Impact of conjugated polymer addition on the properties of paraffin-asphaltene blends for heat storage applications: Insight from computer modeling and experiment.

Adding carbon nanoparticles into organic phase change materials (PCMs) such as paraffin is a common way to enhance their thermal conductivity and to improve the efficiency of heat storage devices. However, the sedimentation stability of such blends can be low due to aggregation of aromatic carbon nanoparticles in the aliphatic paraffin environment. In this paper, we explore whether this important issue can be resolved by the introduction of a polymer agent such as poly(3-hexylthiophene) (P3HT) into the paraffin-nanoparticle blends: P3HT could ensure the compatibility of aromatic carbon nanoparticles with aliphatic paraffin chains. We employed a combination of experimental and computational approaches to determine the impact of P3HT addition on the properties of organic PCMs composed of paraffin and carbon nanoparticles (asphaltenes). Our findings clearly show an increase in the sedimentation stability of paraffin-asphaltene blends, when P3HT is added, through a decrease in average size of asphaltene aggregates as well as in an increase of the blends' viscosity. We also witness the appearance of the yield strength and gel-like behavior of the mixtures. At the same time, the presence of P3HT in the blends has almost no effect on their thermophysical properties. This implies that all properties of the blends, which are critical for heat storage applications, are well preserved. Thus, we demonstrated that adding polyalkylthiophenes to paraffin-asphaltene mixtures led to significant improvement in the performance characteristics of these systems. Therefore, the polymer additives can serve as promising compatibilizers for organic PCMs composed of paraffins and asphaltenes and other types of carbon nanoparticles.

Morphological Analysis of Blood Capillaries and Transport Function of Endothelial Cells in Hepatocellular Carcinoma-29.

Hepatocellular carcinoma is characterized by the pronounced vascularization, high levels of vascular endothelial growth factors, and intensive angiogenesis. Caveola-mediated endocytosis and clathrin-dependent endocytosis contribute to internalization of various growth factors, thus affecting blood supply to the tumor and neoangiogenesis. We performed a quantitative analysis of blood vessels in the tumor and evaluated the basal levels of endocytosis-associated vesicular structures in the endothelial cells of the hepatocellular carcinoma-29. The numbers of blood vessels and clathrin-coated vesicles in endothelial cells in the tumor tissue were significantly higher than in normal tissue. The association between clathrin-dependent endocytosis in the endotheliocytes of the capillaries and tumor angiogenesis can provide the basis for the development of new molecular targets for antiangiogenic antitumor therapy.

Ultrastructural Organization of Uveal Melanoma Stromal Cells.

Typical blood capillaries and vessels in uveal melanoma were shown and different types of uveal melanoma stromal cells were determined by electron microscopy and immunohistochemical analysis. Macrophages, fibroblasts of varying degrees of differentiation and endothelial-like cells with numerous caveolae in the cytoplasm were found in the channels of the extracellular matrix surrounding accumulations of tumor cells. The presence local structures positively stained for markers of the blood and lymphatic vessels (CD31 and podoplanin) in channels of the extracellular matrix suggests that the described endothelial-like cells can be the structural basis for blood and lymphatic vessels of the tumor.

Autophagy in Hepatocytes during Distant Tumor Growth.

Structural changes in the liver of CBA mice were studied during the development of experimental hepatocarcinoma-29 inoculated into the hip. A decrease in the volume density of hepatocyte cytoplasm, mitochondria, endoplasmic reticulum, and lipid inclusions and an increase in the volume density of lysosomal structures during tumor growth were observed. All stages of intracellular autophagy were recorded by the method of electron microscopy. These stages included the appearance of autophagosomes, autophagolysosomes, and secondary lysosomes in the hepatocyte cytoplasm. Fragments of cytoplasm, glycogen rosettes, mitochondria, and fragments of endoplasmic reticulum with ribosomes were found in autophagosomes. The obtained data indicate the development of non-selective autophagy in the liver during distant tumor growth in aimed at the maintenance of intracellular homeostasis in hepatocytes and energy and trophic homeostasis of organism.

APOPTOSIS AND AUTOPHAGY IN HEPATOCARCINOMA CELLS INDUCED BY DIFFERENT FORMS OF LITHIUM SALTS.

Hepatocellular carcinoma (HCC) is one of the aggressive and resistant to drug therapy cancer. It is believed that the development of HCC is correlated with dysregulation of programmed cell death. So, the search for effective inducers of HCC cell death is very important. The aim of the work was to identify structural changes leading to HCC cell death when exposed to nanoscale and original forms of lithium salts. Using light and electron microscopy and flow cytometry, structural features of autophagy and apoptosis in HCC cells after their incubation with various forms of lithium salts has been revealed. It is shown that a more pronounced effect on HCC-29 cells have nanoscale forms of lithium carbonate and lithium citrate. At the same time, nanoscale lithium citrate mainly induced apoptosis, and nanosized form of lithium carbonate, along with apoptosis, induced autophagic death of HCC-29cells.

[Hygienic aspects of dental caries and its prevention]. / Gigienicheskie aspekty kariesa zubov i ego profilaktika.

This review summarizes fluoride content in surface water sources of various Russian regions and its relationship with the prevalence of caries in the population. Low Fluoride content in almost all water sources of Russia highlights the importance of individual prevention of dental caries above all by the use of fluorinated toothpaste. From the standpoint of evidence-based medicine the tooth brushing with fluorinated paste twice daily has the highest level of efficiency of caries reduction.

Effects of nanosized lithium carbonate particles on intact muscle tissue and tumor growth.

The effects of nanosized lithium carbonate particles on muscle tissue structure and development of experimental hepatocarcinoma-29 transplanted into the hip were studied in CBA mice. Necrotic changes in all structural components of the muscle were detected after intramuscular injection of nanosized lithium carbonate particles to intact animals. Regeneration of the muscle fibers after lithium carbonate treatment was associated with a significant increase in macrophage count, number of microvessels, activation of fibroblasts, and complete recovery of the organ structure. Injection of lithium carbonate nanoparticles at the periphery of tumor growth caused tumor cell necrosis, destruction of the vascular bed, and attraction of neutrophils and macrophages to the tumor focus. After the preparation was discontinued, the tumor developed with lesser number of vessels, smaller tumor cells, and lesser deformation of the cell nuclei structure.

[Clinical aspects of analgesia with intravenous paracetamol in the early postoperative period].

This open one-center study included 40 patients operated on the abdomen and chest, who had moderate resting pain in the immediate postoperative hours. Paracetamol was used as a dropwise intravenous 1-g infusion for 10-15 min; the dose of the agent was 4 g. The interval of paracetamol re-infusion was not early than 4 hours. If additional analgesia was required, opioid analgesics (promedol, tramadol) were administered. As a whole, assessment of analgesia within 24 hours showed excellent and good results reported by patients in 85% of cases; and in 71% of the patients the intensity of postoperative pain was less than they had expected before surgery. The use of opioid analgesics was required in 65% of the patients and 25% did not need these agents. The remaining 10% of the patients received a combination of nonsteroidal anti-inflammatory drugs, paracetomol, and opioids. Postoperative analgesia based on the intravenous infusion of paracetamol in a single dose of 1 g (4 g/day) caused a reduction in the intensity and duration of pain. The intravenous formulation of paracetamol should be regarded as one of the essential nonopioid components of multimodality therapy for pain in patients in the early postoperative period.

The dependence of algal H2 production on Photosystem II and O2 consumption activities in sulfur-deprived Chlamydomonas reinhardtii cells.

Chlamydomonas reinhardtii cultures, deprived of inorganic sulfur, undergo dramatic changes during adaptation to the nutrient stress [Biotechnol. Bioeng. 78 (2002) 731]. When the capacity for Photosystem II (PSII) O(2) evolution decreases below that of respiration, the culture becomes anaerobic [Plant Physiol. 122 (2000) 127]. We demonstrate that (a) the photochemical activity of PSII, monitored by in situ fluorescence, also decreases slowly during the aerobic period; (b) at the exact time of anaerobiosis, the remaining PSII activity is rapidly down regulated; and (c) electron transfer from PSII to PSI abruptly decreases at that point. Shortly thereafter, the PSII photochemical activity is partially restored, and H(2) production starts. Hydrogen production, which lasts for 3-4 days, is catalyzed by an anaerobically induced, reversible hydrogenase. While most of the reductants used directly for H(2) gas photoproduction come from water, the remaining electrons must come from endogenous substrate degradation through the NAD(P)H plastoquinone (PQ) oxido-reductase pathway. We propose that the induced hydrogenase activity provides a sink for electrons in the absence of other alternative pathways, and its operation allows the partial oxidation of intermediate photosynthetic carriers, including the PQ pool, between PSII and PSI. We conclude that the reduced state of this pool, which controls PSII photochemical activity, is one of the main factors regulating H(2) production under sulfur-deprived conditions. Residual O(2) evolved under these conditions is probably consumed mostly by the aerobic oxidation of storage products linked to mitochondrial respiratory processes involving both the cytochrome oxidase and the alternative oxidase. These functions maintain the intracellular anaerobic conditions required to keep the hydrogenase enzyme in the active, induced form.

[Photochemical activity of photosystem II and hydrogen photoproduction in sulfur-deprived Chlamydomonas reinhardtii mutants D1-R323D and D1-R323L].

The role of photosystem II in hydrogen photoproduction by Chlamydomonas reinhardtii cells was studied in mutants with modified D1-protein. In D1-R323D and D1-R323L mutants, the replacement of arginine by aspartate or leucine, respectively, resulted in the disruption of electron transport at the donor side of photosystem II. The rate of oxygen evolution in D1-R323D decreased twice as compared to the pseudo-wild type (pWT), and in D1-R323L no oxygen evolution was detected. The latter mutant was not capable of photoautotrophical growth. The dynamics of changes in oxygen content, the reduction of photosystem II active reaction centers (deltaF/F(1)m), and hydrogen production rate in pWT were found to be similar to the wild type if cultivated under sulfur deprivation in a closed bioreactor. The observed gradual decrease in the deltaF/F(1)m value turned to a sharp drop almost to zero followed by a partial recovery during which the production of hydrogen set in. The transition to the anaerobic phase in D1-R323D cultured in a sulfur-deprived medium occurred earlier than it happened in pWt under the same conditions. However, the partial recovery of photosystem II activity and hydrogen production started at a later time, and the rate of hydrogen production was low. The D1-R323L mutant incapable of oxygen evolution entered the rapidly anaerobiosis but produced no hydrogen. The kinetics of photoinduced redox transitions in P700 was similar in all investigated strains and was not affected by diuron addition. This implies that the mutants had a pool of reducers, which could donate electrons through the quinone pool or cytochrome to photosystem I. However, in D1-R323L mutant lacking the active photosystem II, this condition was not sufficient to support hydrogenase activity.

[Effect of stress factors on carboxypeptidase H activity in areas of the rat brain]. / Vliianie stressovykh faktorov na aktivnost' karboksipeptidazy H v otdelakh golovnogo mozga krys.

It is established that carboxypeptidase H activity increases as affected by various stress factors in the rat brain departments. The increase of the enzyme activity because of the emotional-pain stress is of continuous character. Possible role of carboxypeptidase H in the development of the stress response is discussed.

[The use of a concentrate of antithrombin III and disaggregants in the preoperative preparation of patients with pulmonary tuberculosis]. / Primenenie kontsentrata antitrombina III i dezagregantov v predoperatsionnoi podgotovke bol'nykh tuberkulezom legkikh.

A study of the blood coagulation system in 32 patients with pulmonary tuberculosis before surgical intervention showed that reduction of the antithrombine III activity and related enhancement of the thrombin formation reaction and suppression of deaggregation capacities of thrombocytes reflect the latent process of pathological intravascular blood coagulation. The authors suggest justification of restoring the reduced antithrombine blood capacitance and normalization of the deaggregation capacity of thrombocytes by means of the antithrombine III concentrate and disaggregants in the complex preoperative care.

[The hemostatic system in patients with pulmonary tuberculosis during their preparation for surgery]. / Sistema gemostaza u bol'nykh tuberkulezom legkikh v period ikh podgotovki k operatsii.

The basic mechanisms responsible for equilibrium impairment in the hemostatic system in pulmonary tuberculosis patients are reduced activity of antithrombin III and disturbances of platelet functional capacities. These changes were proved to reflect the course of intravascular hemocoagulation whose degree of manifestation is related directly to the extent of specific lesions in the lungs and intoxication phenomena. The process of intravascular hemocoagulation in tuberculosis patients runs in the presence of an increased concentration of plasma fibronectin , while major surgery performed in patients with fibrous-cavernous processes leads to its reduced level. It is pathogenetically proved to use antithrombin III concentrate preparations with anti- and dysaggregatory properties, fibronectin preparations, trasylol or its analogs during complex preoperative preparation of patients.

[Functional activity of thrombocytes in patients with post-tuberculosis spinal osteochondrosis complicated by pain syndrome]. / Funktsional'naia aktivnost' trombotsitov u bol'nykh posttuberkuleznym osteokhondrozom pozvonochnika, oslozhnennym bolevym sindromom.

It was found that in patients with attenuated tuberculous spondylitis and post-tuberculous vertebral osteochondrosis there was a sharp increase in platelet aggregability and a decrease in their disaggregability at the peak of the pain syndrome. With the therapy followed by relief of the pain syndrome, a rise in the platelet aggregability was significantly less noticeable, without significant changes in their disaggregability.

[Hemostasis disorders in patients with pulmonary tuberculosis]. / Narusheniia v sisteme gemostaza u bolnykh tuberkulëzom lëgkikh.

Coagulation studies in 82 patients with pulmonary tuberculosis showed that latent intravascular coagulation occurs not only in patients with active disease, but also in those with marked residual changes. The level of Cl-esterase inactivator may serve as an indicator of the disease prognosis: if its concentration is low, the prognosis is poor. Total fibronectin was measured in 76 patients with different tuberculosis activity. The results suggest that this protein's blood levels reflect the activity of the specific process in the lungs. Normal fibronectin concentrations indicate cure of tuberculosis.

Effect of nitrite on primary photosynthetic processes in isolated chloroplasts of wheat grown under various conditions of nitrogen supply.

In wheat chloroplasts, NO2- (5 mM) inhibited non-cyclic phosphorylation coupled to the linear electron flow through both photosystems but stimulated cyclic phosphorylation with phenazine methosulfate (plus diuron) and electron flux from an artificial electron donor through PSI and methylviologen to oxygen. During light energization of chloroplasts, NO2- increased the F740/F695 ratio in the low-temperature fluorescence spectra, thus suggesting that the energy of absorbed quanta is redistributed in favor of PSI. Nitrite also stimulated the activity of Mg2+-dependent H+-ATPase. Changes in the slow component of the induction curve of delayed fluorescence also suggest that NO2- affects energy transformation processes that are coupled to electron transport in the chloroplasts. Nitrite had no effect on these functional characteristics of thylakoids and chloroplasts isolated from plants grown under nitrogen deficiency in the medium.