4,930 research outputs found

    Solar Wind and its Evolution

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    By using our previous results of magnetohydrodynamical simulations for the solar wind from open flux tubes, I discuss how the solar wind in the past is different from the current solar wind. The simulations are performed in fixed one-dimensional super-radially open magnetic flux tubes by inputing various types of fluctuations from the photosphere, which automatically determines solar wind properties in a forward manner. The three important parameters which determine physical properties of the solar wind are surface fluctuation, magnetic field strengths, and the configuration of magnetic flux tubes. Adjusting these parameters to the sun at earlier times in a qualitative sense, I infer that the quasi-steady-state component of the solar wind in the past was denser and slightly slower if the effect of the magneto-centrifugal force is not significant. I also discuss effects of magneto-centrifugal force and roles of coronal mass ejections.Comment: 6 pages, 1 figure, Earth, Planets, & Space in press (based on 5th Alfven Conference) correction of discussion on a related pape

    Bone mineral content after renal transplantation

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    Forearm bone mineral content (BMC), as evaluated by photonabsorption densitometry, was measured in 28 cadaver kidney donor recipients who entered the study 8 weeks postoperatively and were followed up for 18 months. BMC decreased signifiantly (p<0.05) but marginally in placebo-treated patients (n=14) (initial BMC 1.09±0.25 g/cm; final BMC 1.05±0.24). Fourteen patients were prophylactically given 1,25(OH)2vitamin D3 in a dose which avoided hypercalcemia and hypercalciuria (sim0.25 µg/day); under 1,25(OH)2 vitamin D3 prophylaxis a significant decrease of forearm BMC was observed no longer (initial BMC 0.94±0.21 g/cm; final BMC 0.95±0.21), but the difference between placebo and 1,25(OH)2 vitamin D3 narrowly missed statistical significance (p=0.066). It is concluded that the decrease of forearm BMC is negligible in transplant recipients with low steroid regimens. The data suggest a trend for prophylaxis with 1,25(OH)2 vitamin D3 to slightly ameliorate forearm (cortical) BMC loss

    Genome-wide DNA methylation analysis for diabetic nephropathy in type 1 diabetes mellitus

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    BACKGROUND: Diabetic nephropathy is a serious complication of diabetes mellitus and is associated with considerable morbidity and high mortality. There is increasing evidence to suggest that dysregulation of the epigenome is involved in diabetic nephropathy. We assessed whether epigenetic modification of DNA methylation is associated with diabetic nephropathy in a case-control study of 192 Irish patients with type 1 diabetes mellitus (T1D). Cases had T1D and nephropathy whereas controls had T1D but no evidence of renal disease. METHODS: We performed DNA methylation profiling in bisulphite converted DNA from cases and controls using the recently developed Illumina Infinium(R) HumanMethylation27 BeadChip, that enables the direct investigation of 27,578 individual cytosines at CpG loci throughout the genome, which are focused on the promoter regions of 14,495 genes. RESULTS: Singular Value Decomposition (SVD) analysis indicated that significant components of DNA methylation variation correlated with patient age, time to onset of diabetic nephropathy, and sex. Adjusting for confounding factors using multivariate Cox-regression analyses, and with a false discovery rate (FDR) of 0.05, we observed 19 CpG sites that demonstrated correlations with time to development of diabetic nephropathy. Of note, this included one CpG site located 18 bp upstream of the transcription start site of UNC13B, a gene in which the first intronic SNP rs13293564 has recently been reported to be associated with diabetic nephropathy. CONCLUSION: This high throughput platform was able to successfully interrogate the methylation state of individual cytosines and identified 19 prospective CpG sites associated with risk of diabetic nephropathy. These differences in DNA methylation are worthy of further follow-up in replication studies using larger cohorts of diabetic patients with and without nephropathy

    Absence of sign problem in two-dimensional N=(2,2) super Yang-Mills on lattice

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    We show that N=(2,2) SU(N) super Yang-Mills theory on lattice does not have sign problem in the continuum limit, that is, under the phase-quenched simulation phase of the determinant localizes to 1 and hence the phase-quench approximation becomes exact. Among several formulations, we study models by Cohen-Kaplan-Katz-Unsal (CKKU) and by Sugino. We confirm that the sign problem is absent in both models and that they converge to the identical continuum limit without fine tuning. We provide a simple explanation why previous works by other authors, which claim an existence of the sign problem, do not capture the continuum physics.Comment: 27 pages, 24 figures; v2: comments and references added; v3: figures on U(1) mass independence and references added, to appear in JHE

    Expressing one’s feelings and listening to others increases emotional intelligence: a pilot study of Asian medical students

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    &lt;p&gt;Background: There has been considerable interest in Emotional Intelligence (EI) in undergraduate medical education, with respect to student selection and admissions, health and well-being and academic performance. EI is a significant component of the physician-patient relationship. The emotional well-being of the physician is, therefore, a significant component in patient care. The aim is to examine the measurement of TEIQue-SF in Asian medical students and to explore how the practice of listening to the feelings of others and expressing one’s own feelings influences an individual’s EI, set in the context of the emotional well-being of a medical practitioner.&lt;/p&gt; &lt;p&gt;Methods: A group of 183 international undergraduate medical students attended a half-day workshop (WS) about mental-health and well-being. They completed a self-reported measure of EI on three occasions, pre- and post-workshop, and a 1-year follow-up.&lt;/p&gt; &lt;p&gt;Result: The reliability of TEIQue-SF was high and the reliabilities of its four factors were acceptable. There were strong correlations between the TEIQue-SF and personality traits. A paired t-test indicated significant positive changes after the WS for all students (n=181, p= .014), male students (n=78, p= .015) and non-Japanese students (n=112, p= .007), but a repeated measures analysis showed that one year post-workshop there were significant positive changes for all students (n=55, p= .034), female students (n=31, p= .007), especially Japanese female students (n=13, p= .023). Moreover, 80% of the students reported that they were more attentive listeners, and 60% agreed that they were more confident in dealing with emotional issues, both within themselves and in others, as a result of the workshop.&lt;/p&gt; &lt;p&gt;Conclusion: This study found the measurement of TEIQue-SF is appropriate and reliable to use for Asian medical students. The mental health workshop was helpful to develop medical students’ EI but showed different results for gender and nationality. The immediate impact on the emotional awareness of individuals was particularly significant for male students and the non-Japanese group. The impact over the long term was notable for the significant increase in EI for females and Japanese. Japanese female students were more conscious about emotionality. Emotion-driven communication exercises might strongly influence the development of students’ EI over a year.&lt;/p&gt

    Mucinous cystic neoplasm of the pancreas in a male patient

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    Mucinous cystic neoplasms (MCNs) make up a morphologic family of similar appearing tumors arising in the ovary and various extraovarian organs such as pancreas, hepatobiliary tract and mesentery. MCNs of the pancreas occur almost exclusively in women. Here, we report a rare case of MCN in a male patient. A 39-year-old man was admitted to our hospital with the chief complaint of back pain. Abdominal computed tomography revealed a multilocular cyctic mass 6.3 cm in diameter in the pancreatic tail. In addition, the outer wall and septae with calcification were demonstrated in the cystic lesion. On magnetic resonance imaging , the cystic fluid had low intensity on T1-weighted imaging and high intensity on T2-weighted imaging. Endoscopic retrograde cholangio-pancreatography (ERCP) showed neither communication between the cystic lesion and the main pancreatic duct nor encasement of the main pancreatic duct. Endoscopic ultrasonography revealed neither solid component nor thickness of the septae in the cystic lesion. Consequently, we performed distal pancreatectomy with splenectomy under the diagnosis of cystic neoplasia of the pancreas. Histopathologically, the cystic lesion showed two distinct component: an inner epithelial layer and an outer densely cellular ovarian-type stromal layer. Based on these findings, the cystic lesion was diagnosed as MCN

    Altered metabolism in cancer

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    Cancer cells have different metabolic requirements from their normal counterparts. Understanding the consequences of this differential metabolism requires a detailed understanding of glucose metabolism and its relation to energy production in cancer cells. A recent study in BMC Systems Biology by Vasquez et al. developed a mathematical model to assess some features of this altered metabolism. Here, we take a broader look at the regulation of energy metabolism in cancer cells, considering their anabolic as well as catabolic needs

    Intragenic DNA methylation: implications of this epigenetic mechanism for cancer research

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    Epigenetics is the study of all mechanisms that regulate gene transcription and genome stability that are maintained throughout the cell division, but do not include the DNA sequence itself. The best-studied epigenetic mechanism to date is DNA methylation, where methyl groups are added to the cytosine base within cytosine–guanine dinucleotides (CpG sites). CpGs are frequently clustered in high density (CpG islands (CGIs)) at the promoter of over half of all genes. Current knowledge of transcriptional regulation by DNA methylation centres on its role at the promoter where unmethylated CGIs are present at most actively transcribed genes, whereas hypermethylation of the promoter results in gene repression. Over the last 5 years, research has gradually incorporated a broader understanding that methylation patterns across the gene (so-called intragenic or gene body methylation) may have a role in transcriptional regulation and efficiency. Numerous genome-wide DNA methylation profiling studies now support this notion, although whether DNA methylation patterns are a cause or consequence of other regulatory mechanisms is not yet clear. This review will examine the evidence for the function of intragenic methylation in gene transcription, and discuss the significance of this in carcinogenesis and for the future use of therapies targeted against DNA methylation

    Acute WNT signalling activation perturbs differentiation within the adult stomach and rapidly leads to tumour formation

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    A role for WNT signalling in gastric carcinogenesis has been suggested due to two major observations. First, patients with germline mutations in adenomatous polyposis coli (APC) are susceptible to stomach polyps and second, in gastric cancer, WNT activation confers a poor prognosis. However, the functional significance of deregulated WNT signalling in gastric homoeostasis and cancer is still unclear. In this study we have addressed this by investigating the immediate effects of WNT signalling activation within the stomach epithelium. We have specifically activated the WNT signalling pathway within the mouse adult gastric epithelium via deletion of either glycogen synthase kinase 3 (GSK3) or APC or via expression of a constitutively active β-catenin protein. WNT pathway deregulation dramatically affects stomach homoeostasis at very short latencies. In the corpus, there is rapid loss of parietal cells with fundic gland polyp (FGP) formation and adenomatous change, which are similar to those observed in familial adenomatous polyposis. In the antrum, adenomas occur from 4 days post-WNT activation. Taken together, these data show a pivotal role for WNT signalling in gastric homoeostasis, FGP formation and adenomagenesis. Loss of the parietal cell population and corresponding FGP formation, an early event in gastric carcinogenesis, as well as antral adenoma formation are immediate effects of nuclear β-catenin translocation and WNT target gene expression. Furthermore, our inducible murine model will permit a better understanding of the molecular changes required to drive tumourigenesis in the stomach
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