New functional cyclic aminomethylphosphine ligands for the construction of catalysts for electrochemical hydrogen transformations.

Eight-membered cyclic functional bisphosphines, namely 1,5-di-aryl-3,7-di(2-pyridyl)-1,5-diaza-3,7-diphosphacyclooctanes (aryl=2-pyridyl, m-tolyl, p-tolyl, diphenylmethyl, benzyl, (R)-(+)-(α-methyl)benzyl), with 2-pyridyl substituents on the phosphorus atoms have been synthesized by condensation of 2-pyridylphosphine, formaldehyde, and the corresponding primary amine. The structures of some of these bisphosphines have been investigated by X-ray crystallography. The bisphosphines readily form neutral P,P-chelate complexes [(κ(2)-P,P-L)MCl2], cationic bis-P,P-chelate complexes [(κ(2)-P,P-L)2 M](2+), or a five-coordinate complex [(κ(2)-P,P-L)2 NiBr]Br. The electrochemical behavior of two of the nickel complexes, and their catalytic activities in electrochemical hydrogen evolution and hydrogen oxidation, including the fuel-cell test, have been studied.

Epidemiology of Hepatitis B in Saudi Arabia from 2006 to 2021.

Background: This study describes the epidemiological pattern of acute hepatitis B virus (HBV) infection in Saudi Arabia from 2006 to 2021. It explores case frequency and the crude incidence rate (CIR) by year of diagnosis, age group, region, gender, and nationality of patients. Methods: Retrospective data on acute hepatitis B cases diagnosed across 20 regions of Saudi Arabia during January 2006 to December 2021 were obtained from the Saudi Ministry of Health's Statistical Yearbook. Statistical analyses were conducted using SPSS version 20.0, employing both parametric and non-parametric tests. Results: The highest CIR was reported in the regions of Qunfudah, Jeddah, Tabuk, and Taif (28.6, 25.2, 25.1, and 23.4 per 100,000 people). In contrast, the lowest CIR was documented in the regions of Hail, Qurayyat, Jouf, and Hafr AL-Baten (3.6, 3.5, 2.9, and 1.2 per 100,000 people). Incidence rates were notably elevated in those aged 45 years and above (30.6 per 100,000 individuals), followed by the 15-44 age group (14.2 per 100,000 individuals), and were lowest in children aged 0-14 years (0.8 per 100,000 individuals). Regarding gender differences, HBV infection rates were 1.4 times higher in Saudi males than females and 2.2 times higher in non-Saudi males compared to females. Overall, Saudi nationals had a 4.2 times higher HBV infection rate than non-Saudis during the study period. Conclusion: This study highlights diverse acute Hepatitis B infection rates across Saudi regions, with higher rates in Qunfudah, Jeddah, Tabuk, and Taif, and lower rates in Hail, Qurayyat, Jouf, and Hafr AL-Baten. Predominance among ages 45+, followed by 15-44, and lowest in 0-14 age groups was observed. Gender variations showed notably higher rates in Saudi and non-Saudi males. The notably higher prevalence among Saudi nationals implies key considerations for public health strategies.

Indoor phthalates from household dust in Qatar: implications for non-dietary human exposure.

Phthalates are ubiquitous semi-volatile organic compounds in the indoor environment present in various consumer products such as cosmetics, polyvinylchloride (PVC) flooring, food packing, and many others. Indoor phthalate concentrations were investigated in 15 buildings including 11 homes, 3 laboratories, and 1 from a hospital in Qatar. Dust samples were collected from vacuum cleaning bags usually used for cleaning homes, labs, and hospitals. The main objectives of this study was to determine the occurrence and concentration of phthalates in dust in Qatar and consequently to estimate the non-dietary human exposure. Eleven phthalates was analyzed. The major identified phthalate compounds at homes in Qatar were bis(2-ethylhexyl) phthalate unlabeled (DEHP) and diisononyl phthalate (DINP) at a geometric mean of 288 µg/g (median 395 µg/g) and 106 µg/g (median 101 µg/g) accounting for 57% and 23% of the total measured phthalates, respectively. The major phthalate compounds found in the first lab building were DEHP and DINP with a median of 4861 µg/g and 943 µg/g, respectively, accounting for 82% and 16% of the total phthalates. For the second lab building, the major phthalates were DEHP with a median of 466 µg/g, accounting for 20% of the total phthalates measured, and DINP median of 1725 µg/g, accounting for 71% of the total measured phthalates. The dust sample tested from hospital building had DEHP as the major phthalate compound with a median of 793 µg/g, accounting for 4.0% of the total measured phthalates, and DINP with a median of 19,626 µg/g, accounting for 94%. The estimated human non-dietary exposure for children, adults, and toddlers was based on phthalate concentrations (median) and found to be 225 ng/kg bw/day for children, 2328 ng/kg bw/day for adults, and 2099 ng/kg bw/day for toddlers.

Vacancy ion-exclusion chromatography of inorganic acids on a weakly acidic cation-exchange resin column.

Vacancy ion-exclusion chromatography (VIEC) for inorganic acids such as H(2)SO(4), HCl, H(3)PO(4), HNO(3), HI and HF is tested on a polymethacrylate-based weakly acidic cation-exchange resin column in the H(+)-form. That is, mixture of inorganic acids in the mobile phase is adsorbed to the resin phase passing through the separation column, and each vacant peak induced by injecting water is determined. Retention times are dependent on the degrees of retention for each analyte in the resin phase. In VIEC, well-shaped peaks of inorganic acids are produced, leading to efficient separations. However, retention behaviors of inorganic acids were strongly affected by the concentrations of the acids in the mobile phase. Sulfosalicylic acid was mixed with inorganic acids in the mobile phase prior to the introduction of a separation column in order to obtain the well-resolutions in the lower concentrations of the acids. By using this method, the separations of inorganic acids could be achieved in the range of 0.01-1 mM, and the linear ranges could be extended over two-orders of magnitude. This is considered since the protonated carboxylic groups fixed on the resin phase were increased with increasing the acid concentrations in the mobile phase, and the penetration effects for the acids to the resin phase were thus enhanced. The detection limits (S/N=3) were below 1.0 microM for all analyte acids. Precision values for retention times were below 0.32% and for peak area were below 0.91%.

Validation of various extraction techniques for the quantitative analysis of polycyclic aromatic hydrocarbons in sewage sludges using gas chromatography-ion trap mass spectrometry.

A new GC-ion trap MS method has been developed for the determination of polycyclic aromatic hydrocarbons (PAHs) in sewage sludge samples. The sludge samples were extracted with Soxhlet, Soxtec, and pressurized liquid extraction (PLE) using 1:1 (v/v) dichloromethane (DCM):n-hexane solvent mixture. A multi-layer clean-up (silica/Al2O3) column were used, followed by gel permeation chromatography (GPC) to eliminate the interfering organic compound as well as the lipids. The extracts were quantified with GC-EI-SIS and GC-EI-MS-MS. The method was successfully applied to determine the concentration of PAHs present in sewage sludge samples collected from four waste water treatment plants (WWTPs). The method recovery values varied from 61.5 to 90.5%, 65.0 to 91.8% and 60.0 to 93.4% for Soxtec extraction, Soxhlet extraction and PLE extraction, respectively. The total concentrations of the 16 PAHs in the sewage sludge samples were found to vary from 1.56 to 6.18 mg/kg. The concentration of PAHs in WWTPs did not significantly vary.

High-speed ion-exclusion chromatography of dissolved carbon dioxide on a small weakly acidic cation-exchange resin column with ion-exchange enhancement columns of conductivity detection.

The high-speed ion-exclusion chromatographic determination of dissolved carbon dioxide, i.e., carbonic acid, hydrogencarbonate or carbonate, with conductivity detection was obtained using a small column packed with a weakly acidic cation-exchange resin in the H+-form (40 mm long x 4.6 mm i.d., 3 microm-particle and 0.1 meq./ml-capacity). Two different ion-exchange resin columns, which were a strongly acidic cation-exchange resin in the K+-form and a strongly basic anion-exchange resin in the OH- -form, were connected after the separation column. The sequence of columns could convert dissolved carbon dioxide to KOH having high conductivity response. The enhancement effect for dissolved carbon dioxide could retain even on the vast chromatographic runs, by using the enhancement columns with high ion-exchange capacity above 1.0 meq./ml. The retention time was in 60 s at flow-rate of 1.2 ml/min. The calibration graph of dissolved carbon dioxide estimated as H2CO3- was linear in the range of 0.005-10 mM. The detection limit at signal to noise of 3 was 0.15 microM as H2CO3-. This method was applicable to several rainwater and tap water samples.

No association between the dopamine D3 receptor Bal I polymorphism and schizophrenia in a family-based study of a Palestinian Arab population.

Several recent meta-analyses appear to show a weak but significant effect of both forms of the gly/ser DRD3 polymorphism in conferring risk for schizophrenia. Since most studies have employed the artifact-prone case-control design, we thought it worthwhile to examine the role of this polymorphism using a robust family-based strategy in an ethnic group not previously systematically studied in psychiatric genetics, Palestinian Arabs. We failed to obtain any evidence in 129 Palestinian triads, using the haplotype relative risk (allele frequency: Pearson chi-square = 0.009, P > 0.1, df = 1, n = 258 alleles) or transmission disequilibrium test design (chi-square = 0.38, P > 0.1, n = 86 families) for association/linkage (or increased homozygosity) of the DRD3 Bal I polymorphism to schizophrenia in our sample. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:778-780, 2000.

A family-based study of the Cys23Ser 5HT2C serotonin receptor polymorphism in schizophrenia.

The 5HT2C receptor has a high affinity for clozapine, a nontypical neuroleptic, and has therefore been postulated to play a role in mediating negative symptoms and neuroleptic response in schizophrenia. In the current study, the Cys23Ser 5HT2C serotonin receptor polymorphism was examined for linkage to schizophrenia by genotyping 207 nuclear families consisting of both parents and schizophrenic child and using the transmission disequilibrium test to examine possible preferential transmission of these alleles from 68 heterozygous mothers to their ill child. No evidence was obtained for preferential transmission of the Cys23Ser 5HT2C alleles in schizophrenia in either of the two main ethnic groups examined (German and Palestinian Arab) or in the combined cohort (TDT chi-square = 0.00, NS).

No evidence for linkage by transmission disequilibrium test analysis of microsatellite marker D22S278 and schizophrenia in a Palestinian Arab and in a German population.

Linkage for a schizophrenia susceptibility locus on chromosome region 22q12-q13 was initially suggested by independent studies from two groups and confirmed in a combined analysis of data for the microsatellite marker D22S278 in multiply affected schizophrenic families derived from 11 independent research groups worldwide. In addition to these reports of linkage to schizophrenia on chromosome 22, bipolar disorder has also been linked to markers in this chromosomal region. We now report results from an analysis of 223 Palestinian Arab trios from three different centers in Israel and Palestine using the allele-wise extended transmission disequilibrium test for multiallelic markers. No evidence for linkage is observed in the entire group or in any of the three centers (entire group: chi-square = 5.59, P = 0.78, df = 9; Afula: chi-square = 6.51, P = 0.48, df = 7; Bethlehem: chi-square = 14.11, P = 0.12, df = 9; Beersheva: chi-square = 7.04, P = 0.32, df = 6). Additionally, we examined D22S278 in a group of 114 schizophrenic German triads and failed to observe evidence for linkage (chi-square = 8.13, P = 0.42, df = 8df).

Monolithic octadecylsilyl-silica gel column for the high-speed ion chromatographic determination of acidity.

A monolithic ODS-silica gel column modified by saturating it with lithium dodecylsulfate (Li-DS) was used to demonstrate the high-speed separation of H+ from other mono- and divalent cations, such as Na+, NH4+, K+, Mg2+ and Ca2+ using ion chromatography (IC). Using a 5 mM EDTA-2K solution containing 0.10 mM Li-DS (pH 4.80) as eluent, H+ was eluted with a sharp and symmetrical peak within 1.0 min before other cations at a flow-rate of 1.5 ml min(-1). The rapid elution of H+ and its conductimetric detection could be attributed to the presence of EDTA (HY2-), which can convert H+ ions as anions. i.e. H(+) + H2Y(2-) --> H3Y(-). The acidity of rainwater and deionized water samples was determined using this IC system with satisfactory results.

Qualitative analysis of some carboxylic acids by ion-exclusion chromatography with atmospheric pressure chemical ionization mass spectrometric detection.

A simple, selective and sensitive method for the determination of carboxylic acids has been developed. A mixture of formic, acetic, propionic, valeric, isovaleric, isobutyric, and isocaproic acids has been separated on a polymethacrylate-based weak acidic cation-exchange resin (TSK gel OA pak-A) based on an ion-exclusion chromatographic mechanism with detection using UV-photodiode array, conductivity and atmospheric pressure chemical ionization mass spectrometry (APCI-MS). A mobile phase consisting of 0.85 mM benzoic acid in 10% aqueous methanol (pH 3.89) was used to separate the above carboxylic acids in about 40 min. For LC-MS, the APCI interface was used in the negative ionization mode. Linear plots of peak area versus concentration were obtained over the range 1-30 mM (r2=0.9982) and 1-30 mM (r2=0.9958) for conductimetric and MS detection, respectively. The detection limits of the target carboxylic acids calculated at S/N=3 ranged from 0.078 to 2.3 microM for conductimetric and photometric detection and from 0.66 to 3.82 microM for ion-exclusion chromatography-APCI-MS. The reproducibility of retention times was 0.12-0.16% relative standard deviation for ion-exclusion chromatography and 1.21-2.5% for ion-exclusion chromatography-APCI-MS. The method was applied to the determination of carboxylic acids in red wine, white wine, apple vinegar, and Japanese rice wine.

Vacancy ion-exclusion/adsorption chromatography of aliphatic amines on a polymethacrylate-based weakly basic anion-exchange column.

Vacancy ion-exclusion/adsorption chromatography has been applied to investigate the separation behavior of five aliphatic amines (ethylamine, propylamine, butylamine, pentylamine and hexylamine) on a polymethacrylate-based weakly basic anion-exchange column (Tosoh TSKgel DEAE-5PW). This system is consisted of analytes as a mobile phase and water as an injected sample. In the vacancy ion-exclusion/adsorption chromatography, the elution order was as follows: ethylamine < propylamine < butylamine < pentylamine < hexylamine, depending on their hydrophobicity. The retention times of the amines were decreased with decreasing their concentrations in the mobile phase. The retention times and resolutions of the amines were increased by adding a basic compound (e.g., lithium hydroxide or heptylamine) and by increasing the pH of mobile phase (pH > 11). This was because the dissociations of amine samples in the mobile phase were suppressed and thus the hydrophobic adsorption effects were enhanced. The linearity of calibration graphs could be obtained from the peak areas of the amine samples injected to the 0.05, 0.5 and 5 mM of amine mobile phase at pH 11 by heptylamine. The detection limits of aliphatic amines as injected samples were around 1 microM for five aliphatic amines at three different amine mobile phases. From these results, the retention behaviors of aliphatic amines on vacancy ion-exclusion/adsorption chromatography were concluded to be governed by the hydrophobic adsorption effect.

Ion-exclusion chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation-exchange resin by elution with benzoic acid-beta-cyclodextrin.

In this study, an aqueous solution consisting of benzoic acid with low background conductivity and beta-cyclodextrin (beta-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the ion-exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and hydrophobicity on a polymethacrylate-based weakly acidic cation-exchange resin in the H+ form. With increasing concentration of beta-cyclodextrin in the eluent, the retention times of the carboxylic acids decreased due to the increased hydrophilicity of the polymethacrylate-based cation-exchange resin surface from the adsorption of OH groups of beta-cyclodextrin. Moreover, the eluent background conductivity decreased with increasing concentration of beta-cyclodextrin in 1 mM benzoic acid, which could result in higher sensitivity for conductimetric detection. The ion-exclusion chromatographic separation of carboxylic acids with high resolution and sensitivity was accomplished successfully by elution with a 1 mM benzoic acid-10 mM cyclodextrin solution without chemical suppression.

Vacancy ion-exclusion chromatography of haloacetic acids on a weakly acidic cation-exchange resin.

A new and simple approach is described for the determination of the haloacetic acids (such as mono-, di- and trichloroacetic acids) usually found in drinking water as chlorination by-products after disinfection processes and acetic acid. The new approach, termed vacancy ion-exclusion chromatography, is based on an ion-exclusion mechanism but using the sample solution as the mobile phase, pure water as the injected sample, and a weakly acidic cation-exchange resin column (TSKgel OApak-A) as the stationary phase. The addition of sulfuric acid to the mobile phase results in highly sensitive conductivity detection with sharp and well-shaped peaks, leading to excellent and efficient separations. The elution order was sulfuric acid, dichloroacetic acid, monochloroacetic acid, trichloroacetic acid, and acetic acid. The separation of these acids depends on their pKa values. Acids with lower pKa values were eluted earlier than those with higher pKa, except for trichloroacetic acid due to a hydrophobic-adsorption effect occurring as a side-effect of vacancy ion-exclusion chromatography. The detection limits of these acids in the present study with conductivity detection were 3.4 microM for monochloroacetic acid, 0.86 microM for dichloroacetic acid and 0.15 microM for trichloroacetic acid.

Vacancy ion-exclusion chromatography of aromatic carboxylic acids on a weakly acidic cation-exchange resin.

Determination of aromatic carboxylic acids by conventional ion-exclusion chromatography is relatively difficult and methods generally rely on hydrophobic interaction between the solute and the resin. To overcome the difficulties in determining aromatic carboxylic acids a new approach is presented, termed vacancy ion-exclusion chromatography, which is based on use of the sample as mobile phase and an injection of aqueous 10% methanol onto a weakly acidic cation-exchange column (TSKgel OApak-A). Highly sensitive conductivity detection occurred with sharp and well-shaped peaks, leading to very efficient separations. The effects of sulfuric acid concentration added to the mobile phase, flow-rate, and column temperature on the retention volume of tested aromatic carboxylic acids was investigated. Retention times were found to be affected by the concentration of the analytes in the mobile phase and to some extent also by the addition of an organic modifier such as methanol to the injected water sample. Separation of sulfuric acid (SA), naphthalenetetracarboxylic acid (NTCA), phthalic acid (PA) and benzoic acid (BA) was satisfactory using this new approach. Detection limits were 0.66, 0.67, 0.42 and 0.86 microM and detector responses were linear in the range 1-100, 1-80, 2.5-100 and 10-40 microM, for SA, NTCA, PA and BA, respectively. Precision for retention times was 0.36% and for peak areas was 1.5%.

Selective determination of ammonium ions by high-speed ion-exclusion chromatography on a weakly basic anion-exchange resin column.

This paper describes an ion-exclusion chromatographic system for the rapid and selective determination of ammonium ion. The optimized ion-exclusion chromatographic system was established with a polymethacrylate-based weakly basic anion-exchange resin column (TSKgel DEAE-5PW) as the separation column, an aqueous solution containing 0.05 mM tetramethylammonium hydroxide (pH 9.10) as eluent with conductimetric detection for the analyte determination. Under the optimum chromatographic conditions, ammonium ion was determined within 2.3 min with a detection limit (S/N=3) better than 0.125 microM. Ammonium ion in rain and river waters was precisely determined using this ion-exclusion chromatographic system.

High-speed simultaneous ion-exclusion/cation-exchange chromatography of anions and cations on a weakly acidic cation-exchange resin column.

The simultaneous ion-exclusion/cation-exchange separation column packed with a polymethacrylate-based weakly acidic cation-exchange resin of 3 microm particle size was used to achieve the simultaneous high-speed separation of anions and cations (Cl(-), NO3(-), SO4(2-), Na(+), K(+), NH4(+), Ca(2+) and Mg(2+)) commonly found in environmental samples. The high-speed simultaneous separation is based on a combination of the ion-exclusion mechanism for the anions and the cation-exchange mechanism for cations. The complete separation of the anions and cations was achieved in 5 min by elution with 15 mM tartaric acid-2.5 mM 18-crown-6 at a flow-rate of 1.5 ml/min. Detection limits at S/N=3 ranged from 0.36 to 0.68 microM for anions and 0.63-0.99 microM for cations. This method has been applied to the simultaneous determination of anions and cations in several environmental waters with satisfactory results.

Vacancy ion-exclusion chromatography of carboxylic acids on a weakly acidic cation-exchange resin.

In this preliminary study, a new approach to ion-exclusion chromatography is proposed to overcome the relatively poor conductivity detection response which occurs in ion-exclusion chromatography when acids are added to the eluent in order to improve peak shape. This approach, termed vacancy ion-exclusion chromatography, requires the sample to be used as eluent and a sample of water to be injected onto a weakly acidic cation-exchange column (TSKgel OApak-A). Vacancy peaks for each of the analytes appear at the retention times of these analytes. Highly sensitive conductivity detection is possible and sharp, well-shaped peaks are produced, leading to efficient separations. Retention times were found to be affected by the concentration of the analytes in the eluent, and also by the presence of an organic modifier such as methanol in the eluent. Detection limits for oxalic, formic, acetic, propionic, butyric and valeric acids were 0.1, 0.2, 0.3, 0.3, 0.4 and 0.5 microM, respectively, and linear ranges for some acids extended over two orders of magnitude. Precision values for retention times were 0.21% and for peak areas were <1.90%. The vacancy ion-exclusion chromatography method was found to give detection responses four to 10 times higher than conventional ion-exclusion chromatography using sulfuric acid eluent and two to five times higher than conventional ion-exclusion chromatography using benzoic acid eluent.

The influence of the surgical scrub on hand bacterial flora.

The skin bacterial flora of subjects who scrub their hands routinely was compared to subjects who usually do not scrub their hands, to determine the influence of the surgical scrub on the skin bacterial population. Aerobic, anaerobic and yeast cultures of 15 surgical residents and 15 internal medicine residents were obtained. The skin bacterial population of 15 medical students rotating through surgery was also determined to assess the influence of hand contact with infected wounds on the bacterial flora. The medical students had been in contact with infected wounds as had the surgical residents, but they had not been scrubbing their hands. The internal medicine residents had not been in contact with infected wounds or scrubbing their hands. The number of bacteria cultured from the medical students was superior to the bacterial count obtained from internal medicine residents, but inferior to the number of microorganisms isolated from surgical residents (p less than 0.01). Pathogenic bacteria were isolated from cultures of eight surgical residents, five medical students and one internal medicine resident. Yeast was cultured from one surgical resident's hand. This study indicates that both the frequent contact with infected wounds and the routine use of the ten minute surgical scrub may modify the bacterial flora of the hand. The alterations observed in the two situations were an increased number of both pathogenic and nonpathogenic bacteria.

Psychiatry in the Palestine Authority: legal, ethical and forensic issues.

The historical and political reality of life in the West Bank and Gaza has deeply influenced the development of psychiatric services, and particularly the provision of evaluation and care for Palestinian forensic patients by Palestinian psychiatrists. The difficulties are presented and how they have changed during the events of the last decades.