[Evaluation of malaria rapid diagnostic test Optimal-IT® pLDH along the Plasmodium falciparum distribution limit in Mauritania]. / Evaluation du test de diagnostic rapide du paludisme OptiMal-IT® pLDH à la limite de la distribution de Plasmodium falciparum en Mauritanie.

Performance of the malaria Rapid Diagnostic Test (RDT) OptiMal-IT® was evaluated in Mauritania where malaria is low and dependent on a short transmission season. Slide microscopy was considered as the reference method of diagnosis. Febrile patients with suspected malaria were recruited from six health facilities, 3 urban and 3 rural, during two periods (December 2011 to February 2012, and August 2012 to March 2013). Overall, 780 patients were sampled, with RDT and thick blood film microscopy results being obtained for 759 of them. Out of 774 slides examined, of which 200 were positive, P. falciparum and P. vivax mono-infections were detected in 63.5% (127) and 29.5% (59), while P. falciparum/P. vivax coinfections were detected in 7% (14). Both species were observed in all study sites, although in significantly different proportions. The proportions of thick blood film and OptiMal-IT® RDT positive individuals was 26.3% and 30.3% respectively. Sensitivity and specificity of OptiMal-IT® RDT were 89% [95% CI, 84.7-93.3] and 91.1% [88.6-93.4]. Positives and negative predictive values were 78.1% [72.2-83.7] and 95.9% [94.1-97.5]. These diagnostic values are similar to those generally reported elsewhere, and support the use of RDTs as the main diagnostic tool for malaria in Mauritanian health facilities. In the future, choice of RDTs to be used must take account of thermostability in a hot, dry environment and their ability to detect P. falciparum and P. vivax.

Distributed electrode Mach-Zehnder modulator with double-pass phase shifters and integrated inductors.

A novel high-speed Mach-Zehnder modulator (MZM) fully integrated into a 90 nm CMOS process is presented. The MZM features 'double-pass' optical phase shifter segments, and the first use of integrated inductors in a 'velocity-matched' distributed-electrode configuration.

Hybrid macroporous gelatin/bioactive-glass/nanosilver scaffolds with controlled degradation behavior and antimicrobial activity for bone tissue engineering.

A new composition of gelatin/bioactive-glass/silver nanoparticle was synthesized and employed to prepare antibacterial macroporous scaffolds with potential applications in bone tissue engineering. A set of macroporous nanocomposite scaffolds were developed from an aqueous solution of gelatin by freeze-drying and crosslinking using genipin at ambient temperature. Silver nanoparticles were successfully synthesized in situ in gelatin solution by heat treatment reduction as a simple and "green" method in which gelatin acted as a natural reducing and stabilizing agent. The effect of the incorporation of the bioactive-glass and the silver nanoparticle concentration on the physicochemical properties of the scaffolds, such as the gel fraction, porosity, in vitro enzyme degradation, morphology, and swelling behavior was studied. Furthermore, the in vitro viability of human mesenchymal stem cells (hMSC) and the antibacterial activity against gram-negative Escherichia coli and gram-positive Staphylococcus aureus were tested on the scaffolds. It was found that upon the addition of silver nanoparticles the porosity, pore size, swelling, and antibacterial properties were enhanced. The silver nanoparticles increased the in vitro enzyme degradation in samples without bioactive-glass; however, the degradation was remarkably reduced by addition of bioactive-glass. In addition, formation of apatite particles, the main inorganic constituent of the bone, on the surface of the bioactive-glass containing scaffolds were confirmed after immersion in simulated body fluid (SBF). The viability of hMSC on the scaffold suggested that gelatin/bioactive-glass/nanosilver scaffolds can be used as an antibacterial scaffolds.

Coupling modulation of microrings at rates beyond the linewidth limit.

We demonstrate optical modulation rates exceeding the conventional cavity linewidth limit using a silicon coupling modulated microring. Small-signal measurements show coupling modulation was free of the parasitic cavity linewidth limitations at rates at least 6× the cavity linewidth. Eye diagram measurements show coupling modulation achieved data rates > 2× the rate attainable by conventional intracavity phase modulation. We propose to use DC-balanced encoding to mitigate the inter-symbol interference in coupling modulation. Analysis shows that coupling modulation can be more efficient than intracavity modulation for large output swings and high-Q resonators. Coupling modulation enables very high-Q resonant modulators to be simultaneously low-power and high-speed, features which are mutually incompatible in typical resonant modulators studied to date.

A 25 Gbps silicon microring modulator based on an interleaved junction.

A silicon microring modulator utilizing an interleaved p-n junction phase shifter with a V(π)L of 0.76 V-cm and a minimum off-resonance insertion loss of less than 0.2 dB is demonstrated. The modulator operates at 25 Gbps at a drive voltage of 1.6 V and 2-3 dB excess optical insertion loss, conditions which correspond to a power consumption of 471 fJ/bit. Eye diagrams are characterized at up to 40 Gbps, and transmission is demonstrated across more than 10 km of single-mode fiber with minimal signal degradation.

Inorganic mercury exposure in prairie voles (Microtus ochrogaster) alters the expression of toll-like receptor 4 and activates inflammatory pathways in the liver in a sex-specific manner.

Environmental exposure to mercury can cause a number of adverse effects in humans including the disruption of endocrine function that may result in sex-specific effects. The present study was designed to characterize sex-specific effects of chronic inorganic mercury exposure on toll-like receptor (TLR) 2 and TLR4 and inflammatory signaling in the liver of prairie voles (Microtus ochrogaster). Following 10 weeks of exposure to mercury via drinking water, effects on protein expression levels of TLR2 and TLR4 and the downstream p38 mitogen-activated protein kinase (p38 MAPK) and nuclear factor-kappa (NF-κB) signaling pathways were assessed. Using immunoblot analysis, we found that mercury exposure significantly enhanced the expression of TLR4 and activated p38 MAPK and NF-κB pathways in vole livers. This is the first report indicating that TLR4 may serve as a sensor for chronic mercury exposure in the liver. Further, compared to females, mercury-treated male voles exhibited significant increases in activated p38 MAPK and a greater extent of liver damage. Together, these findings establish sex-specific liver immunomodulation and cellular signaling following chronic inorganic mercury exposure. Furthermore, this study also supports the use of voles as biomarkers of environmental mercury contamination and offers a promising in vivo tool to test various therapeutic strategies for mercury detoxification.

Interferon-beta induction by Chlamydia pneumoniae in human smooth muscle cells.

Clinical studies have suggested a causal or contributory role of Chlamydia pneumoniae infection in asthma and atherosclerosis. The activation of synthetic functions of smooth muscle cells (SMC) including the production of cytokines and growth factors plays a major role in the formation of fibrous atherosclerotic plaques as well as in structural remodelling of the airway wall in chronic asthma. In this study we demonstrated that C. pneumoniae induced the production of low levels of interferon (IFN)-beta in bronchial and vascular SMC when infected cells were treated with tumour necrosis factor-alpha (TNF-alpha). IFN-beta production was analysed by reverse transcription-PCR and enzyme-linked immunosorbent assay. The upregulation of IFN-beta was paralleled by an increase in mRNA levels of interferon regulatory factor-1 and interferon-stimulated gene factor 3gamma, two transcription factors activating the expression of the IFN-beta gene. In addition, C. pneumoniae infection enhanced the mRNA level of indoleamine 2,3-dioxygenase, an IFN-inducible factor mediating the restriction of intracellular chlamydial growth, in TNF-alpha-stimulated SMC. C. pneumoniae-induced IFN-beta production by SMC may modulate inflammation and tissue remodelling during respiratory and vascular infection.

Treatment outcome among Rwandan and Burundian refugees with sputum smear-positive tuberculosis in Ngara, Tanzania.

SETTING: Tuberculosis programme in six camps (Benaco, Musuhura, Lumasi, Lukole, Keza and Kitali) for Rwandan and Burundian refugees in Ngara district, Tanzania, where treatment was directly observed throughout. OBJECTIVES: To evaluate the treatment outcome of sputum smear-positive tuberculosis cases recruited in refugee camps in Ngara, and to determine the cumulative frequency of conversion of sputum smears by direct microscopy. DESIGN: Retrospective review of tuberculosis registers from January 1995 to December 1999. RESULTS: Of 546 patients with smear-positive tuberculosis who were notified in the programme, 363 (66.5%) had completed treatment and were bacteriologically cured after 7 months, 10.9% had died, 7.1% had defaulted and 14.5% had transferred out. Sputum conversion after the 2-month intensive phase was 88%, and increased to 99% after 7 months of chemotherapy. CONCLUSION: The involvement of the Tanzania NTLP in collaboration with health NGOs has led to a satisfactory outcome. These data suggest that it is possible for tuberculosis control programmes to perform successfully in refugee settings.

Diversity among Cynodon accessions and taxa based on DNA amplification fingerprinting.

The genus Cynodon (Gramineae), comprised of 9 species, is geographically widely distributed and genetically diverse. Information on the amounts of molecular genetic variation among and within Cynodon taxa is needed to enhance understanding of phylogenetic relations and facilitate germplasm management and breeding improvement efforts. Genetic relatedness among 62 Cynodon accessions, representing eight species, was assessed using DNA amplification fingerprinting (DAF). Ten 8-mer oligonucleotides were used to amplify specific Cynodon genomic sequences. The DNA amplification products of individual accessions were scored for presence (1) or absence (0) of bands. Similarity matrices were developed and the accessions were grouped by cluster (UPGMA) and principal coordinate analysis. Analyses were conducted within ploidy level (2x = 18 and 4x = 36) and over ploidy levels. Each primer revealed polymorphic loci among accessions within species. Of 539 loci (bands) scored, 496 (92%) were polymorphic. Cynodon arcuatus was clearly separated from other species by numerous monomorphic bands. The strongest species similarities were between C. aethiopicus and C. arcuatus, C. transvaalensis and C. plectostachyus, and C. incompletus and C. nlemfuensis. Intraspecific variation was least for C. aethiopicus, C. arcuatus, and C. transvaalensis, and greatest for C. dactylon. Accessions of like taxonomic classification were generally clustered, except the cosmopolitan C. dactylon var. dactylon and C. dactylon var. afganicus. Within taxa, accessions differing in chromosome number clustered in all instances indicating the 2x and 4x forms to be closely related. Little, if any, relationship was found between relatedness as indicated by the DAF profiles and previous estimates of hybridization potential between the different taxa.