Mechanical and frictional properties of coconut husk powder reinforced polymer immersed in a simulated acidic medium for oil/gas applications.

Polymeric materials are constantly exposed to aggressive environments, negatively impacting their mechanical and chemical properties. In salt, acid, or alkaline solutions, polymer materials degrade due to surface flaws, microcracks, or other irregularities. For the first time, this study considers the behaviour of coconut powder/coir-reinforced synthetic LDPE hybrid composite immersed in an aggressive (acidic) medium for 15, 30 and 45 days. The structural, mechanical, and frictional behaviour of the developed coir/coconut husk powder/LDPE hybrid composites were measured after ageing in hydrochloric acid (HCl) as potential materials for oil and gas applications. From the XRD patterns, the prominent reflections in the control samples increased with the acid ageing days, while less prominent reflections characterized the hybrid composites. The hardness of the reinforced samples immersed for 30 and 45 days (30B and 45A) showed the highest values of 0.28 Hv, while the control samples immersed for 15 days had the least hardness. The reinforced samples immersed for 15 and 30 days (15B and 30B) showed the lowest and highest fracture toughness, respectively. The control samples were observed to absorb little water after immersion for 144 h. The result showed that although the reinforced hybrid composites showed better mechanical properties, with an increase in the days of immersion in an aggressive medium, the properties became compromised compared to the un-reinforced samples. Hence, the applications of the produced reinforced polymers in the oil and gas industries may be limited.

Prognostic accuracy of qSOFA score, SIRS criteria, and EWSs for in-hospital mortality among adult patients presenting with suspected infection to the emergency department (PASSEM) Multicenter prospective external validation cohort study protocol.

BACKGROUND: Early identification of a patient with infection who may develop sepsis is of utmost importance. Unfortunately, this remains elusive because no single clinical measure or test can reflect complex pathophysiological changes in patients with sepsis. However, multiple clinical and laboratory parameters indicate impending sepsis and organ dysfunction. Screening tools using these parameters can help identify the condition, such as SIRS, quick SOFA (qSOFA), National Early Warning Score (NEWS), or Modified Early Warning Score (MEWS). We aim to externally validate qSOFA, SIRS, and NEWS/NEWS2/MEWS for in-hospital mortality among adult patients with suspected infection who presenting to the emergency department. METHODS AND ANALYSIS: PASSEM study is an international prospective external validation cohort study. For 9 months, each participating center will recruit consecutive adult patients who visited the emergency departments with suspected infection and are planned for hospitalization. We will collect patients' demographics, vital signs measured in the triage, initial white blood cell count, and variables required to calculate Charlson Comorbidities Index; and follow patients for 90 days since their inclusion in the study. The primary outcome will be 30-days in-hospital mortality. The secondary outcome will be intensive care unit (ICU) admission, prolonged stay in the ICU (i.e., ≥72 hours), and 30- as well as 90-days all-cause mortality. The study started in December 2021 and planned to enroll 2851 patients to reach 200 in-hospital death. The sample size is adaptive and will be adjusted based on prespecified consecutive interim analyses. DISCUSSION: PASSEM study will be the first international multicenter prospective cohort study that designated to externally validate qSOFA score, SIRS criteria, and EWSs for in-hospital mortality among adult patients with suspected infection presenting to the ED in the Middle East region. STUDY REGISTRATION: The study is registered at ClinicalTrials.gov (NCT05172479).

The effects of COVID-19 on placental morphology.

The impact of the COVID-19 infection, caused by Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), during the pandemic has been considerably more severe in pregnant women than non-pregnant women. Therefore, a review detailing the morphological alterations and physiological changes associated with COVID-19 during pregnancy and the effect that these changes have on the feto-placental unit is of high priority. This knowledge is crucial for these mothers, their babies and clinicians to ensure a healthy life post-pandemic. Hence, we review the placental morphological changes due to COVID-19 to enhance the general understanding of how pregnant mothers, their placentas and unborn children may have been affected by this pandemic. Based on current literature, we deduced that COVID-19 pregnancies were oxygen deficient, which could further result in other pregnancy-related complications like preeclampsia and IUGR. Therefore, we present an up-to-date review of the COVID-19 pathophysiological implications on the placenta, covering the function of the placenta in COVID-19, the effects of this virus on the placenta, its functions and its link to other gestational complications. Furthermore, we highlight the possible effects of COVID-19 therapeutic interventions on pregnant mothers and their unborn children. Based on the literature, we strongly suggest that consistent surveillance for the mothers and infants from COVID-19 pregnancies be prioritised in the future. Though the pandemic is now in the past, its effects are long-term, necessitating the monitoring of clinical manifestations in the near future.

Giant Cell Tumor of the Proximal Phalanx: Report of two Cases Treated by Two Different Methods and Review of the Literature.

The hand is an extremely rare site for giant cell tumor (GCT). There are only a few reported cases of GCT including the hand, and even fewer reporting involvement of phalanges. GCTs in small bones are typically more aggressive and have higher local recurrence and rate of metastasis in younger patients compared to long bone involvement, so the treatment is more clinically challenging in the hand. In this study, we present the management of giant cell tumors of the proximal phalanxin two patients treated with two different method; ray resection and arthrodesis using an iliac crest graft. Key words: giant cell tumor, phalanx, hand, recurrence.

A review of the role of infections in the aetiology of haemolysis in patients with sickle cell diseases: pathogenesis, management, and prevention

Background: Sickle cell disease (SCD) is associated with chronic haemolysis, immuno-suppression and susceptibility to infections, which may trigger infection-associated haemolysis (IAH). SCD patients are vulnerable to anaemic effect of IAH due to vicious interaction between pre-existing 'inherited' chronic haemolysis and 'acquired' IAH. IAH in SCD manifests as febrile haemolytic crisis with clinical and laboratory features of severe anaemia or pancytopenia. Clinico-pathological perspectives of IAH in SCD are fragmented. This review presents a comprehensive but concise overview of pathogenesis, management and prevention of IAH in SCD. Methodology and results: Online literature search using search terms such as 'sickle cell disease, viral, bacterial, parasitic, fungal, infections, hyperhaemolytic crisis, haemophagocytic syndrome, severe anaemia, pancytopenia' in various combinations was done on PubMed/Medline, Google, Google-Scholar and Bing. Overall, 112 relevant publications were retrieved, which included 109 peer reviewed journal articles, 2 World Health Organization (WHO) technical reports, and 1 edited text book. A range of bacterial (Bartonella spp, Mycoplasma spp., Mycobacterium avium complex), viral (Dengue, SARS-CoV-2, Parvovirus-B19, Cytomegalovirus, Epstein-Barr virus), parasitic (Plasmodium spp., Babesia spp.), and fungal (Histoplasma spp.) infections were associated with IAH in SCD. There are two broad types of IAH in patients with SCD; infection associated extra-medullary haemolysis (IAEMH) and infection associated intra-medullary haemolysis (IAIMH). While IAEMH is associated with severe anaemia due to intravascular haemolysis caused by red cell invasion, oxidative injury, auto-antibodies, and/or pathogen-haem interaction, IAIMH is associated with haemophagocytic tri-lineage destruction of haematopoietic precursors in the bone marrow. Conclusion: Various microbial pathogens have been associated with IAH in SCD. SCD patients with fever, severe anaemia or pancytopenia should be investigated for early diagnosis and prompt treatment of IAH, which is a lifethreatening haematological emergency for which transfusion therapy alone may not suffice. Prompt and sustainable termination of IAH may require therapeutic combination of transfusion, anti-microbial chemotherapy, and immune modulation therapy. SCD patients should also receive counselling on hygiene, barrier protection against vectors, routine chemoprophylaxis for locally endemic diseases, and immunization for vaccine-preventable infections as a long-term preventive strategy against IAH.

Physicochemical and molecular characterization of heavy metal-tolerant bacteria isolated from soil of mining sites in Nigeria.

BACKGROUND: Mining for precious metals is detrimental to the composition of soil structure and microbial diversity distribution and is a health risk to human communities around the affected communities. This study was aimed at determining the physical and chemical characteristics and diversity of bacteria in the soil of local mining sites for biosorption of heavy metals. RESULTS: Results of physical and chemical characteristics showed mean pH values and percentage organic carbon to range from 7.1 to 8.2 and 0.18 to 1.12% respectively with statistical significance between sampling sites (P ≤ 0.05). Similarly, cation exchange capacity, electrical conductivity, moisture, total nitrogen, and carbon/nitrogen ratio (C:N) in the soil ranged between 1.52 to 3.57 cmol/kg, 0.15 to 0.32 ds/m, 0.14 to 0.82%, 0.10 to 0.28%, and 1.7 to 4.8 respectively. The highest heavy metal concentration of 59.01 ppm was recorded in soils obtained from site 3. The enumeration of viable aerobic bacteria recorded the highest mean count of 4.5 × 106 cfu/g observed at site 2 with statistical significance (P ≤ 0.05) between the sampled soils. Alcaligenes faecalis strain UBI, Aeromonas sp. strain UBI, Aeromonas sobria, and Leptothrix ginsengisoli that make up 11.2% of total identified bacteria were able to grow in higher amended concentrations of heavy metals. The evolutionary relationship showed the four heavy metal-tolerant bacteria identified belonged to the phylum Proteobacteria of class Betaproteobacteria in the order Burkholderiales. Heavy metal biosorption by the bacteria showed Alcaligenes faecalis strain UBI having the highest uptake capacity of 73.5% for Cu. CONCLUSION: In conclusion, Alcaligenes faecalis strain UBI (MT107249) and Aeromonas sp. strain UBI (MT126242) identified in this study showed promising capability to withstand heavy metals and are good candidates in genetic modification for bioremediation.

Prediction of anemia and estimation of hemoglobin concentration using a smartphone camera.

Anemia, defined as a low hemoglobin concentration, has a large impact on the health of the world's population. We describe the use of a ubiquitous device, the smartphone, to predict hemoglobin concentration and screen for anemia. This was a prospective convenience sample study conducted in Emergency Department (ED) patients of an academic teaching hospital. In an algorithm derivation phase, images of both conjunctiva were obtained from 142 patients in Phase 1 using a smartphone. A region of interest targeting the palpebral conjunctiva was selected from each image. Image-based parameters were extracted and used in stepwise regression analyses to develop a prediction model of estimated hemoglobin (HBc). In Phase 2, a validation model was constructed using data from 202 new ED patients. The final model based on all 344 patients was tested for accuracy in anemia and transfusion thresholds. Hemoglobin concentration ranged from 4.7 to 19.6 g/dL (mean 12.5). In Phase 1, there was a significant association between HBc and laboratory-predicted hemoglobin (HBl) slope = 1.07 (CI = 0.98-1.15), p<0.001. Accuracy, sensitivity, and specificity of HBc for predicting anemia was 82.9 [79.3, 86.4], 90.7 [87.0, 94.4], and 73.3 [67.1, 79.5], respectively. In Phase 2, accuracy, sensitivity and specificity decreased to 72.6 [71.4, 73.8], 72.8 [71, 74.6], and 72.5 [70.8, 74.1]. Accuracy for low (<7 g/dL) and high (<9 g/dL) transfusion thresholds was 94.4 [93.7, 95] and 86 [85, 86.9] respectively. Error trended with increasing HBl values (slope 0.27 [0.19, 0.36] and intercept -3.14 [-4.21, -2.07] (p<0.001) such that HBc tended to underestimate hemoglobin in higher ranges and overestimate in lower ranges. Higher quality images had a smaller bias trend than lower quality images. When separated by skin tone results were unaffected. A smartphone can be used in screening for anemia and transfusion thresholds. Improvements in image quality and computational corrections can further enhance estimates of hemoglobin.

Missed Elevated Blood Pressure in Triaged Outpatients: A Preliminary Cross-Sectional Multicentre Study in Northern Nigeria.

BACKGROUND: Hypertension is a common medical condition but largely undiagnosed, untreated, poorly controlled, and undertreated in low- and middle-income countries. Studies have reported missed hypertension during triage in Emergency Departments; however, little is known about missed elevated blood pressure (EBP) during triage in primary care settings. This study assessed the prevalence and predictors of missed EBP among triaged patients attending General Outpatient Clinics in Northern Nigeria. METHODS: This was a descriptive cross-sectional multi-centre study involving 187 adults randomly selected from patients triaged in four General Outpatient Clinics in northern Nigeria. An investigator-administered questionnaire was employed to obtain data regarding participants' socio-demographic, triage blood pressure (BP) measurement, physician-led BP measurement, and physicians' clinical decision characteristics. Chi-square test and logistic regression analysis were used to determine factors associated with and predictors of missed EBP, respectively. RESULTS: Participants' mean age was 40.6±14.7years. They were predominantly females (122, 65.2%). EBP was missed in 28 (15%) participants at the triage. Participants' age (>40years) (Odds ratio [OR]=3.82, 95% Confidence interval [CI]=1.43-10.22, P=0.008), study site (OR=0.32, 95% CI=0.12-0.82, P=0.018) and perceived receipt of explanation on BP measurement procedure (OR=2.97, 95% CI=1.25-7.07, P=0.014) were predictors of missed EBP among participants. CONCLUSION: The prevalence of missed EBP was low but remarkable because of its huge public health implications. Age, study site, perceived receipt of explanation on BP measurement procedure predicted missed EBP. Effective interventions are needed to curtail missed EBP in these and similar settings.

RÉSUMÉ: L'hypertension est une condition médicale courante mais en grande partie non diagnostiquée, non traitée, mal contrôlée et sous-traitée dans les pays à revenu faible et intermédiaire. Des études ont signalé une hypertension manquée lors du triage dans les services d'urgence; Cependant, on sait peu de choses sur l'hypertension artérielle (EBP) manquée lors du triage dans les établissements de soins primaires. Cette étude a évalué la prévalence et les prédicteurs de l'EBP manquée parmi les patients triés fréquentant les cliniques externes générales dans le nord du Nigeria. MÉTHODES: Il s'agissait d'une étude multicentrique transversale descriptive portant sur 187 adultes choisis au hasard parmi des patients triés dans quatre cliniques ambulatoires générales dans le nord du Nigéria. Un questionnaire administré par l'investigateur a été utilisé pour obtenir des données concernant les données sociodémographiques des participants, la mesure de la pression artérielle (PA) au triage, la mesure de la PA dirigée par un médecin et les caractéristiques de décision clinique des médecins. Un test du chi carré et une analyse de régression logistique ont été utilisés pour déterminer les facteurs associés et les prédicteurs de l'EBP manquée, respectivement. RÉSULTATS: L'âge moyen des participants était de 40,6 ± 14,7 ans. Il s'agissait majoritairement de femmes (122, 65,2 %). L'EBP a été manquée chez 28 (15 %) participants au triage. Âge des participants (> 40 ans) (rapport de cotes [OR] = 3,82, intervalle de confiance à 95 % [IC] = 1,43 à 10,22, P = 0,008), site d'étude (OR = 0,32, IC à 95 % = 0,12 à 0,82, P = 0,018) et la réception perçue d'explications sur la procédure de mesure de la PA (OR=2,97, IC à 95 %=1,25-7,07, P=0,014) étaient des prédicteurs d'EBP manquée chez les participants. CONCLUSION: La prévalence de l'EBP manquée était faible mais remarquable en raison de ses énormes implications pour la santé publique. L'âge, le site d'étude, la réception perçue d'explications sur la procédure de mesure de la PA prédisaient une EBP manquée. Des interventions efficaces sont nécessaires pour réduire l'EBP manquée dans ces contextes et similaires. MOTS CLÉS: tension artérielle élevée, hypertension, absence, consultations externes, soins primaires, triage.

Traditional birth attendants and reproductive health services in the context of covid-19: a scoping review

Background: In developing countries, the lack of accessible, affordable and acceptable orthodox care makes a significant proportion of the populace patronize the nearby available and cheap traditional birth attendants (TBAs) that share similar local custom and tradition. Although there are widely diverging shreds of evidence regarding their effectiveness as health care providers, they may have a limited role as a workforce during the ongoing COVID-19 pandemic where the more community-based distribution of commodities is increasingly considered due to movement restrictions. However, it is still doubtful if their integration into the formal health system may substantially contribute to basic health care delivery especially in the rural often hard to reach areas. Objectives: To explore the various roles of TBAs in reproductive health service delivery with implication for redefining their roles especially with the advent of the COVID-19 pandemic. Methodology: We searched and reviewed relevant literature on TBAs in PubMed, Africa Journals Online (AJOL) and Google scholar and relevant institutional websites for the role of TBAs pre and during the pandemic. The databases searched yielded 92 articles of potential significance to this review. After title/abstract review, 65 articles were moved to full document review. Nineteen articles explicitly and strictly focusing on TBAs concerning reproductive health were included in this review. Results: TBAs are providers of a wide range of reproductive health services and training to expand their roles and makes them safer is necessary for any consideration of their engagement; this implies the fight against COVID-19. TBAs should only be engaged if the gap in the resources for health must be filled by leveraging on their existing traditional roles and acceptance in the community. Conclusion: TBAs are widely utilised providers of care to their communities especially in the area of maternal care. With increasing emphasis on community-based services in healthcare delivery and the emergence of COVID-19, their roles must be reviewed and updated regularly to redefine their role in the health care delivery system especially because of the myriad personal and technical limitations associated with them. Any engagement with them should be with caution and as a stop-gap measur.

Effects of Acupressure and Acupuncture-Like Transcutaneous Electrical Nerve Stimulation on Sleep Quality Among Pregnant Women.

BACKGROUND: Despite the adverse consequences of poor sleep during pregnancy, relatively few safe interventions exist for improving sleep among pregnant women. Nonpharmacological interventions are increasingly gaining acceptance. However, the effects of acupressure and acupuncture-like transcutaneous electrical nerve stimulation (ACUTENS) have not been widely reported. OBJECTIVES: The purpose of this study is to investigate the effects of low-frequency transcutaneous electrical nerve stimulation, otherwise known as ACUTENS, and acupressure on sleep quality among pregnant women. METHODS: Purposive sampling of 42 pregnant women with sleep disorders was conducted, and the participants were randomized into 3 groups, i.e., acupressure, ACUTENS, and usual care. interventions, which were carried out twice weekly for six weeks. The Pittsburgh Sleep Quality index was used to determine the overall sleep quality. RESULTS: The preintervention scores of sleep quality were 12.5 (3.75), 12.5 (4.0), and 13.0 (3.5) in the ACUTENS, acupressure, and usual care groups, respectively. The Kruskal-Wallis test did not show any significant difference in the preintervention sleep quality scores (H = 0.379, p = 0.827). Participants in the usual care group recorded the least improvement, with a score of 5.0 (2.25), the ACUTENS group recorded a score of 4.5 (3.0), and the greatest improvement was recorded in the acupressure group, with a score of 4.0 (2.2) after 6 weeks of intervention. The Kruskal-Wallis test did not show any significant difference in the postintervention sleep quality scores among the 3 groups (H = 0.666, p = 0.717). CONCLUSION: This study showed that ACUTENS and acupressure as an adjunct to usual care are not more effective than usual care alone in improving sleep quality among pregnant women.

Purification of Plasmodium and Babesia- infected erythrocytes using a non-woven fabric filter.

The purification of parasite-infected erythrocytes from whole blood containing leucocytes is crucial for many downstream genetic and molecular assays in parasitology. Current methodologies to achieve this are often costly and time consuming. Here, we demonstrate the successful application of a cheap and simple Non-Woven Fabric (NWF) filter for the purification of parasitized red blood cells from whole blood. NWF filtration was applied to the malaria-parasitized blood of three strains of mice, and one strain of rat, and to Babesia gibsoni parasitized dog blood. Before and after filtration, the white blood cell (WBC) removal rates and red blood cell (RBC) recovery rates were measured. After NWF filter treatment of rodent malaria-infected blood, the WBC removal rates and RBC recovery rates were, for Kunming mice: 99.51%±0.30% and 86.12%±8.37%; for BALB/C mice: 99.61%±0.15% and 80.74%±7.11%; for C57 mice: 99.71%±0.12% and 84.87%±3.83%; for Sprague-Dawley rats: 99.93%±0.03% and 83.30%±2.96%. Microscopy showed WBCs were efficiently removed from infected dog blood samples, and there was no obvious morphological change of B. gibsoni parasites. NWF filters efficiently remove leukocytes from malaria parasite-infected mouse and rat blood, and are also suitable for filtration of B. gibsoni-infected dog blood.

Purification of Plasmodium and Babesia- infected erythrocytes using a non-woven fabric filter

@#The purification of parasite-infected erythrocytes from whole blood containing leucocytes is crucial for many downstream genetic and molecular assays in parasitology. Current methodologies to achieve this are often costly and time consuming. Here, we demonstrate the successful application of a cheap and simple Non-Woven Fabric (NWF) filter for the purification of parasitized red blood cells from whole blood. NWF filtration was applied to the malaria-parasitized blood of three strains of mice, and one strain of rat, and to Babesia gibsoni parasitized dog blood. Before and after filtration, the white blood cell (WBC) removal rates and red blood cell (RBC) recovery rates were measured. After NWF filter treatment of rodent malaria-infected blood, the WBC removal rates and RBC recovery rates were, for Kunming mice: 99.51%±0.30% and 86.12%±8.37%; for BALB/C mice: 99.61%±0.15% and 80.74%±7.11%; for C57 mice: 99.71%±0.12% and 84.87%±3.83%; for Sprague-Dawley rats: 99.93%±0.03% and 83.30%±2.96%. Microscopy showed WBCs were efficiently removed from infected dog blood samples, and there was no obvious morphological change of B. gibsoni parasites. NWF filters efficiently remove leukocytes from malaria parasite-infected mouse and rat blood, and are also suitable for filtration of B. gibsoni-infected dog blood.

The role of the whitefly, Bemisia tabaci (Gennadius), and farmer practices in the spread of cassava brown streak ipomoviruses.

Cassava brown streak disease (CBSD) is arguably the most dangerous current threat to cassava, which is Africa's most important food security crop. CBSD is caused by two RNA viruses: Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV). The roles of the whitefly Bemisia tabaci (Gennadius) and farmer practices in the spread of CBSD were investigated in a set of field and laboratory experiments. The virus was acquired and transmitted by B. tabaci within a short time (5-10 min each for virus acquisition and inoculation), and was retained for up to 48 hr. Highest virus transmission (60%) was achieved using 20-25 suspected viruliferous whiteflies per plant that were given acquisition and inoculation periods of 24 and 48 hr, respectively. Experiments mimicking the agronomic practices of cassava leaf picking or the use of contaminated tools for making cassava stem cuttings did not show the transmission of CBSV or UCBSV. Screenhouse and field experiments in Tanzania showed that the spread of CBSD next to spreader rows was high, and that the rate of spread decreased with increasing distance from the source of inoculum. The disease spread in the field up to a maximum of 17 m in a cropping season. These results collectively confirm that CBSV and UCBSV are transmitted by B. tabaci semipersistently, but for only short distances in the field. This implies that spread over longer distances is due to movements of infected stem cuttings used for planting material. These findings have important implications for developing appropriate management strategies for CBSD.

Biofilm formation and cellulose expression by Bordetella avium 197N, the causative agent of bordetellosis in birds and an opportunistic respiratory pathogen in humans.

Although bacterial cellulose synthase (bcs) operons are widespread within the Proteobacteria phylum, subunits required for the partial-acetylation of the polymer appear to be restricted to a few γ-group soil, plant-associated and phytopathogenic pseudomonads, including Pseudomonas fluorescens SBW25 and several Pseudomonas syringae pathovars. However, a bcs operon with acetylation subunits has also been annotated in the unrelated ß-group respiratory pathogen, Bordetella avium 197N. Our comparison of subunit protein sequences and GC content analyses confirms the close similarity between the B. avium 197N and pseudomonad operons and suggests that, in both cases, the cellulose synthase and acetylation subunits were acquired as a single unit. Using static liquid microcosms, we can confirm that B. avium 197N expresses low levels of cellulose in air-liquid interface biofilms and that biofilm strength and attachment levels could be increased by elevating c-di-GMP levels like the pseudomonads, but cellulose was not required for biofilm formation itself. The finding that B. avium 197N is capable of producing cellulose from a highly-conserved, but relatively uncommon bcs operon raises the question of what functional role this modified polymer plays during the infection of the upper respiratory tract or survival between hosts, and what environmental signals control its production.

Enantioselective Desymmetrization of Glutarimides Catalyzed by Oxazaborolidines Derived from cis-1-Amino-indan-2-ol.

Enantioselective reductive desymmetrization of glutarimides has been achieved employing an oxazaborolidine catalyst derived from cis-1-amino-indan-2-ol. The reaction was found to proceed through a stereoablative process that upgraded the enantioselectivity of an intermediate hydroxy-lactam. The reaction was generally tolerant of a number of substituents in the 4-position, giving enantiomeric excesses of greater than 82%.

Enantioselective catalytic desymmetrization of maleimides by temporary removal of an internal mirror plane and stereoablative over-reduction: synthesis of (R)-pyrrolam A.

A highly enantioselective (>95% ee) strategy to affect the desymmetrization of a maleimide has been performed by temporary attachment to an anthracene template followed by asymmetric reduction with an oxazaborolidine catalyst. A stereoablative over-reduction process was partially responsible for the high levels of enantioselectivity. Exemplification of the strategy by stereoselective functionalization and retro-Diels-Alder reaction provided the natural product pyrrolam A.

Transcriptional response of virus-infected cassava and identification of putative sources of resistance for cassava brown streak disease.

Cassava (Manihot esculenta) is a major food staple in sub-Saharan Africa, which is severely affected by cassava brown streak disease (CBSD). The aim of this study was to identify resistance for CBSD as well as to understand the mechanism of putative resistance for providing effective control for the disease. Three cassava varieties; Kaleso, Kiroba and Albert were inoculated with cassava brown streak viruses by grafting and also using the natural insect vector the whitefly, Bemisia tabaci. Kaleso expressed mild or no disease symptoms and supported low concentrations of viruses, which is a characteristic of resistant plants. In comparison, Kiroba expressed severe leaf but milder root symptoms, while Albert was susceptible with severe symptoms both on leaves and roots. Real-time PCR was used to estimate virus concentrations in cassava varieties. Virus quantities were higher in Kiroba and Albert compared to Kaleso. The Illumina RNA-sequencing was used to further understand the genetic basis of resistance. More than 700 genes were uniquely overexpressed in Kaleso in response to virus infection compared to Albert. Surprisingly, none of them were similar to known resistant gene orthologs. Some of the overexpressed genes, however, belonged to the hormone signalling pathways and secondary metabolites, both of which are linked to plant resistance. These genes should be further characterised before confirming their role in resistance to CBSD.

RNAi-mediated resistance to diverse isolates belonging to two virus species involved in Cassava brown streak disease.

Cassava brown streak disease (CBSD) is emerging as one of the most important viral diseases of cassava (Manihot esculenta) and is considered today as the biggest threat to cassava cultivation in East Africa. The disease is caused by isolates of at least two phylogenetically distinct species of single-stranded RNA viruses belonging to the family Potyviridae, genus Ipomovirus. The two species are present predominantly in the coastal lowland [Cassava brown streak virus (CBSV); Tanzania and Mozambique] and highland [Cassava brown streak Uganda virus (CBSUV); Lake Victoria Basin, Uganda, Kenya and Malawi] in East Africa. In this study, we demonstrate that CBSD can be efficiently controlled using RNA interference (RNAi). Three RNAi constructs targeting the highland species were generated, consisting of the full-length (FL; 894 nucleotides), 397-nucleotide N-terminal and 491-nucleotide C-terminal portions of the coat protein (CP) gene of a Ugandan isolate of CBSUV (CBSUV-[UG:Nam:04]), and expressed constitutively in Nicotiana benthamiana. After challenge with CBSUV-[UG:Nam:04], plants homozygous for FL-CP showed the highest resistance, followed by the N-terminal and C-terminal lines with similar resistance. In the case of FL, approximately 85% of the transgenic plant lines produced were completely resistant. Some transgenic lines were also challenged with six distinct isolates representing both species: CBSV and CBSUV. In addition to nearly complete resistance to the homologous virus, two FL plant lines showed 100% resistance and two C-terminal lines expressed 50-100% resistance, whereas the N-terminal lines succumbed to the nonhomologous CBSV isolates. Northern blotting revealed a positive correlation between the level of transgene-specific small interfering RNAs detected in transgenic plants and the level of virus resistance. This is the first demonstration of RNAi-mediated resistance to CBSD and protection across very distant isolates (more than 25% in nucleotide sequence) belonging to two different species: Cassava brown streak virus and Cassava brown streak Uganda virus.

Malarial retinopathy in northern Nigerian children.

This is a prospective study involving two centres. Children younger than 16 years old who had severe malaria underwent funduscopy. In one centre, direct ophthalmoscopy was performed by both an ophthalmologist and a non-ophthalmologist physician. At the other, two ophthalmologists performed a funduscopy on each patient using different methods (one using direct and the other indirect ophthalmoscopy). The objective was to determine the frequency of retinopathy and evaluate the effectiveness of direct ophthalmoscopy in detecting retinopathy in constantly dilated eyes. Of 62 children seen at both centres, 37% were found to have malarial retinopathy. Macula whitening was the most common finding. There was substantial agreement between the ophthalmologists using either the direct or indirect ophthalmoscopy techniques (Kappa value 0.604). However, at the centre using only direct ophthalmoscopy, there was poor agreement between the ophthalmologist and the non-ophthalmologist (kappa value -0.244). Direct ophthalmoscopy seemed to be effective in detecting malarial retinopathy, but only when performed by experienced personnel.

Effects of melarsamine hydrochloride (Cymelarsan) and diminazene aceturate (Berenil) on the pathology of experimental Trypanosoma brucei infection in red fronted gazelles (Gazella rufifrons).

An experimental infection of red fronted gazelles (Gazella rufifrons) with Trypanosoma brucei strain MKAR/84/NITR/6 was carried out. Two waves of parasitaemia which corresponded with a significant decline (p<0.05) in packed cell volume (PCV) was encountered in the infected untreated controls and those treated at day 8 post-infection with a sub-optimal dosage of diminazene aceturate (Berenil) at 3.5 mg/kg body weight. At postmortem, hepatomegally, splenomegally, lymphadenopathy, nephritis, myocardial degeneration with pulmonary oedema was observed in the two groups. Similarly, histopathological studies of some organs revealed interstitial haemorrhages, severe degenerative changes with cellular infiltrations. On the other hand, those treated by day 8 post-infection with melarsamine hydrochloride (Cymelarsan) at 0.3 mg/kg, 0.6 mg/kg or diminazene aceturate (Berenil) at 7.0 mg/kg body weight had apparently normal organs at the end of the experiment. These results suggest that, T. brucei can cause severe pathological changes in untreated red fronted gazelles (Gazella rufifrons). However, treatments at the onset of parasitaemia, by day 8 post-infection with melarsamine hydrochloride (Cymelarsan) at 0.3 and 0.6 mg/kg or diminazene aceturate (Berenil) at 7.0 mg/kg body weight ameliorated the deleterious effects of the infection in the gazelles.