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Urban-induced land use changes have a significant impact on local weather patterns, leading to increased hydro-meteorological hazards in cities. Despite substantial threats posed to humans, understanding atmospheric hazards related to urbanisation, such as thunderstorms, lightning, and convective precipitation, remains unclear. This study aims to analyse seasonal variability of cloud-to-ground (CG) lightning in the five large metropolitans in Bangladesh utilising six years (2015–2020) of Global Lightning Detection Network (popularly known as GLD360) data. It also investigates factors influencing CG strokes. The analysis revealed substantial seasonal fluctuations in CG strokes, with a noticeable increase in lightning activity during the pre-monsoon months from upwind to metropolitan areas across the five cities. Both season and location appear to impact the diurnal variability of CG strokes in these urban centres. Bivariate regression analysis indicated that precipitation and particulate matter (PM) significantly influence lightning generation, whilst population density, urban size, and mean surface temperature have negligible effects. A sensitivity test employing a random forest (RF) model underscored the pivotal role of PM in CG strokes in four of the five cities assessed, highlighting the enduring impact of extreme pollution on lightning activity. Despite low causalities from CG lightning, the risk of property damage remains high in urban environments. This study provides valuable insights for shaping public policies in Bangladesh, a globally recognised climate hotspot.

Switching from conventional to conservation agriculture (CA) practices may affect the soil microbial community; however, such information in rice-based systems is yet to be explored. Two field experiments were conducted from 2015 to 2020 on contrasting soils (calcareous vs non-calcareous) to evaluate the CA effects on soil microbial populations and their diversity. Experiment No. 1, non-calcareous soils, was comprised of two tillage systems (minimum tillage [MT] vs. conventional tillage, [CT]) in main plots, three cropping patterns (wheat-Aus-Aman rice, [WRR]; lentil-Aus-Aman rice, [LRR]; mustard-Boro-Aman rice, [MRR]) in the sub plots, and two residue levels (with and without 20% residue retention) in the sub-sub plots. Another experiment, calcareous soils, was comprised of three tillage treatments (strip-till [ST]; no-till [NT]; and conventional tillage [CT]) and two previous crop residues (high residue [HR], 50% by height) vs. low residue [LR], 15%). Non-calcareous soils had higher fungal populations with higher microbial biomass carbon but lower nematode and bacterial populations compared to the calcareous soils. In non-calcareous soils, the MT resulted in higher microbial populations than the CT at 0–7.5-cm depth, but not at 7.5–15-cm depth. Likewise, the LRR system maintained higher microbial populations compared to the WRR and MRR systems. In calcareous soils, all the microbial populations were higher in the NT and ST than in the CT, where the former two were alike. Reduced tillage with crop residue retention improved soil microbial populations and their diversity with higher fungal-to-bacteria ratios in both soils.

Severe weather events such as lightning appear to be a significant threat to humans and property in South Asia, an area known for intense convective activity directly related to the tropical climate of these areas. The current study was conducted in Bangladesh and examined the association between cloud-to-ground (CG) lightning and ground surface properties, with the aim of improving existing knowledge regarding this phenomenon. GLD360 data from 2015 to 2020 were used to describe the seasonal lightning climatology. Elevation, land use and land cover, vegetation and surface heat flux data were used to examine all land surface features possibly associated with CG lightning occurrence. Hot and cold spot spatial patterning was calculated using local indicators of spatial association. Results indicated a strong CG lightning seasonality. CG stroke density varied considerably across seasons with the pre-monsoon exhibiting the highest density. This was followed by occurrences in the monsoon season. The March–June period experienced 73% of the total observed. Elevation appeared to influence the post-monsoon CG stroke, however, its role in the other seasons was more difficult to define. The land cover/lightning index indicated that waterbodies and herbaceous wetlands had more influence than other land cover types, both during the day and at night, and it appeared that latent heat flux played a major role. The CG stroke hot and cold spot locations varied diurnally. The findings suggest that large-scale irrigation practices, especially during the pre-monsoon months, can influence the observed spatiotemporal pattern. The production of hotspot maps could be an initial step in the development of a reliable lightning monitoring system and play a part in increasing public awareness of this issue.

Behavioral intention and continued adoption of Facebook: An exploratory study of graduate students in Bangladesh during the Covid-19 pandemic

Objective: The reaction of bis(4-amino-4H-1,2,4-triazole-3-thiol) with hydrazonoyl halides and α-halo-ketones gave a new series of bis-1,2,4-triazolo[3,4-b]thiadiazine derivatives. Methods: The structure of the new products was established on the basis of their elemental and spectral data (mass, 1H NMR, 13C NMR and IR) and an alternate method. Results: Several of the synthesized products were subjected to in vitro anticancer screening against human hepatocellular carcinoma (HepG-2) and the results showed that compounds 16, 14 and 12 have promising activities (IC50 value of 24.8±9.1, 28.3±0.5, and 31±2.9μM, respectively) compared with Harmine reference drug (IC50 value of 22.4±1.11 μM). Conclusion: Moreover, molecular docking studies were performed to analyze the binding modes of the discovered hits into the active site of DYRK1A using iGEMDOCK.

This work aims at optimizing the H2 reduction time of Fe/rGO as a preparatory step for the use of the reduced catalyst in Fisher-Tropsch synthesis (FTS). The catalytic system used was Iron Nanoparticles (NPs) loaded on reduced graphene oxide (rGO) support. The as prepared sample was analyzed by TEM, FTIR and XRD spectroscopy. Samples of the produced Fe/rGO catalyst were used to optimize the reduction conditions in the FBR reactor. The three samples were reduced under 1atm H2 gas flow of 50 sccm at 500°C for 8, 12 and 24 hrs. The samples were collected after reduction and analyzed by XRD, FTIR and TEM imaging. The best condition showing full reduction with minimal sintering was at 12hr.

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Background: Healthy pregnancy and maternal health status influence fetal growth. Studies linking maternal and neonatal anthropometry showed confounding results. Objectives: To study the relationship between maternal and neonatal anthropometry. Methods: This cross-sectional study included 491 full-term healthy newborns born to healthy mothers with uncomplicated pregnancy. Neonatal and maternal anthropometric measurements as well as detailed perinatal history were recorded. Results: Third trimester weight, body mass index (BMI), and mid upper arm circumference (MUAC) were positively related to neonatal birth weight (BW), length and head circumference (HC) (p< 0.001 for all of them except for MUAC with length, p= 0.021). Maternal education was inversely related to BW (p= 0.031) and positively related to HC (p= 0.001). Consanguinity had a positive relation to HC (p< 0.001). Conclusions: Maternal 3rd trimester weight, MUAC, BMI, education, and consanguinity can be related to different neonatal anthropometric measurements.

Background: A novel series of fused imidazole was prepared from the reaction of 2- bromoacetyl-3-phenyl-1,3,4-thiadiazole with various heterocyclic amines under microwave irradiation. The structures of all the novel products were elucidated based on the elemental analysis and spectral data. Results: In addition, the biological activity of the newly synthesized compounds was evaluated and the results obtained indicate their potency as anti-inflammatory, analgesic and anti- ulcer agents. Conclusion: The binding mechanism of the most active compounds was studied using MOE to analyze the molecular interactions.

•Perceived social support plays an important role in COVID-19 vaccine uptake.•Lower levels of social support are associated with lower COVID-19 vaccine uptake.•The association is more evident among older adults.

In this work the Fischer-Tropsch synthesis reaction was catalyzed by reduced graphene oxide supported Fe nanoparticles catalysts in a fixed bed reactor. Also the influence of promotion by K and Mn on the catalytic activity of Fe nanoparticles was investigated. The systems showed acceptable CO conversions reaching as high as 96.2%. The selectivities of the C1-5 ranged from 38 to 62%. There was a very high CO2 selectivity which was explained by incomplete reduction of the catalysts. The Anderson-Schultz-Flory parameter was calculated and varied between 0.25 and 0.3. The strongest promoting effect was achieved by the K promoter which tended to reduce light product selectivities and CO2 production the most.

•Significant disparities exist in cancer outcomes. We examined demographic and geographic representation for pivotal trials in lymphomas.

Nitrogen (N) limitation is well documented for the brown planthopper (BPH) Nilaparvata lugens(Stål), but phosphorus (P) and potassium (K) limitation is poorly studied. We studied the effects of N, P, and K application on chemical composition of rice plants and its consequences on life parameters—adult longevity, fecundity, and egg hatchability of BPH. Life parameters of BPH were regressed as function of plant chemical composition. A completely randomized design with four replicates in a factorial scheme was used considering N, P, and K levels as factors. Nitrogen application increased N and soluble proteins (SP) and decreased silicon (Si) content in the plants resulting in increased adult longevity, fecundity, and egg hatchability of BPH. Phosphorus fertilization increased P content and showed markedly increased fecundity, but not egg hatchability or adult longevity. Significant interaction between N and P was observed for fecundity of BPH. Potassium supplementation increased K content but reduced N, Si, SP, and total free sugars (TFS) content in the plants, but it had no significant effect on life parameters of BPH. The association of BPH life parameters with N, SP, TFS, and P content was significant and positive, but it was negative with the content of Si. Thus, N and P fertilization on rice plants enhanced BPH fitness. In conclusion, judicious nutrient application can be helpful in avoiding generalized infestation of BPH to rice.

Increasing C sequestration through no‐till (NT) can reduce agricultural CO2emissions. However, for long‐term NT, information is lacking on the effect of biophysical C pools and processes on C sequestration. Composite soil samples taken at 7.5‐cm increments to a 30‐cm depth from conventionally tilled (CT) and 2 (NT2), 23 (NT23), and 44 yr (NT44) of NT corn (Zea maysL.) plots in northwest Ohio were analyzed. The microbial biomass (SMB) was 13, 83, and 86% higher in NT2, NT23, and NT44, respectively, than in CT. No‐till had slightly higher basal respiration rates but significantly lower specific maintenance respiration rates and SMB loss than CT. Aggregate stability in NT was 35 to 45% higher than in CT. Macroaggregate‐protected C (CMaA) was 24, 80, and 92% higher in NT2, NT23, and NT44, respectively, than in CT. For all tillage treatments, these properties decreased with depth. The C sequestration rates for SMB were 22, 13, 7, and 3 kg ha−1yr−1at the 0‐ to 7.5‐, 7.5‐ to 15‐, 15‐ to 22.5‐, and 22.5‐ to 30‐cm depths, respectively for the first 10 yr of NT. During the same time, the CMaAsequestration rates were 92, 63, 47, and 37 kg ha−1yr−1at the four depths, and macroaggregate (MaA) formation rates were 3170, 350, 170, and 70 kg ha−1yr−1, respectively However, these rates decreased over the 44 yr of NT. By 20 yr of NT, at all depths the C sequestered in SMB reached a plateau. Similarly, CMaAsequestration plateaued at the surface by 20 yr and MaA formation at the surface leveled out by 10 yr.

ABSTRACTIclaprim is a novel antibacterial agent that is currently in development for the treatment of complicated skin and skin structure infections (cSSSI). Iclaprim specifically and selectively inhibits bacterial dihydrofolate reductase, a critical enzyme in the bacterial folate pathway, and exhibits an extended spectrum of activity against various resistant pathogens, including methicillin (meticillin)-resistant Staphylococcus aureus(MRSA). The objective of this randomized, double-blind phase II study was to compare the efficacy and safety of iclaprim to those of vancomycin in patients with cSSSI. Patients were randomized to receive 0.8 mg iclaprim/kg of body weight, 1.6 mg/kg iclaprim, or 1 g vancomycin twice a day for 10 days. Clinical cure rates for the 0.8- and 1.6-mg/kg-iclaprim treatment groups were comparable to that for the vancomycin treatment group (26/28 patients [92.9%], 28/31 patients [90.3%], and 26/28 patients [92.9%], respectively). Iclaprim also showed high microbiological eradication rates. Iclaprim exhibited an eradication rate of 80% and 72% versus 59% observed with vancomycin for S. aureus, the pathogen most frequently isolated at baseline. Five MRSA cases were observed, four in the 0.8-mg/kg-iclaprim arm and one in the vancomycin arm, and all were both clinically and microbiologically cured. Iclaprim exhibited a safety profile similar to that of vancomycin, an established drug for the treatment of cSSSI. Results from this study indicate that iclaprim is a promising new therapy for the treatment of cSSSI, in particular those caused by S. aureus, including MRSA.

AbstractDetailed behavior of plasmas has been investigated in the course of an optimization phase of wall conditioning in the central-cell of GAMMA 10 tandem mirror. The results are described based on the visible image measurements using CCD camera together with Hα line-emission measurements in the central-cell. Three limiters are installed in the central-cell and the behavior of the plasmas near the each limiter is precisely observed in response to electron cyclotron heating (ECH) for potential formation. In an early stage of wall conditioning in GAMMA 10, plasma parameters obtained in standard hot ion mode plasmas are compared in cases of sustained plasma in ECH pulses and of collapsed one simultaneously with ECH. Dependence of gas puffing from the mirror throat in the central cell and of the diameter of limiters is also investigated on the plasma behavior in ECH. From the measured results, it is recognized that a significant upward shift of the plasma column and imbalance of the Hα intensity between east and west Iris-limiters cause the plasma collapse in ECH. A systematic analysis of the dependence on plasma durability in the number of wall conditioning shots, the position of the plasma just before the ECH injection and suitable quantity of gas puffing is necessary for stably sustaining the plasma during potential formation by ECH.

(1) Four-time progress in ion-confining potentials Φcto 3.0 kV in comparison to Φcattained 1992-2002 is achieved in the hot-ion mode (Ti=several keV). A scaling of Φc, which favorably increases with plug electron-cyclotron heating (ECH) powers (PPECH), is obtained. (2) The advance in Φcleads to a finding of remarkable effects of radially sheared electric fields (dEr/dr) on turbulence suppression and transverse-loss reduction. (3) A weak decrease in Φcwith increasing ncto ˜1019m-3with the recovery of Φcwith increasing PPECHis obtained. (4) The first achievement of active control and formation of an internal transport barrier (ITB) has been carried out with the improvement of transverse energy confinement. Off-axis ECH in an axisymmetric barrier mirror produces a cylindrical layer with energetic electrons, which flow through the central cell and into the end region. The layer, which produces a localized bumped ambipolar potential Φc, generates a strong Ershear and peaked vorticity with the direction reversal of Err× Bsheared flow near the Φcpeak. Intermittent vortex-like turbulent structures near the layer are suppressed in the central cell. This results in Teand Tirises surrounded by the layer. The phenomena are analogous to those in tokamaks with ITB. (5) Preliminary central ECH (170 kW, 20 ms) in a standard tandem-mirror operation raises Te0from 70 to 300 eV together with Ti[perpendicular]0from 4.5 to 6.1 keV, and Ti//0from 0.5 to 1.2 keV with τp0=95 ms for Φc(=1.4 kV) trapped ions. The on-axis particle to energy confining ratio of τp0/τE0is observed to be 1.7 for Φctrapped ions (consistent with Pastukhov’s theory) and 2.4 for central mirror-trapped ions with 240-kW plug ECH and 90-kW ICH (ηICH˜0.3; nlc=4.5×1017m-2). (6) Recently, a 200 kW central ECH with 430 kW plug ECH produces stable central-cell plasmas (Te=600 eV and Ti=6.6 keV) with azimuthal Er×Bsheared flow. However, in the absence of the shear flow, hot plasmas migrate unstably towards vacuum wall with plasma degradation.

Bone marrow-derived mesenchymal stem cells (MSCs) can differentiate into different cell lineages with the appropriate stimulation in vitro. Transplantation of MSCs in human and other animal models was found to repair tissues through the fusion of transplanted MSCs with indigenous cells. We have generated mouse–mouse hybrid cell lines in vitro by polyethylene glycol-mediated fusion of primary mouse MSCs with mouse fibroblasts to investigate the characteristics of hybrid cells, including their potentials for proliferation and differentiation. Similar to the parental MSCs, hybrid cells are positive for the cell-surface markers CD29, CD44, CD49e, and Sca-1, and negative for Gr-1, CD11b, CD13, CD18, CD31, CD43, CD45, CD49d, CD90.2, CD445R/B220, and CD117 markers. The hybrid cells also produce a high level of tissue nonspecific alkaline phosphatase compared to the parental cells. Conditioned medium of hybrid cells contain biologically active factors that are capable of stimulating proliferation of other cells. Although the parental MSCs can differentiate into adipogenic and osteogenic lineages, hybrid cells held disparate differentiation capacity. Hybrid cell lines in general have increased proliferative capacity than the primary MSCs. Our study demonstrates that proliferative hybrid cell lines can be generated in vitro by induced fusion of both immortal and primary somatic cells with primary MSCs.

Following the 2002 Conference on Open Magnetic Systems for Plasma Confinement, a three times progress in the formation of ion-confining potential height is achieved in the hot-ion mode. The advance in the potential formation leads to a finding of remarkable effects of radially produced shear of electric fields dEr/dr on the suppression of not only coherent drift waves but turbulence-like fluctuations for the first time in GAMMA 10. Also, the progress in the potential formation is made in line with the extension of our proposed physics scaling of potential formation covering over representative tandem-mirror operational modes, characterized in terms of (a) a high-potential mode having kV-order plasmaconfining potentials and (b) a hot-ion mode yielding fusion neutrons with 10-20 keV bulk-ion temperatures (Ti).

Soil physical properties are important indicators of the potential for agricultural production. The objective of this research was to examine the difference in soil physical properties 9 yr after the initiation of two water table management (WTM) treatments in Wood County, Ohio. Water table management treatments included both unrestricted subsurface drainage year round (Drainage Treatment) and subirrigation during the crop‐growing season to maintain the water table at 25 cm below the surface with unrestricted subsurface drainage the remainder of the year (Subirrigation Treatment). Soil samples were collected in eight plots, in six depth increments to a 1‐m depth. Soil aggregation and related properties were significantly different in response to WTM treatments and soil depths. The subirrigated treatment had lower aggregate stability at 40 to 50 cm compared with the drainage treatment. The mean weight diameter (MWD) and geometric mean diameter (GMD) of aggregates in the subirrigated treatment were smaller than the drainage treatment at depths of 30 to 75 cm. Percentage of macroaggregates and aggregate ratios were generally lower in the subirrigation treatment than the drainage treatment. Subirrigated soils exhibited relatively lower bulk density with an associated increase in total porosity. The drainage treatment had greater penetration resistance from 30 to 45 cm on readings taken in Spring 2000. Subirrigated soils retained a greater volume of moisture at all matric potentials except −0.00015 and −1.5 MPa. The subirrigated soils are apparently not able to develop large, stable aggregates as seen in the continuously drained soil, perhaps because of the frequent water saturation followed by slaking of soil macroaggregates associated with subirrigation.

In the search for more efficacious drugs to treat neuropathic pain states, a series of phenoxyphenyl pyridines was designed based on 4-(4-flurophenoxy)benzaldehyde semicarbazone. Through variation of the substituents on the pyridine ring, several potent state-dependent sodium channel inhibitors were identified. From these compounds, 23 dose dependently reversed tactile allodynia in the Chung model of neuropathic pain. Administered orally at 10 mg/kg the level of reversal was ca. 50%, comparable to the effect of carbamazepine administered orally at 100 mg/kg.

An enantioselective total synthesis of the novel, biologically active epoxyquinone natural product (−)-cycloepoxydon has been accomplished from the readily available Diels−Alder adduct of cyclopentadiene and p-benzoquinone. A new cycloepoxydon related heptacyclic dimer has been prepared and characterized.

Syntheses of 6-epi- and 8-epi-otteliones, corresponding to earlier proposed structures of the biologically potent natural product ottelione A, have been accomplished from the readily available Diels−Alder adduct of cyclopentadiene and p-benzoquinone.

The major neuronal post-translational modification of tubulin, polyglutamylation, can act as a molecular potentiometer to modulate microtubule-associated proteins (MAPs) binding as a function of the polyglutamyl chain length. The relative affinity of Tau, MAP2, and kinesin has been shown to be optimal for tubulin modified by approximately 3 glutamyl units. Using blot overlay assays, we have tested the ability of polyglutamylation to modulate the interaction of two other structural MAPs, MAP1A and MAP1B, with tubulin. MAP1A and MAP2 display distinct behavior in terms of tubulin binding; they do not compete with each other, even when the polyglutamyl chains of tubulin are removed, indicating that they have distinct binding sites on tubulin. Binding of MAP1A and MAP1B to tubulin is also controlled by polyglutamylation and, although the modulation of MAP1B binding resembles that of MAP2, we found that polyglutamylation can exert a different mode of regulation toward MAP1A. Interestingly, although the affinity of the other MAPs tested so far decreases sharply for tubulins carrying long polyglutamyl chains, the affinity of MAP1A for these tubulins is maintained at a significant level. This differential regulation exerted by polyglutamylation toward different MAPs might facilitate their selective recruitment into distinct microtubule populations, hence modulating their functional properties.

This paper describes the effect of conducting plates installed in the transition region of the minimum-B anchor-cell of GAMMA 10 for the purpose of the improvement in plasma performance. The conducting plates are fixed closely to the plasma surface where the cross section of the plasma is flatly elongated in the transition region. Electrical characteristics of the conducting plates are investigated by changing the resister connected between the plates and the machine ground. Effects on the plasma parameters of the conducting plates are studied and it is found that the floating condition of the plates leads to the increase of the plasma density during potential formation. It is also find that the effect is reduced in the case that the space of main plates facing each other is widened. Existence of electric current in azimuthal direction of plasma cross section is discussed from the viewpoint of radial loss mechanism.

We investigated the relations between ozone (O3), nitrogen dioxide (NO2), and respirable particles less than 10 m in diameter (PM10) and school absenteeism in a cohort of 4th-grade school children who resided in 12 southern California communities. An active surveillance system ascertained the numbers and types of absences during the first 6 months of 1996. Pollutants were measured hourly at central-site monitors in each of the 12 communities. To examine acute effects of air pollution on absence rates, we fitted a two-stage time-series model to the absence count data that included distributed lag effects of exposure adjusted for long-term pollutant levels. Short-term change in O3, but not NO2or PM10, was associated with a substantial increase in school absences from both upper and lower respiratory illness. An increase of 20 ppb of O3was associated with an increase of 62.9 95 confidence interval (95 CI) 18.4–124.1 for illness-related absence rates, 82.9 (95 CI 3.9–222.0) for respiratory illnesses, 45.1 (95 CI 21.3–73.7) for upper respiratory illnesses, and 173.9 (95 CI 91.3–292.3) for lower respiratory illnesses with wet cough. The short-term effects of a 20-ppb change of O3on illness-related absenteeism were larger in communities with lower long-term average PM10223.5 (95 CI 90.4–449.7) compared with communities with high average levels 38.1 (95 CI 8.5–75.8). Increased school absenteeism from O3exposure in children is an important adverse effect of ambient air pollution worthy of public policy consideration.

Midbrain dopaminergic (mDA) neurons are diverse in their projection targets, effect on behavior, and susceptibility to neurodegeneration. Little is known about the molecular mechanisms establishing this diversity during development. We show that the transcription factor BCL11A is expressed in a subset of mDA neurons in the developing and adult murine brain and in a subpopulation of pluripotent-stem-cell-derived human mDA neurons. By combining intersectional labeling and viral-mediated tracing, we demonstrate that Bcl11a-expressing mDA neurons form a highly specific subcircuit within the murine dopaminergic system. In the substantia nigra, the Bcl11a-expressing mDA subset is particularly vulnerable to neurodegeneration upon α-synuclein overexpression or oxidative stress. Inactivation of Bcl11ain murine mDA neurons increases this susceptibility further, alters the distribution of mDA neurons, and results in deficits in skilled motor behavior. In summary, BCL11A defines mDA subpopulations with highly distinctive characteristics and is required for establishing and maintaining their normal physiology.

Objectives: We assessed the 30-day readmission rate of a privately insured population diagnosed with colorectal cancer (CRC) who had primary tumor resection in rural and urban communities.Methods: Claims data of people aged <65 with a diagnosis of CRC between 2012 and 2016 and enrolled in a private health plan administered by BlueCross BlueShield of Nebraska were analyzed. Readmission was defined as the number of discharged patients who were readmitted within 30 days, divided by all discharged patients. Multivariate logistic regression was used to estimate the factors associated with readmission.Results: The urban population had a higher readmission rate (11%) than the rural population (8%). Although the adjusted odds ratio showed that there is no difference in readmission between rural and urban residents, patients with a Charlson Comorbidity Index (CCI) of >1 were more likely than those without CCI to be readmitted (OR 3.59, 1.41-9.11). Patients with open vs. laparoscopic surgery (OR 2.80, 1.39-5.63) and those with an obstructed or perforated colon vs. none (OR 7.17, 3.75-13.72) were more likely to be readmitted.Conclusions: Readmission after CRC surgery occurs frequently. Interventions that target the identified risk factors should reduce readmission rates in this privately insured population.

The filamentous bacteriophage CTXPhi, which encodes cholera toxin (CT) in toxigenic Vibrio cholerae, is known to propagate by infecting susceptible strains of V. cholerae by using the toxin coregulated pilus (TCP) as its receptor and thereby causing the origination of new strains of toxigenic V. cholerae from nontoxigenic progenitors. Besides V. cholerae, Vibrio mimicus strains which are normally TCP negative have also been shown to occasionally produce CT and cause diarrhea in humans. We analyzed nontoxigenic V. mimicus strains isolated from surface waters in Bangladesh for susceptibility and lysogenic conversion by CTXPhi and studied the expression of CT in the lysogens by using genetically marked derivatives of the phage. Of 27 V. mimicus strains analyzed, which were all negative for genes encoding TCP but positive for the regulatory gene toxR, 2 strains (7.4%) were infected by CTX-KmPhi, derived from strain SM44(P27459 ctx::km), and the phage genome integrated into the host chromosome, forming stable lysogens. The lysogens spontaneously produced infectious phage particles in the supernatant fluids of the culture, and high titers of the phage could be achieved when the lysogens were induced with mitomycin C. This is the first demonstration of lysogenic conversion of V. mimicus strains by CTXPhi. When a genetically marked derivative of the replicative form of the CTXPhi genome carrying a functional ctxAB operon, pMSF9.2, was introduced into nontoxigenic V. mimicus strains, the plasmid integrated into the host genome and the strains produced CT both in vitro and inside the intestines of adult rabbits and caused mild-to-severe diarrhea in rabbits. This suggested that in the natural habitat infection of nontoxigenic V. mimicus strains by wild-type CTXPhi may lead to the origination of toxigenic V. mimicus strains which are capable of producing biologically active CT. The results of this study also supported the existence of a TCP-independent mechanism for infection by CTXPhi and showed that at least one species of Vibrio other than V. cholerae may contribute to the propagation of the phage.

Toxigenic Vibrio cholerae strains are lysogens of CTXPhi, a filamentous phage which encodes cholera toxin. The receptor for CTXPhi for invading V. cholerae cells is the toxin-coregulated pilus (TCP), the genes for which reside in a larger genetic element, the TCP pathogenicity island. We analyzed 146 CTX-negative strains of V. cholerae O1 or non-O1 isolated from patients or surface waters in five different countries for the presence of the TCP pathogenicity island, the regulatory gene toxR, and the CTXPhi attachment sequence attRS, as well as for susceptibility of the strains to CTXPhi, to investigate the molecular basis for the emergence of new clones of toxigenic V. cholerae. DNA probe or PCR assays for tcpA, tcpI, acfB, toxR, and attRS revealed that 6.85% of the strains, all of which belonged to the O1 serogroup, carried the TCP pathogenicity island, toxR, and multiple copies of attRS, whereas the remaining 93.15% of the strains were negative for TCP but positive for either one or both or neither of toxR and attRS. An analysis of the strains for susceptibility to CTXPhi, using a genetically marked derivative of the phage CTX-KmPhi, showed that all TCP-positive CTX-negative strains and 1 of 136 TCP-negative strains were infected by the phage either in vitro or in the intestines of infant mice. The phage genome integrated into the chromosome of infected V. cholerae O1 cells forming stable lysogens. Comparative analysis of rRNA gene restriction patterns revealed that the lysogens derived from nontoxigenic progenitors were either closely related to or distinctly different from previously described clones of toxigenic V. cholerae. To our knowledge, this is the first demonstration of lysogenic conversion of naturally occurring nontoxigenic V. cholerae strains by CTXPhi. The results of this study further indicated that strains belonging to the O1 serogroup of V. cholerae are more likely to possess the TCP pathogenicity island and hence to be infected by CTXPhi, leading to the origination of potential new epidemic clones.

In this study the effects of different antifungal agents on the binding of Candida albicans yeast cells to different supports were examined. Pre-treatment with amphotericin B or dithiothreitol (DTT) severely reduced the ability of C. albicans yeasts to bind to plastic, while the effects of pre-treatment with fluconazole, ketoconazole or flucytosine were less marked. Both DTT and amphotericin B reduced the binding of yeasts to bovine serum albumin (BSA) and amino acids at low concentrations, while the other antifungal agents were effective at concentrations several-fold higher than their MICs. These data suggest that DTT and amphotericin B affect the yeast cell wall components, and alter both hydrophobic interactions with plastic, and the more specific interactions with BSA and amino acids. By contrast, the effect of the azoles and flucytosine appears to be largely restricted to hydrophobic interactions.

ABSTRACTThe filamentous bacteriophage CTXΦ, which encodes cholera toxin (CT) in toxigenic Vibrio cholerae, is known to propagate by infecting susceptible strains of V. choleraeby using the toxin coregulated pilus (TCP) as its receptor and thereby causing the origination of new strains of toxigenic V. choleraefrom nontoxigenic progenitors. Besides V. cholerae, Vibrio mimicusstrains which are normally TCP negative have also been shown to occasionally produce CT and cause diarrhea in humans. We analyzed nontoxigenic V. mimicusstrains isolated from surface waters in Bangladesh for susceptibility and lysogenic conversion by CTXΦ and studied the expression of CT in the lysogens by using genetically marked derivatives of the phage. Of 27 V. mimicusstrains analyzed, which were all negative for genes encoding TCP but positive for the regulatory gene toxR, 2 strains (7.4%) were infected by CTX-KmΦ, derived from strain SM44(P27459 ctx::km), and the phage genome integrated into the host chromosome, forming stable lysogens. The lysogens spontaneously produced infectious phage particles in the supernatant fluids of the culture, and high titers of the phage could be achieved when the lysogens were induced with mitomycin C. This is the first demonstration of lysogenic conversion of V. mimicusstrains by CTXΦ. When a genetically marked derivative of the replicative form of the CTXΦ genome carrying a functionalctxABoperon, pMSF9.2, was introduced into nontoxigenicV. mimicusstrains, the plasmid integrated into the host genome and the strains produced CT both in vitro and inside the intestines of adult rabbits and caused mild-to-severe diarrhea in rabbits. This suggested that in the natural habitat infection of nontoxigenic V. mimicusstrains by wild-type CTXΦ may lead to the origination of toxigenic V. mimicusstrains which are capable of producing biologically active CT. The results of this study also supported the existence of a TCP-independent mechanism for infection by CTXΦ and showed that at least one species ofVibrioother than V. choleraemay contribute to the propagation of the phage.

ABSTRACTToxigenic Vibrio choleraestrains are lysogens of CTXΦ, a filamentous phage which encodes cholera toxin. The receptor for CTXΦ for invading V. choleraecells is the toxin-coregulated pilus (TCP), the genes for which reside in a larger genetic element, the TCP pathogenicity island. We analyzed 146 CTX-negative strains of V. choleraeO1 or non-O1 isolated from patients or surface waters in five different countries for the presence of the TCP pathogenicity island, the regulatory genetoxR, and the CTXΦ attachment sequence attRS, as well as for susceptibility of the strains to CTXΦ, to investigate the molecular basis for the emergence of new clones of toxigenicV. cholerae. DNA probe or PCR assays for tcpA,tcpI, acfB, toxR, andattRSrevealed that 6.85% of the strains, all of which belonged to the O1 serogroup, carried the TCP pathogenicity island,toxR, and multiple copies of attRS, whereas the remaining 93.15% of the strains were negative for TCP but positive for either one or both or neither of toxRandattRS. An analysis of the strains for susceptibility to CTXΦ, using a genetically marked derivative of the phage CTX-KmΦ, showed that all TCP-positive CTX-negative strains and 1 of 136 TCP-negative strains were infected by the phage either in vitro or in the intestines of infant mice. The phage genome integrated into the chromosome of infected V. choleraeO1 cells forming stable lysogens. Comparative analysis of rRNA gene restriction patterns revealed that the lysogens derived from nontoxigenic progenitors were either closely related to or distinctly different from previously described clones of toxigenic V. cholerae. To our knowledge, this is the first demonstration of lysogenic conversion of naturally occurring nontoxigenic V. choleraestrains by CTXΦ. The results of this study further indicated that strains belonging to the O1 serogroup of V. choleraeare more likely to possess the TCP pathogenicity island and hence to be infected by CTXΦ, leading to the origination of potential new epidemic clones.

Carbon, as an active component of organic matter, has considerable effects on soil quality and productivity. The objective of this study was to examine the effect of climate change variables on soil organic C (CT) quality in an agroecosystem. Wheat (Triticum aestivumL.) and soybean [Glycine max(L.) Merr] plants were grown in 3 m in diam. open‐top field chambers and exposed to charcoal‐filtered (CF) air at 350 µL CO2L−1; CF air + 150 µL CO2L−1; nonfiltered (NF) air + 35 nL O3L−1; and NF air + 35 nL O3L−1+ 150 µL CO2L−1at two soil moisture levels from 1994 to 1996. The 150 µL CO2L−1addition was 18 h d−1and the 35 nL O3L−1was 7 h d−1from April until late October. In response to treatments, the Cr contents did not change significantly; however, participate, oxidizable, dissolved, humic (CHA) and fulvic (CFA) acid, and carbohydrate C pools increased in soils under CO2enrichment and well‐watered conditions but decreased under O3stress compared with soils under CF ambient air quality. Tropospheric CO2enrichment and well‐watered condition increased, and O3stress decreased the log optical density slope for both CHAand CFAfractions more than CF ambient air and restricted moisture treatment. Also, the E465/E665ratios of both CHAand CFAfractions were higher for the CO2enrichment and smaller for the O3stress compared with CF ambient air quality. Results suggest that tropospheric CO2enrichment and well‐watered conditions may favor an accumulation of low molecular weight and more aliphatic quality of C and O3stress favor high molecular weight and more aromatic quality of C.

The bioavailabilities of orally administered drugs depend to a great extent on their capability of being transported across the intestinal mucosa. In an attempt to develop an in vitro model for studying the intestinal transport of drugs, we used an intestinal epithelial cell line (Caco 2) derived from a human colon adenocarcinoma. A renal epithelial cell line (MDCK) was also used to determine the tissue specificity of drug transport. These cell lines, which were grown on filters, form a monolayer of well-polarized cells coupled by tight junctions and can be used for transcellular transport experiments. We studied the transport of nine antimicrobial agents with different physicochemical and pharmacokinetic characteristics using these epithelial cell monolayers to determine whether this model could be predictive of oral bioavailability. The transepithelial passage was assayed from the apical (AP) to the basolateral (BL) side and in the opposite direction (BL to AP) in both cell lines. Radioactively labeled mannitol was used to monitor the intactness of the cell monolayer during drug passage. The results indicated that all antimicrobial agents tested tended to behave in vitro generally according to their known in vivo absorptive characteristics. In addition, the use of epithelia from different tissues enabled us to divide the drugs into four groups according to their behaviors and suggested the existence of different transport mechanisms. In particular, two antibiotics, gentamicin and teicoplanin, showed no passage in either direction or cell line, in accordance with their very poor in vivo absorbances after oral administration. In contrast, rifapentine, rifampin, and nalidixic acid passed very efficiently at similar rates in both directions and cell lines in a concentration-dependent, nonsaturable manner, which is suggestive of passive diffusion down a concentration gradient. Of the remaining drugs, isoniazid and novobiocin sodium showed some differences in passage between the two cell lines and, given their ionized state at the pH that was used, may use the paracellular route. Finally, trimethoprim and D-cycloserine exhibited differences in passage both with respect to polarity and cell line; in particular, trimethoprim had a faster rate of passage only in Caco 2 cells and in the BL to AP direction, while D-cycloserine was exclusively transported by Caco 2 cells in the AP to BL direction. In both cases it is possible that active transport mechanisms are involved.

One of the most challenging Job have been towards the development of relaying scheme for the protection of transmission line,because of its long length and its consequent, exposure to atmospheric hazards; therefore, BHV and UHV transmission systems need a reliable, fast, efficient and low cost protection scheme. Protection schemes using microprocessor is ahead in this direction as it is capable of realizing any type of complex threshold characteristics with changes in the software along and with minimal changes in the hardware. It is also capable of doing self-checks. The present paper is a step to this direction where microprocessor based protection scheme for on line protection of EHV/UHV transmission line using the fundamental components is designed, fabricated and tested in the lab. The proposed scheme is also Immune to transients.

In this study, we examined the binding of Candida albicans synchronized yeast-phase cells to plastic, immobilized amino acids and bovine serum albumin (BSA) and quantified the binding by using an XTT tetrazolium salt assay and absorbance determination. Our results show that C. albicans binds efficiently and specifically to several nonpolar aliphatic amino acids and positively charged amino acids and to BSA immobilized on tissue culture plastic but not to polar uncharged, negatively charged, or aromatic amino acids. Adhesion of yeasts to immobilized amino acids was not affected by preincubation of cells with BSA, whereas binding to immobilized BSA was affected by preincubation of yeasts with alanine, proline, and leucine but not by arginine or lysine. The ability to distinguish the chirality of these amino acids was also examined by using both the D and L amino acid configurations, and the results show that C. albicans yeasts recognize only the L configuration of these amino acids. The observations that C. albicans specifically binds to certain amino acids indicate that these amino acids may prove useful tools for studying the binding interactions of C. albicans yeasts with host proteins such as components of the extracellular matrix.

The kinetics of assembly of MAP2-tubulin microtubule protein were examined as a function of the GTP concentration in order to test the hypothesis that CTP-induced assembly results from the generation of GTP by nucleoside diphosphate kinase. These studies show that (a) there is no assembly below a minimum GTP concentration and that this represents a nucleation requirement, (b) the rate of elongation is inconsistent with a single assembly-species, and (c) the elongation rate increases markedly as the GTP concentration is raised, although GTP is not absolutely required for elongation. These assembly kinetics have been compared with those with increasing CTP concentrations, by using microtubule protein containing a very low nucleoside diphosphate kinase activity of known substrate specificity. Neither nucleation nor the observed rates of elongation can be attributed to the formation of GTP, either (a) in terms of the generation of free GTP and subsequent binding to tubulin or (b) by the direct charging of GDP bound to the tubulin exchangeable site. The results show that nucleoside diphosphate kinase is not required for CTP-induced microtubule assembly, and suggest that CTP directly effects microtubule assembly.

Nucleoside diphosphate (NDP) kinase has been postulated to generate GTP from the GDP bound to tubulin. The purified chick brain enzyme was studied with respect to its kinetic parameters, and the protein-protein interactions between the NDP kinase and tubulin were examined. No specific interaction is observed between the enzyme and assembled microtubules, tubulin dimers, or tubulin-microtubule-associated protein (MAP) oligomers under a variety of nucleotide conditions. The apparent association is demonstrated to result from NDP kinase binding to a co-purifying contaminant. The absence of detectable NDP kinase-tubulin interactions indicates that NDP kinase does not directly charge up tubulin-GDP.

The chick brain microtubule-associated protein MAP2 can be phosphorylated in vitro to the extent of 12 mol/mol with GTP at the same sites as can be labelled by the cyclic AMP-independent protein kinase utilizing [gamma-32P]ATP as the phosphoryl donor. Consequently, the microtubule protein is chemically modified by the conditions usually employed for studies of microtubule assembly, so that the derived kinetic parameters may not relate to steady-state conditions.