Optical echo in photonic crystals

The dynamics of photonic wavepacket in the effective oscillator potential is studied. The oscillator potential is constructed on a base of one dimensional photonic crystal with a period of unit cell adiabatically varied in space. The structure has a locally equidistant discrete spectrum. This leads to an echo effect, i.e. the periodical reconstruction of the packet shape. The effect can be observed in a nonlinear response of the system. Numerical estimations for porous-silicon based structures are presented for femtosecond Ti:Sapphire laser pump.Comment: 4 page

Borrmann Effect in Photonic Crystals: Nonlinear Optical Consequences

Nonlinear-optical manifestations of the Borrmann effect that are consequences of the spectral dependence of the spatial distributions of the electromagnetic field in a structure are observed in one-dimensional photonic crystals. The spectrum of the light self-focusing effect corresponding to the propagation-matrix calculations has been measured near the edge of the photonic gap.Comment: 4 pages, 3 figures, published in russian at Pis'ma v Zhurnal Eksperimental'noi i Teoreticheskoi Fiziki, 2008, Vol. 87, No. 8, pp. 461-46

Acute cerebellar ataxia in a young woman: Wernicke’s encephalopathy?

Wernicke’s encephalopathy (WE) is a rare but severe neurological syndrome caused by thiamine deficiency. According to the data of autopsy studies, the prevalence of WE in the general population varies from 0.4 to 2.8 per 100,000 population; the disease occurs many times more frequently in alcohol abusers than in people who lead a healthy lifestyle. These studies also showed that most cases of WE were diagnosed postmortem; less than 20% of patients with the disease were diagnosed in life. A healthy adult requires 1–2 mg of thiamine daily, depending on the carbohydrate intake. Body’s reserves of thiamine are only 30–50 mg so any malnutrition condition lasting more than 3–4 weeks can cause complete depletion of the vitamin’s stores. Classically, WE is characterized by the sudden onset of a typical triad of symptoms: an altered mental state, ophthalmoplegia, and ataxia. However, this clinical picture can be seen in only one-third of patients. The onset of the disease may sometimes look completely different: heart failure with hypotension and tachycardia; gastrointestinal symptoms (abdominal pain and nausea); hypothermia due to the involvement of the posterior hypothalamus; deafness affecting the thalamus; epileptic seizures in case of enhanced activity of the glutamatergic system.The paper describes a clinical case of acute cerebellar ataxia that is apparently caused by Wernicke’s encephalopathy in a young woman

Hyaluronic acid at osteoarthrosis: intraarticulate introduction or synthesis stimulation?

In examination comparison of efficiency and safety of local therapy by a hyaluronic acid (HA) specimen and Autologous Conditioned Serum (ACS) is spent. The obtained data testify to the plus clinical effect of intraarticulate introduction ACS surpassing efficiency HA without essential side effects

Restoration of Visual Function by Expression of a Light-Gated Mammalian Ion Channel in Retinal Ganglion Cells or ON-Bipolar Cells

Most inherited forms of blindness are caused by mutations that lead to photoreceptor cell death but spare second- and third-order retinal neurons. Expression of the light-gated excitatory mammalian ion channel light-gated ionotropic glutamate receptor (LiGluR) in retinal ganglion cells (RGCs) of the retina degeneration (rd1) mouse model of blindness was previously shown to restore some visual functions when stimulated by UV light. Here, we report restored retinal function in visible light in rodent and canine models of blindness through the use of a second-generation photoswitch for LiGluR, maleimide-azobenzene-glutamate 0 with peak efficiency at 460 nm (MAG0460). In the blind rd1 mouse, multielectrode array recordings of retinal explants revealed robust and uniform light-evoked firing when LiGluR-MAG0460 was targeted to RGCs and robust but diverse activity patterns in RGCs when LiGluR-MAG0460 was targeted to ON-bipolar cells (ON-BCs). LiGluR-MAG0460 in either RGCs or ON-BCs of the rd1 mouse reinstated innate light-avoidance behavior and enabled mice to distinguish between different temporal patterns of light in an associative learning task. In the rod-cone dystrophy dog model of blindness, LiGluR-MAG0460 in RGCs restored robust light responses to retinal explants and intravitreal delivery of LiGluR and MAG0460 was well tolerated in vivo. The results in both large and small animal models of photoreceptor degeneration provide a path to clinical translation

Annual Sedimentary Record From Lake Donguz-Orun (Central Caucasus) Constrained by High Resolution SR-XRF Analysis and Its Potential for Climate Reconstructions

Bottom sediments of the proglacial Lake Donguz-Orun situated at ∼2500 m a.s.l. in the Elbrus Region (Central Caucasus) reveal regular laminae, characteristic of proglacial varved lakes. This is the first laminated sediment sequence recorded in the region. However, visual counting of the layers was restricted due to partial indistinctness of the lamination. In order to confirm the annual sedimentary cyclicity and proceed with annually resolved data, in addition to the visual identification we used high-resolution geochemical markers. The upper 160 mm of the sediment core were scanned at 200 μm intervals using synchrotron radiation X-ray fluorescence analysis (SR-XRF). Additional ultrahigh resolution scanning at 30 μm increments was employed for the upper 20 mm of the core. The Rb/Sr and Zr/Rb ratios are interpreted to record annual changes in grain-size. Based on this geochemical assessment, we identified 88 annual layers covering the interval between 1922 and 2010, while visually we have been able to identify between 70 and 100 layers. The correctness of the geochemical results is confirmed by mean accumulation rates assessed by 137Cs and 210Pb dating. Cross-correlation between the ring width of local pine chronology and the layer thickness, identified as a distance between the annual Rb/Sr peaks, allowed for the accurate dating of the uppermost preserved year of the sediment sequence (AD 2010). Annually averaged elemental data were then compared with regional meteorological observations, glacier mass balance and tree-ring chronologies. The comparison revealed notable conformities: content of bromine is positively correlated with annual temperatures (r = 0.41, p < 0.01), content of terrigenous elements (major elements with the origin in watershed rocks) is positively correlated (up to r = 0.44, p < 0.01) with annual precipitation. A high statistically significant negative relationship is observed between the concentrations of terrigenous elements and tree-ring width of local pine chronology (up to r = -0.56, p < 0.01). Taken together, these data point to a common composite climatic signal in the two independent records (lake sediments and tree rings) and confirm that the laminae represent annual layers (i.e., varves). These findings open opportunities for high-resolution multiproxy climate reconstructions 300–350 years long using the longer sediment core and tree-ring records

Прямые и косвенные потери, определяющие вредоносность грибов р. Fusarium – возбудителей фузариоза колоса и зерна пшеницы

Fungi p. Fusarium is one of the most harmful pathogens of wheat diseases. Their harmfulness is caused both by direct losses due to decrease in yield, and indirect as a result of infection of the obtained products with mycotoxins and decrease in process, baking and sowing parameters of grain. Due to high potential losses, analysis of quantitative parameters of harmfulness of fusarium pathogens of spike and grain is relevant. The paper presents data showing the harmfulness of Fusarium of spike and wheat grain. The causes of direct and indirect losses in case of damage to wheat spike by fungi of p. Fusarium. Direct losses of crop yield are shown in the natural conditions of Minsk region and with the epiphytotic development of the disease in case of artificial infection, which can reach over 50 %. The effect of Fusaria on baking properties of wheat is analyzed. It was determined that grain damage causes decrease in weight of 1000 grains and the flour yield when it is used in the milling industry, as well as deterioration in its quality due to decrease in protein and crude gluten level. The effect of pathogens on sowing parameters of grain is determined. It is concluded that for use as seeds in terms of laboratory germination capacity, batches of grain infected with Fusarium only up to 15 % can be accepted. The data obtained will allow us to adapt protective measures against Fusarium of spike and grain and reduce its negative impact on crop yield and quality of the products obtained.Грибы р. Fusarium являются одними из наиболее вредоносных возбудителей болезней пшеницы. Их вредоносность обусловлена как прямыми потерями за счет снижения урожая, так и косвенными – в результате заражения полученной продукции микотоксинами и снижением технологических, хлебопекарных и посевных характеристик зерна. В связи с высокими потенциальными потерями исследования количественных параметров вредоносности возбудителей фузариоза колоса и зерна являются актуальными. В статье представлены данные, показывающие вредоносность фузариоза колоса и зерна пшеницы. Приведены причины прямых и косвенных потерь при поражении колоса пшеницы грибами из р. Fusarium. Показаны прямые потери урожайности культуры в естественных условиях Минской области и при эпифитотийном развитии болезни при искусственном заражении, которые могут достигать 50 % и более. Проанализировано влияние фузариев на хлебопекарные свойства пшеницы. Установлено, что поражение зерна вызывает снижение массы 1000 зерен и выход муки при использовании его в мукомольной промышленности, а также ухудшение ее качеств за счет снижения содержания белка и сырой клейковины. Определено влияние патогенов на посевные характеристики зерна. Сделан вывод, что для использования в качестве семян по показателю лабораторной всхожести могут быть допущены партии зерна, инфицированные фузариозом только до 15 %. Полученные данные позволят адаптировать защитные мероприятия против фузариоза колоса и зерна и снизить его негативное влияние на урожайность и качество получаемой продукции

Особенности сополимеризации стирола с винилбензилтриметиламмонийхлоридом в растворителях различной полярности

The solution copolymerization of styrene with vinylbenzyl trimethylammonium chloride (VBTMAC) was investigated. The solvents used in this study form homogeneous solutions with mixtures of monomers and possess different polarity, namely, isopropanol, DMSO, and their mixtures. Reactivity ratios of the copolymerization of these monomers in isopropanol were determined: rstyrene is 0.15 ± 0.01, rVBTMAC is 0.46 ± 0.004. Based on the values of the reactivity ratios authors conclude that the resulting copolymers have a tendency to alternate structural units. It was shown that the copolymerization of these monomers could not be described by means of Mayo-Lewis copolymerization model. The main reason for the deviation from the classical scheme of copolymerization is the bootstrap effect (the selective sorption of growing polymer radical by styrene). This effect increases with increasing polarity of the solvent as well as when the resulting copolymers are allocated in heterophase.Изучена сополимеризация стирола с винилбензилтриметиламмонийхлоридом в растворителях различной полярности: изопропаноле и ДМСО и их смесях. Показано, что основной причиной отклонения от классической схемы бинарной сополимеризации является избирательная сольватация растущих макрорадикалов стиролом