Quasilocal Conservation Laws: Why We Need Them

We argue that conservation laws based on the local matter-only stress-energy-momentum tensor (characterized by energy and momentum per unit volume) cannot adequately explain a wide variety of even very simple physical phenomena because they fail to properly account for gravitational effects. We construct a general quasi}local conservation law based on the Brown and York total (matter plus gravity) stress-energy-momentum tensor (characterized by energy and momentum per unit area), and argue that it does properly account for gravitational effects. As a simple example of the explanatory power of this quasilocal approach, consider that, when we accelerate toward a freely-floating massive object, the kinetic energy of that object increases (relative to our frame). But how, exactly, does the object acquire this increasing kinetic energy? Using the energy form of our quasilocal conservation law, we can see precisely the actual mechanism by which the kinetic energy increases: It is due to a bona fide gravitational energy flux that is exactly analogous to the electromagnetic Poynting flux, and involves the general relativistic effect of frame dragging caused by the object's motion relative to us.Comment: 20 pages, 1 figur

Противосудорожное действие производного 4-бензоил-пиридина (ГИЖ-298) на пароксизмальную активность в структурах мозга крыс с кобальт-индуцированной очаговой эпилепсией на первой стадии формирования эпилептической системы

He aim of the study was to investigate the influence of a derivative of 4-benzoyl pyridine connection, GIZ-298 on electroencephalographic manifestations ranvulsive activity in the brain structures of rats with cobalt-induced focal epilepsy in the first stage of the formation of epileptic system. Methodology of the study. We used the technique of creation (by an application of cobalt to the brain of rats) chronic epileptogenic focus, generating paroxysmal activity in different brain structures: the ipsi- and contralateral cortex, hippocampus and hypothalamus. The results of the study. Established that injection ofGIZ-298 at a dose of 60 mg/kg (intraperitoneally, once) on the first stage of development of the system eliminates epileptic EEG manifestations of seizure activity in all the investigated structures of the brain, with the greatest efficiency in the ipsilateral cortex and the hypothalamus, significantly reducing both the number and duration of seizure discharges.Целью исследования явилось изучение влияния производного 4-бензоил пиридина - соединения ГИЖ-298 на электроэнцефалографические проявления судорожной активности в структурах мозга крыс с кобальт-индуцированной очаговой эпилепсией на первой стадии формирования эпилептической системы. Методика исследования. Использовалась методика создания (путём аппликации кобальта на кору мозга крыс) хронического эпилептогенного очага, генерирующего пароксизмальную активность в различных структурах мозга: ипси- и контрлатеральной коре, гиппокампе и гипоталамусе. Результаты исследования. Установлено, что соединение ГИЖ-298 в дозе 60 мг/кг (внутрибрюшинно, однократно) на первой стадии развития эпилептической системы устраняет электроэнцефалографические проявления судорожной активности во всех исследуемых структурах мозга, с наибольшей эффективностью в ипсилатеральной коре и гипоталамусе, статистически достоверно уменьшая как число, так и длительность судорожных разрядов

The Level of DING Proteins Is Increased in HIV-Infected Patients: In Vitro and In Vivo Studies

DING proteins constitute an interesting family, owing to their intriguing and important activities. However, after a decade of research, little is known about these proteins. In humans, at least five different DING proteins have been identified, which were implicated in important biological processes and diseases, including HIV. Indeed, recent data from different research groups have highlighted the anti-HIV activity of some DING representatives. These proteins share the ability to inhibit the transcriptional step of HIV-1, a key step of the viral cycle that is not yet targeted by the current therapies. Since such proteins have been isolated from humans, we undertook a comprehensive study that focuses on the relationship between these proteins and HIV-infection in an infectious context. Hence, we developed a home-made ELISA for the quantification of the concentration of DING proteins in human serum. Using this method, we were able to determine the concentration of DING proteins in healthy and HIV-infected patients. Interestingly, we observed a significant increase of the concentration of DING proteins in non treated and treated HIV-infected patients compared to controls. In addition, cell cultures infected with HIV also show an increased expression of DING proteins, ruling out the possible role of antiretroviral treatment in the increase of the expression of DING proteins. In conclusion, results from this study show that the organism reacts to HIV-infection by an overexpression of DING proteins

Роль 3-оксиметаболита феназепама и леваны в реализации их нейротропного действия

Work is devoted to a comparative analysis of the pharmacological action and integral indicators pharmacokinetics of 1,4- benzodiazepine - phenazepam and levan, as well as their total active 3-oximetabolite formed by different mechanisms. It is shown that in the tests levan antagonism corazolum and thiosemicarbazide inferior phenazepam anticonvulsant activity, but surpasses phenazepam on activity in the maximal electroshock test and has a lower severity miorelaxation action. Comparison effects of phenazepam and levad with effects of 3-oximetabolite indicate greater similarity effects than metabolite with phenazepam. With the use of radiolabeled compounds were established change in the ratio of the areas under the concentration curve 3-oximetabolite in the brain and blood when administered phenazepam (AUCbrain / AUCblood = 0,96 ± 0,27) or levan (AUCbrain / AUCblood = 1,4 ± 0,1). This fact is associated with different ways of biotransformation: oxidative hydroxylation of phenazepam CYP450 and nonspecific carboxylesterase hydrolysis of levan, which explains the difference in the pharmacological effect of the test compounds.Работа посвящена сравнительному анализу фармакологического действия и интегральных показателей фармакокинетики производных 1,4-бенздиазепина - феназепама и леваны, а также их общего активного 3-оксиметаболита, образующегося различными механизмами. Показано, что левана в тестах антагонизма с коразолом и тиосемикарбазидом уступает по противосудорожной активности феназепаму, но превосходит феназепам по активности в тесте максимального электрошока и имеет меньшую выраженность миорелаксантного действия. Сопоставление эффектов феназепама и левады с эффектами 3-оксиметаболита свидетельствует о большем сходстве эффектов метаболита с феназепамом. С использованием радиоактивно меченых соединений установлено изменение соотношения площадей под концентрационными кривыми 3-оксиметаболита в мозгу и крови при введении феназепама (AUC /AUC = 0,96 ± 0,27) или леваны (AUC /AUC = 1,4 ± 0,1). Данный факт связан с различными путями биотрансформации: окислительное гидроксилирование феназепама P450 и гидролиз неспецифическими карбоксилэстеразами леваны, что и обуславливает отличие в фармакологическом действии исследуемых соединений

Paraoxonase-1 is related to inflammation, fibrosis and PPAR delta in experimental liver disease

<p>Abstract</p> <p>Background</p> <p>Paraoxonase-1 (PON1) is an antioxidant enzyme synthesized by the liver. It protects against liver impairment and attenuates the production of the pro-inflammatory monocyte chemoattractant protein-1 (MCP-1). We investigated the relationships between hepatic PON1 and MCP-1 expression in rats with liver disease and explored the possible molecular mechanisms involved.</p> <p>Methods</p> <p>CCl₄was administered for up to 12 weeks to induce liver damage. Serum and hepatic levels of PON1 and MCP-1, their gene and protein expression, nuclear transcription factors, and histological and biochemical markers of liver impairment were measured.</p> <p>Results</p> <p>High levels of PON1 and MCP-1 expression were observed at 12^thweek in the hepatocytes surrounding the fibrous septa and inflammatory areas. CCl₄-administered rats had an increased hepatic PON1 concentration that was related to decreased gene transcription and inhibited protein degradation. Decreased PON1 gene transcription was associated with PPARδ expression. These changes were accompanied by increased hepatic MCP-1 concentration and gene expression. There were significant direct relationships between hepatic PON1 and MCP-1 concentrations (P = 0.005) and between PON1 and the amount of activated stellate cells (P = 0.001).</p> <p>Conclusion</p> <p>Our results from this experimental model suggest a hepato-protective role for PON1 against inflammation, fibrosis and liver disease mediated by MCP-1.</p

COMPARATIVE ANTICONVULSANT AND ANTIHYPOXIC EFFECTS OF ASTROKS AND MEXIDOL IN INJECTABLE FORM AND 2-ETHYL-6-METHYL-3-HYDROXYPYRIDINE SUCCINATE SUBSTANCE

The purpose of this study was to examine in experiment anticonvulsant and antihypoxic action of 2-ethyl-6-methyl-3-hydroxypyridine succinate medications — Astroks in injectable form (vial of 100 mg in 2 ml) compared with Mexidol injectable form (vial of 100 mg in 2 ml) and the substance 2-ethyl-6- methyl-3-hydroxypyridine succinate (EMHPS). Materials and methods. Simulation of primary generalized eizures was performed using the maximal electroshock (MES) and pentylenetetrazole injection. Antihypoxic effects of drugs was studied on the model of normobaric hypoxia with hypercapnia.Results: it was found that astroks injection at a dose of 200 mg/kg has a similar antihypoxic and anticonvulsant efficacy with EMHPS substance. Compared to injectable form of Meksidol astroks has similar efficacy in the test of antagonism with MES. Astroks exceeds the effect of Mexidol in the test of antagonism with pentylenetetrazole and has more severe antihypoxic action.Conclusion. Аstroks injectable has pronounced antihypoxic and anticonvulsant action in the experiment which have some advantages over injectable Meksidol

Negative magnetoresistance in indium antimonide whiskers doped with tin

Negative magnetoresistance of InSb whiskers with different impurity concentrations 4.4 × 10 ¹⁶–7.16 × 10 ¹⁷ cm −³ was studied in longitudinal magnetic field 0–14 T in the temperature range 4.2–77 K. The negative magnetoresistance reaches about 50% for InSb whiskers with impurity concentration in the vicinity to the metal–insulator transition. The negative magnetoresistance decreases to 35 and 25% for crystals with Sn concentration from the metal and dielectric side of the transition. The longitudinal magnetoresistance twice crosses the axis of the magnetic field induction for the lightly doped crystals. The behavior of the negative magnetoresistance could be explained by the existence of classical size effect, in particular boundary scattering in the subsurface whisker layer