3-D Printed Radar Absorber with Meta-material Features for X-band Application

This paper presents a structured radar absorber with metamaterial features based on graphite SLS composite. The unit cell of the proposed design was simulated on COMSOL Multiphysics to determine its frequencydependent absorption characteristics and fabricated using low-cost selective laser sintering 3-D printing technology. The measurement and simulation results showed an effective absorption bandwidth of 1.04 GHz and 2.08 GHz respectively. The optimized structure however, revealed broadband absorption in a frequency range between 8.35 to 12.20 GHz (X band) under normal incidence. Besides, the absorption performance under different polarizations and incident angles were investigated. Results indicated that the absorber exhibits polarization indifference and high absorptivity at a wide angle of incidence. The advantages of low cost, ultra-broad operating band, wide-angle feature, and polarization insensitivity made the proposed absorber a promising candidate in military and civilian applications

Effects of crude ethanol extract of Tapinanthus globiferus a. Rich on functional and structural integrity of the rats kidney

The present study was carried out to investigate the effects of crude ethanol extract of Tapinanthus globiferuson rat kidney. The toxic effects of the extract on rats kidney after 28 days of oral administration were evaluated on serum levels of urea, creatinine, sodium (Na+), potassium (K+), chloride (Cl-) and bicarbonate (HCO3-) while histopathology was evaluated on sections of the kidney. Results from the acute toxicity studies on the extract were found to be greater than 5,000 mg/kg body weight in rats after oral administration. The biochemical analysis of the extract showed significant (p<0.05) decrease in serum urea, creatinine and sodium levels, and significant (p<0.05) increase in serum potassium and chloride levels at doses of 175 and 350 mg/kg, while serum bicarbonate remained insignificant at tested doses. However, histological observations showed no significant structural changes in the kidney architecture at doses of 87.5 and 175 mg/kg extract compared to control, but at 350 mg/kg dose of extract showed areas of degeneration of Bowman’s capsule.The present work has revealed the non-toxicity of the ethanol extracts of Tapinanthus globiferus at low dose but suggests that its prolonged usage at higher dose should be monitored.Keywords: Tapinanthus globiferus, Creatinine, Electrolytes, nephrotoxic, Bowman’s capsul

Effect of aqueous leaf extract of Combretum Micranthum g. don (Combretaceae) on gastro intestinal smooth muscle.

The effects of the aqueous leaf extract of Combretum micranthum were studied on gastro intestinal smooth muscle of rodents. The extract was screened using isolated rabbit jejunum, guinea pig ileum and rat uterus. The extract produced relaxation of isolated rabbit jejunum and guinea pig ileum. The relaxation of guinea pig ileum was inhibited by phentolamine. The effect of the extract on rabbit jejunum and guinea pig ileum may involve adrenergic receptors. The extract had no effect on pregnant and non-pregnant isolated rat uterus. The result of preliminary phytochemical screening of the extract showed that, the aqueous leaf extract contains alkaloids, flavonoids, glycosides, saponins, tannins and phlabotannins. The properties of the extract may be due to the presence of these active constituents of pharmacological importance that bear relevance to its therapeutic claims in traditional medicine.Keywords: Combretum micranthum, Rabbit jejunum, Rat uterus and Guinea pig ileum

Effect of oral administration of ethanolic extract of Tapinanthus globiferus A. rich on liver function in rats

The effects of ethanol extract of Tapinanthus globiferus in the liver of rats were evaluated on serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total protein (TP), total bilirubin (TB) and conjugated bilirubin (CB) while histological analysis was evaluated on section of liver after 28 days of oral administration. The oral LD50 of the extract in rats was found to be greater than 5,000 mg/kg body weight. The biochemical analysis revealed no significant changes (p > 0.05) in serum levels of AST, ALT, ALP and TP at all doses treated (87.5, 175 and 350 mg/kg) but there was significant (p < 0.05) evaluation of serum TB at higher dose and significant (p < 0.05) dose dependent increase in CB when compared with control. The photomicrograph of transverse section of the liver treated with doses of 175 and 350 mg/kg showed areas of fibrosis at 100 magnifications while no effect was observed at 87.5 mg/kg body weight. This work revealed that, Tapinanthus globiferus extract has no toxic effect on the liver of rats after short and low dose administration but can cause sign of liver damage at higher dose.Key words: Tapinanthus globiferus, Biochemical, Ethanol, Histological, Photomicrograp

Analgesic and anti-inflammatory effects of aqueous leafextract of Combretum micranthumg. Don (Combretaceae)

The analgesic and anti-inflammatory effects of the aqueous leaf extract of Combretum micranthum were studied in mice and rats. The extract was screened for analgesic activity; using acetic acid induced writhing in mice and formalin induced paw licking test in rats. Anti-inflammatory effect was evaluated using formalin induced hind paw oedema in rats. Results showed that, at a dose of 200 mg/kg the extract significantly (p < 0.05) reduced the number of abdominal constrictions in mice and at doses of 100 and 200 mg/kg, the extract significantly (p < 0.05) reduced the licking time in rats in the formalin induced paw licking test. The extract at doses of 50,100 and 200 mg/kg significantly (p < 0.05) reduced hind paw oedema in rats from the first hour of formalin administration. The intraperitoneal LD50 value of the extract was found to be 2,154.1mg/kgin mice and 2,852.l mg/kg in rats. The analgesic and anti-inflammatory activities of the plant extract may probably be due to the presence of phytochemical contents.Keywords: Combrentum micranthum, Analgesic, Anti-inflammatory, Mice, Rats

Capacity Building for Primary Stroke Prevention Teams in Children Living With Sickle Cell Anemia in Africa

Background: Nigeria has the highest proportion of children with sickle cell anemia (SCA) globally; an estimated 150,000 infants with SCA are born annually. Primary stroke prevention in children with SCA must include Nigeria. We describe capacity-building strategies in conjunction with two National Institutes of Health–funded primary stroke prevention trials (a feasibility trial and phase III randomized controlled trial) with initial hydroxyurea treatment for children with SCA and abnormal transcranial Doppler (TCD) velocities in Nigeria. We anticipated challenges to conducting clinical trials in a low-resource setting with a local team that had not previously been involved in clinical research and sought a sustainable strategy for primary stroke prevention. Methods: This is a descriptive, prospective study of challenges, solutions, and research teams in two trials that enrolled a total of 679 children with SCA. Results: As part of the capacity-building component of the trials, over eight years, 23 research personnel (physicians, nurses, research coordinators, a statistician, and a pharmacist) completed a one-month research governance and ethics training program at Vanderbilt University Medical Center, USA. A lead research coordinator for each site completed the Society of Clinical Research Professionals certification. TCD machines were donated; radiologists and nonradiologists were trained and certified to perform TCD. A scalable E-prescription was implemented to track hydroxyurea treatment. We worked with regional government officials to support ongoing TCD-based screening and funding for hydroxyurea for children with SCA at a high risk of stroke. Conclusions: Our trials and capacity building demonstrate a sustainable strategy to initiate and maintain pediatric SCA primary stroke prevention programs in Africa

Multiple Colonization with S. pneumoniae before and after Introduction of the Seven-Valent Conjugated Pneumococcal Polysaccharide Vaccine

Simultaneous carriage of more than one strain of Streptococcus pneumoniae promotes horizontal gene transfer events and may lead to capsule switch and acquisition of antibiotic resistance. We studied the epidemiology of cocolonization with S. pneumoniae before and after introduction of the seven-valent conjugated pneumococcal vaccine (PCV7)

Feasibility trial for primary stroke prevention in children with sickle cell anemia in Nigeria (SPIN trial)

The vast majority of children with sickle cell anemia (SCA) live in Africa, where evidence-based guidelines for primary stroke prevention are lacking. In Kano, Nigeria, we conducted a feasibility trial to determine the acceptability of hydroxyurea therapy for primary stroke prevention in children with abnormal transcranial Doppler (TCD) measurements. Children with SCA and abnormal non-imaging TCD measurements (≥200 cm/s) received moderate fixed-dose hydroxyurea therapy (∼20 mg/kg/day). A comparison group of children with TCD measurements <200 cm/s was followed prospectively. Approximately 88% (330 of 375) of families agreed to be screened, while 87% (29 of 33) of those with abnormal TCD measurements, enrolled in the trial. No participant elected to withdraw from the trial. The average mean corpuscular volume increased from 85.7 fl at baseline to 95.5 fl at 24 months (not all of the children who crossed over had a 24 month visit), demonstrating adherence to hydroxyurea. The comparison group consisted of initially 210 children, of which four developed abnormal TCD measurements, and were started on hydroxyurea. None of the monthly research visits were missed (n = total 603 visits). Two and 10 deaths occurred in the treatment and comparison groups, with mortality rates of 2.69 and 1.81 per 100 patient-years, respectively (P = .67). Our results provide strong evidence, for high family recruitment, retention, and adherence rates, to undertake the first randomized controlled trial with hydroxyurea therapy for primary stroke prevention in children with SCA living in Africa