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The present study describes for the first time the toxin production by Microcystis aeruginosa blooms in three rainwater ponds in Saudi Arabia. The cell density of M. aeruginosa correlated with chlorophyll-a, temperature and nutrient concentrations. Microcystis blooms produced the hepatotoxin microcystin (MCYST) with concentrations of 0.988-3.04 mg g-1 dry weight, and a toxin profile consisting mainly of MCYST-RR, -YR and -LR. MCYSTs were also detected in pond waters at levels exceeding the WHO guideline value (11.2-34.6 µg l-1). The study suggests the monitoring of toxic cyanobacteria in such potable water sources to protect the public from potent toxins. [ABSTRACT FROM AUTHOR]

The present study investigates the allelopathic effects of Stratiotes aloideson the growth and antioxidative biomarkers of epiphytic and planktonic toxic cyanobacteria in a batch experiment over a 15day exposure to different concentrations of aqueous acetone extract of this macrophyte. The results showed that epiphytic and planktonic species of cyanobacteria showed differential responses to the allelopathic activity of this macrophyte. S. aloidesextract reduced the growth, alkaline phosphatase activity APA and toxin production of the planktonic cyanobacterium, Anabaena variabilis, with an increase in lipid peroxidation, glutathione and activities of antioxidative enzymes of this cyanobacterium. Conversely, this extract did not affect the growth and increased the toxin production in epiphytic cyanobacteria, with no significant effect on lipid peroixdation or the activities of APA and antioxidative enzymes of these species. This study is the first to suggest that the macrophyte S. aloidessupports the growth and toxin production of its epiphytic cyanobacteria. © 2010 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim [ABSTRACT FROM AUTHOR]

New complexes of RhIII, RuIII, PdII and PtII with 1H-1,2,4-triazole-3-thiol have been prepared and characterized by spectroscopy [IR, UV-Vis, 1H NMR and 13C NMR] and micro-analysis. The results are consistent with the general formula M(HTAZ)2Cl·(H2O), [M=RhIII and RuIII], M(HTAZ)2(H2O)2 and [M=PdII and PtII]. [ABSTRACT FROM AUTHOR]

Mobile ad-hoc networks (MANETs) have been primarily designed to enhance tactical communications in a battlefield. They provide dynamic connectivity without requiring any pre-existing infrastructure. Their multi-hop capabilities can improve radio coverage significantly. The nature of tactical MANET operations requires more specialized routing protocols compared to the ones which are used in commercial MANET. Routing decisions in MANETs are usually conditioned on signal-to-interference-plus-noise ratio (SINR) measurements. In order to improve routing decisions for use in highly dynamic tactical MANETs, this paper proposes to combine two different metrics to achieve reliable multicast in multi-hop ad hoc networks. The resulting protocol combining received signal strength (RSS) with SINR to make routing decisions is referred to as Link Quality Aware Ad-hoc On-Demand Distance Vector (LQA-AODV) routing. The proposed routing protocol can quickly adapt to dynamic changes in network topology and link quality variations often encountered in tactical field operations. Using computer simulations, the performance of proposed protocol is shown to outperform other widely used reactive routing protocols assuming several performance metrics. [ABSTRACT FROM AUTHOR]

Nanoscale materials are of a foremost desirability in functionalized materials research in almost all areas of science. Nanoscale materials with good biocompatibility and chemical stability possess biomedical usages which comprises drug carrier, cell/DNA parting, wastewater cleaning etc. Hence, magnesium-doped ZnO (Mg@ZnO) nanoparticles (NPs) were prepared by combustion route. Crystallization of Mg@ZnO NPs was investigated using X-ray diffraction and transmission electron microscopy. The particle sizes were in the range of 50–130 nm and 17.5–52.5 nm for x = 1 wt% and 4 wt% in MgxZn1-xO samples, respectively. The Zn2+ substitution by Mg2+ in ZnO increased oxygen vacancies and reduced free electrons concentration. The concentrations of dopant dependent optical band gaps were calculated using diffuse reflectance and found in the range of 3.258–3.278 eV. Antibacterial study of Mg@ZnO NPs was conducted against the Gram- + ve and Gram – ve bacteria and results revealed enrichment in antibacterial activity of Mg@ZnO NPs against all types of bacteria. In vivo test revealed that all Mg@ZnO NPs have no cytotoxic effects on liver and kidneys. Furthermore, photocatalytic activity was performed towards hazardous methylene green dye degradation under UV light irradiation. The presence of Mg in ZnO lattice remarkably improved its photocatalytic performance and the photocatalytic activity of Mg@ZnO ranged from 1.8 to 5.4 times higher than the activity of neat ZnO under the same reaction conditions. Facile synthesis of Mg@ZnO NPs was achieved successfully through flash combustion process and the prepared NPs were exploited for optical, biological and environmental applications. Enhancement of antibacterial, cytotoxicity and photocatalysis activity was observed in ZnO with Mg content doping. The outcomes present the Mg@ZnO NPs as an efficient material for opto-bio-environmental applications. [ABSTRACT FROM AUTHOR]

The different concentrations of 0.0, 1.0, 2.5 and 5.0 wt% Cu-doped ZnO (Cu@ZnO) nanoparticles (NPs) have been synthesized for opto-photocatalytic applications by a facile and cost-effective route. The formation and structural analyses of Cu@ZnO NPs was recognized by X-ray diffraction (XRD), Fourier transform (FT)-Raman and Transmission electron microscopy (TEM). The average crystallite size of 28.9, 27.4 and 26.4 nm was calculated for (101) intense peak and found to be decreased with increasing the contents of Cu. The residual microstrain values are noted ~3.84 × 10−3, 4.03 × 10−3 and 4.19 × 10−3. The particle size of 170, 109, 127 and 175 nm is obtained for undoped and Cu doped ZnO NPs from FESEM. The optical band gap of Cu@ ZnO NPs were estimated through Kubelka-Munk theory and noted ~3.225, 3.150, 3.100 and 2.995 eV for 0.0, 1.0, 2.5 and 5.0 wt% Cu@ZnO NPs; this shows decreases with increasing the Cu contests in ZnO lattice. Photoluminescence (PL) spectra of Cu@ZnO NPs shows near band edge emission at 407–411 nm with emission band 565-572 nm correspond to intrinsic defects in ZnO lattice. The photocatalytic performance of Cu@ZnO NPs was assessed through decolourizing of methyl green beneath the visible light illumination (λ = 425–460 nm). Photocatalytic action of Cu@ZnO samples was 3.5 times greater to neat ZnO. Photocatalytic properties of Cu@ZnO NPs can be used for water purification in environmental applications. Unlabelled Image • Cu@ZnO NPs were facilely synthesized by flash combustion route. • X-ray diffraction, FT-Raman and TEM studies confirm the synthesis of ZnO NPs. • Energy gap was noticed to be reduced from 3.225 to 2.995 eV due to Cu doping. • PL study was performed and explained the effect of Cu on emission features of ZnO. • About 3.5 times improvement in photocatalytic activity was noticed in Cu@ZnO NPs. [ABSTRACT FROM AUTHOR]

A novel FeMoO 4 /g-C 3 N 4 -2D/2D Z-scheme heterojunction photocatalyst was prepared via wet chemical method. The observed structural morphology of FeMoO 4 /g-C 3 N 4 reveals the 2D-iron molybdate (FeMoO 4) nanoplates compiled with the 2D-graphitic carbon nitride (g-C 3 N 4) nanosheets like structure. The photocatalytic activity of the g-C 3 N 4 , FeMoO 4 , and FeMoO 4 /g-C 3 N 4 composites were studied via the degradation of Rhodamine B (RhB) as targeted textile dye under visible light irradiation (VLI). The optimal FeMoO 4 /g-C 3 N 4 (1:3 ratio of g-C 3 N 4 and FeMoO 4) composite show an enhanced degradation performance with rate constant value of 0.02226 min–1 and good stability even after three cycles. Thus, the h+ and O 2 •－are the key radicals in the degradation of RhB under VLI. It is proposed that the FeMoO 4 /g-C 3 N 4 Z-scheme heterojunction effectively enhances the transfer and separation ability of e−/h+ pairs, by the way increasing the photocatalytic efficiency towards the RhB degradation. Thus, the newly constructed Z-scheme FeMoO 4 /g-C 3 N 4 heterojunction photocatalyst is a promising material for the remediation of wastewater relevant to elimination of toxic effect in marine environment. [Display omitted] • Novel Z-scheme FeMoO 4 /g-C 3 N 4 heterojunction photocatalysts were constructed. • Optimal FeMoO 4 /g-C 3 N 4 show excellent degradation of Rhodamine B. • Optimal FeMoO 4 /g-C 3 N 4 exhibits excellent photostability under visible light. • h+ and O 2 • － radicals are playing major role in the degradation of RhB. • Plausible mechanism for direct Z-scheme FeMoO 4 /g-C 3 N 4 heterojunction was proposed. [ABSTRACT FROM AUTHOR]

FT-IR and FT-Raman spectra of 6-chloro-5-isopropylpyrimidine-2,4(1 H ,3 H )-dione were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations and the data obtained from wavenumber calculations are used to assign the experimentally obtained bands. Potential energy distribution was done using GAR2PED software. The geometrical parameters of the title compound are in agreement with the XRD results. NBO analysis, frontier molecular orbital and first and second hyperpolarizability and molecular electrostatic potential results are also reported. The possible electrophile attacking sites of the title compound is identified using MEP surface plot study. Molecule sites prone to electrophilic attacks were identified using average local ionization energy surfaces, while further insight into the local reactivity properties of the title molecule has been gained by calculation of Fukui functions. Intra-molecular non-covalent interactions have been detected and visualized. Degradation properties based on autoxidation and hydrolysis have been investigated by calculation of bond dissociation energies and radial distribution functions, respectively. From the molecular docking study, the ligand binds at the active site of the substrate by weak non-covalent interactions and amino acids Leu89 forms alkyl interaction with the CH 3 groups and Glu90 amino acid forms π-anion interaction with the pyrimidine ring and Thr369 and Ser366 amino acids form H-bond interaction with the C O and NH group, respectively. From the conformational analysis, the calculated structures show that the C 6 C 9 C 10 angle in the most stable form is about 8° smaller compared to the C 8 C 9 C 10 angle, indicating a higher repulsive force between the (CH 3 ) 2 HC– moiety and the chlorine atom due to the size of chlorine compared to oxygen atoms. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe-single atom anchored on carbon nanotubes catalyst was fabricated. • The catalyst exhibits excellent ORR catalytic activity in alkaline and acidic media. • The activity is boosted by the decorated Fe-N 4 on carbon nanotubes. Developing cost-effective and high-performance non-precious electrocatalysts for ORR in acidic and alkaline media is an urgent need for clean energy generation. A significant improvement in the ORR performance has been realized by the single-atom catalysts (SACs). However, activity deterioration caused by the dissolution of catalyst structure is still a lingering challenge. Herein, we report a simple strategy for protecting the structure of SAC by implanting/decorating Fe-ZIF-derived carbon nanotubes with Fe-N 4 , denoted as FeSA@CNTs. The as-developed FeSA@CNTs catalyst exhibits an outstanding ORR activity in an alkaline medium with onset potential (E o) = 0.998 V and half-wave potential E 1/2 = 0.898 V, which are 28 mV and 29 mV higher than commercial 20% Pt/C, respectively. Moreover, FeSA@CNTs in an acidic medium show an impressive high half-wave potential (E 1/2 = 0.8290 V) comparable to Pt/C (E 1/2 = 0.8292 V) which is better than most recently reported ORR catalysts. The density functional theory (DFT) validates that the smaller difference in the energy orbitals of Fe in Fe-N 4 and O 2 improved the electron transfer onto the reaction intermediate (OH*) in the rate-determining step, which provides the higher catalytic activity for FeSA@CNTs' in both acidic and alkaline media. [ABSTRACT FROM AUTHOR]

In this study, Zr-based metal organic frameworks (Zr-MOFs) with different ligands such as terephthalic acid (UiO-66), 2-aminoterephthalic (UiO-66-NH 2) and 2-methylimidazole (UiO‐66‐2M) are synthesized using hydrothermal method in order to investigate their ligand-dependent properties towards photocatalytic degradation of dyes molecules under solar light. The structural analysis by XRD revealed the fundamental cubic-topology of the UiO-66 structure for all the synthesized MOFs, and the presence of respective functional groups is confirmed via their ART-IR spectra. A spherical morphology with average size of ~80 and 200 nm are observed for UiO-66 and UiO-66-NH 2 MOFs, respectively, whereas, bricks-like morphology is observed for UiO‐66‐2M, which is attributed to the binding habit of the respective ligands. Band gap energy of the synthesized UiO-66, UiO-66-NH 2 and UiO‐66‐2M is estimated to be ~3.85, 2.92 and 2.77 eV, respectively. Among the synthesized MOFs, the photocatalytic degradation efficiency of UiO-66-NH 2 MOFs is found to be greater towards the cationic rhodamine B (RhB) dye (~95% in 120 min), while it is relatively less efficient in degrading the anionic Congo red (CR) dye, (~64% in 120 min). The insights gained from the fundamental characterizations, Mott-Schottky, scavenger and electrochemical impedance analysis revealed that the amino-groups in UiO-66-NH 2 MOFs offered the band edge potentials suitable for the effective generation of energetic radical species with the improved carrier delocalization, recombination resistance and charge transfer properties in the MOFs. The further parametric studies revealed that the UiO-66-NH 2 MOFs can be effectively scaled-up and used for dye degradation applications in real-time. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Sources of occurrences of pharmaceutical contaminants (PCs) in various water bodies were stated and discussed. • Ecological values of laccase mediator system to surge efficiency are constructive. • Sources and occurrence of some recalcitrant pollutants were discussed. • Mechanisms of recalcitrant pollutant degradation by laccase were summarized. • Immobilized laccase mediated removal of recalcitrant pollutants was reviewed. The main objective of this review is to provide up to date, brief, irrefutable, organized data on the conducted experiments on a range of emerging recalcitrant compounds such as Diclofenac (DCF), Chlorophenols (CPs), tetracycline (TCs), Triclosan (TCS), Bisphenol A (BPA) and Carbamazepine (CBZ). These compounds were selected from the categories of pharmaceutical contaminants (PCs), endocrine disruptors (EDs) and personal care products (PCPs) on the basis of their toxicity and concentration retained in the environment. In this context, detailed mechanism of laccase mediated degradation has been conversed that laccase assisted degradation occurs by one electron oxidation involving redox potential as underlying element of the process. Further, converging towards biotechnology, laccase immobilization increased removal efficiency, storage and reusability through various experimentally conducted studies. Laccase is being considered noteworthy as mediators facilitate laccase in oxidation of non-phenolic compounds and thereby increasing its substrate range which is being discussed in further in the review. The laccase assisted degradation mechanism of each compound has been elucidated but further studies to undercover proper degradation mechanisms needs to be performed. [ABSTRACT FROM AUTHOR]

To characterize and reduce the harmful effects of Erythemal ultraviolet radiation (EUV), it is vital to recognize the spatial distribution and temporal variation of EUV radiation under various meteorological conditions. In light of these requirements, the problem we address here is to understand the results of a study performed to assess the influence of stratospheric ozone and aerosol loading on the receipt of EUV at six sites located in Saudi Arabia. The selected sites were chosen to represent the climatic zones of the north, middle, and south of Saudi Arabia. Intensive satellite-based measurements of the atmosphere over the period 1979–2005 obtained from the Total Ozone Mapping Spectrometer (TOMS) website ( ftp://toms.gsfc.nasa.gov ) were used, with a four year gap from 1993 to 1996. The results hint that, in spite of the significant decrease in stratospheric ozone, there is a clear decreasing trend in the EUV data series due to the increase in the aerosol loading during summer months. For the other months the correlation is not clear and in all cases there was no decrease in the EUV radiation trend outside summer months, with few exceptions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Agro-industrial food waste can be valorized by creating a waste-based biorefinery approach. • Fermentable sugars recovery from agro-industrial food waste through integrated pretreatment. • Agro-industrial food waste can be used for biochemical, bioproducts and biofuels. • Summarized the challenges in the utilization of agro-industrial food waste. Modernization and industrialization has undoubtedly revolutionized the food and agro-industrial sector leading to the drastic increase in their productivity and marketing thereby accelerating the amount of agro-industrial food waste generated. In the past few decades the potential of these agro-industrial food waste to serve as bio refineries for the extraction of commercially viable products like organic acids, biochemical and biofuels was largely discussed and explored over the conventional method of disposing in landfills. The sustainable development of such strategies largely depends on understanding the techno economic challenges and planning for future strategies to overcome these hurdles. This review work presents a comprehensive outlook on the complex nature of agro-industrial food waste and pretreatment methods for their valorization into commercially viable products along with the challenges in the commercialization of food waste bio refineries that need critical attention to popularize the concept of circular bio economy. [ABSTRACT FROM AUTHOR]

Objective: No evidence-based data exist on the availability, accessibility and utilization of healthcare services in Lahej Governorate, Yemen. The aim of this study was to assess the distribution and utilization of curative services in primary healthcare units and centres in Lahej. Study design: Cross-sectional study (clustering sample). Method: This study was conducted in three of the 15 districts in Lahej between December 2009 and August 2010. Household members were interviewed using a questionnaire to determine sociodemographic characteristics and types of healthcare services available in the area. Results: The distribution of health centres, health units and hospitals did not match the size of the populations or areas of the districts included in this study. Geographical accessibility was the main obstacle to utilization. Factors associated with the utilization of curative services were significantly related to the time required to reach the nearest facility, seeking curative services during illness and awareness of the availability of health facilities (P < 0.01). Conclusion: There is an urgent need to look critically and scientifically at the distribution of healthcare services in the region in order to ensure accessibility and quality of services. [ABSTRACT FROM AUTHOR]

Figure displayed the FE-SEM image of ZnO NPs along with photocatalytic decolourization reaction mechanism, Tauc's profile, first order rate constants and reusability of 1.0 wt.% La@ZnO NPs in consecutive 4 runs. These results show that the prepared ZnO NPs with 1.0 wt.% La content are highly applicable in photocatalysis applications. • Synthesis of pure and La@ZnO NPs was facilely attained by flash combustion route. • The hexagonal phase of La@ZnO was confirmed from structural and vibrational analyses. • The size of SNPs was estimated in range of 46–74 nm for La@ZnO and 120 nm for pure. • Energy gap of La@ZnO NPs was noticed to be decreased from 3.220 to 3.210 eV. • A highest photocatalytic nature was noticed for 1.0 wt.% La@ZnO NPs. The successful one pot flash combustion synthesis of ZnO nanoparticles (NPs) with a diverse LA (La@ZnO) content was achieved simply and economically. X-ray diffraction confirms the synthesis of ZnO with a hexagonal crystal system. The vibrational bands are positioned at 100, 332, 380, 438 and 583 cm−1 for pure and La@ZnO NPs. FESEM images exhibit roughly spherical and oval morphologies of pure ZnO with particles size 120 nm and La@ZnO NPs with particle sizes in the 46–74 nm range. The particle size of a La doped ZnO sample increases with increase in concentration from 1.0 % to 7.5 wt.% of La. The evaluated energy gap of La doped ZnO NPs decreased from 3.220 to 3.210 eV as the concentration of La varied from 1.0–7.5 wt.% as estimated by Kubelka–Munk theory. The photocatalytic analysis of the as-synthesized ZnO nanoparticles is maximized at La (1.0 wt.%) and the mechanism of photocatalytic decolourization reaction is discussed. The results suggest that the La-doped ZnO nanoparticles can be used in optoelectronic and photocatalytic applications. [ABSTRACT FROM AUTHOR]

Several studies have investigated the association of different HLA antigens with multiple sclerosis (MS). However, only few studies have considered the association of high-resolution HLA type and MS with none yet from Saudi Arabia. The aim of this study was to investigate the association of HLA class II alleles with MS in the Saudi population. We used next-generation sequencing to investigate HLA association with MS. This study was conducted at King Abdulaziz Medical City in Riyadh, Saudi Arabia. We found that several HLA-DRB1 and DQB1 alleles were associated with MS. These alleles included HLA-DRB1*15:01 (odds ratio [OR]: 3.01; 95%, confidence interval [CI]: 1.68-5.54; P = .0001), HLA-DQB1*02:01 (OR: 1.76; 95% CI: 1.20-2.58; P = .0022), HLA-DQB1*06:02 (OR: 3.52; 95% CI: 1.87-6.86; P < .0001), and HLA-DQB1*06:03 (OR: 2.42; 95% CI: 1.16-5.25; P = 0.01). Interestingly, HLA-DRB1*15:01 was associated with increased risk of previous relapses. In addition, HLA-DRB1*15:01 and HLA-DQB1*06:02 were found to be associated with lower vitamin D levels. This study provides insights on the association of different HLA alleles with clinical characteristics and outcome of MS among Saudis. These insights can have future implications for the clinical management of MS based on the patient genetic profile., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

As we leave the 20th century, continuing medical education faces many challenges in relation to its effectiveness, efficiency and quality. The young and promising Saudi Council for Health Specialties produces a document on accreditation of continuing medical education, which indicates its interest in this vital subject. This paper aims to enrich the approach to continuing medical education in Saudi Arabia by reviewing the main relevant challenges reported in literature and suggesting that the Saudi Council for Health Specialities may consider developing and implementing a continuing medical education charter that addresses the needs of all stakeholders and emphasizes high quality and cost-effective provision.

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With the aim of stimulating learning which is more self directed, fourth year medical students in Liverpool are encouraged to set personal learning objectives for the general practice attachment. On average, a student defines seven objectives for the three week attachment. A classification of objectives derived from the 1989 cohort of students is presented and the objectives could be seen as focusing on the practice population and its health problems, the role of the general practitioner, the work of general practice, the management of general practice, general practice as a career, and general learning. The validity and reliability of the classification are considered. Along with the advantages of this approach in motivating students to learn, the findings are considered in relation to impending changes in undergraduate medical education and the future role of general practice teaching by departments and by practice based colleagues.