209 research outputs found
Redundant Field Survey Data of Cyclotron with Imperfect Median Plane
An accurate and detailed field map is important for cyclotron beam dynamics
studies. During the long history of cyclotron studies, many techniques have
been developed by cyclotron pioneers for the treatment of median plane field
map. In this paper, we take the TRIUMF 500 MeV cyclotron as an example to study
the asymmetric field resulting from the imperfect median plane symmetry. The
``Gordon approach'' and a highly accurate compact finite differentiation method
are used to investigate the historical field survey data. The redundancy in the
survey data is revealed by the expansion method, which also makes it possible
to correct the error in the measurement. Finally, both the azimuthal field
and the axial gradient of the axial field in the median
plane are corrected using the radial field map . The influence of the
correction is examined by recalculating the equilibrium orbit properties of the
TRIUMF cyclotron. The result shows significantly increased vertical centering
errors of the closed orbits. Further simulation study suggests that these
centering errors can be reduced to below 1.5 cm by adjusting the trim coils'
field within the output limits of our trim coils' power supplies. The
error in the measurement field data may explain why the calculated trim coils'
settings during the cyclotron commissioning in 1974 encountered difficulty
Angiostrongylus cantonensis: morphological and behavioral investigation within the freshwater snail Pomacea canaliculata
An infection with Angiostrongylus cantonensis, the main causative agent for human eosinophilic encephalitis, can be acquired through the consumption of the freshwater snail Pomacea canaliculata. This snail also provides a suitable model to study the developmental morphology and behavior of A. cantonensis larvae, facilitated by the snail's distinct lung structure. We used microanatomy for studying the natural appearance and behavior of A. cantonensis larvae while developing within P. canaliculata. The distribution of refractile granules in the larval body and characteristic head structures changed during the developmental cycle. Two well-developed, rod-like structures with expanded knob-like tips at the anterior part were observed under the buccal cavity as early as the late second developmental stage. A "T”-shaped structure at the anterior end and its tenacity distinguished the outer sheath from that shed during the second molting. Early first-stage larvae obtained from fresh rat feces are free moving and characterized by a coiled tail, whereas a mellifluous "Q”-movement was the behavioral trait of third-stage A. cantonensis larvae outside the host tissue. In combination, the distribution of refractive granules, distinct head features, variations in sheaths, and behavioral characteristics can be utilized for differentiation of larval stages, and for distinguishing A. cantonensis larvae from those of other free-living nematode
The complete mitochondrial genome of the rodent intra-arterial nematodes Angiostrongylus cantonensis and Angiostrongylus costaricensis
The two rodent intra-arterial nematodes, Angiostrongylus cantonensis and Angiostrongylus costaricensis, can cause human ill-health. The present study aimed to characterize and compare the mitochondrial (mt) genomes of these two species, and clarify their phylogenetic relationship and the position in the phylum Nematoda. The complete mt genomes of A. cantonensis and A. costaricensis are 13,497 and 13,585bp in length, respectively. Hence, they are the smallest in the class of Chromadorea characterized thus far. Like many nematode species in the class of Chromadorea, they encode 12 proteins, 22 transfer RNAs, and two ribosomal RNAs. All genes are located on the same strand. Nucleotide identity of the two mt genomes is 81.6%, ranging from 77.7% to 87.1% in individual gene pairs. Our mt genome-wide analysis identified three major gene arrangement patterns (II-1, II-2, and II-3) from 48 nematode mt genomes. Both patterns II-1 and II-2 are distinct from pattern II-3, which covers the Spirurida, supporting a closer relationship between Ascaridida and Strongylida rather than Spirurida. Thymine (T) was highly concentrated on coding strands in Chromadorea, but balanced between the two strands in Enoplea, probably due to the gene arrangement pattern. Interestingly, the gene arrangement pattern of mt genomes and phylogenetic analysis based on concatenated amino acids indicated a closer relationship between the order Ascaridida and Rhabditida rather than Spirurida as indicated in previous studies. These discrepancies call for new research, reassessing the position of the order of Ascaridida in the phylogenetic tree. Once consolidated, the findings are important for population genetic studies and target identificatio
Emerging Angiostrongyliasis in Mainland China
Our review of angiostrongyliasis in China found that the disease is emerging as a result of changes in food consumption habits and long-distance transportation of food. Enhanced understanding of angiostrongyliasis epidemiology, increased public awareness about the risks associated with eating raw food, and enhanced food safety measures are needed
Arabidopsis NMD3 Is Required for Nuclear Export of 60S Ribosomal Subunits and Affects Secondary Cell Wall Thickening
NMD3 is required for nuclear export of the 60S ribosomal subunit in yeast and vertebrate cells, but no corresponding function of NMD3 has been reported in plants. Here we report that Arabidopsis thaliana NMD3 (AtNMD3) showed a similar function in the nuclear export of the 60S ribosomal subunit. Interference with AtNMD3 function by overexpressing a truncated dominant negative form of the protein lacking the nuclear export signal sequence caused retainment of the 60S ribosomal subunits in the nuclei. More interestingly, the transgenic Arabidopsis with dominant negative interference of AtNMD3 function showed a striking failure of secondary cell wall thickening, consistent with the altered expression of related genes and composition of cell wall components. Observation of a significant decrease of rough endoplasmic reticulum (RER) in the differentiating interfascicular fiber cells of the transgenic plant stems suggested a link between the defective nuclear export of 60S ribosomal subunits and the abnormal formation of the secondary cell wall. These findings not only clarified the evolutionary conservation of NMD3 functions in the nuclear export of 60S ribosomal subunits in yeast, animals and plants, but also revealed a new facet of the regulatory mechanism underlying secondary cell wall thickening in Arabidopsis. This new facet is that the nuclear export of 60S ribosomal subunits and the formation of RER may play regulatory roles in coordinating protein synthesis in cytoplasm and transcription in nuclei
Peroxiredoxin 3 Inhibits Cardiac Fibrosis in Mice via NOX4-P38 Signalling
Objective: Peroxiredoxin-3 (Prx-3) is widely acknowledged as an antioxidant that protects against mitochondrialreactive oxygen species. Nonetheless, its role in cardiac fibrosis has not been elucidated. We aim to explore the roleand mechanism of Prx-3 in cardiac fibrosis.Materials and Methods: In this experimental study, mice received subcutaneous injections of isoproterenol (ISO) for 14consecutive days (10 mg/kg/d for three days, followed by 5 mg/kg/d for 11 days) to establish a cardiac fibrosis model. Themice were subsequently injected with adenovirus-Prx-3 (ad-Prx-3) to enable Prx-3 overexpression. Echocardiographywas used to evaluate cardiac function. Mice heart fibroblasts were isolated and stimulated with transforming growthfactor β1 (TGFβ1) to induce fibrosis in vitro. Cells were also transfected with ad-Prx-3 for overexpression of Prx-3.Results: Echocardiographic diameters and fibrosis markers indicated that Prx-3 could inhibit ISO-induced cardiacdysfunction and fibrosis. Fibroblasts with Prx-3 overexpression exhibited reduced activation, proliferation, and collagentranscription. We found that Prx-3 reduced the expression of NADPH oxidase 4 (NOX4) and reduced P38 levels. Aftertreatment with a P38 inhibitor, the Prx-3 overexpression-induced anti-fibrosis effect was mitigated.Conclusion: Prx-3 could protect against ISO-induced cardiac fibrosis by inhibiting the NOX4-P38 pathway
Seroprevalence of Hepatitis E Virus Infection, Rural Southern People’s Republic of China
HEV infection is thought to have been endemic in southern China for >60 years; swine are now the main source of human infection
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