Expanding the scope of ligand substitution from [M(S2C2Ph2] (M = Ni2+, Pd2+, Pt2+) to afford new heteroleptic dithiolene complexes

The scope of direct substitution of the dithiolene ligand from [M(S2C2Ph2)2] [M = Ni2+ (1), Pd2+ (2), Pt2+ (3)] to produce heteroleptic species [M(S2C2Ph2)2Ln] (n = 1, 2) has been broadened to include isonitriles and dithiooxamides in addition to phosphines and diimines. Collective observations regarding ligands that cleanly produce [M(S2C2Ph2)Ln], do not react at all, or lead to ill-defined decomposition identify soft σ donors as the ligand type capable of dithiolene substitution. Substitution of MeNC from [Ni(S2C2Ph2)(CNMe)2] by L provides access to a variety of heteroleptic dithiolene complexes not accessible from 1. Substitution of a dithiolene ligand from 1 involves net redox disproportionation of the ligands from radical monoanions, –S•SC2Ph2, to enedithiolate and dithione, the latter of which is an enhanced leaving group that is subject to further irreversible reactions

Genotype analysis of Escherichia coli strains isolated from children and chickens living in close contact

Escherichia coli isolates from rectal swabs from 62 chickens and stools from 42 children living in close contact with chickens on the same farms in Kiambu district, Kenya, were compared for their genetic relatedness. Antibiotic susceptibility profiles broadly categorized isolates from the children and from the chickens into two separate clusters: the majority (144; 85.5%) of the E. coil isolates from children were multidrug resistant, while the majority (216; 87.1%) of the E. coli isolates from chickens were either fully susceptible or resistant only to tetracycline. Sixty- and 100- to 110- MDA plasmids were found to encode the transferable resistance to co- trimoxazole and tetracycline. HindIII restriction endonuclease digestion of the 60- and 100- to 110-MDA plasmids produced four distinct patterns for isolates from children and three distinct patterns for isolates from chickens. XbaI digestion of genomic DNA followed by pulsed-field gel electrophoresis (PFGE) analysis produced 14 distinct clusters. There were six distinct PFGE clusters among the isolates from children, while among the isolates from chickens there were seven distinct clusters. Only one PFGE cluster contained isolates from both children and chickens, with the isolates displaying an approximately 60% coefficient of similarity. This study showed that although several different genotypes of E. coli were isolated from children and chickens from the same farms, the E. coli strains from these two sources were distinct

Biotransformation of organic wood preservatives by micro-organisms

Wood products are treated with biocides to prevent biodegradation by bacteria, fungi, and insects. Much attention is being directed towards testing of metal-free organic preservative systems. The major disadvantage of organics is that they are biotransformed by micro-organisms in soil and wood. This study explored the biotransformation of the fungicide tebuconazole by a bacteria species (Pseudomonas fluorescens), the mold (Trichoderma harzianum), the white rot fungus (Phanerochaete chrysosporium) and the brown rot (Meruliporia incrassata). After incubation of cultures spiked with tebuconazole, samples were analyzed for chemical remaining and metabolites. M. incrassata, T. harzianum, and the bacterium all cleaved the 1, 2, 4 triazole ring on tebuconazole and performed oxidation reactions forming the alcohol and carboxylic acid oxidation products of the tert butyl moiety on tebuconazole. P. chrysosporium which exhibited the lowest minimum inhibitory concentration (highest tebuconazole efficacy), did not degrade tebuconazole to measurable amounts. T. harzianum, with the highest MIC (lowest efficacy), degraded tebuconazole to the largest extent and tolerated it at concentrations below 200ppm. These suggested that the ability of a fungus to degrade a biocide contributes to the efficacy. The oxidation of tebuconazole was reduced when P450 inhibitors were added to the cultures leading to the conclusion that enzymes involved in the oxidation are cytochrome P450 dependent. Furthermore, the microsomal extract from T. harzianum exhibited a maximum peak at 440-460nm when CO was bubbled into Na2S2O4 treated samples. Testing metal chelators EDTA and TEMED as synergistic additives to tebuconazole showed that EDTA reduced the magnitude of oxidation most likely by binding ions important in the enzymatic system. TEMED had no significant effect while the P450 inhibitors PB and ABT gave the best performance in terms of reducing tebuconazole depletion. T. harzianum was able to germinate and grow in the presence of tebuconazole and all additives used leading to the conclusion that in addition to biotransformation, there are other mechanisms which this species uses to tolerate tebuconazole. While molds and bacteria species are not responsible for decay, they may metabolize a biocide into a less potent derivative making the environment more suitable to wood degrading basidiomycetes and insects

First reported case of fatal tuberculosis in a wild African elephant with past human-wildlife contact

Tuberculosis is emerging/re-emerging in captive elephant populations, where it causes morbidity and deaths, although no case of TB in wild African elephants has been reported. In this paper we report the first case of fatal TB in an African elephant in the wild. The infection with Mycobacterium tuberculosis was confirmed by post-mortem and histological examinations of a female sub-adult elephant aged >12 years that died in Tsavo East National Park, Kenya, while under treatment. This case is unique in that during its lifetime the elephant had contact with both humans and wild elephants. The source of the infection was unclear because the elephant could have acquired the infection in the orphanage or in the wild. However, our results show that wild elephants can maintain human TB in the wild and that the infection can be fata

Epidemiology of Theileria bicornis among black and white rhinoceros metapopulation in Kenya

[Background] A huge effort in rhinoceros conservation has focused on poaching and habitat loss as factors leading to the dramatic declines in the endangered eastern black rhinoceros (Diceros bicornis michaeli) and the southern white rhinoceros (Ceratotherium simum simum). Nevertheless, the role disease and parasite infections play in the mortality of protected populations has largely received limited attention. Infections with piroplasmosis caused by Babesia bicornis and Theileria bicornis has been shown to be fatal especially in small and isolated populations in Tanzania and South Africa. However, the occurrence and epidemiology of these parasites in Kenyan rhinoceros is not known.[Results] Utilizing 18S rRNA gene as genetic marker to detect rhinoceros infection with Babesia and Theileria, we examined blood samples collected from seven rhinoceros populations consisting of 114 individuals of black and white rhinoceros. The goal was to determine the prevalence in Kenyan populations, and to assess the association of Babesia and Theileria infection with host species, age, sex, location, season and population mix (only black rhinoceros comparing to black and white rhinoceros populations). We did not detect any infection with Babesia in the sequenced samples, while the prevalence of T. bicornis in the Kenyan rhinoceros population was 49.12% (56/114). White rhinoceros had significantly higher prevalence of infection (66%) compared to black rhinoceros (43%). The infection of rhinoceros with Theileria was not associated with animal age, sex or location. The risk of infection with Theileria was not higher in mixed species populations compared to populations of pure black rhinoceros.[Conclusion] In the rhinoceros studied, we did not detect the presence of Babesia bicornis, while Theileria bicornis was found to have a 49.12% prevalence with white rhinoceros showing a higher prevalence (66%) comparing with black rhinoceros (43%). Other factors such as age, sex, location, and population mix were not found to play a significant role.We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)Peer reviewe

Biotransformation of Tebuconazole by Microorganisms: Evidence of a Common Mechanism

A major problem with organic wood preservatives is biotransformation by both wood decaying and wood-inhabiting but nondecaying microorganisms in long-term service. Detoxification of organic biocides may contribute significantly to treated wood failure. In this study, a bacterium (Pseudomonas fluorescens), mold (Trichoderma harzianum), soft rot (Chaetomium globosum), white rot (Phanerochaete chrysosporium), and brown rot (Meruliporia. incrassata) were used to access the extent of biotransformation and the initial metabolite products of tebuconazole in liquid cultures. This study proposed metabolic pathway(s) and explored the possibility of a common biotransformation mechanism for all species. P. chrysosporium showed little ability to metabolize tebuconazole. Within 21 da, 40.4, 59.9, 68.2, and 70.2% tebuconazole was metabolized by M. incrassata, C. globosum, T. harzianum, and P. fluorescens, respectively, into a form that may be less toxic. Mass spectroscopy and infrared analysis of isolated metabolites indicated that the major pathway was cleavage of the triazole ring on tebuconazole and that most species mainly performed oxidation reactions to form the alcohol monolog, which was further oxidized to form the carboxylic acid analog of tebuconazole. Only T. harzianum metabolized the hydroxyl group on the tert-butyl moiety by acetylation to form an ester

The effect of vaccinating S. mansoni–infected BALB/c mice either before or after treatment

In Schistosoma mansoni endemic areas, there are people with ongoing S. mansoni infection, others have been infected and treated while others have never been infected. What would happen if these different groups of people were vaccinated against S. mansoni? BALB/c mice were divided into five groups: Infected-Treated-Vaccinated; Infected-Vaccinated-Treated; Vaccinated-Treated Control; Challenge Control and Untreated challenge Control. Vaccination (500 20krad irradiated S. mansoni cercariae), Treatment (praziquantel), Infection and Challenge (150 S. mansoni cercariae) were carried out at specified times. Proliferation assay, Enzyme linked immunosorbent assay, gross pathology, histopathology and perfusion were performed. High protection levels were obtained in mice treated after vaccination: Vaccinated-Treated control, 96.5%; Infected-Vaccinated-Treated, 68.9%; and Infected-Treated-Vaccinated, 41%. A good correlation was obtained between proliferative responses and protective levels, implying cellular involvement in protection. Although all protected animals had high IgG levels, there was no strong correlation between the two. Specificity rather than amounts of IgG, seem more important in protection. Praziquantel seemed to boost protective immunity when administered after vaccination. Granuloma development and modulation in the two test groups was similar. It seems better to vaccinate infected patients before treatment, the ideal situation being vaccinating people who have not encountered S. mansoni. African Journal of Health Sciences Vol. 13 (1-2) 2008: pp. 55-6

Reverse logistics capabilities and supply chain performance in a developing country context

Today and in the highly complex pharmaceutical industry, reverse logistics is a core capability for pharma companies that seek competitive advantages from the efficient management of returns and recalls, e.g. due to errors, expired stocks, quality-related or environmental issues, non-compliance and other consumer-related concerns. And yet in many developing countries where the pharma industry is a big part of the economy, the value of RL is not well understood. In this study, we examine the ambivalent impact of reverse logistics capabilities within the pharmaceutical supply chains in a developing country by focusing on four key reverse logistics capabilities, i.e. logistics information systems, process formalisation, flexibility, and top management support. The findings show that logistics information management systems, process formalisation, and flexibility significantly affect supply chain performance of pharmaceutical firms. However, the hierarchical regression found no significant moderating effect of top management support between reverse logistics capabilities and supply chain performance. Our subsequent discussion and implications for practice and future research are based on these findings.publishedVersio

Multi-sensor fire detection system using an Arduino Uno microcontroller

Thesis submitted in partial fulfillment of the requirements for the Degree of Master of Science in Information Technology (MSIT) at Strathmore UniversityUntimely response, constrained navigation due to poor urban planning and traffic jams, highly flammable construction materials, insufficient capacity by the fire department and lack of access to automated fire detection systems by residents due to purchasing costs are among the factors that affect fire-fighting services in Kenya and across the African continent. The aftermath of a fire outbreak could very acute leading to widespread loss of property and loss of lives. Residential areas contain numerous flammable materials such as clothing, books, wooden cabinets, beddings and plastics while also housing sources of ignition that include cooking gas and electronic devices thus are prone to severe fire accidents. Fire outbreaks have an inception period of about 3 to 5 minutes which is the optimal time to detect it and put it out after which it might get out of control.This implies that timely identification of a potential fire outbreak is crucial to managing it.Currently, most residential establishments as well as business premises are not fitted with fire detection systems owing to lack of awareness, high purchasing costs and inefficiency of the devices given the high false alarm rates which have a cost attached to them such as the unnecessary deployment of fire-fighting personnel. The fire detection devices are highly susceptible to false alarms because reliance on one sensor that reads only one percept from the environment for instance smoke or heat. However, the advancement of the Internet-of-Things has led to the development of ‘smart’ technologies where multiple sensors can be incorporated into objects like fire detectors additionally enabling them to communicate wirelessly with other objects and carry out programmed tasks. This research aimed at proposing a prototype of a fire detection system using a multi-sensor approach. This research applied rapid prototyping methodology for development of the prototype. Data was collected from secondary sources and experimentation.The prototype used an MQ2 gas sensor, a Grove temperature sensor, a Grove light sensor and an Arduino microcontroller, a GSM and GPS shield. In the event of a fire outbreak, the device will be able to send an SMS alert to the home owner as well as the firefighting department with GPS coordinates of the residence. The prototype recorded 83% success rate and 17% false alarm rate based on 6 test cases of which only one failed

An extract of Urtica dioica L. mitigates obesity induced insulin resistance in mice skeletal muscle via protein phosphatase 2A (PP2A)

The leaf extract of Urtica dioica L. (UT) has been reported to improve glucose homeostasis in vivo, but definitive studies on efficacy and mechanism of action are lacking. We investigated the effects of UT on obesity-induced insulin resistance in skeletal muscle. Male C57BL/6J mice were divided into three groups: low-fat diet (LFD), high-fat diet (HFD) and HFD supplemented with UT. Body weight, body composition, plasma glucose and plasma insulin were monitored. Skeletal muscle (gastrocnemius) was analyzed for insulin sensitivity, ceramide accumulation and the post translational modification and activity of protein phosphatase 2A (PP2A). PP2A is activated by ceramides and dephosphorylates Akt. C2C12 myotubes exposed to excess free fatty acids with or without UT were also evaluated for insulin signaling and modulation of PP2A. The HFD induced insulin resistance, increased fasting plasma glucose, enhanced ceramide accumulation and PP2A activity in skeletal muscle. Supplementation with UT improved plasma glucose homeostasis and enhanced skeletal muscle insulin sensitivity without affecting body weight and body composition. In myotubes, UT attenuated the ability of FFAs to induce insulin resistance and PP2A hyperactivity without affecting ceramide accumulation and PP2A expression. UT decreased PP2A activity through posttranslational modification that was accompanied by a reduction in Akt dephosphorylation