Origin and hydrothermal alteration of rare-metal granites in the Al-Hamra area, northeastern Arabian Shield, Saudi Arabia

Abstract The Jabal Hamra (538 Ma) and Jabal Abu ad Dud plutons in northeast Saudi Arabia are epizonal bodies consisting of alkali feldspar granite and alkali feldspar syenite. Fracture-controlled zones of highly altered granites are recorded along the margins of the plutons. The granites intrude metamorphosed volcano-sedimentary successions of the Matran Formation. The rocks of the two plutons are chemically indistinguishable. They are characterized by above-average Th, Nb, Y, Ta, Hf and Zr, very low CaO, TiO2, MgO, FeO and MnO, and by high contents of rare earth elements (REE). Tectonic discrimination diagrams suggest an intra-plate environment, with many geochemical and mineralogical features resembling post-orogenic A-type granites. Numerous local and regional geologic constraints indicate that the plutons were intruded in an extension-related setting following the cessation of Neoproterozoic arc-related magmatism. Geochemical data are consistent with their derivation by partial melting of depleted crust followed by fractional crystallization of feldspars, ferromagnesian minerals and REE-rich accessory phases. The radiogenic isotope data [eNd (T) values are +3.5 to +4.2] indicate that the granite magma was generated from a ‘juvenile’ source, which is typical of the rocks making up most of the Arabian-Nubian Shield. Rare-metal mineralization is associated with the fracture-controlled alteration zones that occur at Jabal Al Hamra and Jabal Abu ad Dud. The altered rocks are characterized by higher TiO2, Fe2O3, SiO2 and lower Al2O3, CaO, Na2O, than the unaltered rocks. They show high and wide range in the total REE contents (804–15579 ppm), Ta (6–194 ppm), Nb (51–3483 ppm), Hf (13–368 ppm), Zr (394–14887 ppm), Th (16–572 ppm) and U (4–143 ppm). Field observations and further petrographic and chemical studies suggest that the altered rocks and the rare metal enrichment are the products of hydrothermal-metasomatic alteration of the quartz alkali feldspar syenite and the alkali feldspar granite. The rare-metal enrichment was explained by orthomagmatic fluid transport of these elements as fluoride complexes, and their subsequent deposition as a result of mixing with externally derived Fe-rich fluids

Brain abscess following rituximab infusion in a patient with pemphigus vulgaris.

BackgroundImmunocompromised patients are at increased risk for developing meningitis or, rarely, brain abscess with opportunistic organisms like Listeria monocytogenes.Case reportA 52 year-old Saudi Arabian woman who was diagnosed with pemphigus vulgaris and diabetes and had been on prednisolone and azathioprine for about 4 years. She presented with headache, low-grade fever, and left-sided weakness 2 weeks after receiving the second dose of rituximab infusion. Magnetic resonance imaging revealed an enhanced space-occupying lesion with multiple small cyst-like structures and vasogenic edema in the right temporoparietal area. Her blood culture was positive for Listeria monocytogenes, and a brain biopsy showed necrotic tissues with pus and inflammatory cells. She recovered after a 6-week course of antibiotics with ampicillin and gentamycin.ConclusionsBrain abscess due to Listeria monocytogenes is a risk that should be considered when adding rituximab to the regimen of a patient who is already Immunocompromised

Human Inborn Errors of Immunity: 2019 Update of the IUIS Phenotypical Classification.

Since 2013, the International Union of Immunological Societies (IUIS) expert committee (EC) on Inborn Errors of Immunity (IEI) has published an updated phenotypic classification of IEI, which accompanies and complements their genotypic classification into ten tables. This phenotypic classification is user-friendly and serves as a resource for clinicians at the bedside. There are now 430 single-gene IEI underlying phenotypes as diverse as infection, malignancy, allergy, autoimmunity, and autoinflammation. We herein report the 2019 phenotypic classification, including the 65 new conditions. The diagnostic algorithms are based on clinical and laboratory phenotypes for each of the ten broad categories of IEI

Neutralizing antibody response during acute and chronic hepatitis C virus infection

Little is known about the role of Abs in determining the outcome of hepatitis C virus (HCV) infection. By using infectious retroviral pseudotypes bearing HCV glycoproteins, we measured neutralizing Ab (nAb) responses during acute and chronic HCV infection. In seven acutely infected health care workers, only two developed a nAb response that failed to associate with viral clearance. In contrast, the majority of chronically infected patients had nAbs. To determine the kinetics of strain-specific and crossreactive nAb emergence, we studied patient H, the source of the prototype genotype 1a H77 HCV strain. An early weak nAb response, specific for the autologous virus, was detected at seroconversion. However, neutralization of heterologous viruses was detected only between 33 and 111 weeks of infection. We also examined the development of nAbs in 10 chimpanzees infected with H77 clonal virus. No nAb responses were detected in three animals that cleared virus, whereas strain-specific nAbs were detected in six of the seven chronically infected animals after approximately 50 weeks of infection. The delayed appearance of high titer crossreactive nAbs in chronically infected patients suggests that selective mechanism(s) may operate to prevent the appearance of these Abs during acute infection. The long-term persistence of these nAbs in chronically infected patients may regulate viral replication

Association between proton pump inhibitor therapy and clostridium difficile infection: a contemporary systematic review and meta-analysis.

Abstract Introduction Emerging epidemiological evidence suggests that proton pump inhibitor (PPI) acid-suppression therapy is associated with an increased risk of Clostridium difficile infection (CDI). Methods Ovid MEDLINE, EMBASE, ISI Web of Science, and Scopus were searched from 1990 to January 2012 for analytical studies that reported an adjusted effect estimate of the association between PPI use and CDI. We performed random-effect meta-analyses. We used the GRADE framework to interpret the findings. Results We identified 47 eligible citations (37 case-control and 14 cohort studies) with corresponding 51 effect estimates. The pooled OR was 1.65, 95% CI (1.47, 1.85), I2 = 89.9%, with evidence of publication bias suggested by a contour funnel plot. A novel regression based method was used to adjust for publication bias and resulted in an adjusted pooled OR of 1.51 (95% CI, 1.26–1.83). In a speculative analysis that assumes that this association is based on causality, and based on published baseline CDI incidence, the risk of CDI would be very low in the general population taking PPIs with an estimated NNH of 3925 at 1 year. Conclusions In this rigorously conducted systemic review and meta-analysis, we found very low quality evidence (GRADE class) for an association between PPI use and CDI that does not support a cause-effect relationship

A water-gated organic thin film transistor as a sensor for water-borne amines

The p-type semiconducting polymer Poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) displays innate sensitivity to water-borne amines. We demonstrate this with the help of water- gated PBTTT thin film transistors (TFTs). When octylamine is added to the gating water, TFTs respond with a significantly reduced saturated drain current. Underlying TFT drift is minimised by initial conditioning, and remaining drift can be accounted for by normalising current response to the current level under purge immediately before exposure. Normalised current response vs. amine concentration is reproducible between different transistors, and can be modelled by a Langmuir surface adsorption isotherm, which suggests physisorption of analyte at the PBTTT surface, rather than bulk penetration. Same PBTTT transistors do not respond to 1- octanol, confirming the specific affinity between amines and thiophene- based organic semiconductors

Inhaled mometasone furoate for the management of refractory oral corticosteroid-dependent asthma: a case report

We report a case study of a 55-year-old white male with severe persistent refractory corticosteroid-dependent asthma receiving inhaled combination therapy with fluticasone propionate 500 μg and salmeterol 50 μg twice-daily in addition to 6-week cycles of oral corticosteroid treatment for the previous 7 months. The patient was switched to high-dose mometasone furoate delivered via a dry powder inhaler (660 μg twice-daily) for 6 weeks

Influence of Yb:YAG laser beam parameters on Haynes 188 weld fusion zone microstructure and mechanical properties

The weldability of 1.2 mm thick Haynes 188 alloy sheets by a disk Yb:YAG laser welding was examined. Butt joints were made, and the influence of parameters such as power, size, and shape of the spot, welding speed, and gas flow has been investigated. Based on an iconographic correlation approach, optimum process parameters were determined. Depending on the distribution of the power density (circular or annular), acceptable welds were obtained. Powers greater than 1700 W, welding speeds higher than 3.8 m mm1, and spot sizes between 160 and 320 lm were needed in the circular (small fiber) configuration. By comparison, the annular (large fiber) configuration required a power as high as 2500 W, and a welding speed less than 3.8 m min�1. The mechanical properties of the welds depended on their shape and microstructure, which in turn depended on the welding conditions. The content of carbides, the proportion of areas consisting of cellular and dendritic substructures, and the size of these substructures were used to explain the welded joint mechanical properties