcomas. However, the correct diagnoses were made in only 27 patients (43.6%). Kaposi sarcoma and dermatofibrosarcoma protuberans were the most recognized sarcomas, while leiomyosarcoma, myxofibrosarcoma, and malignant peripheral nerve sheath tumor were the least recognized sarcomas. The most reported parameters included the histologic type (100%) and size (89.7%), while the percentage of necrosis (0%) and the stage (0%) were the least reported parameters. CONCLUSION: A pattern based approach is important for the accurate diagnosis of soft tissue sarcomas. Some essential prognostic parameters and information needed for management were not included in the histopathology reports. The adoption of a structured reporting format and multidisciplinary team meetings will help to ensure the inclusion of such important information in the pathology report.

Contraceptive knowledge and compliance with guidelines for providing contraceptive services by patent medicine vendors in Ibadan North Local Government Area, Nigeria

Previous studies conducted in Nigeria have shown that Patent Medicine Vendors (PMVs) provide a substantial proportion of contraceptive services. The Federal Ministry of Health (FMOH) provided guidelines for the delivery of contraceptive services by PMVs. This study was therefore designed to identify types of contraceptives dispensed by PMVs and determine their compliance with the FMOH guidelines in Ibadan North Local Government Area. An observational check-list and a validated interviewer administered questionnaire containing a 47- point knowledge scale were used for data collection. Data were analysed using descriptive and Chi-square statistics. Respondents' mean age was 32.8±7.0 years, 80.9% were females, 63.5% were West African School Certificate holders. Most respondents (98.2%) were trained through the apprenticeship system. Only 17.4% were formally trained on the provision of contraceptive services. Contraceptive- related services offered by PMVs as stipulated by the guidelines were: counselling (96.5%), community sensitization (46.3%) and referral (96.4%). Virtually all (98.6%) respondents had ever dispensed contraceptives. A large proportion (72.7%) of respondents dispensed oral contraceptives contrary to the FMOH guidelines. The contraceptives ever dispensed by respondents included: male condoms (96.1%), female condoms (4.3%), doufem (72.3%), pregnon (18.8%), spermicide (4.9%) and intrauterine device (1.8%). Respondents' mean knowledge score was 25.9±5.8. Mean knowledge score on the provision of contraceptives services among males and females were 27.7±5.9 and 25.6±5.7 respectively. On compliance 3.7% of respondents complied fully with the FMOH guidelines on contraceptive service delivery. Compliance with stipulated guidelines by the Federal Ministry of Health on the provision of contraceptive services was low among the study population. The patent medicine licensing authorities should ensure that all patent medicine vendors are provided with the Federal Ministry of Health guidelines relating to the dispensing of contraceptives. Patent Medicine Vendors should be trained on the effective use of the guidelines

Mitochondrial DNA sequence analyses and phylogenetic relationships among two Nigerian goat breeds and the South African Kalahari Red.

The first hypervariable (HV1) region of mitochondrial DNA (mtDNA) of two popular Nigerian goat breeds: West African Dwarf (WAD) (n=35) and Red Sokoto (RS) (n=37) and one exotic breed: Kalahari Red (KR) (n=38) imported from South Africa were sequenced to investigate sequence diversity, genetic structure, origin, and demographic history of the populations. A total of 68 polymorphic sites were found in 110 sequences that grouped into 68 haplotypes. Average haplotype and nucleotide diversities for all breeds were 0.982±0.005 and 0.02350±0.00213, respectively. Phylogenetic analysis revealed two mtDNA lineages (A and B). Lineage A was predominant and included all haplotypes from WAD and RS and 5 out of 11 haplotypes of KR goats. The remaining haplotypes (6) of KR belong to lineage B. The analysis of molecular variance revealed a high-within breed genetic variance of 82.4% and a low-between breed genetic variance of 17.6%. The three breeds clustered with Capra aegagrus as their wild ancestor. Mismatch distribution analysis showed that WAD, RS and haplogroup A have experienced population expansion events. The study has revealed very high diversity within the three breeds which are not strongly separated from each other based on mtDNA analysis. The information obtained on the genetic structure of the breeds will be useful in planning improvement and conservation programs for the local populations.

Use of robust multivariate linear mixed models for estimation of genetic parameters for carcass traits in beef cattle.

Assumptions of normality of residuals for carcass evaluation may make inferences vulnerable to the presence of outliers, but heavy-tail densities are viable alternatives to normal distributions and provide robustness against unusual or outlying observations when used to model the densities of residual effects. We compare estimates of genetic parameters by fitting multivariate Normal (MN) or heavy-tail distributions (multivariate Student's t and multivariate Slash, MSt and MS) for residuals in data of hot carcass weight (HCW), longissimus muscle area (REA) and 12th to 13th rib fat (FAT) traits in beef cattle using 2475 records from 2007 to 2008 from a large commercial operation in Nebraska. Model comparisons using deviance information criteria (DIC) favoured MSt over MS and MN models, respectively. The posterior means (and 95% posterior probability intervals, PPI) of v for the MSt and MS models were 5.89 ± 0.90 (4.35, 7.86) and 2.04 ± 0.18 (1.70, 2.41), respectively. Smaller values of posterior densities of v for MSt and MS models confirm that the assumption of normally distributed residuals is not adequate for the analysis of the data set. Posterior mean (PM) and posterior median (PD) estimates of direct genetic variances were variable with MSt having the highest mean value followed by MS and MN, respectively. Posterior inferences on genetic variance were, however, comparable among the models for FAT. Posterior inference on additive heritabilities for HCW, REA and FAT using MN, MSt and MS models indicated similar and moderate heritability comparable with the literature. Posterior means of genetic correlations for carcass traits were variable but positive except for between REA and FAT, which showed an antagonistic relationship. We have demonstrated that genetic evaluation and selection strategies will be sensitive to the assumed model for residuals.

Progesterone, selected heavy metals and micronutrients in pregnant Nigerian women with a history of recurrent spontaneous abortion.

BACKGROUND: Environmental and endocrine factors have been implicated in the aetiology of recurrent abortion, with poorly understood roles. Luteal phase insufficiency marked with insufficient progesterone secretion has been reported. OBJECTIVE: To define the involvement of progesterone, trace metals, and Vitamin E in pregnant women with history of recurrent spontaneous abortion. METHODS: Convenience sampling method was used to recruit 69 pregnant women aged 21-41 years with gestational age of 0-20 weeks in this case-control study. Thirty five (cases) and thirty four (controls) had previous and no history of recurrent spontaneous abortion respectively. Demographic characteristics and 10 mls of blood samples were obtained from each subject. Serum obtained was used for the determination of progesterone, zinc, copper, selenium, iron, magnesium, manganese, chromium, lead, cadmium, and serum vitamin E by standard methods. RESULTS: Results showed statistically significant decreases (p<0.05) in the serum zinc, copper, and vitamin E and a significant elevation (p<0.05) in the serum selenium, lead, and cadmium in cases compared with controls. Insignificant decrease (p=0.07) was observed in the serum progesterone when cases were compared with controls. CONCLUSION: Results suggest that elevated serum heavy metals (cadmium and lead) and reduction of essential micronutrients (zinc, copper and vitamin E) may contribute to recurrent spontaneous abortion.

The quality of Internet sites providing information relating to hip resurfacing.

OBJECTIVE: To establish the accuracy of information available on the Internet regarding hip resurfacing. METHOD: The top 100 sites found in response to the query 'hip resurfacing' using Google were assessed for quality using the DISCERN instrument and the JAMA benchmarks. RESULTS: Of the top 100 sites found, only 30 were relevant, available and unique. Of these only six (20%) scored highly for overall quality; however, ten (33%) sites achieved the lowest possible score. Risks and complications were not commonly presented nor were results of surgery. In one case, results presented were grossly misleading. CONCLUSIONS: The use of the Internet to directly market specific products to the public raises the concern that patients are not always fully informed. The quality of health information on the Internet relating to hip resurfacing is of frequently poor and variable quality. Eighty per cent of the sites that we assessed had serious shortcomings.

Performance optimization of coagulant/flocculant in the treatment of wastewater from a beverage industry.

This study investigated the effect of coagulation/flocculation treatment process on wastewater of Fumman Beverage Industry, Ibadan, Nigeria. The study also compared different dosages of coagulant, polyelectrolyte (non-ionic polyacrylamide) and different pH values of the coagulation processes. The effect of different dosages of polyelectrolyte in combination with coagulant was also studied. The results reveal that low pH values (3-8), enhance removal efficiency of the contaminants. Percentage removal of 78, 74 and 75 of COD, TSS and TP, respectively, were achieved by the addition of 500 mg/L Fe2(SO4)3.3H2O and 93, 94 and 96% removal of COD, TSS and TP, respectively, were achieved with the addition of 25 mg/L polyelectrolyte to the coagulation process. The volume of sludge produced, when coagulant was used solely, was higher compared to the use of polyelectrolyte combined with Fe2(SO4)3.3H2O. This may be as a result of non-ionic nature of the polyelectrolyte; hence, it does not chemically react with solids of the wastewater. Coagulation/flocculation may be useful as a pre-treatment process for beverage industrial wastewater prior to biological treatment.

Deposition, characterization, and tribological applications of near-frictionless carbon films on glass and ceramic substrates.

As an element, carbon is rather unique and offers a range of rare opportunities for the design and fabrication of zero-, one-, two-, and three-dimensional nanostructured novel materials and coatings such as fullerenes, nanotubes, thin films, and free-standing nano-to-macroscale structures. Among these, carbon-based two-dimensional thin films (such as diamond and diamond-like carbon (DLC)) have attracted an overwhelming interest in recent years, mainly because of their exceptional physical, chemical, mechanical, electrical, and tribological properties. In particular, certain DLC films were found to provide extremely low friction and wear coefficients to sliding metallic and ceramic surfaces. Since the early 1990s, carbon has been used at Argonne National Laboratory to synthesize a class of novel DLC films that now provide friction and wear coefficients as low as 0.001 and 10(-11)-10(-10) mm(3) N(-1) m(-1), respectively, when tested in inert or vacuum test environments. Over the years, we have optimized these films and applied them successfully to all kinds of metallic and ceramic substrates and evaluated their friction and wear properties under a wide range of sliding conditions. In this paper, we will provide details of our recent work on the deposition, characterization, and tribological applications of near-frictionless carbon films on glass and ceramic substrates. We will also provide chemical and structural information about these films and describe the fundamental tribological mechanisms that control their unusual friction and wear behaviour.

Breast cancer in Nigeria.

Breast cancer is now the commonest malignancy affecting women in Nigeria. It is likely to become an important public health issue in the next millennium. Recent years have witnessed an explosion in knowledge about the basic sciences of the disease, including the genetic basis and the pathology. These changes are leading to revisions in the management of the disease with a positive impact on prognosis. In this review, the recent developments in the various aspects of breast cancer are reviewed with reference to how they affect the disease in this environment.

Frequency of human toxocariasis in Jos, Plateau State, Nigeria

The enzyme-linked immunosorbent assay (Elisa) was used to examine sera of 104 children and adults in Jos, Plateau State, Nigeria for anti-toxocaral antibodies, out of which 31 (29.8) were reactive. The seropositive rates were 30.4 for adults, 29.6 for children, 34 for females and 25.9 for males. However, the differences were not significant by age and sex. A highly significant association (p < 0.001) was observed between seropositivity and geography but none between seropositivity and dog ownership (p > 0.05).

Frequency of human toxocariasis in Jos, Plateau State, Nigeria.

The enzyme-linked immunosorbent assay (Elisa) was used to examine sera of 104 children and adults in Jos, Plateau State, Nigeria for anti-toxocaral antibodies, out of which 31 (29.8%) were reactive. The seropositive rates were 30.4% for adults, 29.6% for children, 34% for females and 25.9% for males. However, the differences were not significant by age and sex. A highly significant association (p < 0.001) was observed between seropositivity and geography but none between seropositivity and dog ownership (p > 0.05).

Surgery in Nigeria.

Nigeria, like most other developing countries, is today experiencing an increasing incidence of noncommunicable diseases and the unsolved problem of infectious diseases. The role of surgery in the management of these diseases has continued to increase. Surgical training has traditionally been of a high standard, and this has made it possible for surgeons trained in Nigeria to cope with this change in the spectrum of diseases. A low success rate at the diploma examinations and an increasing loss of local talent to foreign countries has increased calls for a modification of the training programs. There is a need to improve the working conditions and environment of surgeons to stem the attrition. Surgery in a poor resource environment demands more, rather than less, skill from the surgeon, and the training programs must ensure that the specialist is adequately equipped to deal with conditions that may not be considered general surgery. While the unavailability of modern technology has limited the scope of research, it is still possible to conduct appropriate, "low-tech," and relevant research that is subject to excellent study design, proper controls, and scientifically valid interpretations.

Cup-and-spill gastric deformity following Hassab's procedure for oesophageal varices: case report.

Hassab's operation for selected case of oesophageal varices is believed by many workers to be a very satisfactory procedure. Various complications following this procedure have been reported, but none has reported a case of Cup-and-Spill gastric deformity following this operation. We present such a complication following this procedure on a senior medical colleague with oesophageal varices resulting from a subclinical or previously undiagnosed hepatitis resulting in liver fibrosis. He responded fairly well to conservative treatment and small feed at frequent interval.