Fluctuation in e-mail sizes weakens power-law correlations in e-mail flow

Power-law correlations have been observed in packet flow over the Internet. The possible origin of these correlations includes demand for Internet services. We observe the demand for e-mail services in an organization, and analyze correlations in the flow and the sequence of send requests using a Detrended Fluctuation Analysis (DFA). The correlation in the flow is found to be weaker than that in the send requests. Four types of artificial flow are constructed to investigate the effects of fluctuations in e-mail sizes. As a result, we find that the correlation in the flow originates from that in the sequence of send requests. The strength of the power-law correlation decreases as a function of the ratio of the standard deviation of e-mail sizes to their average.Comment: 8 pages, 6 figures, EPJB accepte

Negative Resistance in Semiconductors (InSb)

We extend the theory of double injection in insulators, derived by Lampert, so as to adapt it to the case of extrinsic semiconductors. This new treatment is shown to agree reasonably well with our experimentally observed features for n⁺p-InSb diodes at low temperature (77°K). Three outstanding features are revealed by the present analysis : (1) The relation of Vᴍ=(1/β)·VᴛH pointed out by Lampert is available only in the case that the recombination density NR is much larger than the free carrier density P₀ (or N₀), i.e., NR>l0⁵·P₀, where Vᴍ and VᴛH are the minimum and maximum voltages respectively, β is the capture rate for electrons and holes. (2) The greater the capture rate β is, the greater the region of the negative resistance becomes. In semiconductors, however, the magnitude of the region is vigorously depedent on a modified recombination density R=NR/P₀ (or NR/N₀). (3) The value of the mobility ratio b=μₙ/μₚ is concerned with a rise in the semicoductor region, and the relation of J∝V² is satisfactory, if b<lO. In the material with high mobility as a case of InSb, however, the current rises steeply in proportion to the several powers of the voltage, e.g. J∝ V⁴, when b=50. As above mentioned, we can sufficiently explain the behavior of double injection in semiconductors or insulators by this treatment

Compensatory Thrombopoietin Production from the Liver and Bone Marrow Stimulates Thrombopoiesis of Living Rat Megakaryocytes in Chronic Renal Failure

Background/Aims: Decreased thrombopoiesis has been ascribed a role in the pathogenesis of uremic bleeding in chronic renal failure (CRF). However, serum thrombopoietin (TPO) levels are usually elevated in CRF patients, suggesting increased thrombopoiesis. The aim of this study was to determine the thrombopoietic activity in CRF. Methods: Male Sprague-Dawley rats that underwent 5/6 nephrectomy were used as the model of CRF. Age-matched sham-operated rats were used as controls. Single megakaryocytes were isolated from the rat bone marrow, and their size distribution was examined. Megakaryocyte membrane invaginations were monitored by confocal imaging of di-8-ANEPPS staining, and patch clamp whole-cell recordings of membrane capacitance. TPO gene expression was assessed in various tissues. Results: Circulating platelet counts and the number of large megakaryocytes were increased in the bone marrow of CRF rats. Massive di-8-ANEPPS staining and increased membrane capacitance in large megakaryocytes demonstrated increased membrane invaginations. Unaffected Kv1.3-channel currents per cell surface area demonstrated unaltered channel densities. TPO transcription was decreased in the renal cortex but increased in the liver and bone marrow of CRF rats. Conclusion: Increased thrombopoiesis in CRF was thought to be a reactive mechanism to platelet dysfunction. Increased TPO production from the liver and bone marrow compensated for decreased production from damaged kidneys

Impact of phase angle on postoperative prognosis

Objective Phase angle (PhA), by bioelectrical impedance analysis, has been used in patients with several diseases; however, its prognostic value in patients with gastrointestinal and hepatobiliary–pancreatic (HBP) cancer is unclear. The present study aimed to investigate the impact of PhA on postoperative short-term outcomes and long-term survival in these patients. Research Methods & Procedures This retrospective study reviewed data of 501 patients with gastrointestinal and HBP cancers who underwent first resection surgery and divided the data into the following groups according to the preoperative PhA quartile values by sex: high-PhA group with the highest quartile (Q4), normal-PhA group with middle quartiles (Q3 and Q2), and low-PhA group with the lowest quartile (Q1). Preoperative nutritional statuses, postoperative short-term outcomes during hospitalization, and 5-year survival between three groups were compared. Cox proportional hazard models were used to evaluate the prognostic effect of PhA. Results PhA positively correlated with body weight, skeletal muscle mass, and handgrip strength, and negatively correlated with age and C-reactive protein levels. The low-PhA group showed a high prevalence of malnutrition (48%) than normal-PhA (25%), and high-PhA (9%) (P < 0.001). The incidence of postoperative severe complications was 10% in all patients [14% in low-PhA, 12% in normal-PhA, and 4% in high-PhA (P = 0.018)]. The incidence of prolonged postoperative high care unit or/and intensive care unit stays was 8% in all patients [16% in low-PhA, 8% in normal-PhA, and 2% in high-PhA (P < 0.001)]. The 5-year survival rate was 74% in all patients [68% in low-PhA, 74% in normal-PhA, and 79% in high-PhA (P < 0.001)]. The multivariate analysis demonstrated that a low-PhA group was an independent risk factor for mortality (hazard ratio, 1.99; 95% confidence interval 1.05–3.90; P = 0.034). Conclusion PhA is a useful short-term and long-term postoperative prognostic marker for patients with gastrointestinal and HBP cancers

Malnutrition by European Society for Clinical Nutrition and Metabolism criteria predicts prognosis in patients with gastrointestinal and hepatobiliary–pancreatic cancer

Background & Aims: The European Society for Clinical Nutrition and Metabolism (ESPEN) proposed the ESPEN diagnostic criteria (EDC) for malnutrition in 2015. There is no report on the association between the EDC and prognosis in patients with gastrointestinal (GI) and hepatobiliary–pancreatic (HBP) cancer. This study aimed to (1) determine the prevalence of EDC malnutrition, (2) investigate the validity of the EDC as a nutritional and prognostic indicator, and (3) examine which components of the EDC are most related to long-term prognosis in patients with GI and HBP cancers. Methods: A total of 634 patients with primary GI and HBP cancers who underwent their first resection surgery between July 2014 and March 2018 were retrospectively recruited. According to the EDC, patients were divided into malnourished and non-malnourished groups. Clinical parameters and survival between these two groups were compared. The prognostic effects of the EDC and the EDC components were analyzed using Cox proportional hazard models. Results: The prevalence of EDC malnutrition was 22%. Anthropometric data and biochemical data were associated with EDC malnutrition. The 5-year survival rate was lower in the malnourished group (72%) than in the non-malnourished group (73%; P = 0.007). The multivariate analysis demonstrated that the malnourished group was an independent risk factor for mortality (hazard ratio = 1.70 in the malnourished group; 95% confidence interval 1.08–2.63; P = 0.024). Among EDC components, body mass index (BMI) of <18.5 kg/m2 was an independent poor prognostic factor. Conclusions: EDC malnutrition is associated with poor postoperative long-term prognosis. Among the EDC components, BMI of <18.5 kg/m2 is most associated with prognosis in patients with preoperative GI and HBP cancers

A Dipeptidyl Peptidase-4 Inhibitor, Des-Fluoro-Sitagliptin, Improves Endothelial Function and Reduces Atherosclerotic Lesion Formation in Apolipoprotein E–Deficient Mice

ObjectivesThe aim of this study was to investigate the antiatherogenic effects of the dipeptidyl peptidase-4 inhibitor, des-fluoro-sitagliptin (DFS).BackgroundThe new class of anti–type 2 diabetes drugs, dipeptidyl peptidase-4 inhibitors, improves glucose metabolism by increasing levels of active glucagon-like peptide (GLP)-1.MethodsEndothelial function was examined by acetylcholine-induced endothelium-dependent vasorelaxation using aortic rings and atherosclerotic lesion development in the entire aorta in apolipoprotein E–deficient mice fed a high-fat diet with or without DFS, and the antiatherogenic effects of DFS were investigated in cultured human macrophages and endothelial cells. Plasma levels of active GLP-1 were measured in patients with or without coronary artery disease.ResultsDFS significantly improved endothelial dysfunction (89.9 ± 3.9% vs. 79.2 ± 4.3% relaxation at 10−4 mol/l acetylcholine, p < 0.05) associated with increased endothelial nitric oxide synthase phosphorylation and reduced atherosclerotic lesion area (17.7% [15.6% to 25.8%] vs. 24.6% [19.3% to 34.6%], p < 0.01) compared with vehicle treatment. In cultured human macrophages, DFS significantly increased GLP-1-induced cytosolic levels of cyclic adenosine monophosphate compared with GLP-1 alone, resulted in inhibiting phosphorylation of c-jun N-terminal kinase and extracellular signal-regulated kinase 1/2 and nuclear factor-kappa B p65 nuclear translocation through the cyclic adenosine monophosphate/protein kinase A pathway, and suppressed proinflammatory cytokines (i.e., interleukin-1-beta, interleukin-6, and tumor necrosis factor-alpha) and monocyte chemoattractant protein-1 production in response to lipopolysaccharide. DFS-enhanced GLP-1 activity sustained endothelial nitric oxide synthase phosphorylation and decreased endothelial senescence and apoptosis compared with GLP-1 alone. In the human study, fasting levels of active GLP-1 were significantly lower in patients with coronary artery disease than those without (3.10 pmol/l [2.40 to 3.62 pmol/l] vs. 4.00 pmol/l [3.10 to 5.90 pmol/l], p < 0.001).ConclusionsA DPP-4 inhibitor, DFS, exhibited antiatherogenic effects through augmenting GLP-1 activity in macrophages and endothelium