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1.
Inorg Chem ; 62(44): 18049-18055, 2023 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-37870243

RESUMEN

There is an ongoing interest in kagome materials because they offer tunable platforms at the intersection of magnetism and electron correlation. Herein, we examine single crystals of new kagome materials, LnxCo3(Ge1-ySny)3 (Ln = Y, Gd; y = 0.11, 0.133), which were produced using the Sn flux-growth method. Unlike many of the related chemical analogues with the LnM6X6 formula (M = transition metal and X = Ge, Sn), the Y and Gd analogues crystallize in a hybrid YCo6Ge6/CoSn structure, with Sn substitution. While the Y analogue displays temperature-independent paramagnetism, magnetic measurements of the Gd analogue reveal a magnetic moment of 8.48 µB, indicating a contribution from both Gd and Co. Through anisotropic magnetic measurements, the direction of Co-magnetism can be inferred to be in plane with the kagome net, as the Co contribution is only along H//a. Crystal growth and structure determination of YxCo3(Ge,Sn)3 and GdxCo3(Ge,Sn)3, two new hybrid kagome materials of the CoSn and YCo6Ge6 structure types. Magnetic properties, heat capacity, and resistivity on single crystals are reported.

2.
J Pak Med Assoc ; 73(8): 1709-1711, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37697767

RESUMEN

Prostate cancer is the second most commonly diagnosed malignancy in men worldwide. The prevalence has been increasing with significant differences between regions. This study assesses the prevalence of incidental prostate cancer detected in specimens removed during bladder outlet obstruction operation. A retrospective analysis of the records of patients who had either endoscopic or open prostatectomy from January 1998 to December 2021 was conducted. The variables analysed were age, procedure, date of surgery, and Gleason score. A total of 2,842 patients underwent surgery on the prostate gland during the study period. Most of the patients, i.e. 2,733 (96.2%), were pathologically diagnosed with benign prostatic hyperplasia, while only 110 (3.9%) had prostate cancer. The frequency of incidental prostate cancer following surgery for bladder outlet obstruction has decreased over the last two decades at our centre, possibly because of an increase in PSA testing.


Asunto(s)
Neoplasias Primarias Secundarias , Neoplasias de la Próstata , Obstrucción del Cuello de la Vejiga Urinaria , Masculino , Humanos , Estudios Retrospectivos , Centros de Atención Terciaria , Neoplasias de la Próstata/diagnóstico , Neoplasias de la Próstata/epidemiología , Neoplasias de la Próstata/cirugía , Próstata/cirugía
3.
Science ; 381(6658): 642-644, 2023 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-37561853

RESUMEN

Highlights from the Science family of journals.

4.
Sci Adv ; 9(28): eadg7269, 2023 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-37436976

RESUMEN

Materials with Kagome nets are of particular importance for their potential combination of strong correlation, exotic magnetism, and electronic topology. KV3Sb5 was discovered to be a layered topological metal with a Kagome net of vanadium. Here, we fabricated Josephson Junctions of K1-xV3Sb5 and induced superconductivity over long junction lengths. Through magnetoresistance and current versus phase measurements, we observed a magnetic field sweeping direction-dependent magnetoresistance and an anisotropic interference pattern with a Fraunhofer pattern for in-plane magnetic field but a suppression of critical current for out-of-plane magnetic field. These results indicate an anisotropic internal magnetic field in K1-xV3Sb5 that influences the superconducting coupling in the junction, possibly giving rise to spin-triplet superconductivity. In addition, the observation of long-lived fast oscillations shows evidence of spatially localized conducting channels arising from edge states. These observations pave the way for studying unconventional superconductivity and Josephson device based on Kagome metals with electron correlation and topology.

5.
Artículo en Inglés | MEDLINE | ID: mdl-36901255

RESUMEN

A breast tissue biopsy is performed to identify the nature of a tumour, as it can be either cancerous or benign. The first implementations involved the use of machine learning algorithms. Random Forest and Support Vector Machine (SVM) were used to classify the input histopathological images into whether they were cancerous or non-cancerous. The implementations continued to provide promising results, and then Artificial Neural Networks (ANNs) were applied for this purpose. We propose an approach for reconstructing the images using a Variational Autoencoder (VAE) and the Denoising Variational Autoencoder (DVAE) and then use a Convolutional Neural Network (CNN) model. Afterwards, we predicted whether the input image was cancerous or non-cancerous. Our implementation provides predictions with 73% accuracy, which is greater than the results produced by our custom-built CNN on our dataset. The proposed architecture will prove to be a new field of research and a new area to be explored in the field of computer vision using CNN and Generative Modelling since it incorporates reconstructions of the original input images and provides predictions on them thereafter.


Asunto(s)
Neoplasias , Redes Neurales de la Computación , Algoritmos , Aprendizaje Automático , Procesamiento de Imagen Asistido por Computador/métodos
6.
J Ayub Med Coll Abbottabad ; 35(Suppl 1)(4): S721-S725, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38406900

RESUMEN

Background: The use of unhealthy food and a sedentary lifestyle increases daily health problems. Renal stones are one among others. Endourology promises the minimum complications and the highest stone clearance rate. Indications of the two procedures overlap micro-PCNL and RIRS. The objective was to evaluate stone clearance and complication rate of micro-PCNL and RIRS for lower pole renal stones. Methods: The research design of this study was a randomized trial and was done after approval of the ethical review committee. The sampling technique was consecutive sampling at the Urology department. Patients included in the study according to inclusion criteria were 96 in number. Randomization into two groups (RIRS vs micro-PCNL) was done by even odd method. All the procedure was done by a single senior urologist. Results: Their ratio among males and females was 2:1. Mean LOS in the RIRS group was 2.89±0.86 days and in the micro-PCNL group 2.58±0.65 days (p=0.047). The complication rate in the RIRS group was 6.2% and 8.3% in micro-PCNL (p=0.695). Mean post-operative haemoglobin was 12.30±1.07 g/dL among the RIRS group and among the micro-PCNL group it was 11.21±1.08 g/dL (p<0.001). There was an average haemoglobin drop in the micro-PCNL group of 1.09±0.01 g/dL. 75% clearance of stone after one session was achieved in the RIRS group while 79.2% was achieved in the micro-PCNL group (p=0.627). Conclusion: Length of hospital stay (LOS) and stone clearance rate (SFR) were similar in both groups with insignificant statistical differences. There is a need to conduct more studies with a large number of study participants and involving multi-centers.


Asunto(s)
Cálculos Renales , Litotricia , Nefrolitotomía Percutánea , Nefrostomía Percutánea , Masculino , Femenino , Humanos , Nefrolitotomía Percutánea/efectos adversos , Nefrostomía Percutánea/métodos , Cálculos Renales/cirugía , Hemoglobinas , Resultado del Tratamiento
7.
Sci Rep ; 12(1): 13210, 2022 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-35915211

RESUMEN

Timely and accurate estimation of rice-growing areas and forecasting of production can provide crucial information for governments, planners, and decision-makers in formulating policies. While there exists studies focusing on paddy rice mapping, only few have compared multi-scale datasets performance in rice classification. Furthermore, rice mapping of large geographical areas with sufficient accuracy for planning purposes has been a challenge in Pakistan, but recent advancements in Google Earth Engine make it possible to analyze spatial and temporal variations within these areas. The study was carried out over southern Punjab (Pakistan)-a region with 380,400 hectares devoted to rice production in year 2020. Previous studies support the individual capabilities of Sentinel-2, Landsat-8, and Moderate Resolution Imaging Spectroradiometer (MODIS) for paddy rice classification. However, to our knowledge, no study has compared the efficiencies of these three datasets in rice crop classification. Thus, this study primarily focuses on comparing these satellites' data by estimating their potential in rice crop classification using accuracy assessment methods and area estimation. The overall accuracies were found to be 96% for Sentinel-2, 91.7% for Landsat-8, and 82.6% for MODIS. The F1-Scores for derived rice class were 83.8%, 75.5%, and 65.5% for Sentinel-2, Landsat-8, and MODIS, respectively. The rice estimated area corresponded relatively well with the crop statistics report provided by the Department of Agriculture, Punjab, with a mean percentage difference of less than 20% for Sentinel-2 and MODIS and 33% for Landsat-8. The outcomes of this study highlight three points; (a) Rice mapping accuracy improves with increase in spatial resolution, (b) Sentinel-2 efficiently differentiated individual farm level paddy fields while Landsat-8 was not able to do so, and lastly (c) Increase in rice cultivated area was observed using satellite images compared to the government provided statistics.


Asunto(s)
Oryza , Agricultura , Pakistán , Imágenes Satelitales
8.
Sensors (Basel) ; 22(11)2022 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-35684640

RESUMEN

In recent decades, Vehicular Ad Hoc Networks (VANET) have emerged as a promising field that provides real-time communication between vehicles for comfortable driving and human safety. However, the Internet of Vehicles (IoV) platform faces some serious problems in the deployment of robust authentication mechanisms in resource-constrained environments and directly affects the efficiency of existing VANET schemes. Moreover, the security of the information becomes a critical issue over an open wireless access medium. In this paper, an efficient and secure lightweight anonymous mutual authentication and key establishment (SELWAK) for IoT-based VANETs is proposed. The proposed scheme requires two types of mutual authentication: V2V and V2R. In addition, SELWAK maintains secret keys for secure communication between Roadside Units (RSUs). The performance evaluation of SELWAK affirms that it is lightweight in terms of computational cost and communication overhead because SELWAK uses a bitwise Exclusive-OR operation and one-way hash functions. The formal and informal security analysis of SELWAK shows that it is robust against man-in-the-middle attacks, replay attacks, stolen verifier attacks, stolen OBU attacks, untraceability, impersonation attacks, and anonymity. Moreover, a formal security analysis is presented using the Real-or-Random (RoR) model.


Asunto(s)
Redes de Comunicación de Computadores , Seguridad Computacional , Comunicación , Humanos , Internet
9.
Nature ; 604(7907): 653-656, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35478238

RESUMEN

The superconducting analogue to the semiconducting diode, the Josephson diode, has long been sought with multiple avenues to realization being proposed by theorists1-3. Showing magnetic-field-free, single-directional superconductivity with Josephson coupling, it would serve as the building block for next-generation superconducting circuit technology. Here we realized the Josephson diode by fabricating an inversion symmetry breaking van der Waals heterostructure of NbSe2/Nb3Br8/NbSe2. We demonstrate that even without a magnetic field, the junction can be superconducting with a positive current while being resistive with a negative current. The ΔIc behaviour (the difference between positive and negative critical currents) with magnetic field is symmetric and Josephson coupling is proved through the Fraunhofer pattern. Also, stable half-wave rectification of a square-wave excitation was achieved with a very low switching current density, high rectification ratio and high robustness. This non-reciprocal behaviour strongly violates the known Josephson relations and opens the door to discover new mechanisms and physical phenomena through integration of quantum materials with Josephson junctions, and provides new avenues for superconducting quantum devices.

11.
Adv Mater ; 34(8): e2101730, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34908193

RESUMEN

Current-induced control of magnetization in ferromagnets using spin-orbit torque (SOT) has drawn attention as a new mechanism for fast and energy efficient magnetic memory devices. Energy-efficient spintronic devices require a spin-current source with a large SOT efficiency (ξ) and electrical conductivity (σ), and an efficient spin injection across a transparent interface. Herein, single crystals of the van der Waals (vdW) topological semimetal WTe2  and vdW ferromagnet Fe3 GeTe2 are used to satisfy the requirements in their all-vdW-heterostructure with an atomically sharp interface. The results exhibit values of ξ ≈ 4.6 and σ ≈ 2.25 × 105  Ω-1 m-1 for WTe2 . Moreover, the significantly reduced switching current density of 3.90 × 106 A cm-2 at 150 K is obtained, which is an order of magnitude smaller than those of conventional heavy-metal/ferromagnet thin films. These findings highlight that engineering vdW-type topological materials and magnets offers a promising route to energy-efficient magnetization control in SOT-based spintronics.

12.
PLoS One ; 16(10): e0255043, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34613980

RESUMEN

Majority of Pakistani soils are deficient in phosphorus. Phosphorus is usually applied in form of synthetic fertilizer. However integrated use of P from synthetic and organic sources can be more profitable and beneficial on sustainable basis. Field trials were conducted at research farm University of Poonch, Rawalakot, AJK, Pakistan for two consecutive years to check the comparative effects of synthetic fertilizer and organic manures applied alone and in combinations on the phosphorus use efficiency (PUE), wheat yield and yield components. Shafaq-06 cultivar of wheat was used as test cultivar. Ten treatments were included: (I) Control (P0) without application of fertilizer; (II) SSP @ 60 kg/ha (P60SSP); (III) SSP @ 90 kg/ha (P90SSP); (IV) SSP @ 120 kg/ha (P120SSP); (V) PM @60 kg/ha (P60PM); (VI) PM @90 kg/ha (P90PM); (VII) PM @120 kg/ha (P120PM); (VIII) SSP @30 kg/ha + PM @30 kg/ha (P30SSP+30PM); (IX) SSP @45 kg/ha + PM @45 kg/ha (P45SSP+45PM); (X) SSP @60 kg/ha + PM @60 kg/ha (P60SSP+60PM) which were laid out under the Randomized Complete Block Design. Significantly higher values for yield of grain (2397 kg/ha) was recorded with PM + SSP @ 60 kg P2O5 ha-1 each. Likewise, FPUE, PIR of wheat and AFPUE was quite higher with combined use of PM and SSP i.e. P60SSP+60PM treatment. Additionally, increase in PUE, wheat yield and yield components associated with combined treated plot would help to minimize the use of high cost synthetic mineral fertilizers and represents an environmentally and agronomically sound management strategy.


Asunto(s)
Nutrientes/sangre , Fósforo/química , Triticum/química , Triticum/crecimiento & desarrollo , Agricultura/métodos , Granjas , Fertilizantes , Estiércol , Pakistán , Suelo/química
13.
Molecules ; 26(11)2021 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-34070241

RESUMEN

Lipoic acid (LA) and melatonin (MT) are pleiotropic molecules participating in plant stress resistance by modulating cellular biochemical changes, ion homeostasis, and antioxidant enzyme activities. However, the combined role of these two molecules in counteracting the detrimental impacts of salinity stress is still unknown. In the present study, we determined the effects of exogenous LA (0.5 µM), MT (1 µM) and their combination (LA + MT) on growth performance and biomass accumulation, photosynthetic pigments, enzymatic and non-enzymatic antioxidant activities, and ions homeostatic in canola (Brassica napus L.) seedlings under salinity stress (0, 100 mM) for 40 days. The results indicate that exogenous application of LA + MT improved the phenotypic growth (by 25 to 45%), root thickness (by 68%), number of later lateral roots (by 52%), root viability (by 44%), and root length (by 50%) under salinity stress. Moreover, total soluble protein, chlorophyll pigments, the concentration of superoxide dismutase (SOD), catalase peroxidase (CAT), and ascorbic peroxidase (ASA) increased with the presence of salt concentration into the growth media and then decreased with the addition of LA + MT to saline solution. Leaf protein contents and the degradation of photosynthetic pigments were lower when LA + MT treatments were added into NaCl media. The proline and phenol contents decreased in the exogenous application of LA + MT treatments more than individual LA or MT treatments under the salinity stress. The incorporation of LA or MT or a combination of LA + MT to saline solution decreased salinity-induced malondialdehyde and electrolyte leakage. In conclusion, the alteration of metabolic pathways, redox modulation, and ions homeostasis in plant tissues by the combined LA and MT application are helpful towards the adaptation of Brassica napus L. seedlings in a saline environment. The results of this study provide, for the first time, conclusive evidence about the protective role of exogenous LA + MT in canola seedlings under salinity stress.


Asunto(s)
Brassica napus/crecimiento & desarrollo , Productos Agrícolas/crecimiento & desarrollo , Melatonina/farmacología , Estrés Oxidativo/efectos de los fármacos , Raíces de Plantas/efectos de los fármacos , Estrés Salino , Ácido Tióctico/farmacología , Antioxidantes/metabolismo , Biomasa , Brassica napus/metabolismo , Productos Agrícolas/metabolismo , Homeostasis , Malondialdehído/metabolismo , Minerales/metabolismo , Fenoles/metabolismo , Fotosíntesis/efectos de los fármacos , Pigmentos Biológicos/metabolismo , Hojas de la Planta/metabolismo , Raíces de Plantas/crecimiento & desarrollo
14.
Mamm Genome ; 32(5): 389-400, 2021 10.
Artículo en Inglés | MEDLINE | ID: mdl-34089082

RESUMEN

Acute Kidney Injury (AKI) is a common manifestation of COVID-19 and several cases have been reported in the setting of the high-risk APOL1 genotype (common genetic variants). This increases the likelihood that African American people with the high-risk genotype APOL1 are at increased risk for kidney disease in the COVID-19 environment. Single-nucleotide polymorphisms (SNPs) are found in various microRNAs (miRNAs) and target genes change the miRNA activity that leads to different diseases. Evidence has shown that SNPs increase/decrease the effectiveness of the interaction between miRNAs and disease-related target genes. The aim of this study is not only to identify miRSNPs on the APOL1 gene and SNPs in miRNA genes targeting 3'UTR but also to evaluate the effect of these gene variations in kidney patients and their association with SARS-COV-2 infection. In 3'UTR of the APOL1 gene, we detected 96 miRNA binding sites and 35 different SNPs with 10 different online software in the binding sites of the miRNA (in silico). Also we studied gene expression of patients and control samples by using qRT-PCR (in vitro). In silico study, the binding site of miR-6741-3p on APOL1 has two SNPs (rs1288875001, G > C; rs1452517383, A > C) on APOL1 3'UTR, and its genomic sequence is the same nucleotide as rs1288875001. Similarly, two other SNPs (rs1142591, T > A; rs376326225, G > A) were identified in the binding sites of miR-6741-3p at the first position. Here, the miRSNP (rs1288875001) in APOL1 3'UTR and SNP (rs376326225) in the miR-6741-3p genomic sequence are cross-matched in the same binding region. In vitro study, the relative expression levels were calculated by the 2-ΔΔCt method & Mann-Whitney U test. The expression of APOL1 gene was different in chronic kidney patients along with COVID-19. By these results, APOL1 expression was found lower in patients than healthy (p < 0.05) in kidney patients along with COVID-19. In addition, miR-6741-3p targets many APOL1-related genes (TLR7, SLC6A19, IL-6,10,18, chemokine (C-C motif) ligand 5, SWT1, NFYB, BRF1, HES2, NFYB, MED12L, MAFG, GTF2H5, TRAF3, angiotensin II receptor-associated protein, PRSS23) by evaluating online software in the binding sites of the miR-6741-3p. miR-6741-3p has not previously shown any association with kidney diseases and SARS-COV-2 infection. It assures that APOL1 can have a significant consequence in kidney-associated diseases by different pathways. Henceforth, this study represents and demonstrates an effective association between miR-6741-3p and kidney diseases, i.e., collapsing glomerulopathy, chronic kidney disease (CKD), acute kidney injury (AKI), and tubulointerstitial lesions susceptibility to SARS-COV-2 infection via in silico and in vitro exploration and recommended to have better insight.


Asunto(s)
Regiones no Traducidas 3'/genética , Apolipoproteína L1/genética , COVID-19/genética , Enfermedades Renales/genética , MicroARNs/genética , Polimorfismo de Nucleótido Simple/genética , Sitios de Unión/genética , Estudios de Casos y Controles , Genotipo , Humanos , Riñón/patología , SARS-CoV-2/patogenicidad
15.
Saudi J Biol Sci ; 28(4): 2291-2300, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33935567

RESUMEN

To assess comparative losses of Trianthema portulacastrum (HP) relative to other weeds, the experiment was set during consecutive summer seasons 2018 and 2019 at the Research Farm MNS-University of Agriculture, Multan, Pakistan. Experiment consisted three replications which were laid out under randomized complete block design. Experiment consisted of ten treatments viz: weeds free (whole season), HP free till 20 Days after emergence (DAE), HP free till 40 DAE, HP free till 60 DAE, all weeds free 20 DAE, all weeds free 40 DAE, all weeds free 60 DAE, weedy check (all weeds), weedy check except HP and weedy check containing only HP. During 2018 in all weeds weedy check, maximum HP relative density (33.33%) was observed while in 2019, plot where weeds were controlled from growing till 20 DAE showed (80%) relative density at 30 DAE. HP maximum frequency (66.67%, 77.78%) and relative frequency (66%, 100%) was recorded at 45 DAE in plots where HP was kept controlled till 20 DAE and all weeds kept controlled till 20 DAE, respectively. Maximum number of grains per cob (738, 700.68), 1000 grain weight (306.66, 271.51 g) and grain yield (6150, 8015 kg hec-1) were recorded in plots which were kept all weed free till 60 DAE. As the competition period of weeds increased over 40 DAE, it substantially reduced yield of maize. Keeping the plots HP free till 40 DAE in the maize fields with HP as the major dominating weed, likely increase in maize grain yield is up to 30% compared to the fields where HP left un attended throughout the growing season. However, if maize field is infested with a mix of weeds with more than one dominating weeds including HP, compared to weedy situation the whole season, 30% higher grain yield can be obtained if all weeds are kept controlled till 40 DAE. Hence it can be concluded that whether the farmers face heavy HP infestation only or the mix of weeds as dominating weeds, in either case farmer should control weeds within first 40 days in maize field for better grain yield.

16.
Nano Lett ; 20(11): 7860-7867, 2020 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-32986438

RESUMEN

Time-reversal-symmetry-breaking Weyl semimetals (WSMs) have attracted great attention recently because of the interplay between intrinsic magnetism and topologically nontrivial electrons. Here, we present anomalous Hall and planar Hall effect studies on Co3Sn2S2 nanoflakes, a magnetic WSM hosting stacked Kagome lattice. The reduced thickness modifies the magnetic properties of the nanoflake, resulting in a 15-time larger coercive field compared with the bulk, and correspondingly modifies the transport properties. A 22% enhancement of the intrinsic anomalous Hall conductivity (AHC), as compared to bulk material, was observed. A magnetic field-modulated AHC, which may be related to the changing Weyl point separation with magnetic field, was also found. Furthermore, we showed that the PHE in a hard magnetic WSM is a complex interplay between ferromagnetism, orbital magnetoresistance, and chiral anomaly. Our findings pave the way for a further understanding of exotic transport features in the burgeoning field of magnetic topological phases.

17.
Sci Adv ; 6(31): eabb6003, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32789181

RESUMEN

The anomalous Hall effect (AHE) is one of the most fundamental phenomena in physics. In the highly conductive regime, ferromagnetic metals have been the focus of past research. Here, we report a giant extrinsic AHE in KV3Sb5, an exfoliable, highly conductive semimetal with Dirac quasiparticles and a vanadium Kagome net. Even without report of long range magnetic order, the anomalous Hall conductivity reaches 15,507 Ω-1 cm-1 with an anomalous Hall ratio of ≈ 1.8%; an order of magnitude larger than Fe. Defying theoretical expectations, KV3Sb5 shows enhanced skew scattering that scales quadratically, not linearly, with the longitudinal conductivity, possibly arising from the combination of highly conductive Dirac quasiparticles with a frustrated magnetic sublattice. This allows the possibility of reaching an anomalous Hall angle of 90° in metals. This observation raises fundamental questions about AHEs and opens new frontiers for AHE and spin Hall effect exploration, particularly in metallic frustrated magnets.

18.
19.
Nat Mater ; 19(9): 974-979, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32632280

RESUMEN

Td-WTe2 (non-centrosymmetric and orthorhombic), a type-II Weyl semimetal, is expected to have higher-order topological phases with topologically protected, helical one-dimensional hinge states when its Weyl points are annihilated. However, the detection of these hinge states is difficult due to the semimetallic behaviour of the bulk. In this study, we have spatially resolved the hinge states by analysing the magnetic field interference of the supercurrent in Nb-WTe2-Nb proximity Josephson junctions. The Josephson current along the a axis of the WTe2 crystal, but not along the b axis, showed a sharp enhancement at the edges of the junction, and the amount of enhanced Josephson current was comparable to the upper limits of a single one-dimensional helical channel. Our experimental observations suggest a higher-order topological phase in WTe2 and its corresponding anisotropic topological hinge states, in agreement with theoretical calculations. Our work paves the way for the study of hinge states in topological transition-metal dichalcogenides and analogous phases.

20.
Environ Sci Pollut Res Int ; 27(32): 39852-39864, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-32696407

RESUMEN

The presence of toxic substances in aquifers, particularly potentially toxic heavy metals, is an important environmental and social concern worldwide. These heavy metals are capable to exert many injurious health effects in human beings by intake of drinking metal-contaminated water. However, very little attention is paid towards quantitative and qualitative analysis of groundwater used for drinking purpose in several less-developed countries. Therefore, this study was intended to estimate, for the first time, the heavy metal levels in groundwater/drinking water in District Vehari, Pakistan. A total of 129 groundwater samples were obtained and subjected to analyze heavy metal concentrations (lead, copper, cadmium, nickel, manganese, chromium, iron, and zinc). Moreover, pH, electrical conductivity, temperature, total dissolved solids, and anion (carbonates, chloride, and bicarbonates) and cation (calcium, potassium, sodium, lithium, and barium) contents of groundwater were also determined. It was noticed that the values of several groundwater physicochemical characteristics such as cation contents, alkalinity, chloride concentration, and especially the concentrations of heavy metals such as Pb (93%), Cd (68%), and Fe (100%) were higher than their limit values given by WHO. Principal component analysis separately grouped heavy metals and physicochemical characteristics of groundwater. The risk assessment indices predicted potential carcinogenic risks due to the consumption of metal-rich groundwater, predominantly with Cd (0.0007-0.03). The mean hazard quotient (HQ) values for all the metals were < 1, while Pb showed HQ > 1 envisaging non-carcinogenic risk with the consumption of studied groundwater. The findings of the study emphasized on the need of appropriate approaches to remediate groundwater before being used for drinking purpose.


Asunto(s)
Agua Potable , Agua Subterránea , Metales Pesados , Contaminantes Químicos del Agua , Agua Potable/análisis , Monitoreo del Ambiente , Humanos , Metales Pesados/análisis , Pakistán , Medición de Riesgo , Contaminantes Químicos del Agua/análisis
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