Monoaxial Dzyaloshinskii-Moriya interaction-induced topological Hall effect in a new chiral-lattice magnet GdPt2_2B

We investigate the topological Hall effect (THE) in the monoaxial chiral crystal GdPt$_2$B, a recently discovered compound that exhibits putative helimagnetism below 87 K. The distinct THE was observed in GdPt2B in the magnetically ordered state. The scaling relations for anomalous and topological Hall conductivities differed from those of conventional models based on the scattering process. We further demonstrate the clear scaling behavior of the THE in a wide temperature range, which we attribute to the monoaxial Dzyaloshinskii-Moriya (DM) interaction under external magnetic fields perpendicular to the screw axis. The THE induced by the monoaxial DM interaction as well as the THE in a monoaxial chiral crystal of f-electron system are demonstrated in this study.Comment: 6 pages, 4 figures. To be published in Phys. Rev.

Fermi surface topology and electronic transport properties of a chiral crystal NbGe2_2 with strong electron-phonon interaction

We report the electronic structures and transport properties of a chiral crystal NbGe$_2$, which is a candidate for a coupled electron-phonon liquid. The electrical resistivity and thermoelectric power of NbGe$_2$ exhibit clear differences compared to those of NbSi2 even though both niobium ditetrelides are isostructural and isoelectronic. We discuss the intriguing transport properties of NbGe$_2$ based on a van Hove-type singularity in the density of states. The analysis of de Haas-van Alphen oscillations measured by the field modulation and magnetic torque methods reveals the detailed shape of the Fermi surface of NbGe$_2$ by comparison with the results of energy band structure calculations using a local density approximation. The electron and hole Fermi surfaces of NbGe$_2$ split into two because of the anti-symmetric spin-orbit interaction. The temperature dependence of quantum oscillations indicates that the effective mass is isotropically enhanced in NbGe$_2$ due to strong electron-phonon interaction.Comment: 9 pages, 7 figures, To be published in Phys. Rev.

Pathology of myelin oligodendrocyte glycoprotein antibody-associated disease: a comparison with multiple sclerosis and aquaporin 4 antibody-positive neuromyelitis optica spectrum disorders

Myelin oligodendrocyte glycoprotein (MOG) is expressed on the outermost layer of the myelin sheath in the central nervous system. Recently, the clinical concept of MOG antibody-associated disease (MOGAD) was established based on the results of human MOG-transfected cell-based assays which can detect conformation-sensitive antibodies against MOG. In this review, we summarized the pathological findings of MOGAD and discussed the issues that remain unresolved. MOGAD pathology is principally inflammatory demyelination without astrocyte destruction, characterized by perivenous demyelination previously reported in acute disseminated encephalomyelitis and by its fusion pattern localized in both the white and gray matter, but not by radially expanding confluent demyelination typically seen in multiple sclerosis (MS). Some of demyelinating lesions in MOGAD show severe loss of MOG staining compared with those of other myelin proteins, suggesting a MOG-targeted pathology in the disease. Perivascular cuffings mainly consist of macrophages and T cells with CD4-dominancy, which is also different from CD8+ T-cell-dominant inflammation in MS. Compared to aquaporin 4 (AQP4) antibody-positive neuromyelitis optica spectrum disorders (NMOSD), perivenous complement deposition is less common, but can be seen on myelinated fibers and on myelin degradation products within macrophages, resembling MS Pattern II pathology. Thus, the pathogenetic contribution of complements in MOGAD is still debatable. Together, these pathological features in MOGAD are clearly different from those of MS and AQP4 antibody-positive NMOSD, suggesting that MOGAD is an independent autoimmune demyelinating disease entity. Further research is needed to clarify the exact pathomechanisms of demyelination and how the pathophysiology relates to the clinical phenotype and symptoms leading to disability in MOGAD patients

Acetylcholinesterase Secretion by Brugia pahangi in vitro

The experiment was designed to demonstrate acetylcholinesterase (AChE) secretion by Brugia pahangi in vitro. Seventy five B. pahangi adult female worms were cultured in 2 ml of Eagle\u27s minimal essential medium (MEM), and the culture fluid was measured for AChE activity by the colorimetric method of Ellman et al. (1961). The enzymic activity increased by the incubation time during the first 24 hours of culture. In an experiment where 25-150 female worms were cultured for 24 hours, higher enzymic activity was detected in the culture fluid where the larger number of worms were cultured. Since AChE activity was not detected in the culture fluid where 100,000 microfilariae were cultured, the results showed that the AChE was secreted by B. pahangi adult female worms. The adult male worms did not have enzyme secreting potential. The secreted AChE was identified as a single protein by disc electrophoresis and possessed the characteristics of the true AChE for its substrate specificity and inhibition by eserine

Simple and Sensitive Enzyme-Linked Immunosorbent Assay for Ivermectin

A sensitive and reproducible enzyme-linked immunosorbent assay (ELISA) for the determination of the concentration of ivermectin (IVM) in biological fluids was developed. A conjugate of IVM on bovine serum albumin and poly-L-lysine was used to produce antibodies in rabbits and served as a solid-phase marker for titration of antibodies, respectively. The competitive ELISA was conducted by simultaneously incubating IVM and IVM-biotin conjugate with anti-IVM antiserum over goat anti-rabbit IgG (Fc) and then determining the amount of bound IVM-biotin with avidin-peroxidase conjugate as a tracer. The coefficient of variation for the assay was less than 10% in the range of 0.3?10 ng/ml. The limit of detection was 0.1 ng/ml. The cross-reactivities of anti-IVM antiserum with some anthelmintic drugs were negligible. Using this ELISA, serum levels of IVM were easily determined in Mongolian jirds (Meriones unguiculatus) up to 72 hr following a single oral dose of 500 μg/kg of body weight

Sleeping arrangement and house structure affect bed net use in villages along Lake Victoria

<p>Abstract</p> <p>Background</p> <p>Although insecticide-treated bed nets are effective tools, use often does not follow ownership. House structure and space arrangements may make the attempt to use bed nets difficult, especially for school age children. The objectives of this study were to explore whether an individual's sleeping arrangements and house structure affect bed net use in villages along Lake Victoria in western Kenya.</p> <p>Methods</p> <p>Sleeping arrangements of residents were directly observed for use of a bed net, use of a bed, and location. House size, number and types of rooms, bed availability, and residents' ages were estimated. The family heads and mothers were asked about the reason for not using bed nets. Individual bed net use was examined against age and sleeping arrangement. Net use at the household level was examined against four variables: bed availability, bed net availability, house size, and number of rooms.</p> <p>Results</p> <p>Bed net use by children between five and 15 years of age was lower than that among the other age classes. However, age was dropped from the final model, and sleeping arrangement was significantly associated with net use. Net use was significantly associated with bed availability, number of rooms and their interaction.</p> <p>Conclusion</p> <p>Net use was affected by sleeping arrangement and availability of suitable locations for hanging nets, in addition to net availability. Most residents had likely not realized that sleeping arrangement was a factor in net use. The ease of hanging a net is particularly important for children.</p

Parasitic Pathogens Associated with Diarrhoea in Mombasa, Kenya

A microscopic examination of a faecal specimens was designed to identify the enteropathogenic parasites in the diarrhoeal stool specimens in which neither enteropathogenic bacteria nor rotavirus was isolated in Caost Provincial General Hospital, Mombasa, Kenya. The parasites incriminated as causes of diarrhoea were Entamoeba histolytica, Giardia lamblia, Trichuris trichiura, hookworm and Ascaris lumbricoides. The cysts and ova of these parasites, however, were present with equal frequency in diarrhoeal, semi-formed and formed stool specimens, except the trophozoites of E. histolytica. The role of parasites in causation of diarrhoea is difficult to evaluate by the routine stool examination for parasites