Ga Samples Research Articles

Stool-based Xpert testing for diagnosis of TB in children and critically ill adults.

<sec><title>BACKGROUND</title>We describe our approach and experience with the routine implementation of stool-based Xpert MTB/RIF Ultra (Xpert) testing for the diagnosis of childhood TB in Zambia.</sec><sec><title>METHODS</title>We conducted a method validation and subsequently introduced stool as an alternative sample for routine Xpert testing for children and critically ill adults. We reviewed the impact of stool-based Xpert testing during the first 18 months of routine implementation.</sec><sec><title>RESULTS</title>The method validation showed 98.0% (95% CI 92.9-99.4) agreement between Xpert results on sputum/gastric aspirate (GA) and stool specimens. During 18 months of routine implementation, 16,210 stool samples were tested, yielding 157 TB cases in children, including five rifampicin (RIF) resistant cases, and 45 cases in critically ill adults. In children aged 0-4 years, 10,288 stool samples were tested compared to 2,459 GA samples in the same period. Childhood TB notifications and the bacteriological confirmation rate increased by 30% and 53%, respectively, in 2021 compared to 2020.</sec><sec><title>CONCLUSION</title>The routine implementation of stool testing provided access to Xpert testing for children who could not produce sputum or have GA collected, contributing to increased bacteriological confirmation of TB in children. For critically ill adults with difficulty expectorating sputum, it facilitated a rapid test result.</sec>.

Effective CdS:(Ce, Ga) Nanoparticles for Photocatalytic H2 Production Under Artificial Solar Light Exposer

To encounter the burgeoning energy demands of the future, it is imperative to focus on the progress of innovative and profitable techniques for hydrogen (H2) evolution, coupled with an enriched stability of photocatalysts. In this work, we have effectually prepared CdS, CdS:Ce, and CdS:(Ce, Ga) nanoparticles through a chemical refluxing method at 120 °C. Comprehensive structural analysis confirmed the effectual incorporation of Ce and Ga ions in the place of Cd2+ in a CdS matrix. Morphology analysis indicates that the prepared samples are irregularly shaped nanoparticles. Chemical analysis confirmed that the Ce and Ga ions incorporated in the Cd site occurred with 3+ and 4+ valence states. All the samples were assessed for H2 production through water splitting via artificial solar light irradiation. Amid all the samples, CdS:(Ce, Ga) nanoparticles portrayed a giant H2 evolution efficacy (3012 µmol h−1g−1) in 300 min, which is 13.9 times larger than that of the bar CdS sample. Thus, we firmly propose that CdS:(Ce, Ga) samples are authentic and potent candidates for efficient photocatalytic H2 production in sterile environments.

Структурa і властивості матеріалів Fe—Al—Ga в області концентрацій, збагачених залізом

The structure and mechanical properties of materials of the Fe—Al—Ga system (in the concentration range of 78—82% (wt.) Fe), obtained by sintering at 1150 oC in Ar medium for 1 hour, were studied. The starting materials were mixtures of Fe, Al powders and crushed Fe—Ga ligature alloy of equiatomic composition. Seven mixtures were produced, of which two mixtures had a binare compo¬sition (% (wt.)): Fe—17,5Al and Fe—21,4Ga; and all the others were three-component, with gradual substitution of Al for Ga. The phase composition of the samples was studied by the methods of X-ray diffraction and local X-ray microspectral analyses. To determine the mechanical characteristics, the Brinell method was used, microdurometric studies were carried out, and mechanical tests of the samples were carried out under conditions of uniaxial compression. The effect of Al on the change in the porosity of Fe—Al—Ga ternary alloys and the maximum manifestation of the “swelling” effect for Fe—Al composition samples was established. It is shown that the main phase of the obtained materials is a solid solution based on Fe, in which Al and Ga are dissolved in the appropriate proportions. In the Fe—Al samples and in the samples of the ternary composition, there are local separations of phases containing, in addition to the main metals, carbon and oxygen in significant quantities. In the structure of Fe—Ga samples, carbon is not detected, and oxygen is present in a small amount. The results of the mechanical compression tests showed that the Fe—21,4Ga composition samples, like the pure Fe samples, are quite plastic and do not break up to a degree of compression of 75—82%. For materials with binary composition with Ga, an increase in the elastic range was recorded compared to pure Fe, and the replacement of a small proportion of Ga with Al (up to 2% by weight) in the material composition contributes to its strengthening. Keywords: Fe, Al, Ga, microstructure, phase formation, microhardness, mechanical compression characteristics.

Fractal Characterization of the Pore-Throat Structure in Tight Sandstone Based on Low-Temperature Nitrogen Gas Adsorption and High-Pressure Mercury Injection

The pore-throat structure is a critical factor in the study of unconventional oil and gas reservoirs, drawing particular attention from petroleum geologists, and it is of paramount significance to analyze to enhance oil and gas production. In tight sandstone, which serves as a significant hydrocarbon reservoir, the internal pore-throat structure plays a decisive role in the storage and migration of fluids such as water, gases, and hydrocarbons. This paper employs casting thin section (CTS), field emission scanning electron microscope (FE-SEM), high-pressure mercury injection (HPMI), and low-temperature nitrogen gas adsorption (LT−N2−GA) experimental tests to qualitatively and quantitatively analyze the characteristics of the pore-throat structure in tight sandstone. The results indicate that the pore types in tight sandstone include intergranular residual pores, dissolution pores, intercrystalline pores, and microfractures, while the throat types encompass sheet-shaped, curved-sheet-shaped, and tubular throats. Analysis of the physical and structural parameters from 13 HPMI and 5 LT−N2−GA samples reveals a bimodal distribution of pore-throat radii. The complexity of the pore-throat structure is identified as a primary controlling factor for reservoir permeability. The fractal dimension (D) exhibits an average value of 2.45, displaying a negative correlation with porosity (R2 = 0.22), permeability (R2 = 0.65), the pore-throat diameter (R2 = 0.58), and maximum mercury saturation (R2 = 0.86) and a positive correlation with threshold pressure (R2 = 0.56), median saturation pressure (R2 = 0.49), BET specific surface area (R2 = 0.51), and BJH total pore volume (R2 = 0.14). As D increases, reservoir pores tend to decrease in size, leading to reduced flow and deteriorated physical properties, indicative of a more complex pore-throat structure.

Quantification of shape parameters of Co-Cr-Mo-Si multiphase compounds and their role in the processing of metal injection molding feedstocks

Quantification of shape parameters of Co-Cr-Mo-Si multiphase compounds and their role in the processing of metal injection molding feedstocks

Non-zero I/(Ca + Mg) recorded in Archean and Paleoproterozoic shallow marine Ca-carbonate sediments

Non-zero I/(Ca + Mg) recorded in Archean and Paleoproterozoic shallow marine Ca-carbonate sediments

Influence of AlOx Interlayers on LeTID Kinetics in Ga-Doped Cz-Si

Light and elevated temperature-induced degradation (LeTID) is causing a reduction in efficiency especially in p-type silicon based solar cells. It is assumed to be strongly influenced by the hydrogen content in the bulk material. The presented work focuses on the impact of differently thick (5-25 nm) atomic layer-deposited aluminum oxide (AlOx) interlayers underneath the hydrogen-rich silicon nitride (SiNy:H) capping layer. The interlayer acts as a diffusion barrier for H during the firing step. It is demonstrated that the AlOx interlayer has a comparable effect on the LeTID kinetics in Ga-doped Cz-Si (Cz-Si:Ga) as it is observed in B-doped Cz-Si (Cz-Si:B). Additionally, it substantially minimizes lifetime degradation in the Cz-Si:Ga sample. With a determined ratio of electron to hole capture cross sections k=26(3), the degradation phenomena are attributed to the LeTID kinetics. Deposition of AlOx barrier layers exceeding 10 nm in thickness does not yield additional positive effects. Resistivity measurements revealed that the change in hole concentration correlates with the defect density for varying AlOx layer thicknesses. The doping concentration seems to influence the change in maximum defect density for varying AlOx layer thicknesses.

Secular change of tectonic setting in the Archean Takanen greenstone belt, northeastern Karelia Province, Fennoscandian Shield

The target of this study is the Takanen greenstone belt (TGB), a small 11-km-long and east-west oriented supracrustal belt in the northern Lentua complex of the Western Karelia Subprovince (eastern Finland). We present a new geological interpretation of the TGB based on lithology, geochemistry, stratigraphy, and two new zircon U-Pb age determinations and Lu-Hf-in-zircon data. The TGB forms a ���≥800-m-thick synclinal sequence composed of intercalated mafic-���komatiitic and felsic-intermediate volcanic and volcaniclastic rocks (lavas, tuffs, and tuffites) crosscut by granitoid dykes, and metamorphosed in lower amphibolite facies with few primary volcanic textures visible. The felsic-intermediate rocks are calc-alkaline and split into strongly and weakly REE-fractionated groups. The mafic-ultramafic rocks are tholeiitic with flat REE-patterns, but some samples show LREE-enrichment. Massive Fe-sulfide layers (≤��1 m) are associated with volcanoclastic rocks. Komatiites are Al-undepleted and comprise differentiated (peridotite-gabbro) and undifferentiated (dunite/serpentinite) cumulates and thin undifferentiated flows. Channel-facies komatiitic cumulates are found stratigraphically above Fe-sulfide-rich unites and have �potential for komatiite-hosted Ni-deposits. Our new isotope data from two felsic-intermediate volcanic rock samples shows that the TGBs stratigraphically lowermost and uppermost units are 2.96 Ga and 2.71 Ga old, respectively. Based on Hf isotope data, the older 2.96 Ga sample contains reworked crustal material, possibly originating from ~3.2 Ga crust.In contrast, the 2.71 Ga sample is isotopically juvenile (near-chondritic), indicating an episode of juvenile crust formation in the northern Lentua Complex. No unconformity is found between the stratigraphically upper and lower parts of the TGB, but the ~250 Ma age difference (and geochemical indicators) suggests they may have formed in different tectonic settings. The lower part of TGB stratigraphy is correlated with the ~2.94 Ga Luoma Formation in the nearby Suomussalmi greenstone belt. The 2.71 Ga volcanic unit does not have a known equivalent in greenstone belts in Finland, but a corollary is found in Russia, and a tentative correlation to a possible 2.75–2.70 Ga arc-system in Takanen–Khedozero-Bolshozero–Ilomantsi is suggested.

Characterization of the volatile flavour compounds in Yunnan Arabica coffee prepared by different primary processing methods using HS-SPME/GC-MS and HS-GC-IMS

Characterization of the volatile flavour compounds in Yunnan Arabica coffee prepared by different primary processing methods using HS-SPME/GC-MS and HS-GC-IMS

Synthesis of High Near-Infrared Reflective Black Pigment Based on YMn2O5

Y(Mn0.95M0.05)2O5 (M = Al, Fe, Ga, Ti, and Zr) samples were synthesized via a sol–gel method using citric acid to find a new near-infrared (NIR) reflective black pigment. Among these samples, the optical reflectance of Y(Mn0.95Fe0.05)2O5 and Y(Mn0.95Ga0.05)2O5 in the near-infrared region was found to be larger than that of YMn2O5. Then, the concentration of the dopant (Fe or Ga) was changed between 0 and 15%, and the resulting UV–Vis–NIR reflectance spectra were measured. As a result, the optical reflectance of the Fe-doped samples decreased in the near-infrared region, while that of the Ga-doped samples increased. Accordingly, Y(Mn1−xGax)2O5 (0 ≤ x ≤ 0.20) samples were synthesized, and the crystal structure, particle size, optical properties, and color of the samples were characterized. The single-phase samples were obtained in the composition range of 0 ≤ x ≤ 0.15, and the lattice volume decreased with increasing Ga3+ concentration. Optical absorption below 850 nm was attributed to the charge transfer transition between O2p and Mn3d orbitals, and the absorption wavelength of Y(Mn1−xGax)2O5 shifted to the shorter wavelength side as the Ga3+ content increased, because of the decrease in the Mn3+ concentration. Although the sample color became slightly reddish black by the Ga3+ doping, the solar reflectance in the near-infrared region reached 47.6% at the composition of Y(Mn0.85Ga0.15)2O5. Furthermore, this NIR reflectance value was higher than those of the commercially available products (R &lt; 45%).

Decoupling topological antiskyrmion and non-topological magnetic phases in D2d symmetric Mn–Ni–Ga single crystalline device

Here, we present the finding of two types of distinct Hall signals in the single crystalline Hall devices of a D2d symmetric antiskyrmion host Mn–Ni–Ga sample. The out-of-plane device, where the magnetic field is applied along the [001] direction, exhibits a dip-like anomaly in the Hall resistivity data, signifying the presence of topological Hall signal originating from the antiskyrmion phase. Most importantly, we demonstrate the robustness of the antiskyrmion phase against an oblique field where the topological Hall signal survives up to a tilting angle of 75° with respect to the c-axis. In contrast, the Hall resistivity data for the in-plane device exhibit an aberrant hump-like feature that can be tuned with applying a rotating magnetic field. We show that this hump-like anomaly emerges from the existence of a two-component anomalous Hall effect arising due to the presence of twinning microstructure. The present study provides an important insight into the stability and evolution of the antiskyrmion phase under the oblique magnetic fields and helps in decoupling of anomalous Hall signals in the non-topological magnetic phases.

Investigation of Dynamic-Mechanical-Thermal Analysis of Innovative Hybrid Carbon/Glass Fibers Reinforced by GNPs and Al2O3 for Marine Structures

AbstractMarine structural applications face numerous challenges related to environmental load, corrosion, and fatigue under varying time and temperature conditions. One of the major challenges faced by marine structural applications is dynamic mechanical thermal analysis (DMTA). In this study, innovative hybrid carbon/glass fibers (CGF) reinforced with different contents (1.5 wt. % and 3 wt. %) of dual nano-powders, including graphene nanoplatelets (GNPs) and aluminium oxide (Al2O3), were developed as reinforcements inside the epoxy matrix. The nanocomposites were fabricated using a hand lay-up technique, resulting in a nanocomposite sheet with dimensions of 300 mm length, 200 mm width, and 2.3 mm thickness. DMTA test specimens were prepared with dimensions of 50 mm length, 10 mm width, and 2.3 mm thickness. To ensure accuracy, three replicates were conducted for each condition, and the average values were calculated for analysis. Before DMTA, the prepared nanocomposites were analyzed using optical microscopy (OM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDAX) to compare the influence of incorporating dual nano-powders. DMTA was carried out at different temperature values (ranging from 10 °C to 105 °C) and times (ranging from 5 to 575 min) at 1 Hz frequency with a heating rate of 4 °C/min and a nitrogen flow rate of 20 ml/min. The main objective of this study was to investigate the influence of incorporating dual nano-powders such as GNPs and Al2O3on various dynamic mechanical properties including storage modulus, loss modulus, damping factor (DF), and glass transition temperature (Tg) of the hybrid carbon/glass fiber-reinforced epoxy composites. The fabricated hybrid CGF composite with 1.5% wt. GA nanoparticles exhibited higher values for the DF of 0.68 and the Tg of 73.4 °C. However, increasing the nanoparticle content to 3% wt. GA led to a deterioration in the DF (0.54) and a reduction in Tg (27.8 °C) due to decreased bonding between the carbon fibers (CF) and glass fibers (GF) caused by the higher nanoparticle concentration. The complex modulus (E*) values demonstrated expected trends with temperature and time for the CGF-1.5% wt. GA composite, indicating acceptable behaviour. In contrast, the CGF-3% wt. GA composite exhibited lower E* values, indicating a decrease in stiffness and mechanical properties compared to the CGF-1.5% wt. GA composite. Microstructural observations after DMTA revealed a uniform scattering of nanoparticles in the CGF-1.5% wt. GA sample, while the CGF-3% wt. GA sample demonstrated improved scattering of Al2O3nanoparticles on the surface. The microstructural analysis further indicated a brittle nature with high resistance to crack initiation and propagation in the CGF-1.5% wt. GA composite.

Investigation of the LME Susceptibility of Dual Phase Steel with Different Zinc Coatings

The application of anti-corrosion coated, high-strength steels in the automotive industry has increased in recent years. In combination with various zinc-based surface coatings, liquid metal embrittlement cracking can be observed in some of these materials. A high-quality, crack-free spot-welded joint is essential to realize the lightweight potential of the materials. In this work, the LME susceptibility of different coatings, which will be determined by the crack length and the occurrence rate, will be investigated using a welding under external load setup. The uncoated specimens did not show any LME. EG, GI and GA showed significantly less LME than ZM coatings. The latter coatings showed much larger crack lengths than the EG, GI and GA coatings. Furthermore, two mechanisms regarding the LME occurrence rate were observed: the occurrence of LME in zinc–magnesium coatings was theorized to be driven by the material properties of the coatings, whereas the occurrence of LME at EG, GI and GA samples was forced mainly by the application of the external tensile load. In the experimental setup of this work, the materials were exposed to unusually high mechanical loads (up to 80% of their yield strength) to evoke LME cracks.

Ga intercalation in van der Waals layers for advancing p-type Bi2Te3-based thermoelectrics

Tetradymite-structured chalcogenides, such as Bi2Te3 and Sb2Te3, are quasi-two-dimensional (2D) layered compounds, which are significant thermoelectric materials applied near room temperature. The intercalation of guest species in van der Waals (vdW) gap implemented for tunning properties has attracted much attention in recent years. We attempt to insert Ga atoms in the vdW gap between the Te layers in p-type Bi0.3Sb1.7Te3 (BST) for further improving thermoelectrics. The vdW-related defects (including extrinsic interstitial and intrinsic defects) induced by Ga intercalation can not only modulate the carrier concentration but also enhance the texture, thereby yielding excellent electrical properties, which are reflected in the power factor PF ∼ 4.43 mW⋅m−1⋅K−2. Furthermore, the intercalation of Ga produces multi-scale lattice imperfections such as point defects, Te precipitations, and nanopores, realizing the low lattice thermal conductivity in BST-Ga samples. Ultimately, a peak zT ∼ 1.1 at 373 K is achieved in the BST-1% Ga sample and greatly improved by ∼ 22% compared to the pristine BST. The weak bonding of vdW interlayer interaction can boost the synergistic effect for advancing BST-based or other layered thermoelectrics.

The Eoarchean Muzidian gneiss complex: Long-lived Hadean crustal components in the building of Archean continents

The Eoarchean Muzidian gneiss complex: Long-lived Hadean crustal components in the building of Archean continents

Influence of neutron/gamma irradiation on damage and scintillation of Ga-doped ZnO thin films

Influence of neutron/gamma irradiation on damage and scintillation of Ga-doped ZnO thin films

Improving thermoelectric performance of half-Heusler Ti0.2Hf0.8CoSb0.8Sn0.2 compounds via the introduction of excessive Ga and Co-deficiencies

Improving thermoelectric performance of half-Heusler Ti0.2Hf0.8CoSb0.8Sn0.2 compounds via the introduction of excessive Ga and Co-deficiencies

Graphene-maleic anhydride-grafted-carboxylated acrylonitrile butadiene-rubber nanocomposites

Ethylene-propylene grafted-maleic anhydride (EPR-g-MA) and a pure maleic anhydride (MA) were separately used to compound carboxylated acrylonitrile butadiene-rubber (XNBR) together with reduced graphene oxide (G) to form nanocomposites, by using melt compounding technique. The G-sheets in the presence of MA (GA samples) or EPR-g-MA (GB samples) generally increased the physico-mechanical properties including; crosslinking density, tensile strength and thermal degradation resistance etc., when compared with sample without MA or EPR-g-MA (GAO) and the virgin matrix. For the thermal degradation resistance measured by the char residue (%), by using thermal gravimetric analysis technique; GA1 (0.1 ph G and 0.5 ph MA) was 106.4% > XNBR and 58% > GAO (0.1 ph G) while that of GB1 (0.1 ph G and 0.5 ph EPR-g-MA) was 60% > XNBR and 22.2% > GAO respectively. Although, homogeneous dispersions of the G-sheets assisted by MA or EPR-g-MA was a factor, but the strong bonding (covalent, hydrogen and physical entanglements) occurring in GA and GB was observed to be the main contributing factor for these property enhancements. Thus, these nanostructured materials have exhibited multifunctional capabilities and could be used for advanced applications including high temperature (heat sinks), flame retardants, and structural applications.

Temporal evolution of 142Nd signatures in SW Greenland from high precision MC-ICP-MS measurements

Measurements of 142 Nd isotope signatures in Archean rocks are a powerful tool to investigate the earliest silicate differentiation events on Earth. Here, we introduce a new analytical protocol that allows high precision radiogenic and mass-independent Nd isotope measurements by MC-ICP-MS. To validate our method, we have measured well-characterized ~3.72 to ~3.8 Ga samples from the Eoarchean Itsaq Gneiss Complex and associated supracrustal belts, as well as Mesoarchean greenstones and a Proterozoic dike in SW Greenland, including lithostratigraphic units that were previously analyzed for 142-143 Nd isotope systematics, by both TIMS and MC-ICP-MS. Our μ 142 Nd values for ~3.72 to ~3.8 Ga rocks from the Isua region range from +9.2 ± 2.6 to +13.2 ± 1.1 ppm and are in good agreement with previous studies. Using coupled 142,143 Nd/ 144 Nd isotope systematics from our data for ~3.8 Ga mafic-ultramafic successions from the Isua region, we can confirm previous age constraints on the earliest silicate differentiation events with differentiation age of 4.390 −0.060 +0.045 4.426 −0.064 +0.084 4.426 −0.055 +0.042 Ga. Moreover, we can resolve a statistically significant decrease of 142 Nd/ 144 Nd isotope compositions in the ambient mantle of SW Greenland that already started to commence by Eoarchean time, between ~3.8 Ga (μ 142 Nd = +13.0 ± 1.1) and ~ 3.72 Ga (μ 142 Nd = +9.8 ± 1.0). Even lower but homogeneous μ 142 Nd values of +3.8 ± 1.1 are found in ~3.4 Ga mantle-derived rocks from the Ameralik dike swarms. Our study reveals that ε 143 Nd (i) and εHf (i) values of Isua rocks scatter more than it would be expected from a single stage differentiation event as implied from nearly uniform μ 142 Nd values, suggesting that the previously described decoupling of Hf and Nd isotopes is not a primordial magma ocean signature. Instead, we conclude that some of second stage processes like younger mantle depletion events or recycling of subducted material affected the 147 Sm 143 Nd isotope systematics. The preservation of pristine whole-rock isochrons largely rules out a significant disturbance by younger alteration events. Based on isotope and trace element modelling, we argue that the temporal evolution of coupled 142,143 Nd/ 144 Nd isotope compositions in the ambient mantle beneath the Isua rocks is best explained by the progressive admixture of material to the Isua mantle source that must have had present-day-like μ 142 Nd compositions. In contrast, Mesoarchean mafic rocks from the ~3.08 Ga Ivisaartoq greenstone belt and the 2.97 Ga inner Ameralik Fjord region as well as a 2.0 Ga Proterozoic dike within that region all have higher μ 142 Nd values as would be expected from our simple replenishment model. This argues for reworking of older Isua crustal material that carried elevated μ 142 Nd compositions.

Low Temperature Epitaxy of In Situ GaDoped Si1-XGex: Dopant Incorporation, Structural and Electrical Properties

The effect of the growth temperature and the Ga precursor flow on the epitaxy of Si1-xGex:Ga is studied. These parameters are found to have a significant impact on the Ga surface segregation behavior. In particular, Ga in situ doping impacts the growth rate of the epilayer, the Si1-xGex alloy composition, and the onset of strain relaxation. The growth temperature can be used to modulate the Ga segregation, enabling the deposition of materials with enhanced dopant concentrations and improved electrical properties. The Ga local atomic environment was studied in both a Si0.4Ge0.6:Ga and a Ge:Ga sample by X-ray absorption fine structure. The local environment of the Ga determined confirmed that the majority of dopants occupy a substitutional position within the lattice.