Precision Measurement of the Proton Flux in Primary Cosmic Rays from Rigidity 1 GV to 1.8 TV with the Alpha Magnetic Spectrometer on the International Space Station

A precise measurement of the proton flux in primary cosmic rays with rigidity (momentum/charge) from 1 GV to 1.8 TV is presented based on 300 million events. Knowledge of the rigidity dependence of the proton flux is important in understanding the origin, acceleration, and propagation of cosmic rays. We present the detailed variation with rigidity of the flux spectral index for the first time. The spectral index progressively hardens at high rigidities.

Cytoplasmic p21 is responsible for paclitaxel resistance in ovarian cancer A2780 cells

PURPOSE

P21 which bound to cyclin-dependent kinase complexes was originally described as a suppressor of cancer cell prolifera- tion, while many recent studies have shown p21, when accumulated in the cell cytoplasm, could promote tumor progression. This study was conducted to investigate the role of p21 in the paclitaxel (PTX) resistance of ovarian cancer.

MATERIALS AND METHODS

Regulation of cytoplasmic p21 was performed through transfection of Akt2 constitutively active vector, Akt2 shRNA and p21 siRNA in the ovar- ian cancer cell line A2780. Akt2, p-Akt, and p21 expression were examined by Western blot and cell apoptosis rates were assessed by flow cytometry after treatment with PTX.

RESULTS

Induction of p21 translocation into the cytoplasm via constitutively active Akt2 transfection in A2780 enhanced the resistance to PTX, while inhibition of p21 translocation into the cytoplasm via Akt2 shRNA trans- fection in A2780 cells significantly increased PTX treatment sensitivity. Furthermore, knockdown of cytoplasmic p21 by direct p21 siRNA transfection in Akt2 overexpressed A2780 cells notably increased PTX-induced apoptosis.

CONCLUSION

Cytoplasmic p21 may represent a potential therapeutic target for ovarian tumors that are resistant to PTX treatment.

Precision Measurement of the (e^{+}+e^{-}) Flux in Primary Cosmic Rays from 0.5 GeV to 1 TeV with the Alpha Magnetic Spectrometer on the International Space Station

We present a measurement of the cosmic ray (e^{+}+e^{-}) flux in the range 0.5 GeV to 1 TeV based on the analysis of 10.6 million (e^{+}+e^{-}) events collected by AMS. The statistics and the resolution of AMS provide a precision measurement of the flux. The flux is smooth and reveals new and distinct information. Above 30.2 GeV, the flux can be described by a single power law with a spectral index γ=-3.170±0.008(stat+syst)±0.008(energy scale).

Search for a light sterile neutrino at Daya Bay

A search for light sterile neutrino mixing was performed with the first 217 days of data from the Daya Bay Reactor Antineutrino Experiment. The experiment's unique configuration of multiple baselines from six 2.9 GW(th) nuclear reactors to six antineutrino detectors deployed in two near (effective baselines 512 m and 561 m) and one far (1579 m) underground experimental halls makes it possible to test for oscillations to a fourth (sterile) neutrino in the 10(-3) eV(2)<|Δm(41)(2) |< 0.3 eV(2) range. The relative spectral distortion due to the disappearance of electron antineutrinos was found to be consistent with that of the three-flavor oscillation model. The derived limits on sin(2) 2θ(14) cover the 10(-3) eV(2) ≲ |Δm(41)(2)| ≲ 0.1 eV(2) region, which was largely unexplored.

Electron and positron fluxes in primary cosmic rays measured with the alpha magnetic spectrometer on the international space station

Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at ∼30  GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index. The determination of the differing behavior of the spectral indices versus energy is a new observation and provides important information on the origins of cosmic-ray electrons and positrons.

High statistics measurement of the positron fraction in primary cosmic rays of 0.5-500 GeV with the alpha magnetic spectrometer on the international space station

A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200  GeV the positron fraction no longer exhibits an increase with energy.

Prevalence and characterization of Salmonella enterica in dried milk-related infant foods in Shaanxi, China

The aim of this study was to investigate the existence and characteristics of Salmonella enterica in dried milk-related infant foods. Twenty-four (3.4%) of 705 samples, including 5 (2.0%) of 246 powdered infant formula, 18 (4.0%) of 445 infant rice cereal, and 1 (7.1%) of 14 other infant foods, were positive for Salmonella. Fifteen serotypes were identified in 40 Salmonella isolates; Salmonella Duesseldorf (15.0%) and Salmonella Indiana (15.0%) were more frequently detected than other serotypes. Resistance to chloramphenicol (82.5%) was most common, followed by tetracycline (57.5%), ceftiofur (52.5%), kanamycin (52.5%), streptomycin (50.0%), gentamycin (45.0%), nalidixic acid (35.0%), ceftriaxone (32.5%), ciprofloxacin (25.0%), amikacin (20.0%), and cefoxitin (15.0%). Twenty-eight (70.0%) isolates were resistant to ≥ 8 antimicrobials, with 5 (12.5%) being resistant to 14 antimicrobials. Amino acid substitutions in gyrase A (GyrA) were most frequently detected as Ser83Arg/Asp87Glu and in p53-associated Parkin-like cytoplasmic protein (ParC), they were all Ser80Arg; the quinolone resistance gene qnrS (47.5%) was commonly detected as well as aminoglycoside acetyltransferase [aac(6')-Ib; 25.0%], qnrA (17.5%), and qnrB (15.0%) genes. Thirty distinct pulsed-field gel electrophoresis patterns were identified among 40 isolates; no identical pulsed-field gel electrophoresis pattern was detected among Salmonella isolates with the same serovar that was recovered in 2010 and 2012. Our results suggest that dried milk-related infant foods could be contaminated with Salmonella and highlight that the dangers to infant health should not be neglected.

Establishing HbA1c -mean blood glucose formulae for patients on continuous ambulatory peritoneal dialysis

AIM

To determine the relationship between HbA1c and mean blood glucose concentrations by using HbA1c -mean blood glucose formulae for people on continuous ambulatory peritoneal dialysis.

METHODS

A total of 305 people on continuous ambulatory peritoneal dialysis, including 13 people with Type 1 diabetes mellitus, 161 people with Type 2 diabetes mellitus and 131 people without diabetes, from a single peritoneal dialysis centre at the First Affiliated Hospital of Sun Yat-sen University, were enrolled between January 2006 and June 2011. Serum HbA1c concentration was measured quarterly and other laboratory variables, including blood glucose, were measured every month. The formulae were established using regression analysis and adjusted for other factors. The estimated blood glucose level calculated using our formulae was compared with that using previous formulae namely the Diabetes Control and Complications Trial and A1c -Derived Average Glucose formulae for people not on dialysis and the Hoshino formula for people on haemodialysis.

RESULTS

The HbA1c -mean blood glucose formulae obtained by linear regression analysis were: 1) mBGmmol/l = 0.107 × HbA1c (mmol/mol) + 1.764 [adjusted R(2) (Radj2)  = 0.494]; 2) mBGmmol/l  = 0.101 × HbA1c  (mmol/mol) - 0.001 × Cr (μmol/l) + 2.850 (Radj2 = 0.507); 3) mBGmmol/l  = 0.102 × HbA1c  (mmol/mol) - 0.095 × Alb (g/l) + 5.394 (Radj2 = 0.521); and 4) mBGmmol/l  = 0.099 × HbA1c (mmol/mol) - 0.001 × Cr (μmol/l)-0.084 × Alb (g/l) + 5.754 (Radj2 = 0.526), where mBG is mean blood glucose, Cr is serum creatinine and Alb is serum albumin. These new formulae performed as well as or better than previous formulae.

CONCLUSIONS

The relationship between HbA1c and mean blood glucose for people on continuous ambulatory peritoneal dialysis differs from that for people not on dialysis or for those on haemodialysis. Clinicians and patients can determine glycaemic control targets by applying our formulae.

Cell-to-cell variability in cell death: can systems biology help us make sense of it all?

One of the most common observations in cell death assays is that not all cells die at the same time, or at the same treatment dose. Here, using the perspective of the systems biology of apoptosis and the context of cancer treatment, we discuss possible sources of this cell-to-cell variability as well as its implications for quantitative measurements and computational models of cell death. Many different factors, both within and outside of the apoptosis signaling networks, have been correlated with the variable responses to various death-inducing treatments. Systems biology models offer us the opportunity to take a more synoptic view of the cell death process to identify multifactorial determinants of the cell death decision. Finally, with an eye toward 'systems pharmacology', we discuss how leveraging this new understanding should help us develop combination treatment strategies to compel cancer cells toward apoptosis by manipulating either the biochemical state of cancer cells or the dynamics of signal transduction.

[Physiological response to acetic acid stress of Acetobacter pasteuranus during vinegar fermentation]

OBJECTIVE

The aim of the study is to propose a dynamic acetic acid resistance mechanism through analysis on response of cellular morphology, physiology and metabolism of A. pasteurianus CICIM B7003 during vinegar fermentation.

METHODS

Vinegar fermentation was carried out in a Frings 9 L acetator by strain B7003 and cultures were sampled at different cellular growth phases. Simultaneously, percentage of capsular polysaccharide versus dry cells weight, ratio of unsaturated fatty acids to saturated fatty acids, transcription of acetic acid resistance genes, activity of alcohol respiratory chain enzymes and ATPase were detected for these samples to assay the responses of bacterial morphology, physiology and metabolism.

RESULTS

When acetic acid was existed, no obvious capsular polysaccharide was secreted by cells. As vinegar fermentation proceeding, percentage of capsular polysaccharide versus dry cells weight was reduced from 2.5% to 0.89%. Ratio of unsaturated fatty acids to saturated fatty acids was increased obviously which can improve membrane fluidity. Also transcription level of acetic acid resistance genes was promoted. Interestingly, activity of alcohol respiratory chain and ATPase was not inhibited but promoted obviously with acetic acid accumulation which could provide enough energy for acetic acid resistance mechanism.

CONCLUSION

On the basis of the results obtained from the experiment, A. pasteurianus CICIM B7003 relies mainly on the cooperation of changes of extracellular capsular polysaccharide and membrane fatty acids, activation of acid resistance genes transcription, enhancement of activity of alcohol respiratory chain and rapid energy production to tolerate acidic environment.

Spectral measurement of electron antineutrino oscillation amplitude and frequency at Daya Bay

A measurement of the energy dependence of antineutrino disappearance at the Daya Bay reactor neutrino experiment is reported. Electron antineutrinos (ν¯(e)) from six 2.9  GW(th) reactors were detected with six detectors deployed in two near (effective baselines 512 and 561 m) and one far (1579 m) underground experimental halls. Using 217 days of data, 41 589 (203 809 and 92 912) antineutrino candidates were detected in the far hall (near halls). An improved measurement of the oscillation amplitude sin(2)2θ(13)=0.090(-0.009)(+0.008) and the first direct measurement of the ν¯(e) mass-squared difference |Δm(ee)2|=(2.59(-0.20)(+0.19))×10(-3)  eV2 is obtained using the observed ν¯(e) rates and energy spectra in a three-neutrino framework. This value of |Δm(ee)2| is consistent with |Δm(μμ)2| measured by muon neutrino disappearance, supporting the three-flavor oscillation model.

Bioinformatics analysis of gene expression profiles in the rat cerebral cortex following traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a serious neurodisorder commonly caused by sports related events or violence. It is the leading cause of disability in people under 40.

AIM

In order to elucidate the molecular mechanism of the secondary injury after TBI.

MATERIALS AND METHODS

In this study, we downloaded gene expression profile on TBI model with sham controls for gene set enrichment analysis and pathway analysis.

RESULTS

At a q-value of 5%, 361 genes were up-regulated and 373 were down-regulated in samples obtained at 48 hours after TBI. Functional analyses revealed that steroid biosynthesis, cell cycle, metal ion transport, inflammation and apoptosis were significantly dysregulated during the late period after trauma. In addition, MAPK3 (mitogen-activated protein kinase 3), was identified as the hub node in the protein-protein interaction (PPI) network constructed by the differentially expressed genes (DEGs).

CONCLUSIONS

Further elucidation of genes and proteins in our study may reveal their potential as novel therapeutic targets.

Androgens regulate prostate cancer cell growth via an AMPK-PGC-1α-mediated metabolic switch

Prostate cancer is the most commonly diagnosed malignancy among men in industrialized countries, accounting for the second leading cause of cancer-related deaths. Although we now know that the androgen receptor (AR) is important for progression to the deadly advanced stages of the disease, it is poorly understood what AR-regulated processes drive this pathology. Here we demonstrate that AR regulates prostate cancer cell growth via the metabolic sensor 5'-AMP-activated protein kinase (AMPK), a kinase that classically regulates cellular energy homeostasis. In patients, activation of AMPK correlated with prostate cancer progression. Using a combination of radiolabeled assays and emerging metabolomic approaches, we also show that prostate cancer cells respond to androgen treatment by increasing not only rates of glycolysis, as is commonly seen in many cancers, but also glucose and fatty acid oxidation. Importantly, this effect was dependent on androgen-mediated AMPK activity. Our results further indicate that the AMPK-mediated metabolic changes increased intracellular ATP levels and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α)-mediated mitochondrial biogenesis, affording distinct growth advantages to the prostate cancer cells. Correspondingly, we used outlier analysis to determine that PGC-1α is overexpressed in a subpopulation of clinical cancer samples. This was in contrast to what was observed in immortalized benign human prostate cells and a testosterone-induced rat model of benign prostatic hyperplasia. Taken together, our findings converge to demonstrate that androgens can co-opt the AMPK-PGC-1α signaling cascade, a known homeostatic mechanism, to increase prostate cancer cell growth. The current study points to the potential utility of developing metabolic-targeted therapies directed toward the AMPK-PGC-1α signaling axis for the treatment of prostate cancer.