Ultrafast conversion of carcinogenic 4-nitrophenol into 4-aminophenol in the dark catalyzed by surface interaction on BiPO4/g-C3N4 nanostructures in the presence of NaBH4.

The heterogeneous catalytic conversion of pollutants into useful industrial compounds is a two-goals at once process, which is highly recommended from the environmental, economic, and industrial points of view. In this regard, design materials with high conversion ability for a specific application is required to achieve such a goal. Herein, the synthesis conditions for the fabrication of BiPO4 nanorod bundles supported on g-C3N4 nanosheets as heterojunction composites was achieved using a facile ex situ chemical deposition for the reductive conversion of carcinogenic 4-nitrophenol (4-NP) into 4-aminophenol (4-AP). To better understand the mechanistic reduction pathways, BiPO4/g-C3N4 composites with varying ratios where obtained. The morphology and structure of BiPO4/g-C3N4 composites were checked using several methods: XRD, FE-SEM, HRTEM, XPS, and FT-IR, and it was found that hexagonal phase BiPO4 nanorod bundles were randomly distributed on the g-C3N4 nanosheets. Overall, the reduction ability of BiPO4/g-C3N4 composites was far better than bare BiPO4 and g-C3N4. A total reductive conversion of 4-NP at a concentration of 10 mg L-1 into 4-AP was found with 50% BiPO4/g-C3N4 composite within only one minute of reaction. Moreover, the presence of reducing agent (NaBH4) enhanced the kinetic rate constant up to 2.914 min-1 using 50% BiPO4/g-C3N4, which was much faster than bare BiPO4 (0.052 min-1) or g-C3N4 (0.004 min-1). The effects of some operating parameters including the initial concentration of 4-NP and catalyst dosage were also evaluated during the experiments. BiPO4/g-C3N4 showed great stability and recyclability, wherein, the catalytic reduction efficiency remains the same after five runs. A plausible 4-NP reduction mechanism was discussed. The high catalytic activity with the good stability of BiPO4/g-C3N4 make it a potential candidate for the reduction of nitroaromatic compounds in real wastewaters.

Correction: Ultrafast conversion of carcinogenic 4-nitrophenol into 4-aminophenol in the dark catalyzed by surface interaction on BiPO4/g-C3N4 nanostructures in the presence of NaBH4.

[This corrects the article DOI: 10.1039/D1RA02852A.].

One-pot fabrication of BiPO4/Bi2S3 hybrid structures for visible-light driven reduction of hazardous Cr(VI).

For the first time, a novel BiPO4/Bi2S3 heterostructures with different morphologies have been fabricated through a facile and rapid one pot precipitation route followed by anion-exchange strategy for the photoreduction of toxic Cr(VI) to harmless Cr (III). The hybrid structures systematically investigated using XRD, FE-SEM, EDS, TEM, HRTEM, XPS, FT-IR, UV-vis DRS, and PL. Changing the solvent type has a significant role for controllable morphologies of BiPO4/Bi2S3 hybrid as well as the catalytic activity. The BiPO4/Bi2S3 hybrid synthesized in diethylene glycol (DEG) performed the highest reduction efficiency of Cr(VI) within 20 min, compared with pure hexagonal phase of BiPO4 under visible light. The rate constant for BiPO4/Bi2S3 synthesized in DEG found to be 20.3 times larger than that for pure BiPO4. In addition, the presence of tartaric acid as hole scavenger could enhance the Cr(VI) reduction efficiency to 97.9%. No significant decrease in the catalytic efficiency after recycling up to four cycles. This promising study could present a significant approach towards Cr(VI) photoreduction from water through the novel BiPO4/Bi2S3 photocatalyst.

Contributions of multipolar polarizabilities to the isotropic and anisotropic light scattering induced by molecular interactions in gaseous methane.

The binary isotropic and anisotropic collision-induced light scattering spectra of gaseous methane at room temperature are analyzed in terms of a recent ab initio intermolecular potential and interaction-induced pair polarizability trace and anisotropy models, using quantum line-shapes computations. The translational spectra at relatively low frequencies are determined largely by the effects of bound and free transitions. At intermediate frequencies the spectra are sensitive to both the attractive part of the potential and the short-range part of the polarizability trace and anisotropy. The high frequency wings are discussed in terms of the collision-induced rotational Raman effect and estimates for the dipole-quadrupole polarizability A and the dipole-octopole polarizability E are obtained and checked with recent ab initio theoretical values.

Facile fabrication of a novel BiPO4 phase junction with enhanced photocatalytic performance towards aniline blue degradation.

A novel BiPO4 photocatalyst has been fabricated via a facile precipitation route using dimethyl sulfoxide (DMSO) as a solvent. The physical and chemical properties of the BiPO4 photocatalyst material were analyzed using XRD, Rietveld refinements XRD, FE-SEM, TEM, HR-TEM, EDS, XPS, FT-IR, Raman spectra, UV-Vis (DRS), and PL. The results confirm that hexagonal phase BiPO4 (HBIP) nanorods were successfully synthesized. FE-SEM images reveal that the addition of surfactant "CTAB" during preparation can control the surface morphology of BiPO4. The Rietveld refinement technique revealed the formation of a monazite monoclinic (nMBIP) and monoclinic (mMBIP) phase junction resulting from the calcination of HBIP at 500 °C. The photocatalytic behavior of the as-synthesized hexagonal and monoclinic BiPO4 nanostructures towards aniline blue (AB) degradation under UV light was systematically investigated. Among all catalysts, the phase junction (nMBIP-mMBIP) structure demonstrated the highest photocatalytic activity. The degradation rate of AB over the (nMBIP-mMBIP) phase junction structure was 3.4 times higher than that by HBIP. These results suggested that the surface-phase junction provides a synergistic effect for the electron-hole transfer process.

Tuning the redox potential of vitamin K3 derivatives by oxidative functionalization using a Ag(i)/GO catalyst.

We propose herein initial results to develop optimum redox mediators by the combination of computational simulation and catalytic functionalization of the core structure of vitamin K3. We aim to correlate the calculated energy value of the LUMO of different vitamin K3 derivatives with their actual redox potential. For this, we optimized the catalytic alkylation of 1,4-naphthoquinones with a designed Ag(i)/GO catalyst and synthesized a series of molecules.

Polypoid endocervical stromal sarcoma with heterologous elements. Report of a case with review of the literature.

A 44 year old woman presented with six recurrent endocervical polyps within the span of 28 months. The last two of these polyps exhibited sarcomatous changes within the endocervical stroma with heterologous cartilagenous elements. Abdominal hysterectomy with bilateral salpingo-oophorectomy was performed. No chemotherapy or radiotherapy was administered. The patient is alive and free of recurrent disease 9 years following surgery.

Prevalence of viral, bacterial and parasitic enteropathogens among young children with acute diarrhoea in Jeddah, Saudi Arabia.

The prevalence of viral, bacterial and parasitic pathogens among children of Jeddah, Saudi Arabia, was investigated. During December 1995-October 1996, 576 faecal samples were collected from children (0-5 year(s) old) suffering from acute diarrhoea and attending hospitals and outpatient clinics in Jeddah. One or more enteropathogen(s) were identified in 45.6% of the stool specimens. Mixed infections were detected in 12.2% of the diarrhoeal cases. Rotavirus was detected in 34.6% of the specimens of the hospitalized patients and in 5.9% of the specimens of the outpatients. Fifty-one percent of the rotavirus-positive specimens were long electropherotype, 26% were short electropherotype, and 23% could not be electropherotyped specifically. Among those of the long electropherotype, there were six patterns; and of the short electropherotypes, there were four patterns. Serotyping of these specimens revealed a distribution of 39.6%, 4.2%, 6.3%, and 15.6% for rotavirus serotype 1, 2, 3, and 4 respectively. Mixed serotypes were found in 3.1%, and 31.3% of the specimens were untypeable. Other aetiologic agents recognized included Escherichia coli (13%), of which 3.8% were enteropathogenic E. coli (EPEC) and 1.9% enterohaemorrhagic E. coli. Among the E. coli (EPEC) serotypes, O111:K58:B4, O55:K59:B11, and 0127:K63:B8 were found in 31.8%, 18.2%, and 13.6% of the cases respectively. Serotype 026:K60:B6, 0124:K72:B17, and 0112:K66:B11 each was found in 9.1% of the EPEC cases. 0128:K67:B12 and 0125:K70:B13 each was found in one case only. Other detected pathogens were: Klebsiella pneumoniae (4%), Giardia lamblia (3.1%), Salmonella sp. (3%), Shigella flexneri (2.6%), Entamoeba histolytica (2.2%), Trichuris trichiura, Hymenolepis nana, and Ascaris lumbricoides (0.7% each), and Candida albicans (0.5%). Based on the results of this study, it is concluded that the high prevalence of the various enteropathogens among young children is a significant public health problem.

Epstein-Barr virus in head and neck squamous cell carcinoma.

We compared 50 patients with head and neck squamous cell carcinomas (cases) and 45 matched healthy controls. Biopsy specimens were taken from tumours and normal tissue of the cases and controls respectively and serial paraffin embedded sections were processed to detect Epstein-Barr (EB) viral antigen. We found EB viral proteins in 38% of cases and none in controls, which suggests a positive correlation. Serum samples were also tested for the presence of EB virus IgG by ELISA for comparison with immunohistochemical findings. Patients with positive immunohistochemical staining results had significantly higher mean antibody titres compared with those with negative results. ELISA may be useful in determining the etiology of head and neck cancers, but the results are not unequivocally reliable.

Phase transitions of methane using molecular dynamics simulations.

Using a short ranged Lennard-Jones interaction and a long ranged electrostatic potential, CH4 under high pressure was modeled. Molecular dynamics simulations on small clusters (108 and 256 molecules) were used to explore the phase diagram. Regarding phase transitions at different temperatures, our numerical findings are consistent with experimental results to a great degree. In addition, the hysteresis effect is displayed in our results.

New inclusion body in a rat renal cell.

BACKGROUND AND METHODS: In an effort to review ultrastructural features of cells in the kidney of a male rat, transmission electron microscopy was used to study ultrathin sections. RESULTS: One light cell in a collecting tubule contained a 2.3-microns long linear array of electron-dense asymmetric structures in a granular zone of greater electron density than the general cytoplasm. This inclusion body could be interpreted to consist of a parallel array of 100-150-nm x 24-nm electron-dense rodlets, or a parallel array of 100-150-nm x 67-nm tubules. The inclusion showed no association with any cell organelle. The origin, chemical nature, frequency of occurrence, and functional significance of this inclusion are unknown. CONCLUSIONS: Although this inclusion body somewhat resembles previously described inclusions or granules, the differences in dimensions, frequency, and relation to other cell structures suggest it is a new observation.

Opioid and cannabinoid modulation of precipitated withdrawal in delta(9)-tetrahydrocannabinol and morphine-dependent mice.

The goal of the present study was to elucidate the relationship between cannabinoid and opioid systems in drug dependence. The CB(1) cannabinoid receptor antagonist SR 141716A precipitated both paw tremors and head shakes in four different mouse strains that were treated repeatedly with Delta(9)-tetrahydrocannabinol (Delta(9)-THC). SR 141716A-precipitated Delta(9)-THC withdrawal was ameliorated in mu-opioid receptor knockout mice compared with the wild-type control animals and failed to occur in mice devoid of CB(1) cannabinoid receptors. An acute injection of morphine in Delta(9)-THC-dependent mice undergoing SR 1417161A-precipitated withdrawal dose dependently decreased both paw tremors, antagonist dose 50 (AD(50)) (95% CL) = 0.035 (0.03--0.04), and head shakes, AD(50) (95% CL) = 0.07 (0.04--0.12). In morphine-dependent mice, the opioid antagonist naloxone precipitated head shakes, paw tremors, diarrhea, and jumping. As previously reported, naloxone-precipitated morphine withdrawal failed to occur in mu-opioid knockout mice and was significantly decreased in CB(1) cannabinoid receptor knockout mice. Acute treatment of Delta(9)-THC in morphine-dependent mice undergoing naloxone-precipitated withdrawal blocked paw tremors, AD(50) (95% CL) = 0.5 (0.3--1.0), and head shakes AD(50) (95% CL) = 0.6 (0.57--0.74) in dose-dependent manners, but failed to diminish the occurrence of diarrhea or jumping. Finally, naloxone and SR 141716A failed to elicit any overt effects in Delta(9)-THC-dependent and morphine-dependent mice, respectively. These findings taken together indicate that the mu-opioid receptor plays a modulatory role in cannabinoid dependence, thus implicating a reciprocal relationship between the cannabinoid and opioid systems in dependence.

Normal conduction of surface action potentials in detubulated amphibian skeletal muscle fibres.

1. The influence of the transverse (T) tubules on surface action potential conduction was investigated by comparing electrophysiological and confocal microscopic assessments of tubular changes in osmotically shocked and control fibres from frog sartorius muscle. 2. The membrane-impermeant fluorescent dye, di-8-ANEPPs spread readily from the bathing extracellular solution into the tubular membranes in control, intact fibres. Prior exposure of muscles to a hypertonic glycerol-Ringer solution, its replacement by an isotonic Ca(2+)-Mg(2+) Ringer solution and cooling sharply reduced such access. In contrast, dye application in the course of this osmotic shock procedure stained the large tubular vacuoles hitherto associated with successful muscle detubulation. 3. Conduction velocities in intact, control fibres (1.91 +/- 0.048 m s(-1), mean +/- S.E.M., n = 32 fibres) agreed with earlier values reported at room temperature (18-21 degrees C) and were unaffected by prior episodes of steady cooling to 8-10 degrees C (1.91 +/- 0.043 m s(-1), n = 30). 4. Cooling to 11.5 degrees C reduced these velocities (1.47 +/- 0.081 m s(-1), n = 25) but action potential waveforms still included early overshoots and the delayed after-depolarizations associated with tubular electrical activity. 5. In contrast, action potentials from cooled, superficial fibres in osmotically shocked muscles lacked after-depolarization phases implying tubular detachment. Their mean conduction velocities (1.62 +/- 0.169 m s(-1), n = 25) were not significantly altered from values obtained in untreated controls or in intact fibres in muscle similarly treated with glycerol, in direct contrast to earlier results. 6. Cooling produced similar reductions in maximum rates of voltage change dV/dt in action potentials from all fibre groups with lower rates of change shown by detubulated fibres. 7. Use of an antibody to a conserved epitope of the alpha-subunit of voltage-gated sodium channels suggested a concentration of sodium channels close to the mouths of the T tubules. 8. These electrophysiological and anatomical findings are consistent with a partial independence of electrical events in the transverse tubules from those responsible for the rapid conduction of surface regenerative activity. 9. The findings are discussed in terms of a partial separation of the electrical activity propagated over the surface membrane, from the initiation of propagated activity within the T tubules, by the triggering of the sodium channels clustered selectively around the mouths of the T tubules.

Bacteria and viruses that cause respiratory tract infections during the pilgrimage (Haj) season in Makkah, Saudi Arabia.

OBJECTIVE: To determine the incidence and type of RTI-causing bacteria and viruses during a period of epidemic infections. METHOD: A total of 395 sputum specimens and 761 throat swabs were collected during the 1991 and 1992 pilgrimage seasons (Haj to Makkah Al-Mukarama, Saudi Arabia) from patients referred to one hospital and three dispensaries with symptoms of respiratory tract infections. All 761 throat swabs of both Haj seasons were also screened for the presence of viral pathogens with monoclonal antibodies specific for 7 viruses known to cause respiratory infections. RESULTS: Bacterial pathogens were detected in 118 (29.9%) specimens. During the 1991 Haj season Haemophilus influenzae was the most frequent bacterial pathogen detected (10%), followed by Klebsiella pneumoniae (5.2%), Streptococcus pneumoniae (4.8%), Staphylococcus aureus (3.8%) and Streptococcus pyogenes (2.4%). In the 1992 Haj season Klebsiella pneumoniae was predominant (15.1%), followed by Haemophilus influenzae and Streptococcus pneumoniae (12.3%). Screening of all sputum specimens for acid-fast bacteria showed that the overall incidence rate of tuberculosis was 1%. Cultures from the 761 throat swabs were largely negative for bacteria except for Streptococcus pyogenes isolated from 7 patients. Viruses were detected in 148 (19.5%) specimens with influenza A and adenovirus being the most common viruses. CONCLUSION: The pattern of virus prevalence in the 1991 and 1992 pilgrimage seasons was identical: influenza A and adenovirus predominated. Thus these two viruses should be targeted in future prophylactic measures.

Epstein-Barr virus in head and neck squamous cell carcinoma

We compared 50 patients with head and neck squamous cell carcinomas [cases] and 45 matched healthy controls. Biopsy specimens were taken from tumours and normal tissue of the cases and controls respectively and serial paraffin embedded sections were processed to detect Epstein-Barr [EB] viral antigen. We found EB viral proteins in 38% of cases and none in controls, which suggests a positive correlation. Serum samples were also tested for the presence of EB virus IgG by ELISA for comparison with immunohistochemical findings. Patients with positive immunohistochemical staining results had significantly higher mean antibody titres compared with those with negative results. ELISA may be useful in determining the etiology of head and neck cancers, but the results are not unequivocally reliable