Summary
Escherichia coli biofilm consists of a bacterial colony embedded in a matrix of extracellular polymeric substances (EPS) which protects the microbes from adverse environmental conditions and ...results in infection. Besides being the major causative agent for recurrent urinary tract infections, E. coli biofilm is also responsible for indwelling medical device‐related infectivity. The cell‐to‐cell communication within the biofilm occurs due to quorum sensors that can modulate the key biochemical players enabling the bacteria to proliferate and intensify the resultant infections. The diversity in structural components of biofilm gets compounded due to the development of antibiotic resistance, hampering its eradication. Conventionally used antimicrobial agents have a restricted range of cellular targets and limited efficacy on biofilms. This emphasizes the need to explore the alternate therapeuticals like anti‐adhesion compounds, phytochemicals, nanomaterials for effective drug delivery to restrict the growth of biofilm. The current review focuses on various aspects of E. coli biofilm development and the possible therapeutic approaches for prevention and treatment of biofilm‐related infections.
In the present paper various gasification technologies/gasifiers and syngas cleaning options are critically reviewed keeping in view various types of feedstocks and various downstream applications of ...syngas such as power generation, chemicals and hydrogen production, liquid fuels production and synthetic natural gas (SNG) production. Recent developments on gasification technologies including fixed bed dry bottom (FBDB) gasification, power high temperature Winkler (PHTW) gasification, catalytic steam gasification, transport reactor gasifier as well as syngas cleanup technique including hot gas filter and warm cleaning are discussed. Techno-economic analysis of various gasifiers as well as syngas cleaning processes along with the world scenario of syngas production and its various downstream applications is also discussed.
► Critical review on various gasification technologies and syngas cleaning options along with their techno-economic analysis. ► Selection of gasifier type for various feedstocks and for various downstream applications of syngas. ► Recent developments in gasifiers, gasification processes and syngas cleaning options. ► World scenario of syngas production and its downstream applications along with R &D efforts.
We herein report that surface modification of metal halide perovskites using graphene would be beneficial to improving the energy conversion efficiencies of perovskite solar cells. The present ...first-principles calculations on MAPbI
with a single vacancy created by removing either I, Pb or MA show that the I and Pb vacancies near the surface result in the formation of Pb-Pb and I-I dimers, respectively. They are predicted to yield mid-gap levels, and would degrade the energy conversion efficiency of perovskite solar cells through carrier trapping. The present calculations suggest that when the surface of MAPbI
is covered with a graphene sheet, the formation of the carrier trapping dimers would be suppressed. The origin of the "healing effect" of graphene on the lattice defect is ascribed to electronic interactions on the surface, which prevent charge localization at the lattice defects beneath the surface.
Abstract
We presented timing results of PSR B2035+36 using ∼9-yr observations with the Nanshan 25-m radio telescope. PSR B2035+36 was reported to exhibit significant changes in pulse profile ...correlated with spin-down state variations. We found that the pulsar underwent a glitch with a jump in frequency of $\Delta {\nu }\sim 12.4(5)\, \rm nHz$ around MJD 52950. Unusually, the spin-down rate increased persistently over 800 d after the glitch, and the average spin-down rate post-glitch was about $9.6 \, {per\,cent}$ larger than that pre-glitch. After the glitch activity, the pulse profile became narrower and the pulsar began to switch between two emission modes, with pulse widths ($W_{\ 50 \rm mean}$) of 8.5(7)° and 3.7(3)°, respectively. In addition to that, the relatively narrow pulse profile gradually became dominant. All of the observations indicate that there should be a connection between magnetospheric behaviour and glitch activity. We discuss one possibility of magnetosphere fluctuation triggered by the glitch event.
Abstract Understanding the jitter noise resulting from single-pulse phase and shape variations is important for the detection of gravitational waves using pulsar timing arrays. We present ...measurements of the jitter noise and single-pulse variability of 12 millisecond pulsars that are part of the International Pulsar Timing Array sample using the Five-hundred-meter Aperture Spherical radio Telescope. We find that the levels of jitter noise can vary dramatically among pulsars. A moderate correlation with a correlation coefficient of 0.57 between jitter noise and pulse width is detected. To mitigate jitter noise, we perform matrix template matching using all four Stokes parameters. Our results reveal a reduction in jitter noise ranging from 6.7% to 39.6%. By performing longitude-resolved fluctuation spectrum analysis, we identify periodic intensity modulations in 10 pulsars. In PSR J0030+0451, we detect single pulses with energies more than 10 times the average pulse energy, suggesting the presence of giant pulses. We also observe a periodic mode-changing phenomenon in PSR J0030+0451. We examine the achievable timing precision by selecting a subset of pulses with a specific range of peak intensity, but no significant improvement in timing precision is achievable.
Abstract
We report the observations of periodic nulling in PSR B2111+46 at 1250 MHz with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The nulling fractions (NF) as well as ...nulling period of this pulsar were calculated. The NF and nulling period are 17% ± 1% and 62.49 ± 0.99
P
1
, respectively, and the periodic nulling shows variations in periodicity with time. The durations of each consecutive burst and nulling were investigated, which show that the power-law distribution and the indices are −1.11 ± 0.04 and −2.08 ± 0.23. In the observed frequency band, the width of the profile is narrowed with the increase in frequency, and the degree of polarization has no obvious trend with the increase in frequency. We discovered a weak emission component in front of the leading component of this triple-type profile pulsar that was not observed in other bands and by other telescopes. With the fitting of rotation vector model, we obtained that the angles of the magnetic inclination
α
and the line of sight
ζ
are ∼13.°0 and ∼11.°6, respectively. The high-sensitivity observation of FAST improves our understanding of the emission of this pulsar.
Many pathogenic strains have acquired multidrug-resistant patterns in recent a year, which poses a major public health concern. The growing need for effective antimicrobial agents as novel therapies ...against multidrug-resistant pathogens has drawn scientist attention toward nanotechnology. Silver nanoparticles are considered capable of killing multidrug-resistant isolates due to their oligo-dynamic effect on microorganisms. In this research study NPs were synthesized using the gram-positive bacteria Lactobacillus bulgaricus and its activity against selected pathogenic strains. Lactobacillus bulgaricus pure cultures were isolated from raw milk and grown in "De Man, Rogasa, and Sharp" broth for synthesis of nanoparticles. Lactobacillus bulgaricus culture was centrifuged and Cell- free supernatant of it was employed with aqueous silvery ions and evaluated their antibacterial activities against bacterial strains i.e. Staphylococcus aureus, Staphylococcus epidermidis and Salmonella typhi using agar well diffusion assay. Antibiotic profiling against selected pathogenic strains were also conducted using disc diffusion method. The synthesis and characterization of silver nanoparticles were monitored primarily by the conversion of the pale-yellow color of the mixture into a dark-brown color and via ultraviolet-visible absorption spectroscopy and Scanning electron microscopy respectively. The result showed that that AgNPs with size (30.65-100 nm) obtained from Lactobacillus bulgaricus were found to exhibit antibacterial activities against selected bacterial strains. Taken together, these findings suggest that Lactobacillus bulgaricus has great potential for the production of AgNPs with antibacterial activities and highly effective in comparison to tested antibiotics.
Chinese women in Western nations frequently report less engagement with sexuality, such as lower sexual response and behaviors, and more restrictive sexual attitudes, than their Euro-Caucasian peers. ...This difference is likely related to sexual conservatism within traditional Chinese culture, though the mechanisms underlying how culture influences sexual responding are not well understood. The current study investigated if these differences were consistent with the dual control model, a well-established model for understanding regulation of sexual response. Chinese and Euro-Caucasian women (
N
= 471; age
M
= 20.7 years, SD = 3.3) residing in Canada from a university sample completed self-report questionnaires on sexual excitation and inhibition, sexual attitudes, and various sexual response and behavior measures. Sexual excitation was significantly lower in Chinese than Euro-Caucasian women and was significantly associated with sexual response in both groups. Structural equation modeling showed that sexual response variables were associated with a latent sexual excitation factor and that sexual attitudes partially mediated the relationship between this latent factor and ethnicity. The findings showed that sexual excitation and sexual attitudes contribute to cross-cultural differences in women’s sexual responding. Theoretical and clinical considerations are discussed.
Abstract This study presents a comprehensive analysis of the spectral properties of 886 pulsars across a wide frequency range from 20 MHz–343.5 GHz, including a total of 86 millisecond pulsars ...(MSPs). The majority of the pulsars exhibit power-law behavior in their spectra, although some exceptions are observed. Five different spectral models, namely, simple power law, broken power law, low-frequency turnover, high-frequency cutoff, and double turnover, were employed to explore the spectral behaviors. The average spectral index for pulsars modeled with a simple power law is found to be −1.64 ± 0.80, consistent with previous studies. Additionally, significant correlations between the spectral index and characteristic parameters are observed, particularly in MSPs, while no strong correlation is observed in normal pulsars. Different models show variations in the most influential characteristic parameters associated with the spectral index, indicating diverse dominant radiation mechanisms in MSPs. Finally, this study identifies 22 pulsars of the gigahertz-peaked spectra type for the first time based on the Akaike information criterion.
Abstract
We have carried out a detailed study of polarimetric individual pulse emission from the pulsar J1701−3726 (B1658−37), observed at 1369 MHz using the Parkes 64 m radio telescope. The ...single-pulse sequences reveal the presence of the three major emission phenomena of pulse nulling, mode changing, and subpulse drifting. Trimodal distribution of the pulse energy is present, implying one population of nulls and two others of emission in the phase window. The mean flux density of the normal mode is almost two times that of the abnormal mode. Our data show that, for PSR J1701−3726, 64% of the time was spent in the normal mode and 12% was in the abnormal mode. The single pulses show the presence of two distinct periodic modulations using a fluctuation spectral analysis. About 24% of the nulls are found to create alternating bunches of nulls and bursts in a quasiperiodic manner with a longer periodicity of 48 ± 4 rotational periods. Additionally, the pulsar presents a steady even–odd modulated feature with a stationary longitude within the pulse window. The ramifications for constraining the viewing geometry and understanding the radio emission mechanisms are discussed.
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