Experimental observation of the ν2_{2}+4ν3_{3} bands of HD16^{16}O and HD18^{18}O between 14975 and 15275 cm−1^{-1}

The ν$_{2}$+4ν$_{3}$ combination bands of HD$^{16}$O and HD$^{18}$O were measured using Fourier transform-incoherent broadband cavity-enhanced absorption spectroscopy (FT-IBBCEAS) with a spectral resolution of 0.08 cm$^{-1}$. The ro-vibrational lines of these bands were assigned through comparison with ab-initio molecular lines from the Tomsk variational calculation database (http://spectra.iao.ru/). For HD$^{18}$O and HD$^{16}$O in total 114 and 141 strong lines were assigned in the region between 14975.3 cm$^{-1}$ and 15243.3 cm$^{-1}$ and between 14998.5 cm$^{-1}$ and 15274.7 cm$^{-1}$, respectively. While the very satisfactory agreement of line intensities was used for line assignments, a systematic average discrepancy of ~0.305 cm$^{-1}$ in line positions was identified between the measured lines of HD$^{18}$O and the theoretically predicted lines from the Tomsk database. Similarly for HD$^{16}$O, an approximate wavenumber difference of ~0.361 cm$^{-1}$ was observed. The wavenumber accuracy of the Fourier transform cavity enhanced absorption spectrometer was confirmed on basis of concurrently measured H$_{2}$$^{16}$O spectra in the region between 15254.2 cm$^{-1}$ and 15376.9 cm$^{-1}$ and corroborated the systematic shifts of the ab initio data. A few lines of the ν$_{1}$+4ν$_{2}$+2ν$_{3}$ bands of HD$^{16}$O and HD$^{18}$O were also identified. The data are compared and discussed on basis of existing literature data

Investigation on adsorption performance of mesoporous activated biomass prepared from Cocos nucifera husk for harzadous cyanide wastewater treatment

The influence of various factors namely pH, absorbent dosage; contact time and initial ion concentration was studied to identify the adsorption capacity of the adsorbent. The optimum pH was obtained at pH =3 for all the adsorbent. Other physiochemical parameters, ranging from the surface area to the scanning electron microscope (SEM) were studied and indicate that the cocos nucifera husk is a good precursor for investigation on activated biomass for hardzadous cyanide wastewater. Adsorption data were modeled using Langmuir, Freundlich, Temkin, Henry and Harkin Jura equation. Henry with the correlation coefficient R2 0.875 had a better fit than Freundlich which is R2= 0.836, Temkin; R2= 0.875, Langmuir; R2= 0.742 and Harkin Jura which is R2= 0.471 with maximum monolayer saturation capacity of cyanide ions adsorbed per gram of activated Cocos nucifera husk. Equibrium data were best described by Henry model. Kinetic models were also carried out including pseudo first order with R2= 0.969, Pseudo-second order R2 = 0.998, Intra-particle diffusion R2 = 0.909, and Elovich Kinetic model with R2 of 0.814, the kinetic data were best described and seen by Pseudo second order model. It is then proven that the study of the entire adsorbent are most efficient for the removal of cyanide from waste waters and it can be used as low-cost adsorbent for the removal of cyanide ions from wastewater.Keywords: Cocos nucifera, Kinetics, Adsorbent, Models, Wastewater, Cyanide Ions

Gravitational waves from self-ordering scalar fields

Gravitational waves were copiously produced in the early Universe whenever the processes taking place were sufficiently violent. The spectra of several of these gravitational wave backgrounds on subhorizon scales have been extensively studied in the literature. In this paper we analyze the shape and amplitude of the gravitational wave spectrum on scales which are superhorizon at the time of production. Such gravitational waves are expected from the self ordering of randomly oriented scalar fields which can be present during a thermal phase transition or during preheating after hybrid inflation. We find that, if the gravitational wave source acts only during a small fraction of the Hubble time, the gravitational wave spectrum at frequencies lower than the expansion rate at the time of production behaves as $\Omega_{\rm GW}(f) \propto f^3$ with an amplitude much too small to be observable by gravitational wave observatories like LIGO, LISA or BBO. On the other hand, if the source is active for a much longer time, until a given mode which is initially superhorizon ($k\eta_* \ll 1$), enters the horizon, for $k\eta \gtrsim 1$, we find that the gravitational wave energy density is frequency independent, i.e. scale invariant. Moreover, its amplitude for a GUT scale scenario turns out to be within the range and sensitivity of BBO and marginally detectable by LIGO and LISA. This new gravitational wave background can compete with the one generated during inflation, and distinguishing both may require extra information.Comment: 21 pages, 2 figures, added discussion about numerical integration and a new figure to illustrate the scale-invariance of the GW power spectrum, conclusions unchange

Toxicity and Cytotoxicity Effects of Selected Nanoparticles: A Review

The appreciable development in nanotechnology has drawn the attention of several researchers cutting across different fields. However, some nanoparticles have been identified to possess harmful effects on humans and the environment. Hence, putting these cause and effect patternsinto context is highly required for future research and discussions about nanotechnology. This study reviewed existing literature on the toxicity and cytotoxicity effects of some nanoparticles to compare reaction patterns. Many kinds of research used different cell cultures, including cancer cell lines, human endothelial cells, hepatic cells, which were tested both in vitro and in vivo to check the mechanism of the possible toxicity effects. Adverse effects of nanoparticles identified involved damaged DNA leading to mutations and generation of reactive oxygen species (ROS). The prominent identified common toxicity responses in nanoparticle-cell interaction were lysosomes formation interference, necrosis and apoptosis, nanoparticles and protein interaction, and agglomerate formation in other body parts. Some reports showed that the causes of these responses might be due to the physicochemical properties of the interrogated particles, such as particle size, shape, surface functionalisation, surface charge. Furthermore, nanoparticles' toxicity effects are both concentration-dependent and time-dependent, highly pronounced in chemical or physical-based synthetic routes. Cytotoxic effects of nanoparticles were mainly linked to their synthetic method, nature of the reducing agent, and culture media

Synthesis of low toxic silver-cobalt nanoparticles using Annona muricata leaf extract: Antimicrobial evaluation

In a bid for green chemistry, a sustainable approach using Annona muricata aqueous extract was engaged as a reducing agent to synthesise bimetallic silver-cobalt nanoparticles (Ag-Co NPS). Hot extraction using distilled water was done on the locally sourced plant (leaf part). It was then screened for biomolecules present as geographical location affects phytochemical compositions. Phytoreduction reaction with nanoparticle formation rate was monitored with a UV–Vis spectrophotometer. Then, further characterisations were achieved by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared (FTIR), and X-ray diffraction (XRD). The average particle size of 39.34 nm 9.21 nm was obtained. This study shows an interesting result, as the increase in Ag-Co NPs concentration did not significantly affect the flies’ survival compared to the control. At P < 0.05, similar behaviour was observed in the locomotive assay of the model used. An antibacterial agent can also be developed, as revealed in the antimicrobial assay on Staphylococcus aureus (ATCC25923), Streptococcus pneumoniae, Escherichia coli (ATCC 25922), Klebsiella sp., and Salmonella sp. and a fungus strain: Candida albicans

Synthesis of low toxic silver-cobalt nanoparticles using Annona muricata leaf extract: Antimicrobial evaluation

In a bid for green chemistry, a sustainable approach using Annona muricata aqueous extract was engaged as a reducing agent to synthesise bimetallic silver-cobalt nanoparticles (Ag-Co NPS). Hot extraction using distilled water was done on the locally sourced plant (leaf part). It was then screened for biomolecules present as geographical location affects phytochemical compositions. Phytoreduction reaction with nanoparticle formation rate was monitored with a UV–Vis spectrophotometer. Then, further characterisations were achieved by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared (FTIR), and X-ray diffraction (XRD). The average particle size of 39.34 nm ± 9.21 nm was obtained. This study shows an interesting result, as the increase in Ag-Co NPs concentration did not significantly affect the flies’ survival compared to the control. At P < 0.05, similar behaviour was observed in the locomotive assay of the model used. An antibacterial agent can also be developed, as revealed in the antimicrobial assay on Staphylococcus aureus (ATCC25923), Streptococcus pneumoniae, Escherichia coli (ATCC 25922), Klebsiella sp., and Salmonella sp. and a fungus strain: Candida albicans

Dilatonic global strings

We examine the field equations of a self-gravitating global string in low energy superstring gravity, allowing for an arbitrary coupling of the global string to the dilaton. Massive and massless dilatons are considered. For the massive dilaton the spacetime is similar to the recently discovered non-singular time-dependent Einstein self-gravitating global string, but the massless dilaton generically gives a singular spacetime, even allowing for time-dependence. We also demonstrate a time-dependent non-singular string/anti-string configuration, in which the string pair causes a compactification of two of the spatial dimensions, albeit on a very large scale.Comment: 18 pages RevTeX, 3 figures, references amende

Adiabatic perturbations in pre big bang models: matching conditions and scale invariance

At low energy, the four-dimensional effective action of the ekpyrotic model of the universe is equivalent to a slightly modified version of the pre big bang model. We discuss cosmological perturbations in these models. In particular we address the issue of matching the perturbations from a collapsing to an expanding phase in full generality. We show that, generically, one obtains $n=0$ for the spectrum of scalar perturbations in the original pre big model (with vanishing potential). When an exponential potential for the dilaton is included, a scale invariant spectrum ($n=1$) of adiabatic scalar perturbations is produced under very generic matching conditions, both in a modified pre big bang and ekpyrotic scenario. We also derive general results valid for power law scale factors matched to a radiation dominated era.Comment: 11 pages, 1 figure, revised version with small corrections to match version in print. Results and conclusions unchange

Effects of sleep disturbance on dyspnoea and impaired lung function following hospital admission due to COVID-19 in the UK:a prospective multicentre cohort study

BACKGROUND: Sleep disturbance is common following hospital admission both for COVID-19 and other causes. The clinical associations of this for recovery after hospital admission are poorly understood despite sleep disturbance contributing to morbidity in other scenarios. We aimed to investigate the prevalence and nature of sleep disturbance after discharge following hospital admission for COVID-19 and to assess whether this was associated with dyspnoea. METHODS: CircCOVID was a prospective multicentre cohort substudy designed to investigate the effects of circadian disruption and sleep disturbance on recovery after COVID-19 in a cohort of participants aged 18 years or older, admitted to hospital for COVID-19 in the UK, and discharged between March, 2020, and October, 2021. Participants were recruited from the Post-hospitalisation COVID-19 study (PHOSP-COVID). Follow-up data were collected at two timepoints: an early time point 2-7 months after hospital discharge and a later time point 10-14 months after hospital discharge. Sleep quality was assessed subjectively using the Pittsburgh Sleep Quality Index questionnaire and a numerical rating scale. Sleep quality was also assessed with an accelerometer worn on the wrist (actigraphy) for 14 days. Participants were also clinically phenotyped, including assessment of symptoms (ie, anxiety [Generalised Anxiety Disorder 7-item scale questionnaire], muscle function [SARC-F questionnaire], dyspnoea [Dyspnoea-12 questionnaire] and measurement of lung function), at the early timepoint after discharge. Actigraphy results were also compared to a matched UK Biobank cohort (non-hospitalised individuals and recently hospitalised individuals). Multivariable linear regression was used to define associations of sleep disturbance with the primary outcome of breathlessness and the other clinical symptoms. PHOSP-COVID is registered on the ISRCTN Registry (ISRCTN10980107). FINDINGS: 2320 of 2468 participants in the PHOSP-COVID study attended an early timepoint research visit a median of 5 months (IQR 4-6) following discharge from 83 hospitals in the UK. Data for sleep quality were assessed by subjective measures (the Pittsburgh Sleep Quality Index questionnaire and the numerical rating scale) for 638 participants at the early time point. Sleep quality was also assessed using device-based measures (actigraphy) a median of 7 months (IQR 5-8 months) after discharge from hospital for 729 participants. After discharge from hospital, the majority (396 [62%] of 638) of participants who had been admitted to hospital for COVID-19 reported poor sleep quality in response to the Pittsburgh Sleep Quality Index questionnaire. A comparable proportion (338 [53%] of 638) of participants felt their sleep quality had deteriorated following discharge after COVID-19 admission, as assessed by the numerical rating scale. Device-based measurements were compared to an age-matched, sex-matched, BMI-matched, and time from discharge-matched UK Biobank cohort who had recently been admitted to hospital. Compared to the recently hospitalised matched UK Biobank cohort, participants in our study slept on average 65 min (95% CI 59 to 71) longer, had a lower sleep regularity index (-19%; 95% CI -20 to -16), and a lower sleep efficiency (3·83 percentage points; 95% CI 3·40 to 4·26). Similar results were obtained when comparisons were made with the non-hospitalised UK Biobank cohort. Overall sleep quality (unadjusted effect estimate 3·94; 95% CI 2·78 to 5·10), deterioration in sleep quality following hospital admission (3·00; 1·82 to 4·28), and sleep regularity (4·38; 2·10 to 6·65) were associated with higher dyspnoea scores. Poor sleep quality, deterioration in sleep quality, and sleep regularity were also associated with impaired lung function, as assessed by forced vital capacity. Depending on the sleep metric, anxiety mediated 18-39% of the effect of sleep disturbance on dyspnoea, while muscle weakness mediated 27-41% of this effect. INTERPRETATION: Sleep disturbance following hospital admission for COVID-19 is associated with dyspnoea, anxiety, and muscle weakness. Due to the association with multiple symptoms, targeting sleep disturbance might be beneficial in treating the post-COVID-19 condition. FUNDING: UK Research and Innovation, National Institute for Health Research, and Engineering and Physical Sciences Research Council