21,929 research outputs found
The effect of diabetes mellitus on portal blood hepatotrophic factors in dogs
Ten nondiabetic dogs were submitted to a procedure called splanchnic division which directed the nutrient rich venous return from the intestines into the left lobes of the liver and the hormone rich pancreatico gastroduodeno splenic venous return into the right lobes. Two mth later, the right lobes had undergone the expected gross and microscopic hypertrophy. Compared with the abnormal shrunken and glycogen depleted hepatocytes of the left lobes, the large and otherwise normal hepatocytes of the right lobes had a higher rate of cell division as judged by microscopic examination, measurements of deoxyribonucleic acid synthesis and the results of autoradiography. Both sides had greater cell replication than in the livers of normal unaltered dogs. The dominance of the right lobes following splanchnic division was almost completely eliminated by the prior creation of alloxan induced diabetes in 4 dogs and by the performance of total pancreatectomy at the same time as splanchnic division in 6 dogs. In these 10 diabetic dogs, which were treated with Sc administered insulin for the 2 mth period of the postoperative study, hepatic lobar and cell size were nearly equal on both sides. By light and electron microscopy, the hepatocytes on both sides had abnormalities, somewhat less pronounced on the right. However, the most active cell division was now transferred to the left lobes. The results with alloxan induced diabetes were similar to those after total pancreatectomy, except that lipid deposits were less on both liver sides in the alloxan experiments, and the glycogen was selectively reduced in the right lobes. The latter finding presumably was due to the continued action of glucagon in dogs made diabetic with alloxan. 12 nondiabetic dogs had a procedure called partial portacaval transposition which directed systemic venous blood from the hindquarters, kidneys and adrenal glands into the left lobes of the liver and the total splanchnic venous return into the right lobes. Two mth later, the degree of relative hypertrophy and hyperplasia of the glycogen rich right lobes was even greater than after splanchnic division, as was the morphologic damage to the left lobar hepatocytes. The degree of right lobar hypertrophy following partial portacaval transposition was reduced but not eliminated by pre existing alloxan induced diabetes in 4 dogs and by concomitant total pancreatectomy in 6 more dogs. The dogs were Sc treated with insulin. Structurally, the hepatocytes on the right side after 2 mth were in better condition than were those on the left, although both were abnormal. The dominance of cell division on the right side was reduced, as judged by standard microscopy and by autoradiography, but there was not a shifting of sides. The biochemical analyses reflected the presence or absence of glucagon. These findings are consistent with the earlier multifactorial hypothesis which holds that portal hepatotrophic factors are mainly interreacting hormones generated by splanchnic organs and delivered straight to the liver and that the hormone interrelationships might have augmented significance because of the high concentration of nutritional substrate in the same venous blood. The observations also substantiate by direct testing the suggestion that insulin is the most important hepatotrophic factor and that it profoundly affects many aspects of liver cell structure, division and function
Sphingosine mediates FTY720-induced apoptosis in LLC-PK1 cells
FTY720, a synthetic sphingoid base analog, was examined as a new sphingosine kinase inhibitor, which converts endogenous sphingosine into its phosphate form. With 20 ??M of FTY720, sphingosine accumulated in the LLC-PK1 cells in a time- and dose-dependent manner. The FTY720 treated cells showed a high concentration of fragmented DNA, a high caspase-3 like activity and TUNEL staining cells. It was also found that the sphingosine and sphinganine level increased in a time- and dose-dependent manner within 12 h after the FTY720 treatment. The sphingosine kinase activity was reduced by FTY720 as much as other sphingosine kinase inhibitors, N, N-dimethylsphingosine (DMS), dl-threo-dihydrosphingosine (DHS). The fragmented DNA content as a result of the 20 ??M of FTY720 treatment and by 5 ??M of the exogenously added BSA-sphingosine complex indicated typical apoptosis. Under similar conditions, the accumulated sphingosine concentration in all the cells was almost identical even though the sphingosine distribution inside the cells was somewhat different. These results indicate that the FTY720 induced apoptosis is associated with the inhibition of the sphingosine kinase activity and is strongly associated with the successive accumulation of sphingosine.open172
Prevalence of Anderson-Fabry disease in male patients with late onset hypertrophic cardiomyopathy
Background-Although studies have suggested that "late-onset" hypertrophic cardiomyopathy (HCM) may be caused by sarcomeric protein gene mutations, the cause of HCM in the majority of patients is unknown. This study determined the prevalence of a potentially treatable cause of hypertrophy, Anderson-Fabry disease, in a HCM referral population.Methods and Results-Plasma alpha-galactosidase A (alpha-Gal) was measured in 79 men with HCM who were diagnosed at greater than or equal to40 years of age (52.9 +/- 7.7 years; range, 40-71 years) and in 74 men who were diagnosed at <40 years (25.9 +/- 9.2 years; range, 8-39 years). Five patients (6.3%) with late-onset disease and 1 patient (1.4%) diagnosed at <40 years had low alpha-Gal activity. Of these 6 patients, 3 had angina, 4 were in New York Heart Association class 2, 5 had palpitations, and 2 had a history of syncope. Hypertrophy was concentric in 5 patients and asymmetric in 1 patient. One patient had left ventricular outflow tract obstruction. All patients with low alpha-Gal activity had alpha-Gal gene mutations.Conclusion-Anderson-Fabry disease should be considered in all cases of unexplained hypertrophy. Its recognition is important given the advent of specific replacement enzyme therapy
Plasmonic colloidal nanoparticles with open eccentric cavities via acid-induced chemical transformation
Surface-enhanced Raman spectroscopy (SERS) has been considered a promising technique for the detection of trace molecules in biomedicine and environmental monitoring. The ideal metal nanoparticles for SERS must not only fulfill important requirements such as high near-field enhancement and a tunable far-field response but also overcome the diffusion limitation at extremely lower concentrations of a target material. Here, we introduce a novel method to produce gold nanoparticles with open eccentric cavities by selectively adapting the structure of non-plasmonic nanoparticles via acid-mediated surface replacement. Copper oxide nanoparticles with open eccentric cavities are first prepared using a microwave-irradiation-assisted surfactant-free hydrothermal reaction and are then transformed into gold nanoparticles by an acidic gold precursor while maintaining their original structure. Because of the strong near-field enhancement occurring at the mouth of the open cavities and the very rough surfaces resulting from the uniformly covered hyperbranched sharp multi-tips and the free access of SERS molecules inside of the nanoparticles without diffusion limitation, adenine, one of the four bases in DNA, in an extremely diluted aqueous solution (1.0 pM) was successfully detected with excellent reproducibility upon laser excitation with a 785-nm wavelength. The gold nanoparticles with open eccentric cavities provide a powerful platform for the detection of ultra-trace analytes in an aqueous solution within near-infrared wavelengths, which is essential for highly sensitive, reliable and direct in vivo analysis.None1132sciescopu
Flatband voltage control in p-metal gate metal-oxide-semiconductor field effect transistor by insertion of TiO2 layer
Titanium oxide (TiO2) layer was used to control the flatband voltage (V-FB) of p-type metal-oxide-semiconductor field effect transistors. TiO2 was deposited by plasma enhanced atomic layer deposition (PE-ALD) on hafnium oxide (HfO2) gate dielectrics. Comparative studies between TiO2 and Al2O3 as capping layer have shown that improved device properties with lower capacitance equivalent thickness (CET), interface state density (D-it), and flatband voltage (V-FB) shift were achieved by PE-ALD TiO2 capping layer.open111210sciescopu
A Ru-catalyzed one-pot synthesis of homopropargylic amines from alkyl azides under photolytic conditions
A new synthetic method for homopropargylic amines from alkyl azides is presented. A salient feature of this reaction is the involvement of N-unsubstituted imines as the key intermediates, which are generated from alkyl azides by Ru catalysis under photolytic conditions. Notably, this method avoids the use of a protective group strategy in the homopropargylic amine synthesis.X111312sciescopu
The archaeological contribution of forensic craniofacial reconstruction to a portrait drawing of a Korean historical figure
Craniofacial reconstruction (CFR) is a technique used to rebuild the living facial appearance onto a skull in order to recognise or identify an individual. This technique is primarily employed in forensic investigation, but also utilised in archaeological research to recreate the faces of paleontological and archaeological humans. In this study, the face of a 17th century historical figure from Korea was reconstructed utilising computerized tomography from the mummified remains. A geographic surface comparison programme was employed to evaluate the accuracy of the CFR produced using a three-dimensional computerized modelling system. Analysis of the facial tissue depth discrepancies demonstrated that the CFR may have acceptable resemblance to the living face of the historical individual. Using computerised graphic technology, the CFR outcome, along with the archaeological information about the hair style, ornaments, and dress discovered in the tomb, a portrait-styled in the typical drawing trend from the era was created. The research suggests that current CFR techniques can provide an accurate portrait drawing of historical figures in Korea
Plasma-Enhanced ALD of TiO2 Thin Films on SUS 304 Stainless Steel for Photocatalytic Application
Plasma-enhanced atomic layer deposition (PE-ALD) of TiO2 thin films using Ti(NMe2)(4) [tetrakis(dimethylamido) Ti] and O-2 plasma were prepared on stainless steel to show the self-cleaning effect. The TiO2 thin films deposited on stainless steel have high growth rate, large surface roughness, and low impurities. The film deposited below 200 degrees C was amorphous, while the films deposited at 300 and 400 degrees C showed anatase and rutile phases, respectively. The contact angle measurements on crystalline PE-ALD TiO2 thin films exhibited superhydrophilicity after UV irradiation. The TiO2 thin film with anatase phase deposited at 300 degrees C showed the highest photocatalytic efficiency, which is higher than on Activ glass or thermal ALD TiO2 films. We suggest that anatase structure and large surface area of TiO2 thin film on stainless steel are the main factors for the high photocatalytic efficiency. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3095515] All rights reserved.X117sciescopu
Ultrafast phase-change logic device driven by melting processes.
The ultrahigh demand for faster computers is currently tackled by traditional methods such as size scaling (for increasing the number of devices), but this is rapidly becoming almost impossible, due to physical and lithographic limitations. To boost the speed of computers without increasing the number of logic devices, one of the most feasible solutions is to increase the number of operations performed by a device, which is largely impossible to achieve using current silicon-based logic devices. Multiple operations in phase-change-based logic devices have been achieved using crystallization; however, they can achieve mostly speeds of several hundreds of nanoseconds. A difficulty also arises from the trade-off between the speed of crystallization and long-term stability of the amorphous phase. We here instead control the process of melting through premelting disordering effects, while maintaining the superior advantage of phase-change-based logic devices over silicon-based logic devices. A melting speed of just 900 ps was achieved to perform multiple Boolean algebraic operations (e.g., NOR and NOT). Ab initio molecular-dynamics simulations and in situ electrical characterization revealed the origin (i.e., bond buckling of atoms) and kinetics (e.g., discontinuouslike behavior) of melting through premelting disordering, which were key to increasing the melting speeds. By a subtle investigation of the well-characterized phase-transition behavior, this simple method provides an elegant solution to boost significantly the speed of phase-change-based in-memory logic devices, thus paving the way for achieving computers that can perform computations approaching terahertz processing rates.This is the author's accepted manuscript. The final version is published by PNAS here: http://www.pnas.org/content/early/2014/08/27/1407633111.full.pdf+html?with-ds=yes
Processes and boreal summer impacts of the 2004 El Nino Modoki: An AGCM study
The sea surface temperature anomalies (SSTA) of tropical Pacific in the boreal summer of 2004 show a distinct tripolar pattern with warm SSTA in the central tropical Pacific, flanked on both sides by cold SSTA. The distinct conditions during the boreal summer of 2004 and the following winter were catalogued as a new coupled phenomenon named El Niño Modoki in a recent generalized study. The 2004 event is unique in the sense that it occurred without any co-occurring IOD, thereby without any possibility of external modulation of its processes and impacts in the tropics. Using observed data since 1979, we show that the 2004 event indeed involves the distinct equatorial coupled ocean-atmosphere dynamics different from the conventional El Niño. Further, using an AGCM, we confirm that during boreal summer anomalous twin Walker circulation cells associated with the El Niño Modoki SSTA give rise to observed rainfall anomalies in the tropic
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