58 research outputs found
Dispersed copper (I) oxide particles encapsulated by polylactide
One of the approaches for the production of polymer composite materials with a biocidal effect is based on the use of dispersed particles of some metal oxides as a filler (for example, copper oxide or zinc oxide). Such an approach allows not only providing a biocidal effect, but also increasing such mechanical characteristics as the modulus of elasticity, hardness, and abrasion resistance. The mechanical characteristics of such polymer composite materials can be controlled by formation of a sheath (for example, from polylactide) of a given thickness on the surfaces of dispersed particles. Polylactide is a biodegradable polymer, widely used as coating material for particles with biocidal properties. The parameters of the methods for forming a polylactide sheath are determined by the sheath’s thickness and the sheath’s adhesion to the particle surface. The purpose of the study was to determine the parameters of the polymer sheath’s formation on the surfaces of dispersed submicron copper oxide (I) particles during coacervation of polylactide from the solution.
The encapsulation of copper (I) oxide particles was carried out by the coacervation process in a solution. Polylactide was displaced from the solution in benzene by hexane in the presence of copper (I) oxide particles. It was shown that a sheath thickness of about 250 nm can be obtained by using the polylactide sheath formation method. The recommended parameters of the polylactide sheath formation method were determined: solution temperature of 35÷38 °C, hexane volume not more than 30±2 ml. The sheath had weak adhesion to particle surfaces: adhesion was determined by the roughness of the particle
surface.
The mechanical characteristics of the epoxy resin ED-20 polymer composition filled with the encapsulated particles were considered in the study. The increase in the mechanical properties of the polymer composition with encapsulated particles in comparison with the samples of polymer composition with non-encapsulated particles was revealed. That can indicate the increased adhesion of encapsulated particles to such polymer matrix
Evidence and ideology as a rationale for light-therapy in Russia: from the Soviet Union to the present day.
Light therapy is still used to treat a number of common diseases in Russia. The practice is firmly anchored in history: Soviet clinical practice was divorced from the emerging field of evidence-based medicine. Medical researchers were cut off from international medical research and scientific literature, with much Soviet scientific activity based on a particular socialist ideology. In this study, the use of light therapy serves as a case study to explore tensions between international evidence-based medicine and practices developed in isolation under the Soviet Union, the legacy of which is to the detriment of many patients today. We used four different search methods to uncover scientific and grey literature, both historical and contemporary. We assessed the changing frequency of publications over time and contrasted the volume of literature on light therapy with more orthodox treatments such as statins and painkillers. Our search found an increasing number and comparatively large body of scientific publications on light therapy in the Russian language, and many publications emanating from prestigious Russian institutions. Combined with our analysis of the historical literature and our appraisal of 22 full text articles, this leads us to suggest that light therapy entered mainstream Soviet medical practice before the Stalinist period and still occupies an important position in contemporary Russian clinical practice. We propose that this outdated treatment survives in Russia in part due to the political, economic and social forces that helped to popularize it during Soviet times, and by the seeming justification offered by poorly executed studies
Contrasting arbuscular mycorrhizal responses of vascular and non-vascular plants to a simulated Palaeozoic CO2 decline
Применение квантовых электронных устройств в периоперационном периоде у больных при ампутациях нижних конечностей
The authors present their experience in applying quantum electronic devices in patients undergoing lower limb amputations.Object. To develop a technique for potentiating the traditional multimodal anesthesia by optoelectronic devices with wavelength 650 nm (red range) and 470 nm (blue range) (manufactured in Russia) in amputation of lower extremities.Material and methods. Multimodal anesthesia with quantum electronic devices was performed in 48 patients (11 women and 37 men) aged 68–89 and having comorbidities. In the main group, for contact LED irradiation portable semiconductor LED device AFS к-630/670 emitting in red range with wavelength 650 ± 20 nm and portable AFS device emitting in blue range with wavelength 470 ± 10 nm and power 30 mW at the end of surgery were used. The above mentioned devices were made in the form of bracelets for non-invasive and non-contact application in the multimodal anesthesia during amputations of lower extremities. In the comparison group, multimodal anesthesia was not potentiated by contact LED irradiation.Results. The discussed Russian bracelets emitting in red and blue bands of the spectrum during amputation of lower extremities promoted the decrease of narcotic dosage (Fentanyl) during general multimodal anesthesia. In the main group, cardiac index increased at the end of surgery, and the total peripheral vascular resistance decreased if to compare to baseline values. In the comparison group, cardiac index increased somewhat less if to compare to baseline values, and the total peripheral vascular resistance decreased somewhat less if to compare to baseline values.Conclusion. The discussed bracelets emitting in red range (650 nm) which were applied during surgical interventions for the amputation of lower extremities and bracelets emitting in blue range (470 nm) which were applied at the end of surgery reduce the dose of narcotic preparations (Fentanyl) as well as stabilize hemodynamic parameters during surgery. Besides, in the immediate postoperative period, patients who survived amputation of lower extremities and in who the abovementioned bracelets were used do not require additional narcotic painkillers after amputation.В статье представлены результаты использования квантовых электронных устройств у пациентов при ампутациях нижних конечностей.Цель исследования – разработка методики потенцирования оптоэлектронными устройствами традиционной мультимодальной анестезии в области красного 650 нм и синего 470 нм диапазонов действия при ампутациях нижних конечностей.Материалы и методы исследования. Мультимодальная анестезия с применением квантовых электронных устройств была проведена у 48 пациентов (11 женщин и 37 мужчин) в возрасте от 68 до 89 лет с сопутствующими заболеваниями. Контактное светодиодное воздействие осуществляли в основной группе портативным полупроводниковым светодиодным аппаратом АФС к-630/670 в красном диапазоне действия с длиной волны 650 ± 20 нм и портативным аппаратом АФС в синем диапазоне действия с длиной волны 470 ± 10 нм мощностью 30 мВт в конце оперативного вмешательства. Устройства выполнены в виде браслетов на руку с целью неинвазивного бесконтактного применения, они использовались во время мультимодальной анестезии при ампутациях нижних конечностей. В группе сравнения мультимодальная анестезия не потенцировалась контактным светодиодным воздействием.Результаты исследования. Использование российских браслетов в красном и синем диапазонах действия во время проведения ампутаций нижних конечностей способствовало снижению дозы наркотических средств (фентанила) во время общей мультимодальной анестезии. В основной группе показатель сердечного индекса увеличивался в конце оперативного вмешательства, общее периферическое сосудистое сопротивление уменьшалось по сравнению с исходными значениями. В группе сравнения сердечный индекс увеличивался несколько меньше по сравнению с исходными данными, а общее периферическое сосудистое сопротивление также уменьшалось по сравнению с исходными данными.Заключение. Использование квантовых электронных устройств во время проведения оперативных вмешательств при ампутациях нижних конечностей позволяет снизить дозу наркотического препарата (фентанила) и стабилизировать гемодинамические показатели во время оперативного вмешательства. Кроме того, в ближайшем послеоперационном периоде не требуется дополнительное введение наркотических обезболивающих средств у пациентов с ампутациями нижних конечностей
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Ecto- and arbuscular mycorrhizal symbiosis can induce tolerance to toxic pulses of phosphorus in jarrah (Eucalyptus marginata) seedlings
In common with many plants native to low P soils, jarrah (Eucalyptus marginata) develops toxicity symptoms upon exposure to elevated phosphorus (P). Jarrah plants can establish arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) associations, along with a non-colonizing symbiosis described recently. AM colonization is known to influence the pattern of expression of genes required for P uptake of host plants and our aim was to investigate this phenomenon in relation to P sensitivity. Therefore, we examined the effect on hosts of the presence of AM and ECM fungi in combination with toxic pulses of P and assessed possible correlations between the induced tolerance and the shoot P concentration. The P transport dynamics of AM (Rhizophagus irregularis and Scutellospora calospora), ECM (Scleroderma sp.), non-colonizing symbiosis (Austroboletus occidentalis), dual mycorrhizal (R. irregularis and Scleroderma sp.), and non-mycorrhizal (NM) seedlings were monitored following two pulses of P. The ECM and A. occidentalis associations significantly enhanced the shoot P content of jarrah plants growing under P-deficient conditions. In addition, S. calospora, A. occidentalis, and Scleroderma sp. all stimulated plant growth significantly. All inoculated plants had significantly lower phytotoxicity symptoms compared to NM controls 7 days after addition of an elevated P dose (30 mg P kg−1 soil). Following exposure to toxicity-inducing levels of P, the shoot P concentration was significantly lower in R. irregularis-inoculated and dually inoculated plants compared to NM controls. Although all inoculated plants had reduced toxicity symptoms and there was a positive linear relationship between rank and shoot P concentration, the protective effect was not necessarily explained by the type of fungal association or the extent of mycorrhizal colonization
ДИФФЕРЕНЦИРОВАННАЯ ХИРУРГИЧЕСКАЯ ТАКТИКА ПРИ ПОРАЖЕНИИ МОЧЕВОГО ПУЗЫРЯ У БОЛЬНЫХ МЕСТНО-РАСПРОСТРАНЕННЫМИ ЗЛОКАЧЕСТВЕННЫМИ НОВООБРАЗОВАНИЯМИ МАЛОГО ТАЗА
An analysis of surgical treatment of 154 patients with locally advanced and recurrent malignant tumors of the pelvic organs with secondary lesions of the bladder was performed. Described surgical technique used for resection and reconstructive stages of surgery. In 73.4 % of the volume of the intervention was complete or anterior pelvic exenteration. Morbidity after operations was 30.5 %, postoperative mortality — 7.8 %. The perspective of large-scale interventions to improve outcomes of patients with tumors of the pelvic localization is marked.Проведен анализ хирургического лечения 154 больных местно-распространенными и рецидивными злокачественными новообразованиями органов малого таза с вторичным поражением мочевого пузыря. Описан дифференцированный подход на резекционном и реконструктивном этапах хирургического вмешательства у данной категории пациентов. В 73,4 % случаев объемом вмешательства была полная или передняя эвисцерация малого таза, в 26,6 % удалось ограничиться комбинированным вмешательством с резекцией мочевого пузыря. Ранние послеоперационные осложнения развились у 30,5 % пациентов. Умерли 12 (7,8 %) больных. Отмечена перспективность масштабных вмешательств в улучшении результатов лечения больных с опухолями тазовой локализации
Molecular Cloning, Characterization and Expression Analysis of Two Members of the Pht1 Family of Phosphate Transporters in Glycine max
BACKGROUND: Phosphorus is one of the macronutrients essential for plant growth and development. The acquisition and translocation of phosphate are pivotal processes of plant growth. In a large number of plants, phosphate uptake by roots and translocation within the plant are presumed to occur via a phosphate/proton cotransport mechanism. PRINCIPAL FINDINGS: We cloned two cDNAs from soybean (Glycine max), GmPT1 and GmPT2, which show homology to the phosphate/proton cotransporter PHO84 from the budding yeast Saccharomyces cerevisiae. The amino acid sequence of the products predicted from GmPT1 and GmPT2 share 61% and 63% identity, respectively, with the PHO84 in amino acid sequence. The deduced structure of the encoded proteins revealed 12 membrane-spanning domains with a central hydrophilic region. The molecular mass values are ∼58.7 kDa for GmPT1 and ∼58.6 kDa for GmPT2. Transiently expressed GFP-protein fusions provide direct evidence that the two Pi transporters are located in the plasma membrane. Uptake of radioactive orthophosphate by the yeast mutant MB192 showed that GmPT1 and GmPT2 are dependent on pH and uptake is reduced by the addition of uncouplers of oxidative phosphorylation. The K(m) for phosphate uptake by GmPT1 and GmPT2 is 6.65 mM and 6.63 mM, respectively. A quantitative real time RT-PCR assay indicated that these two genes are expressed in the roots and shoots of seedlings whether they are phosphate-deficient or not. Deficiency of phosphorus caused a slight change of the expression levels of GmPT1 and GmPT2. CONCLUSIONS: The results of our experiments show that the two phosphate transporters have low affinity and the corresponding genes are constitutively expressed. Thereby, the two phosphate transporters can perform translocation of phosphate within the plant
Phosphate concentration and arbuscular mycorrhizal colonisation influence the growth, yield and expression of twelve PHT1 family phosphate transporters in foxtail millet (Setaria italica)
Phosphorus (P) is an essential element which plays several key roles in all living organisms. Setaria italica (foxtail millet) is a model species for panacoid grasses including several millet species widely grown in arid regions of Asia and Africa, and for the bioenergy crop switchgrass. The growth responses of S. italica to different levels of inorganic phosphate (Pi) and to colonisation with the arbuscular mycorrhizal fungus Funneliformis mosseae (syn. Glomus mosseae) were studied. Phosphate is taken up from the environment by the PHT1 family of plant phosphate transporters, which have been well characterized in several plant species. Bioinformatic analysis identified 12 members of the PHT1 gene family (SiPHT1;1-1;12) in S. italica, and RT and qPCR analysis showed that most of these transporters displayed specific expression patterns with respect to tissue, phosphate status and arbuscular mycorrhizal colonisation. SiPHT1;2 was found to be expressed in all tissues and in all growth conditions tested. In contrast, expression of SiPHT1;4 was induced in roots after 15 days growth in hydroponic medium of low Pi concentration. Expression of SiPHT1;8 and SiPHT1;9 in roots was selectively induced by colonisation with F. mosseae. SiPHT1;3 and SiPHT1;4 were found to be predominantly expressed in leaf and root tissues respectively. Several other transporters were expressed in shoots and leaves during growth in low Pi concentrations. This study will form the basis for the further characterization of these transporters, with the long term goal of improving the phosphate use efficiency of foxtail millet
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Sensitivity of jarrah (Eucalyptus marginata) to phosphate, phosphite, and arsenate pulses as influenced by fungal symbiotic associations
Many plant species adapted to P-impoverished soils, including jarrah (Eucalyptus marginata), develop toxicity symptoms when exposed to high doses of phosphate (Pi) and its analogs such as phosphite (Phi) and arsenate (AsV). The present study was undertaken to investigate the effects of fungal symbionts Scutellospora calospora, Scleroderma sp., and Austroboletus occidentalis on the response of jarrah to highly toxic pulses (1.5 mmol kg−1 soil) of Pi, Phi, and AsV. S. calospora formed an arbuscular mycorrhizal (AM) symbiosis while both Scleroderma sp. and A. occidentalis established a non-colonizing symbiosis with jarrah plants. All these interactions significantly improved jarrah growth and Pi uptake under P-limiting conditions. The AM fungal colonization naturally declines in AM-eucalypt symbioses after 2–3 months; however, in the present study, the high Pi pulse inhibited the decline of AM fungal colonization in jarrah. Four weeks after exposure to the Pi pulse, plants inoculated with S. calospora had significantly lower toxicity symptoms compared to non-mycorrhizal (NM) plants, and all fungal treatments induced tolerance against Phi toxicity in jarrah. However, no tolerance was observed for AsV-treated plants even though all inoculated plants had significantly lower shoot As concentrations than the NM plants. The transcript profile of five jarrah high-affinity phosphate transporter (PHT1 family) genes in roots was not altered in response to any of the fungal species tested. Interestingly, plants exposed to high Pi supplies for 1 day did not have reduced transcript levels for any of the five PHT1 genes in roots, and transcript abundance of four PHT1 genes actually increased. It is therefore suggested that jarrah, and perhaps other P-sensitive perennial species, respond positively to Pi available in the soil solution through increasing rather than decreasing the expression of selected PHT1 genes. Furthermore, Scleroderma sp. can be considered as a fungus with dual functional capacity capable of forming both ectomycorrhizal and non-colonizing associations, where both pathways are always accompanied by evident growth and nutritional benefits
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