2,024 research outputs found
Nonequilibrium thermodynamics as a symplecto-contact reduction and relative information entropy
Both statistical phase space (SPS), which is of
-body particle system, and kinetic theory phase space (KTPS), which is the
cotangent bundle of the probability space thereon, carry canonical symplectic structures. Starting from this
first principle, we provide a canonical derivation of thermodynamic phase space
(TPS) of nonequilibrium thermodynamics as a contact manifold in two steps.
First, regarding the collective observation of observables in SPS as a moment
map defined on KTPS, we apply the Marsden-Weinstein reduction and obtain a
mesoscopic phase space in between KTPS and TPS as a (infinite dimensional)
symplectic fibration. Then we show that the reduced relative information
entropy defines a generating function that provides a covariant construction of
a thermodynamic equilibrium as a Legendrian submanifold. This Legendrian
submanifold is not necessarily graph-like. We interpret the Maxwell
construction of \emph{equal-area law} as the procedure of finding a continuous,
not necessarily differentiable, thermodynamic potential and explain the
associated phase transition by identifying the procedure with that of finding a
graph selector in symplecto-contact geometry and in the Aubry-Mather theory of
dynamical system.Comment: v4) 53 pages, presentation and English much improved, new references
added, v5) 59 pages, the accepted version in Reports on Math. Physic
Sodium-Glucose Cotransporter-2 Inhibitors Ameliorate Liver Enzyme Abnormalities in Korean Patients With Type 2 Diabetes Mellitus and Nonalcoholic Fatty Liver Disease
Sodium-glucose cotransporter-2 inhibitors (SGLT2is) are reported to reduce body fat in patients with type 2 diabetes mellitus (T2DM), and SGLT2i-induced weight reduction may help improve comorbid nonalcoholic fatty liver disease (NAFLD). This study aimed to investigate the potential benefit of SGLT2is over other oral antidiabetic drugs (OADs) in patients with T2DM-associated NAFLD. We enrolled real-world Korean patients with T2DM-associated NAFLD in whom initial metformin therapy had been modified by stepwise addition of OAD(s) due to insufficient glucose control. Propensity score (PS) matching was used for the comparison of changes in clinical and biochemical parameters to balance potential covariates. Among the 765 enrolled patients, 663 patients received additional OADs other than SGLT2i and 102 patients received SGLT2i therapy. PS matching selected 150 and 100 patients from the control and the SGLT2i group, respectively. The SGLT2i group lost more weight than the control group at 6 months (mean –1.3 kg vs. 0.0 kg; P < 0.001). Alanine aminotransferase (ALT) levels also decreased more in the SGLT2i group at 3 (–11 U/L vs. –1 U/L), 6 (–12 U/L vs. –1 U/L), and 12 months (–14 U/L vs. –2 U/L) (all P < 0.05). Addition of SGLT2is was an independent predictor of ALT improvement in a multivariate logistic regression model (odds ratio 1.91; P = 0.016). Compared with other OADs, addition of SGLT2is was more effective in weight reduction and ALT improvement in patients with T2DM and comorbid NAFLD
Characterization of the ATP transporter in the reconstituted rough endoplasmic reticulum proteoliposomes
AbstractAdenosine triphosphate (ATP) transporter from rat liver rough endoplasmic reticulum (RER) was solubilized and reconstituted into phosphatidylcholine liposomes. The RER proteoliposomes, resulting from optimizing some reconstitution parameters, had an apparent Km value of 1.5 μM and a Vmax of 286 pmol min−1 (mg protein)−1 and showed higher affinity for ATP and a lower Vmax value than intact RER (Km of 6.5 μM and Vmax of 1 nmol). ATP transport was time- and temperature-dependent, inhibited by 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid, which is known as an inhibitor of anion transporters including ATP transporter, but was not affected by atractyloside, a specific inhibitor of mitochondrial ADP/ATP carrier. The internal and external effects of various nucleotides on the ATP transport were examined. ATP transport was cis-inhibited strongly by ADP and weakly by AMP. ADP-preloaded RER proteoliposomes showed a specific increase of ATP transport activity while AMP-preloaded RER proteoliposomes did not show the enhanced overshoot peak in the ATP uptake plot. These results demonstrate the ADP/ATP antiport mechanism of ATP transport in rat liver RER
Laparoscopic low anterior resection for hematogenous rectal metastasis from gastric adenocarcinoma: A Case Report
<p>Abstract</p> <p>Background</p> <p>Gastric cancer is one of the most common malignancies in the world and is the second most common cause of cancer-related death in Korea. Colorectal metastases from gastric adenocarcinoma are known to be very rare. We report an unusual case of rectal metastasis of gastric adenocarcinoma.</p> <p>Case presentation</p> <p>We report a case of a 43-year-old female patient with gastric cancer who first presented with epigastric pain. The endoscopic and radiologic findings were suggestive of Borrmann type III advanced gastric cancer with linitis plastica. Radical total gastrectomy with D2 lymph node dissection was performed. The pathology report was AJCC TNM Stage II gastric adenocarcinoma (T3N0M0). On follow up at 34 months after surgery, the patient complained of difficulty in defecation. On colonoscopy, a hard, indurated extraluminal mass was detected 7 cm proximal to the anal verge. The biopsy demonstrated chronic nonspecific colitis. Abdominal CT, rectal MRI and PET-CT revealed rectal metastasis from gastric cancer. Laparoscopic ultralow anterior resection with diverting ileostomy was performed. The pathology report was metastatic adenocarcinoma, and this diagnosis was identical to the gastric pathology reported in the previous pathology report. The patient was discharged after the 11<sup>th </sup>postoperative day with no adverse events.</p> <p>Conclusion</p> <p>Rectal metastasis from gastric cancer is known to be very rare. However, metastatic gastric adenocarcinoma should be considered as a differential diagnosis for patients presenting with a colorectal mass and a past history of gastric cancer.</p
Temperature dependence of Mott transition in VO_2 and programmable critical temperature sensor
The temperature dependence of the Mott metal-insulator transition (MIT) is
studied with a VO_2-based two-terminal device. When a constant voltage is
applied to the device, an abrupt current jump is observed with temperature.
With increasing applied voltages, the transition temperature of the MIT current
jump decreases. We find a monoclinic and electronically correlated metal (MCM)
phase between the abrupt current jump and the structural phase transition
(SPT). After the transition from insulator to metal, a linear increase in
current (or conductivity) is shown with temperature until the current becomes a
constant maximum value above T_{SPT}=68^oC. The SPT is confirmed by micro-Raman
spectroscopy measurements. Optical microscopy analysis reveals the absence of
the local current path in micro scale in the VO_2 device. The current uniformly
flows throughout the surface of the VO_2 film when the MIT occurs. This device
can be used as a programmable critical temperature sensor.Comment: 4 pages, 3 figure
Two distinct red giant branch populations in the globular cluster NGC 2419 as tracers of a merger event in the Milky Way
Recent spectroscopic observations of the outer halo globular cluster (GC) NGC
2419 show that it is unique among GCs, in terms of chemical abundance patterns,
and some suggest that it was originated in the nucleus of a dwarf galaxy. Here
we show, from the Subaru narrow-band photometry employing a calcium filter,
that the red giant-branch (RGB) of this GC is split into two distinct
subpopulations. Comparison with spectroscopy has confirmed that the redder RGB
stars in the [=(Ca] index are enhanced in [Ca/H] by 0.2
dex compared to the bluer RGB stars. Our population model further indicates
that the calcium-rich second generation stars are also enhanced in helium
abundance by a large amount (Y = 0.19). Our photometry, together with
the results for other massive GCs (e.g., Cen, M22, and NGC 1851),
suggests that the discrete distribution of RGB stars in the index might be
a universal characteristic of this growing group of peculiar GCs. The planned
narrow-band calcium photometry for the Local Group dwarf galaxies would help to
establish an empirical connection between these GCs and the primordial building
blocks in the hierarchical merging paradigm of galaxy formation.Comment: 4 pages, 4 figures, 1 table, accepted for the publication in ApJ
- …