889 research outputs found
Effet de la salinité sur la croissance et la production de biomasse de deux provenances de Jatropha curcas L. cultivés en serre
La salinisation des sols est un processus important de dĂ©gradation des sols. Ce phĂ©nomĂšne ne cesse de prendre de lâampleur. Il affecte la croissance et le rendement des cultures. Lâutilisation dâespĂšces Ă usages multiples telle que Jatropha curcas L. et capable de se dĂ©velopper dans ces milieux est dâune importance capitale. Cette Ă©tude a portĂ© sur lâeffet de diffĂ©rentes concentrations de NaCl (0 g/l, 2 g/l, 4 g/l, 8 g/l, 16 g/l et 35 g/l) pendant une durĂ©e de 42 jours sur des jeunes plants de deux provenances (Nioro et Kaffrine) de Jatropha curcas L en condition de serre vitrĂ©e. La tolĂ©rance des deux provenances par rapport aux diffĂ©rentes concentrations de NaCl a Ă©tĂ© Ă©tudiĂ©e en tenant compte des paramĂštres de croissance et de rendement. Les rĂ©sultats ont montrĂ© que la hauteur des tiges, le diamĂštre au collet, la biomasse sĂšche des parties aĂ©riennes et des parties racinaires Ă©valuĂ©s Ă la fin de lâexpĂ©rience varient en fonction du niveau du stress salin. Les deux provenances ont montrĂ© une tolĂ©rance Ă la salinitĂ© manifestĂ©e par la rĂ©duction dâun appareil aĂ©rien et racinaire important. La provenance Nioro prĂ©sente une croissance des organes aĂ©riens plus importante que celle de Kaffrine. Cependant, la provenance Kaffrine produit plus de biomasse sĂšche aĂ©rienne. Cette diffĂ©rence se situe au niveau de la quantitĂ© de biomasse sĂšche apportĂ©e par les tiges.Mots clĂ©s : Stress salin, croissance, biomasse, Jatropha curcas L., provenance
Upconversion Nanoparticle-Based Cell Membrane-Coated cRGD Peptide Bioorthogonally Labeled Nanoplatform for Glioblastoma Treatment
Glioblastoma is hard to be eradicated partly because of the obstructive blood-brain barrier (BBB) and the dynamic autophagy activities of glioblastoma. Here, hydroxychloroquine (HDX)-loaded yolk-shell upconversion nanoparticle (UCNP)@Zn0.5Cd0.5S nanoparticle coating with the cyclic Arg-Gly-Asp (cRGD)-grafted glioblastoma cell membrane for near-infrared (NIR)-triggered treatment of glioblastoma is prepared for the first time. [email protected] (abbreviated as YSN, yolk-shell nanoparticle) under NIR radiation will generate reactive oxygen species for imposing cytotoxicity. HDX, the only available autophagy inhibitor in clinical studies, can enhance cytotoxicity by preventing damaged organelles from being recycled. The cRGD-decorated cell membrane allowed the HDX-loaded nanoparticles to efficiently bypass the BBB and specifically target glioblastoma cells. Exceptional treatment efficacy of the NIR-triggered chemotherapy and photodynamic therapy was achieved in U87 cells and in the mouse glioblastoma model as well. Our results provided proof-of-concept evidence that HDX@YSN@CCM@cRGD could overcome the delivery barriers and achieve targeted treatment of glioblastoma
Breast cancer incidence following low-dose rate environmental exposure: Techa River Cohort, 1956â2004
In the 1950s, the Mayak nuclear weapons facility in Russia discharged liquid radioactive wastes into the Techa River causing exposure of riverside residents to protracted low-to-moderate doses of radiation. Almost 10â000 women received estimated doses to the stomach of up to 0.47 Gray (Gy) (mean dose=0.04âGy) from external Îł-exposure and 137Cs incorporation. We have been following this population for cancer incidence and mortality and as in the general Russian population, we found a significant temporal trend of breast cancer incidence. A significant linear radiation doseâresponse relationship was observed (P=0.01) with an estimated excess relative risk per Gray (ERR/Gy) of 5.00 (95% confidence interval (CI), 0.80, 12.76). We estimated that approximately 12% of the 109 observed cases could be attributed to radiation
Atomic-scale combination of germanium-zinc nanofibers for structural and electrochemical evolution
Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of similar to 50% at 20 C compared to that at 0.2 C-rate) and cycle retention (73% at 3.0 C-rate) with a retaining capacity of 546 mAh g(-1) even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system
Effect of non-linearity in predicting doppler waveforms through a novel model
BACKGROUND: In pregnancy, the uteroplacental vascular system develops de novo locally in utero and a systemic haemodynamic & bio-rheological alteration accompany it. Any abnormality in the non-linear vascular system is believed to trigger the onset of serious morbid conditions like pre-eclampsia and/or intrauterine growth restriction (IUGR). Exact Aetiopathogenesis is unknown. Advancement in the field of non-invasive doppler image analysis and simulation incorporating non-linearities may unfold the complexities associated with the inaccessible uteroplacental vessels. Earlier modeling approaches approximate it as a linear system. METHOD: We proposed a novel electrical model for the uteroplacental system that uses MOSFETs as non-linear elements in place of traditional linear transmission line (TL) model. The model to simulate doppler FVW's was designed by including the inputs from our non-linear mathematical model. While using the MOSFETs as voltage-controlled switches, a fair degree of controlled-non-linearity has been introduced in the model. Comparative analysis was done between the simulated data and the actual doppler FVW's waveforms. RESULTS & DISCUSSION: Normal pregnancy has been successfully modeled and the doppler output waveforms are simulated for different gestation time using the model. It is observed that the dicrotic notch disappears and the S/D ratio decreases as the pregnancy matures. Both these results are established clinical facts. Effects of blood density, viscosity and the arterial wall elasticity on the blood flow velocity profile were also studied. Spectral analysis on the output of the model (blood flow velocity) indicated that the Total Harmonic Distortion (THD) falls during the mid-gestation. CONCLUSION: Total harmonic distortion (THD) is found to be informative in determining the Feto-maternal health. Effects of the blood density, the viscosity and the elasticity changes on the blood FVW are simulated. Future works are expected to concentrate mainly on improving the load with respect to varying non-linear parameters in the model. Heart rate variability, which accounts for the vascular tone, should also be included. We also expect the model to initiate extensive clinical or experimental studies in the near future
Circulation and characterization of seasonal influenza viruses in Cambodia, 2012â2015
Background: Influenza virus circulation is monitored through the Cambodian influenzaâlike illness (ILI) sentinel surveillance system and isolates are characterized by the National Influenza Centre (NIC). Seasonal influenza circulation has previously been characterized by yearâround activity and a peak during the rainy season (JuneâNovember).
Objectives: We documented the circulation of seasonal influenza in Cambodia for 2012â2015 and investigated genetic, antigenic, and antiviral resistance characteristics of influenza isolates.
Patients/Methods
Respiratory samples were collected from patients presenting with influenzaâlike illness (ILI) at 11 hospitals throughout Cambodia. Firstâline screening was conducted by the National Institute of Public Health and the Armed Forces Research Institute of Medical Sciences. Confirmation of testing and genetic, antigenic and antiviral resistance characterization was conducted by Institute Pasteur in Cambodia, the NIC. Additional virus characterization was conducted by the WHO Collaborating Centre for Reference and Research on Influenza (Melbourne, Australia).
Results: Between 2012 and 2015, 1,238 influenzaâpositive samples were submitted to the NIC. Influenza A(H3N2) (55.3%) was the dominant subtype, followed by influenza B (30.9%; predominantly B/Yamagataâlineage) and A(H1N1)pdm09 (13.9%). Circulation of influenza viruses began earlier in 2014 and 2015 than previously described, coincident with the emergence of A(H3N2) clades 3C.2a and 3C.3a, respectively. There was high diversity in the antigenicity of A(H3N2) viruses, and to a smaller extent influenza B viruses, during this period, with some mismatches with the northern and southern hemisphere vaccine formulations. All isolates tested were susceptible to the influenza antiviral drugs oseltamivir and zanamivir.
Conclusions: Seasonal and yearâround coâcirculation of multiple influenza types/subtypes were detected in Cambodia during 2012â2015
Galactic star formation and accretion histories from matching galaxies to dark matter haloes
We present a new statistical method to determine the relationship between the
stellar masses of galaxies and the masses of their host dark matter haloes over
the entire cosmic history from z~4 to the present. This multi-epoch abundance
matching (MEAM) model self-consistently takes into account that satellite
galaxies first become satellites at times earlier than they are observed. We
employ a redshift-dependent parameterization of the stellar-to-halo mass
relation to populate haloes and subhaloes in the Millennium simulations with
galaxies, requiring that the observed stellar mass functions at several
redshifts be reproduced simultaneously. Using merger trees extracted from the
dark matter simulations in combination with MEAM, we predict the average
assembly histories of galaxies, separating into star formation within the
galaxies (in-situ) and accretion of stars (ex-situ). The peak star formation
efficiency decreases with redshift from 23% at z=0 to 9% at z=4 while the
corresponding halo mass increases from 10^11.8M\odot to 10^12.5M\odot. The star
formation rate of central galaxies peaks at a redshift which depends on halo
mass; for massive haloes this peak is at early cosmic times while for low-mass
galaxies the peak has not been reached yet. In haloes similar to that of the
Milky-Way about half of the central stellar mass is assembled after z=0.7. In
low-mass haloes, the accretion of satellites contributes little to the assembly
of their central galaxies, while in massive haloes more than half of the
central stellar mass is formed ex-situ with significant accretion of satellites
at z<2. We find that our method implies a cosmic star formation history and an
evolution of specific star formation rates which are consistent with those
inferred directly. We present convenient fitting functions for stellar masses,
star formation rates, and accretion rates as functions of halo mass and
redshift.Comment: 20 pages, 12 figures, 1 table, submitted to MNRA
Golgi protein 73 versus alpha-fetoprotein as a biomarker for hepatocellular carcinoma: a diagnostic meta- analysis
Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay
The decay channel
is studied using a sample of events collected
by the BESIII experiment at BEPCII. A strong enhancement at threshold is
observed in the invariant mass spectrum. The enhancement can be fit
with an -wave Breit-Wigner resonance function with a resulting peak mass of
and a
narrow width that is at the 90% confidence level.
These results are consistent with published BESII results. These mass and width
values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics
- âŠ