62 research outputs found
Chikungunya: A Potentially Emerging Epidemic?
Chikungunya virus is a mosquito-borne emerging pathogen that has a major health impact in humans and causes fever disease, headache, rash, nausea, vomiting, myalgia, and arthralgia. Indigenous to tropical Africa, recent large outbreaks have been reported in parts of South East Asia and several of its neighboring islands in 2005–07 and in Europe in 2007. Furthermore, positive cases have been confirmed in the United States in travelers returning from known outbreak areas. Currently, there is no vaccine or antiviral treatment. With the threat of an emerging global pandemic, the peculiar problems associated with the more immediate and seasonal epidemics warrant the development of an effective vaccine. In this review, we summarize the evidence supporting these concepts
Polarization-selective modulation of supercavity resonances originating from bound states in the continuum
Bound states in the continuum (BICs) are widely studied for their ability to confine light, produce sharp resonances for sensing applications and serve as avenues for lasing action with topological characteristics. Primarily, the formation of BICs in periodic photonic band gap structures are driven by symmetry incompatibility; structural manipulation or variation of incidence angle from incoming light. In this work, we report two modalities for driving the formation of BICs in terahertz metasurfaces. At normal incidence, we experimentally confirm polarization driven symmetry-protected BICs by the variation of the linear polarization state of light. In addition, we demonstrate through strong coupling of two radiative modes the formation of capacitively-driven Freidrich-Wintgen BICs, exotic modes which occur in off-Γ points not accessible by symmetry-protected BICs. The capacitance-mediated strong coupling at 0° polarization is verified to have a normalized coupling strength ratio of 4.17% obtained by the Jaynes-Cummings model. Furthermore, when the polarization angle is varied from 0° to 90° (0° ≤ ϕ \u3c 90°), the Freidrich-Wintgen BIC is modulated until it is completely switched off at 90°
Associations of CDH1 germline variant location and cancer phenotype in families with hereditary diffuse gastric cancer (HDGC)
INTRODUCTION: Hereditary diffuse gastric cancer (HDGC) is a cancer syndrome associated with variants in E-cadherin (CDH1), diffuse gastric cancer and lobular breast cancer. There is considerable heterogeneity in its clinical manifestations. This study aimed to determine associations between CDH1 germline variant status and clinical phenotypes of HDGC.
METHODS: One hundred and fifty-two HDGC families, including six previously unreported families, were identified. CDH1 gene-specific guidelines released by the Clinical Genome Resource (ClinGen) CDH1 Variant Curation Expert Panel were applied for pathogenicity classification of truncating, missense and splice site CDH1 germline variants. We evaluated ORs between location of truncating variants of CDH1 and incidence of colorectal cancer, breast cancer and cancer at young age (gastric cancer at \u3c40 or breast cancer \u3c50 years of age).
RESULTS: Frequency of truncating germline CDH1 variants varied across functional domains of the E-cadherin receptor gene and was highest in linker (0.05785 counts/base pair; p=0.0111) and PRE regions (0.10000; p=0.0059). Families with truncating CDH1 germline variants located in the PRE-PRO region were six times more likely to have family members affected by colorectal cancer (OR 6.20, 95% CI 1.79 to 21.48; p=0.004) compared with germline variants in other regions. Variants in the intracellular E-cadherin region were protective for cancer at young age (OR 0.2, 95% CI 0.06 to 0.64; p=0.0071) and in the linker regions for breast cancer (OR 0.35, 95% CI 0.12 to 0.99; p=0.0493). Different CDH1 genotypes were associated with different intracellular signalling activation levels including different p-ERK, p-mTOR and β-catenin levels in early submucosal T1a lesions of HDGC families with different CDH1 variants.
CONCLUSION: Type and location of CDH1 germline variants may help to identify families at increased risk for concomitant cancers that might benefit from individualised surveillance and intervention strategies
A DNA Vaccine against Chikungunya Virus Is Protective in Mice and Induces Neutralizing Antibodies in Mice and Nonhuman Primates
Chikungunya virus (CHIKV) is an emerging mosquito-borne alphavirus indigenous to tropical Africa and Asia. Acute illness is characterized by fever, arthralgias, conjunctivitis, rash, and sometimes arthritis. Relatively little is known about the antigenic targets for immunity, and no licensed vaccines or therapeutics are currently available for the pathogen. While the Aedes aegypti mosquito is its primary vector, recent evidence suggests that other carriers can transmit CHIKV thus raising concerns about its spread outside of natural endemic areas to new countries including the U.S. and Europe. Considering the potential for pandemic spread, understanding the development of immunity is paramount to the development of effective counter measures against CHIKV. In this study, we isolated a new CHIKV virus from an acutely infected human patient and developed a defined viral challenge stock in mice that allowed us to study viral pathogenesis and develop a viral neutralization assay. We then constructed a synthetic DNA vaccine delivered by in vivo electroporation (EP) that expresses a component of the CHIKV envelope glycoprotein and used this model to evaluate its efficacy. Vaccination induced robust antigen-specific cellular and humoral immune responses, which individually were capable of providing protection against CHIKV challenge in mice. Furthermore, vaccine studies in rhesus macaques demonstrated induction of nAb responses, which mimicked those induced in convalescent human patient sera. These data suggest a protective role for nAb against CHIKV disease and support further study of envelope-based CHIKV DNA vaccines
Sapogenins of Clerodendron serratum: constitution of a new pentacyclic triterpene acid, serratagenic acid
The sapogenin mixture obtained from the bark of Clerondendron serratum has been found to contain three major triterpenoid constituents, viz. oleanolic acid. queretaroic acid, and a new acid, named serratagenic acid, for which the structure 3β-hydroxy-Δ12-oleane 28,29-dioic acid has been deduced
Saponins of the seeds of Bassia latifolia
Two saponins A and B have been isolated from the defatted seeds of Bassia latifolia. The structure of saponin A has been elucidated as 2,3-di-O-glucopyranoside of bassic acid (IV) and that of saponin B as rhamnopyranosyl 1→4 xylopyranosyl 1→2 arabopyranosyl 1→OOC(28) of saponin A (IX)
Computational fluid dynamics analysis on heat transfer and friction factor characteristics of a turbulent flow for internally grooved tubes
The article presents computational fluid dynamics studies on heat transfer,
pressure drop, friction factor, Nusselt number and thermal hydraulic
performance of a plain tube and tube equipped with the three types of
internal grooves (circular, square and trapezoidal).Water was used as the
working fluid. Tests were performed for Reynolds number ranges from 5000 to
13500 for plain tube and different geometry inside grooved tubes. The maximum
increase of pressure drop was obtained from numerical modeling 74% for
circular, 38% for square and 78% for trapezoidal grooved tubes were compared
with plain tube. Based on computational fluid dynamics analysis the average
Nusselt number was increased up to 37%, 26% and 42% for circular, square and
trapezoidal grooved tubes respectively while compared with the plain tube.
The thermal hydraulic performance was obtained from computational fluid
dynamics analysis up to 38% for circular grooved tube, 27% for square grooved
tube and 40% for trapezoidal grooved tube while compared with the plain tube
Study on the effect of plant roots for stability of slopes
There have been several studies on the properties of plants which are beneficial to critical slopes in preventing failures. However, the impacts of the tensile properties of the plant roots have to be studied in detail. In this study, three different situations were addressed; completely dry, saturated and unsaturated. Under these three situations, stability of different slopes with different soil conditions was studied. Some roots were tested through the tensile testing machine normally used for yarn testing and some were tested with the traditional tensometer. Variation of root diameter was established by measuring the roots of tea plants available at cut slopes. Literature was found on the variation of tensile strength of tea roots with its diameter. Slopes of the tea estates were modeled considering the number of tea plants available in a particular slope. This was later converted to a percentage of coverage and values of factor of safety (FOS) were compared by changing different soil properties with the percentage of cover. It was found that the FOS tends to increase with the percentage of coverage under completely dry, saturated and unsaturated situations. However, it was learnt that the impact of tensile capacity of roots had not been so high under dry and saturated cases for cohesionless soils compared to the same situation of unsaturated condition which is having high FOS value s due to plant properties
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