Ocean warming-acidification synergism undermines dissolved organic matter assembly.

Understanding the influence of synergisms on natural processes is a critical step toward determining the full-extent of anthropogenic stressors. As carbon emissions continue unabated, two major stressors--warming and acidification--threaten marine systems on several scales. Here, we report that a moderate temperature increase (from 30°C to 32°C) is sufficient to slow--even hinder--the ability of dissolved organic matter, a major carbon pool, to self-assemble to form marine microgels, which contribute to the particulate organic matter pool. Moreover, acidification lowers the temperature threshold at which we observe our results. These findings carry implications for the marine carbon cycle, as self-assembled marine microgels generate an estimated global seawater budget of ~1016 g C. We used laser scattering spectroscopy to test the influence of temperature and pH on spontaneous marine gel assembly. The results of independent experiments revealed that at a particular point, both pH and temperature block microgel formation (32°C, pH 8.2), and disperse existing gels (35°C). We then tested the hypothesis that temperature and pH have a synergistic influence on marine gel dispersion. We found that the dispersion temperature decreases concurrently with pH: from 32°C at pH 8.2, to 28°C at pH 7.5. If our laboratory observations can be extrapolated to complex marine environments, our results suggest that a warming-acidification synergism can decrease carbon and nutrient fluxes, disturbing marine trophic and trace element cycles, at rates faster than projected

Human stem cell neuronal differentiation on silk-carbon nanotube composite

Human embryonic stem cells [hESCs] are able to differentiate into specific lineages corresponding to regulated spatial and temporal signals. This unique attribute holds great promise for regenerative medicine and cell-based therapy for many human diseases such as spinal cord injury [SCI] and multiple sclerosis [MS]. Carbon nanotubes [CNTs] have been successfully used to promote neuronal differentiation, and silk has been widely applied in tissue engineering. This study aims to build silk-CNT composite scaffolds for improved neuron differentiation efficiency from hESCs

Ectopy on a single 12‐lead ECG, incident cardiac myopathy, and death in the community

BackgroundAtrial fibrillation and heart failure are 2 of the most common diseases, yet ready means to identify individuals at risk are lacking. The 12-lead ECG is one of the most accessible tests in medicine. Our objective was to determine whether a premature atrial contraction observed on a standard 12-lead ECG would predict atrial fibrillation and mortality and whether a premature ventricular contraction would predict heart failure and mortality.Methods and resultsWe utilized the CHS (Cardiovascular Health) Study, which followed 5577 participants for a median of 12 years, as the primary cohort. The ARIC (Atherosclerosis Risk in Communities Study), the replication cohort, captured data from 15 792 participants over a median of 22 years. In the CHS, multivariable analyses revealed that a baseline 12-lead ECG premature atrial contraction predicted a 60% increased risk of atrial fibrillation (hazard ratio, 1.6; 95% CI, 1.3-2.0; P<0.001) and a premature ventricular contraction predicted a 30% increased risk of heart failure (hazard ratio, 1.3; 95% CI, 1.0-1.6; P=0.021). In the negative control analyses, neither predicted incident myocardial infarction. A premature atrial contraction was associated with a 30% increased risk of death (hazard ratio, 1.3; 95% CI, 1.1-1.5; P=0.008) and a premature ventricular contraction was associated with a 20% increased risk of death (hazard ratio, 1.2; 95% CI, 1.0-1.3; P=0.044). Similarly statistically significant results for each analysis were also observed in ARIC.ConclusionsBased on a single standard ECG, a premature atrial contraction predicted incident atrial fibrillation and death and a premature ventricular contraction predicted incident heart failure and death, suggesting that this commonly used test may predict future disease

The Expression and Localization of N-Myc Downstream-Regulated Gene 1 in Human Trophoblasts

The protein N-Myc downstream-regulated gene 1 (NDRG1) is implicated in the regulation of cell proliferation, differentiation, and cellular stress response. NDRG1 is expressed in primary human trophoblasts, where it promotes cell viability and resistance to hypoxic injury. The mechanism of action of NDRG1 remains unknown. To gain further insight into the intracellular action of NDRG1, we analyzed the expression pattern and cellular localization of endogenous NDRG1 and transfected Myc-tagged NDRG1 in human trophoblasts exposed to diverse injuries. In standard conditions, NDRG1 was diffusely expressed in the cytoplasm at a low level. Hypoxia or the hypoxia mimetic cobalt chloride, but not serum deprivation, ultraviolet (UV) light, or ionizing radiation, induced the expression of NDRG1 in human trophoblasts and the redistribution of NDRG1 into the nucleus and cytoplasmic membranes associated with the endoplasmic reticulum (ER) and microtubules. Mutation of the phosphopantetheine attachment site (PPAS) within NDRG1 abrogated this pattern of redistribution. Our results shed new light on the impact of cell injury on NDRG1 expression patterns, and suggest that the PPAS domain plays a key role in NDRG1's subcellular distribution. © 2013 Shi et al

DNA Checkpoint and Repair Factors Are Nuclear Sensors for Intracellular Organelle Stresses-Inflammations and Cancers Can Have High Genomic Risks.

Under inflammatory conditions, inflammatory cells release reactive oxygen species (ROS) and reactive nitrogen species (RNS) which cause DNA damage. If not appropriately repaired, DNA damage leads to gene mutations and genomic instability. DNA damage checkpoint factors (DDCF) and DNA damage repair factors (DDRF) play a vital role in maintaining genomic integrity. However, how DDCFs and DDRFs are modulated under physiological and pathological conditions are not fully known. We took an experimental database analysis to determine the expression of 26 DNA D

Peritoneal and hemodialysis: I. Differences in patient characteristics at initiation

Peritoneal and hemodialysis: I. Differences in patient characteristics at initiation.BackgroundComparisons of mortality outcomes between peritoneal dialysis (PD) and hemodialysis (HD) patients have shown varying results, which may be caused by the unequally distributed clinical conditions of patients at initiation. To address this issue, we evaluated the clinical characteristics of 105,954 patients at the initiation of PD and HD, using the U.S. national incidence data on treated end-stage renal disease from the Medical Evidence Form, 1995 to 1997.MethodsA general linear model was used to analyze differences of age, albumin, creatinine, blood urea nitrogen (BUN), and hematocrit; categorical data analysis to evaluate body mass index (BMI), grouped into four categories: !19, 19–25 (!25), 25–30 (!30), and 30+; and logistic regression to assess the likelihood of initiating PD versus HD. Diabetics (DM) were analyzed separately from non-diabetics (NDM). Explanatory variables in the logistic regression included incidence year, race, gender, age, BMI, albumin, creatinine, BUN, and hematocrit. Race included white and black. Age was categorized into four groups: 20–44, 45–64, 65–74, and 75+.ResultsAt the initiation of dialysis PD patients were approximately 6 years younger (P ! 0.0001) than HD patients. PD patients also had higher (P ! 0.0001) albumin (+0.35 g/dL for DM and +0.23 g/dL for NDM) and hematocrit (+1.64% for DM and +1.71% for NDM) levels, and lower (P ! 0.04) BUN (-8.75 mg/dL for DM and -5.24 mg/dL for NDM) and creatinine (-0.51 mg/dL for DM and -0.23 mg/dL for NDM) levels than HD patients. Whites had a higher (P ! 0.0001) likelihood of starting PD than blacks, and patients with BMI !19 had a lower (P ! 0.0001) chance of beginning on PD.ConclusionPD patients had favorable clinical conditions at the initiation of dialysis, which should be taken into consideration when comparing dialysis outcomes between the two modalities

Mean-atom-trajectory model for the velocity autocorrelation function of monatomic liquids

We present a model for the motion of an average atom in a liquid or supercooled liquid state and apply it to calculations of the velocity autocorrelation function $Z(t)$ and diffusion coefficient $D$. The model trajectory consists of oscillations at a distribution of frequencies characteristic of the normal modes of a single potential valley, interspersed with position- and velocity-conserving transits to similar adjacent valleys. The resulting predictions for $Z(t)$ and $D$ agree remarkably well with MD simulations of Na at up to almost three times its melting temperature. Two independent processes in the model relax velocity autocorrelations: (a) dephasing due to the presence of many frequency components, which operates at all temperatures but which produces no diffusion, and (b) the transit process, which increases with increasing temperature and which produces diffusion. Because the model provides a single-atom trajectory in real space and time, including transits, it may be used to calculate all single-atom correlation functions.Comment: LaTeX, 8 figs. This is an updated version of cond-mat/0002057 and cond-mat/0002058 combined Minor changes made to coincide with published versio

Mesons with Beauty and Charm: Spectroscopy

Applying knowledge of the interaction between heavy quarks derived from the study of $c\overline{c}$ and $b\overline{b}$ bound states, we calculate the spectrum of $c\overline{b}$ mesons. We compute transition rates for the electromagnetic and hadronic cascades that lead from excited states to the $^1\text{S}_0$ ground state, and briefly consider the prospects for experimental observation of the spectrum.Comment: 32 pages + 2 uuencoded PostScript figures Fermilab-Pub-94/032-

Maintenance treatment with quetiapine versus discontinuation after one year of treatment in patients with remitted first episode psychosis: randomised controlled trial

Objective To study rates of relapse in remitted patients with first episode psychosis who either continued or discontinued antipsychotic drugs after at least one year of maintenance treatment