Dimensionality-Driven Photoproduction of Massive Dirac Pairs near Threshold in Gapped Graphene Monolayers.

Generation of quasiparticle-hole pairs in gapped graphene monolayers in the combined field of two counterpropagating light waves is studied. The process represents an analog of electron-positron pair production from the vacuum of quantum electrodynamics (QED) by the Breit-Wheeler effect. We show, however, that the two-dimensional structure of graphene causes some striking differences between both scenarios. In particular, contrary to the QED case, it allows for nonzero pair production rates at the energy threshold when the Breit-Wheeler reaction proceeds nonlinearly with absorption of three photons.

Design, synthesis and biological evaluation of 5-amino-4-(1H-benzoimidazol-2-yl)-phenyl-1,2-dihydro-pyrrol-3-ones as inhibitors of protein kinase FGFR1.

Fibroblast growth factor receptor 1 (FGFR1) plays an important role in tumorigenesis and is therefore an attractive target for anticancer therapy. Using molecular docking approach we have identified inhibitor of FGFR1 belonging to 5-amino-4-(1H-benzoimidazol-2-yl)-phenyl-1,2-dihydro-pyrrol-3-ones with IC50 value of 3.5 µM. A series of derivatives of this chemical scaffold has been synthesized and evaluated for inhibition of FGFR1 kinase activity. It was revealed that the most promising compounds 5-amino-1-(3-hydroxy-phenyl)-4-(6-methyl-1H-benzoimidazol-2-yl)-1,2-dihydro-pyrrol-3-one and 5-amino-4-(1H-benzoimidazol-2-yl)-1-(3-hydroxy-phenyl)-1,2-dihydro-pyrrol-3-one inhibit FGFR1 with IC50 values of 0.63 and 0.32 µM, respectively, and posses antiproliferative activity against KG1 myeloma cell line with IC50 values of 5.6 and 9.3 µM. Structure-activity relationships have been studied and binding mode of this chemical class has been proposed.

[Surgical Site Infections after Open Appendectomy and Effectiveness of Complex Approach to Their Prevention].

AIM: To assess an incidence rate of surgical site infections (SSI) after open appendectomy and effectiveness of combined preventive measures (CPM). MATERIAL AND METHODS: This study was performed at three surgical departments of Smolensk hospitals. A total of 150 consecutive patients (50 at each department) hospitalized since January 2012 were included into the retrospective observation (period I). In order to perform prospective evaluation of CPM, a total of 66 consecutive patients (randomized 1:1) hospitalized since December 2012 (period II) were followed up at each of the departments. Antibiotic prophylaxis (AP) with IV amoxicillin/clavulanate (1.2 g) was planned for all patients from period II. The study group (group 1) included patients with surgical wound closure with triclosan-coated polyglactin 910 and additionally with a skin 2-octylcyanoacrylate-based adhesive. The control group (group 2) included patients with surgical wound closure with non-triclosan-coated polyglactin 910. Each patient from the period II was assigned to an "Individual SSI Prevention Package" (IPP), which included an antibiotic, sutures, skin adhesive (only in a package for CPM) and label "AP" for patients' medical records. Patients' medical records were reviewed by one expert. Exclusion criteria were: age <14 years; transition to midline laparotomy; drainage of the abdominal cavity through the surgical wound; simultaneous interventions; secondary appendicitis; refusal to use of sutures from the IPP. In order to determine signs of SSI presence/absence within 30 days after surgery, attempts to contact with patients by phone were made. The data obtained was recorded into case report forms and then entered into the study database. RESULTS: A total of 322 patients were included into the final analysis (mean age: 34.8±17.1 years). The mean length of hospital stay was 8.2±2.5 days. The mean duration of hospital stay with or without SSI was 7.9±1.8 and 14.2±4.0 days, respectively (p<0.001). The AP during the periods I and II was performed in 56.1% (83/148) and 97.7% (170/174) of patients, respectively (p<0.00001). Cephalosporins I-IV were the most frequently used antibiotics during the period I (85.6%). During the period II, amoxicillin/clavulanate from IPP was used in 98.2% of patients. Percentage of IV antibiotic administration in different time periods was 57.3% and 98.2%, respectively (p<0.0001); frequency of the first administration before skin incision was 53.6% and 97.1%, respectively (p<0.0001). The telephone contact with patient was successful in 74.8% (both periods), 56.8% (period I) and 90.2% (period II) of cases, respectively. SSI was recorded only once per patient with the following priority: SSI was documented in the patient's medical record; patient developed SSI that was not documented (in the expert's opinion) in the patient's medical record; SSI signs were determined during the telephone contact or reported by the patient. The incidence of SSI in both study periods, period I and period II was 14.9%, 15.5% and 14.4%, respectively (p>0.05 for all comparisons). In the patient subgroup with successful telephone contact, the incidence of SSI in both study periods, period I and period II was 17.4%, 21.4% and 15.3%, respectively; the incidence of SSI in group 1 and group 2 of the period II was 12.0% and 18.9%, respectively (p>0.05 for all comparisons). CONCLUSION: SSI after an open appendectomy remains an important problem. In order to determine a true incidence of SSI, it is necessary to improve the national nosocomial infection surveillance system. The CMP used in the study have showed a trend to significant SSI risk reduction and may be recommended to maximize patient protection. Further large studies are needed to confirm effectiveness of the proposed CMP.

Design, synthesis and biological evaluation of N-phenylthieno[2,3-d]pyrimidin-4-amines as inhibitors of FGFR1.

Fibroblast grow factor receptor 1 (FGFR1) is an important anti-cancer target that plays crucial role in oncogenesis and oncogenic angiogenesis. The structure-activity relationship (SAR) of N-phenylthieno[2,3-d]pyrimidin-4-amines was investigated. Binding of active compounds with FGFR1 kinase was analyzed by molecular modeling studies. Selected active thieno[2,3-d]pyrimidines were tested for selectivity and antiproliferative activity. The most active compounds, 3-({6-phenylthieno[2,3-d]pyrimidin-4-yl}amino)phenol and 3-({5-phenylthieno[2,3-d]pyrimidin-4-yl}amino)phenol have IC50 0.16 and 0.18 µM, respectively. The results presented here may help to identify new thienopyrimidines with optimized cell growth inhibitory activity which may be further used as anticancer agents.

Effects of SertaSil on wound healing in the rat.

OBJECTIVE: SertaSil is a novel product for the topical management of wound exudate. The purpose of this study was to evaluate the ability of SertaSil to promote wound healing in a pre-clinical wound model. METHODS: An aseptic wound was induced in rats by administering 1ml 10% calcium chloride solution into the subcutaneous layer under local anaesthesia. Following opening of the abscess, animals were divided into a control group (no treatment) and either SertaSil or Gentaxane, which were applied topically to the wound every 24 hours until a clean wound was achieved, that is, free from necrosis, pus and fibrinogenous thickenings. RESULTS: Rats (n=15 per group) receiving SertaSil reached the clean wound stage in 3.0 ± 0.4 days compared to 7.0 ± 0.4 days for Gentaxane and 10.0 ± 0.4 days for the control. Time to wound closure was 13.9 ± 0.3 days for SertaSil, 18.7 ± 0.6 days for Gentaxane, and 23.0 ± 0.4 days for the control. The surface area of the wounds were measured at day 1 and day 13. At day 1, the wound surface areas (mm2) were similar in all three groups (157.4 ± 8.9), but at day 13 the SertaSil group had significantly smaller wound areas (5.2 ± 1.7) compared to the Gentaxane (38.0 ± 1.5) and control groups (95.7 ± 11.3). The study was conducted in young rats that are still growing and gaining weight. At day 19, only the rats receiving SertaSil exhibited a weight increase (271 ± 5 g) indicating good recovery, whereas rats receiving Gentaxane did not gain weight (249 ± 5 g) and rats in the control group lost weight (242 ± 16 g). CONCLUSION: The study found that SertaSil reduced the time to reaching a clean wound by 60% compared to Gentaxane and promoted faster wound closure and better recovery. These findings suggest that SertaSil may be valuable for use in the treatment of wounds in patients.

Kondo correlations and Majorana bound states in a metal to quantum-dot to topological-superconductor junction.

Electron transport through a normal-metal-quantum-dot-topological-superconductor junction is studied and reveals interlacing physics of Kondo correlations with two Majorana fermions bound states residing on the opposite ends of the topological superconductor. When the strength of the Majorana fermion coupling exceeds the temperature T, this combination of Kondo-Majorana fermion physics might be amenable for an experimental test: The usual peak of the temperature dependent zero bias conductance σ(V=0,T) splits and the conductance has a dip at T=0. The heights of the conductance side peaks decrease with magnetic field.

Treatment of cultured human astrocytes and vascular endothelial cells with protein kinase CK2 inhibitors induces early changes in cell shape and cytoskeleton.

Ubiquitous protein kinase CK2 is a key regulator of cell migration, proliferation and tumor growth. CK2 is abundant in retinal astrocytes, and its inhibition suppresses retinal neovascularization in a mouse retinopathy model. In human astrocytes, CK2 co-distributes with GFAP-containing intermediate filaments, which implies its association with cytoskeleton. Contrary to astrocytes, CK2 is co-localized in microvascular endothelial cells (HBMVEC) with microtubules and actin stress fibers, but not with vimentin-containing intermediate filaments. Specific CK2 inhibitors (TBB, TBI, TBCA and DMAT) and nine novel CK2 inhibiting compounds (TID43, TID46, Quinolone-7, Quinolone-39, FNH28, FNH62, FNH64, FNH68 and FNH74) were tested at 10-200 µM for their ability to induce morphological alterations in cultured human astrocytes (HAST-40), and HBMVEC (For explanation of the inhibitor names, see "Methods" section). CK2 inhibitors caused dramatic changes in shape of cultured cells with effective inhibitor concentrations between 50 and 100 µM. Attached cells retracted, acquired shortened processes, and eventually rounded up and detached. CK2 inhibitor-induced morphological alterations were completely reversible and were not blocked by caspase inhibition. However, longer treatment or higher inhibitor concentration did cause apoptosis. The speed and potency of the CK2 inhibitors effects on cell shape and adhesion were inversely correlated with serum concentration. Western analyses showed that TBB and TBCA elicited a significant (about twofold) increase in the activation of p38 and ERK1/2 MAP kinases that may be involved in cytoskeleton regulation. This novel early biological cell response to CK2 inhibition may underlie the anti-angiogenic effect of CK2 suppression in the retina.

Evaluation of 4,5,6,7-tetrahalogeno-1H-isoindole-1,3(2H)-diones as inhibitors of human protein kinase CK2.

Protein kinase CK2 (Casein Kinase 2) is an extremely pleiotropic Ser/Thr kinase with high constitutive activity. The observation of CK2 deregulations in various pathological processes suggests that CK2 inhibitors may have a therapeutic value, particularly as anti-neoplastic and antiviral drugs. Here, we present the 4,5,6,7-tetrahalogeno-1H-isoindole-1,3(2H)-diones as a novel potent class of CK2 inhibitors. We identified this class of inhibitors by high-throughput docking of a compound collection in the ATP-binding site of human CK2. The most active compounds are 2-(4,5,6,7-tetraiodo-1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)propanoic acid and 2-(4,5,6,7-tetraiodo-1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)acetic acid with IC(50) values of 0.15 microM and 0.3 microM, respectively. These inhibitors are ATP-competitive and they only minimally inhibit the activities of protein kinases DYRK1a, MSK1, GSK3 and CDK5. Binding modes for the most active inhibitors are proposed.

Incubation effects in behavior induction in rats.

Incubation (rest) periods interposed during donor training regimens significantly enhance the "memory transfer" effect reported by some investigators. When extracts from ihe brains of donor rats given interpolated rest during acquisition training were injected into recipient animals, statistically reliable and experimentally reproducible "memory transfer" effects were found.

Use of a system of differential equations to analyze the functioning of a catalytic bio macromolecule under non equilibrium conditions.

The aim of the work is to analyze the response of a biomolecule to an external influence based on the study of its hidden states by identifying differential equations with constant coefficients. The relevance of the work lies in the fact that often the main reaction of an object to an external action can be represented as a sum of various exponential functions with a common starting point and a material balance equation. In this case, the response of an object to an external action corresponds to a system of differential equations with constant coefficients. This character of the main reaction may be due to the influence of the hidden properties of the object, which play the role of regulatory parameters. The problem is that the hidden factors and the system of differential equations are not identified. As an object, isolated reaction centers (RC) of the bacteria Rhodobacter sphaeroides , which possess the above properties, has used. Their structure is well studied. As result of studying of photo excitation processes of the reaction center has shown that electron transfer kinetics (the main reaction) can be approximated by three normalized exponential functions. Program was developed to identify for four differential equations of electron transfer and the balance equation, the behavior of hidden states of the reaction center. It was concluded that time the dependence the probability density of finding an electron in different conformational states of the reaction center characterizes the space-time changes in the structure of the reaction center.

Specific fluorescent detection of fibrillar alpha-synuclein using mono- and trimethine cyanine dyes.

With the aim of searching of novel amyloid-specific fluorescent probes the ability of series of mono- and trimethine cyanines based on benzothiazole, pyridine and quinoline heterocycle end groups to recognize fibrillar formations of alpha-synuclein (ASN) was studied. For the first time it was revealed that monomethine cyanines can specifically increase their fluorescence in aggregated ASN presence. Dialkylamino-substituted monomethine cyanine T-284 and meso-ethyl-substituted trimethine cyanine SH-516 demonstrated the higher emission intensity and selectivity to aggregated ASN than classic amyloid stain Thioflavin T, and could be proposed as novel efficient fluorescent probes for fibrillar ASN detection. Studies of structure-function dependences have shown that incorporation of amino- or diethylamino- substituents into the 6-position of the benzothiazole heterocycle yields in a appearance of a selective fluorescent response to fibrillar alpha-synuclein presence. Performed calculations of molecular dimensions of studied cyanine dyes gave us the possibility to presume, that dyes bind with their long axes parallel to the fibril axis via insertion into the neat rows (so called 'channels') running along fibril.

[The effect of reproduction biotopes on the genetic differentiation of populations of sockeye salmon Oncorhynchus nerka].

Variation of mitochondrial DNA (mtDNA) was examined in nine populations from three lake-river systems of Chukotka and Kamchatka. Significant differences were found between most of the sockeye salmon samples studied. The genetic differences among populations were not high and often did not correlate with the geographical distances between them. The low population divergence is explained by a short time of existence of most of them, having been formed after the recession of the upper Pleistocene glacier. When the populations were grouped according to their spawning biotopes (river or lake), they in general appeared more genetically similar than upon their grouping by geographical location (the lake-river systems). The differences between the river and lake populations in the lake--river systems increased from north to south.

Nonautonomous function of a pancreatic insulinoma.

A 56-year-old woman with symptoms of weakness, visual blurring, and sweating underwent diagnostic studies to evaluate the etiology of her hypoglycemia. Fasting hypoglycemia was never documented; in diagnostic studies performed during her two hospitalizations and several outpatient glucose tolerance tests, the lowest fasting plasma glucose recorded was 56 mg/dl. The patient displayed exaggerated plasma insulin responses following oral glucose (peak response: 447 muU/ml at 30 min) and following 1 gm of iv tolbutamide (peak response: 719 muU/ml at 5 min) with symptomatic profound hypoglyceria during both tests. Basal per cent proinsulin was elevated at 49% (normal range 5-22%). Throughout a 72 h fast, values for plasma glucose, insulin, and glucose/insulin ratios were all within the normal range. During the infusion of exogenous insulin (0.1 U/kg for 60 min) serum C-peptide reactivity suppressed to less than 1.3 ng/ml when the plasma glucose fell below 40 mg/dl representing normal suppression. At surgery, a pancreatic beta cell adenoma was found and removed. This patient represents the uncommon circumstances in which stimulation tests with tolbutamide and glucose were more helpful in establishing a preoperative diagnosis than were the suppression tests.

An open-label dose-escalation trial of oral dehydroepiandrosterone tolerance and pharmacokinetics in patients with HIV disease.

Dehydroepiandrosterone (DHEA) is a naturally occurring adrenal steroid reported to have immunomodulatory and antiviral activity in cellular and animal models as well as modest in vitro antiretroviral activity against human immunodeficiency virus (HIV). A phase I dose-escalation study was performed to evaluate the safety and pharmacokinetics of DHEA in subjects with symptomatic HIV disease and an absolute CD4 lymphocyte count between 250 and 600 cells/microliters. Thirty-one subjects were evaluated and monitored for safety and tolerance. The oral drug was administered three times daily in doses ranging from 750 mg/day to 2,250 mg/day for 16 weeks. Some immunological and virological parameters were monitored as well. The drug was well tolerated and no dose-limiting side effects were noted. Dose proportionality was evidenced neither by the serum DHEA nor by DHEA-S time-concentration curves for the three dosing groups. However, the study cohort appeared to consist of two subpopulations with markedly different bioavailability for a given DHEA dose. No sustained improvements in CD4 counts nor decreases in serum p24 antigen or beta-2 microglobulin levels were observed. However, serum neopterin levels decreased transiently by 23-40% at week 8 compared with baseline in all dosing groups. DHEA was well tolerated by patients with mild symptomatic HIV disease; evaluation of this agent for efficacy in HIV disease would require randomized, controlled trials.

Studies on the action mechanism of the antihemostatic effect of lodopeptides.

A synthetic iodopeptide having a glutamic acid-diiodotyrosine molar ratio of 1:1 has been shown to be an effective anticoagulant both in vivo and in vitro. Contrasted with heparin the following general conclusions may be made regarding its action. The iodopeptide does not act through the inactivation of thrombin in plasma. Iodopeptide does interact with fibrinogen to form a complex which, in vitro, is not soluble in buffered saline at physiological pH. At pH 8, iodopeptide interacts with fibrinogen to form a soluble complex in the presence of 0.9% NaCl that is not coaguable either by thrombin or Crotalus venom enzymes. All the available evidence indicates that the fibrinogen to fibrin conversion is not inhibited under these conditions, but that fibrin, once formed, is not able to polymerize due to interference by iodopeptide. Similar results were obtained with heparin in vitro with thrombin-fibrinogen mixtures in the absence of NaCl. Studies with Russell's viper venom in native PRP strongly suggest that the iodopeptide also interferes with processes in the early coagulation pathway associated with prothrombin activation.

A clinical screening program for topical chemotherapeutic drugs in psoriasis.

In this national, multicenter cooperative study, a standardized drug screening program was designed and evaluated to test the clinical effectiveness of 30 topically applied chemotherapeutic drugs to psoriasis. Appropriate concentrations and vehicles for topical administration were selected with regard to clinical testing consisted of a double-blind application of test agents to psoriatic plaques under occlusion daily for up to nine days. Drugs known to be topically active in psoriasis, eg, thiotepa, fluorouracil, and betamethasone valerate, were easily detected in the clinical protocol, confirming the validity of this topical drug screening program. Seven drugs produced substantial clinical improvement with evidence of clearing; nine drugs produced slight improvement; 14 drugs had no effect. No systemic toxid reactions occurred. This screen should be useful to test other potential antipsoriatic drugs and to evaluate potential animal model screens for their predictive values with the same drugs.

Analysis of phosphorescence decay in heterogeneous systems: consequences of finite excitation flash duration.

Analysis of phosphorescence lifetimes using the Stern-Volmer equation is a reliable means of determining quencher concentration for a uniform sample. Methods of analysis for heterogeneous systems are based on the assumption that the excitation is produced by a momentary flash. This condition is an idealization because a real flash has a finite duration and a complex time profile. In the case of a heterogeneous quencher concentration, an excitation flash produces different initial intensities and different times of peak intensity from compartments having different concentrations of quencher. We formulated a model to explore the effects of flash duration on the shape of the emission curve obtained from systems in which the heterogeneity is continuous. We developed mathematical models that can be used to recover fitting parameters of continuous distributions of reciprocal lifetimes approximated as rectangular or Gaussian distributions, or an arbitrary histogram. We also formulated a procedure to convert the distribution of reciprocal lifetimes into a volume distribution of quencher concentration. We found that (1) the Stern-Volmer ratio of phosphorescence intensities cannot be employed for interpretation of pulse phosphorometric data in terms of a volume distribution of quencher; (2) shortening the flash duration decreases the difference of initial intensities between compartments having high and low quencher concentration; (3) the parameters of the volume distribution of quencher concentration can be recovered correctly only after taking account of the difference in initial intensities; and (4) calibration of the initial intensities for a given fitting delay and flash function is necessary.

Relative bioavailability of a new transdermal nitroglycerin delivery system.

The purpose of this study was to measure the bioavailability of nitroglycerin from a new transdermal delivery system, Nitro-Dur II, relative to that of Nitro-Dur. Twenty-four healthy male volunteers completed a two-way crossover study. Each subject randomly received Nitro-Dur (I) and Nitro-Dur II (II) for a 24-h period. Both transdermal systems had an active surface area of 20 cm2. Blood samples were collected immediately before treatment, at 0.5, 1, 2, 3, 4, 6, 8, 12, 18, and 24 h after topical application of the units, and 30 min after the units were removed. Nitroglycerin was determined with an analytical sensitivity of 50 pg/mL using gas chromatography with electron capture detection (GC-EC). Mean steady-state concentrations of nitroglycerin were 182 and 224 pg/mL for I and II, respectively. There were no statistical differences between I and II in the pharmacokinetic parameters measured (Css, AUC, Cmax, % fluctuation). Residual nitroglycerin content was measured in each transdermal unit after application to each of the 24 volunteers. The amounts of nitroglycerin delivered by I and II were 9.78 +/- 4.11 and 10.67 +/- 4.78 mg, respectively, or approximately 10 mg in 24 h. Statistical analysis of these data using an analysis of variance indicated no significant difference between these treatments (p = 0.27). Since there were also no differences in the plasma concentrations and pharmacokinetic parameters calculated after treatment with I and II, the bioequivalence of the two delivery systems was established.

Weakly dissipative dust-ion-acoustic solitons.

We investigate the possibility for dust ion-acoustic solitons to exist. Compressive solitonlike perturbations are damped and slowed down, mainly due to the plasma absorption and ion scattering on microparticles. The perturbations are shown to possess the main properties of solitons. There is a principal possibility to study experimentally the role of trapped electrons in the soliton formation.