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1.
J Clin Gastroenterol ; 55(4): 355-360, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32796193

RESUMO

BACKGROUND AND AIM: There is limited data regarding the safety of endoscopic mucosal resection (EMR) in the cirrhotic population. Our study aimed to evaluate the safety of colonoscopic EMR in cirrhosis. MATERIALS AND METHODS: This was a retrospective review of cirrhotics who underwent colonic EMR at 8 Cleveland Clinic Centers between January 1, 2006, and December 31, 2018. Patient data including polyp details and complications occurring within 30 days of the procedure were noted. Univariable and multivariable logistic regression analyses were conducted to find risk factors for post-EMR bleeding. RESULTS: A total of 238 patients who underwent EMR were included. There were 145 males (60.9%) and the mean age was 61.9±8.6 years. Immediate and delayed bleeding, and postpolypectomy syndrome rates were 9.2%, 5.8%, and 1.3%, respectively. Significant risk factors for postpolypectomy bleeding were: increased age (P=0.001), procedure duration >37 minutes (P=0.001), antiplatelet use within 5 days (P=0.023), and lesion diameter >15 mm (P=0.004). Multivariable analysis revealed independent predictors of procedure-related bleeding: age above 65 years [odds ratio (OR) 2.14, P=0.044], antiplatelet use within 5 days (OR 2.42, P=0.047), right colon polyp (OR 3.51, P=0.001), and lesion diameter >15 mm (OR 3.22, P=0.003). CONCLUSIONS: EMR in cirrhotics has an acceptable bleeding risk. Age above 65 years, right colon polyp, polyp size >15 mm, and use of antiplatelets within 5 days are independent risk factors for bleeding.


Assuntos
Pólipos do Colo , Hemorragia Pós-Operatória , Idoso , Pólipos do Colo/cirurgia , Colonoscopia , Humanos , Cirrose Hepática/complicações , Masculino , Pessoa de Meia-Idade , Hemorragia Pós-Operatória/epidemiologia , Hemorragia Pós-Operatória/etiologia , Estudos Retrospectivos , Fatores de Risco
2.
Environ Monit Assess ; 193(7): 382, 2021 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-34089115

RESUMO

Oxycarenus hyalinipennis Costa is a polyphagous insect pest and can develop insecticide resistance. The resistance of O. hyalinipennis to neonicotinoids (clothianidin and dinotefuran), flonicamid, and conventional insecticides; carbamates (methomyl and carbosulfon), organophosphates (chlorpyrifos and malathion), and pyrethroids (cypermethrin and zeta-cypermethrin) was evaluated. The O. hyalinipennis populations were sampled from four locations in Pakistan and performed bioassays against the insecticides by leaf dip protocol. The O. hyalinipennis' populations showed low resistance to carbosulfan (resistance ratio (RR) = 2.06-6.34) and methomyl (RR = 2.78-7.27), moderate to high resistance to chlorpyrifos (RR = 30-45), malathion (RR = 20.29-88.19), and flonicamid (RR = 14.24-46.97), in comparison with the susceptible strain. Susceptibility to low resistance against cypermethrin (RR = 1.27-2.82), zeta-cypermethrin (RR = 2.62-3.38), and clothianidin (RR = 1.74-3.40), and low to moderate resistance to dinotefuran (RR = 3.84-13.43) in the field populations, was observed compared to the susceptible strain. A rotational usage of carbamates and pyrethroids with an integrated pest management tool should be considered to deal with O. hyalinipennis' insecticide resistance.


Assuntos
Inseticidas , Monitoramento Ambiental , Inseticidas/toxicidade , Neonicotinoides , Niacinamida/análogos & derivados , Paquistão
3.
J Nat Prod ; 83(5): 1383-1393, 2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32364734

RESUMO

The ethanolic root extract of Berberis brevissima afforded a new bisbenzylisoquinoline alkaloid, 13-nitrochondrofoline (2), and two known bisbenzylisoquinoline alkaloids, chondrofoline (1) and curine (4). The acetylation of chondrofoline (1) gave O-acetylchondrofoline (3). The dimeric structures of 1 and 2 were studied through variable-temperature 1H NMR spectroscopy at 25, 40, 60, and 80 °C and conformational analysis, using density functional theory employing the M06-2X functional and the 6-31G* basis set. The in vitro antitrypanosomal activity of compounds 1, 2, 3, and 4 against Trypanosoma brucei showed significant potential with MIC values of 2.6, 2.2, 2.3, and 3.8 µM, respectively. Molecular docking evaluation of alkaloids 1, 2, 3, and 4 against known T. brucei protein targets revealed T. brucei phosphodiesterase B1 to be the preferred target. The docking energies of the alkaloids with Tb6PGL (PDB 3EB9) ranged from -88.8 to -106.0 kJ/mol and was comparable to the cocrystallized ligand, citrate (Edock = -78.3 kJ/mol). It seems reasonable that the curine alkaloids may compete with the natural substrates for these protein targets and serve as leads in designing and developing more potent and selective drugs against T. brucei.


Assuntos
Berberis/química , Isoquinolinas/química , Isoquinolinas/farmacologia , Tripanossomicidas/farmacologia , Animais , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , Simulação de Acoplamento Molecular , Estrutura Molecular , Inibidores de Fosfodiesterase/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Espectroscopia de Prótons por Ressonância Magnética , Temperatura , Tripanossomicidas/química , Trypanosoma brucei brucei/efeitos dos fármacos
4.
J Pak Med Assoc ; 68(6): 950-952, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30323367

RESUMO

Optic nerve Schwannoma is a very rare tumour described in literature. The rarity of this tumour is due to the fact that the optic nerve is myelinated by oligodendrocytes. We present a case of an ancient optic nerve schwannoma in a 16 year old girl who presented to the clinic with right sided proptosis and bilateral loss of vision. She underwent complete excision of the tumour via a craniotomy and histopathology was confirmatory. The various theories explaining the origin of this tumour are discussed along with surgical nuances of removing this tumour. The importance of taking every precaution to preserve vision and avoiding imaging confusion in patients with von Recklinghausen syndrome is also discussed. Only 6 cases of optic nerve schwannomas are described in literature while none have been described in a patient with NF 1.


Assuntos
Neurilemoma/diagnóstico por imagem , Neurofibromatose 1/diagnóstico , Neoplasias do Nervo Óptico/diagnóstico por imagem , Adolescente , Feminino , Humanos , Imageamento por Ressonância Magnética , Neurilemoma/complicações , Neurilemoma/patologia , Neurilemoma/cirurgia , Neurofibromatose 1/complicações , Neurofibromatose 1/patologia , Neoplasias do Nervo Óptico/complicações , Neoplasias do Nervo Óptico/patologia , Neoplasias do Nervo Óptico/cirurgia
5.
J Pak Med Assoc ; 68(2): 170-174, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29479088

RESUMO

OBJECTIVE: To determine the presentation and frequency of various intracranial neoplasms and assess outcomes for patients who underwent surgery without neuronavigation. METHODS: This retrospective study was conducted at Combined Military Hospital, Peshawar, Pakistan, and comprised medical records related to the period from August 2011 to July 2014. Patient histories, examination reports and preoperative and post-operative radiological scans were reviewed and extent of excision was determined based on these coupled with recurrence rates. Intraoperatively, tumour excision was determined largely by the experience of the surgeon and preoperative planning using bony landmarks and radiological scans as an objective guide to resection. SPSS 21 was used for data analysis. RESULTS: Of the 143 patients, 83(57.9%) were males and 60(42.1%)were females. Gliomas were the most common tumours, occurring in 20(33.3%) females and 35(42.2%) males. One-year survival rate for grade 4 astrocytomas was poor (39.4%) and was excellent for meningiomas (100%) and pituitary tumours (100%). CONCLUSIONS: Time-tested methods of careful neurological examination and knowledge of neuroanatomy can allow a surgeon with limited resources to plan and accommodate for accurate tumour resection with adequate margins.


Assuntos
Neoplasias Encefálicas/cirurgia , Glioma/cirurgia , Neoplasias Meníngeas/cirurgia , Meningioma/cirurgia , Procedimentos Neurocirúrgicos/métodos , Adenoma/cirurgia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Neuronavegação , Neoplasias Hipofisárias/cirurgia , Estudos Retrospectivos , Taxa de Sobrevida , Adulto Jovem
6.
Pak J Med Sci ; 34(3): 691-695, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30034441

RESUMO

OBJECTIVE: This study was conducted to assess outcomes in patients with hydrocephalus who underwent ventriculoperitoneal shunting at Keen's point. METHODS: This retrospective study was conducted in Combined Military Hospital (CMH) Peshawar. Time frame was four years from January 2011 to January 2015. The presenting complaints, clinical findings, investigations, treatment plans and surgical outcomes were noted. Ventriculo-Peritoneal (VP) shunting was done at Keen's point. The presence of shunt complications in the first week post-surgery was noted and at a three-month follow up in the outpatient department. General condition of the patient, shunt complications, presence of seizure and worsening of vision were noted. RESULTS: Study included 143 patients, out of whom 46 were females and 95 were male patients. Most common causes of hydrocephalus were congenital (79). Majority of adults had hydrocephalus due to central nervous system tumors while congenital hydrocephalus in children was most frequently due to aqueductal stenosis. Good clinical improvement was seen in 114 patients after shunt placement, satisfactory in 20 patients, 7 patients died while we observed no change in two patients. CONCLUSION: Our experience with VP shunting at Keen's point resulted in excellent outcomes. It can be used for the management of hydrocephalus both in pediatric as well as adult population.

7.
Pak J Med Sci ; 34(6): 1412-1417, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30559795

RESUMO

OBJECTIVES: To study clinical and radiological outcomes in patients who had undergone the procedure of anterior cervical discectomy and fusion with titanium or PEEK (polyetheretherketone) cages for cervical disc prolapse. METHODS: This is a retrospective/non-randomized study which was conducted at the Combined Military Hospital Peshawar. Study interval was four years from 1st October, 2010 to 31st September, 2014. Total number of included patients were 149. All of the patients had undergone the procedure of anterior cervical discectomy and fusion with titanium or PEEK (polyetheretherketone) cages. All of the patients had plain MRI cervical spine done for diagnosis of anterior cervical disc prolapse. RESULTS: Most of the patients had stenosis at the C5 / C6 (PEEK cage group 63% and titanium cage group 47.6%) and C6 / C7 (PEEK cage group 15.38% and titanium cage group 19.04%) cervical level. Bi-level involvement was also seen. In the patients who complained of brachialgia, total resolution of symptoms was seen after the operation. Three (2.01%) of the patients in titanium cage group, who presented with axial neck pain, continued to complain of pain after the operation. Four (2.6%) of the patients in PEEK (polyetheretherketone) cage group and 2 (1.3%) in titanium cage group complained of pain at the donor site (iliac crest). Fusion rate was 100% with both titanium and PEEK (polyetheretherketone) cages at one year. CONCLUSION: Results with titanium and PEEK (polyetheretherketone) cages are excellent. There was no significant difference in clinical and radiological outcome between two groups of patients (p > 0.05). Fusion rate was 100% at one year with both cages.

8.
Pak J Med Sci ; 33(4): 915-919, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29067065

RESUMO

BACKGROUND AND OBJECTIVE: Craniotomy bone flaps should be replaced for both cosmetic and protective purposes. Different methods are available commercially. The aim of this study was to assess outcome of bone flap fixation using mini titanium plates and screws. METHODS: Between March, 2011 and March, 2014, 71 patients underwent cranial bone flap fixation with mini titanium plates and screws after craniotomy and excision of supratentorial lesions at Combined Military Hospital, Peshawar. There were 42 males and 30 females with a mean age of 40.07. All patients had supratentorial lesions. Intracranial lesion size ranged from 3 cm by 2 cm to 7 cm by 5 cm. The changes of local incision and general condition were observed. RESULTS: Subcutaneous effusion occurred in two patients. One patient developed a mild postoperative wound infection. CT scan showed good repositioning of the flap and edge to edge apposition at two weeks after operation. All the patients were followed up for 12 months post operatively. Skull had good appearance without any discharge and, local deformity or effusion. Repeat CT/MRI showed no subsidence or displacement of cranial flap or artifacts. CONCLUSION: Mini titanium plate and screw fixation of cranial flaps is a simple, cost effective and safe option for repositioning and immediate stability as compared to traditional sutures.

9.
J Ayub Med Coll Abbottabad ; 28(2): 281-284, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28718561

RESUMO

BACKGROUND: Characteristics of Prolapsed Intervertebral Disc (PID) in two tertiary care hospitals of Pakistan. The objective of this was to study the demographic characteristics of lumbar PID by age, gender, clinical presentation, levels of spinal column involvement, treatment options and post-operative complications for lumber disc prolapse. METHODS: One thousand and fifty eight cases (708 males, 350 females) of prolapsed intervertebral disc over six years between January 2009 and December 2014 were studied for location of prolapsed disks, gender, age, clinical presentation, treatment options and complications of surgery. RESULTS: Of the determined locations L5/S1 was the commonest (34.6%), followed by L4/L5 (33.4%). 24.2%of the patients had prolapsed disks at 2 levels (L3/L4, L4/L5 andL4/L5, L5/S1). Prolapsed disc was commonest in the 31-49 year age group. Male were mostly affected with male to female ratio of 2.02%. Most common surgery performed was discectomy with fenestration (60.64% of total surgeries performed) and most common postoperative complication being mechanical backache (4.8%). CONCLUSIONS: Prolapsed intervertebral disc is common in the lower lumbar region at the level of L4/L5 and L5/S1. The outcome of the patients who underwent surgery is very good with 92.19% of patients, being free of postoperative complications.


Assuntos
Deslocamento do Disco Intervertebral/epidemiologia , Vértebras Lombares/fisiopatologia , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Paquistão/epidemiologia , Estudos Retrospectivos , Centros de Atenção Terciária , Adulto Jovem
10.
Cleve Clin J Med ; 91(1): 33-39, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38167394

RESUMO

Gastric intestinal metaplasia (GIM), a common histologic finding, is associated with increased risk of gastric cancer, and GIM associated with Helicobacter pylori infection is classified as an environmental metaplastic atrophic gastritis. Patients may be asymptomatic or present with various dyspeptic symptoms. Autoimmune metaplastic atrophic gastritis is a less common but important cause of chronic gastritis. The Correa cascade describes the evolution of precancerous mucosal changes that lead to development of GIM, with differentiation of 2 histologic types of GIM (complete and incomplete) and the consequences of each type. The risk of progression to malignancy is higher with incomplete GIM. It is also higher for those who immigrate from regions with a high incidence of H pylori infection to areas where the incidence is low. Guidelines regarding endoscopic management of GIM vary by geographic region.


Assuntos
Gastrite Atrófica , Gastrite , Infecções por Helicobacter , Helicobacter pylori , Lesões Pré-Cancerosas , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/etiologia , Neoplasias Gástricas/prevenção & controle , Gastrite Atrófica/complicações , Infecções por Helicobacter/complicações , Conduta Expectante , Gastrite/complicações , Gastrite/diagnóstico , Gastrite/patologia , Lesões Pré-Cancerosas/complicações , Lesões Pré-Cancerosas/diagnóstico , Lesões Pré-Cancerosas/epidemiologia , Metaplasia/complicações
11.
World J Clin Cases ; 11(2): 316-321, 2023 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-36686357

RESUMO

Coronavirus disease 2019 significantly impacted the liver transplant process worldwide. Consequently, it brought significant challenges and limitations to transplant policies and organ allocation forcing liver transplant centers to adjust their protocols to ensure maximum benefit and avoid harm to their patients. Our center, like many others, was obliged to adapt to the challenges. This paper provided an overview of the effects of coronavirus disease 2019 on liver transplantations and detailed our center's experience and efforts during this unprecedented pandemic to serve as a guide for future public health crises.

12.
World J Hepatol ; 15(4): 477-496, 2023 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-37206648

RESUMO

As a result of the obesity epidemic, Nonalcoholic fatty liver disease (NAFLD) and its complications have increased among millions of people. Consequently, a group of experts recommended changing the term NAFLD to an inclusive terminology more reflective of the underlying pathogenesis; metabolic-associated fatty liver disease (MAFLD). This new term of MAFLD has its own disease epidemiology and clinical outcomes prompting efforts in studying its differences from NAFLD. This article discusses the rationale behind the nomenclature change, the main differences, and its clinical implications.

13.
Surg Oncol ; 43: 101742, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35370049

RESUMO

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are two well-known endoscopic resection procedures used for advance gastrointestinal lesions. As compared to standard polypectomy techniques, EMR and ESD provide wider and deeper resection margins and allow en bloc removal of lesions for more detailed pathology with curative intent for early neoplastic gastrointestinal lesions. Both procedures have their advantages and disadvantages which will be discussed in detail in this review article. Recently there have been advancements in the techniques of EMR and ESD with addition in new equipment. We will also discuss current guidelines recommending use of EMR and/or ESD in various clinical scenarios.


Assuntos
Ressecção Endoscópica de Mucosa , Ressecção Endoscópica de Mucosa/métodos , Humanos , Resultado do Tratamento
14.
ACS Omega ; 6(46): 31366-31374, 2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34841180

RESUMO

Owing to their natural abundance, seawater together with sunlight has a potential to meet the global challenges in terms of water scarcity and energy crisis. Herein, we demonstrate a solar vapor generator composed of an inner flame candle soot (IFCS) deposited on a cellulose filter paper (FP) prepared by a simple two-step process. The resultant IFCS/FP device exhibits a high photothermal conversion ability owing to the broadband solar absorption of the IFCS layer along with the multiple scattering of the incoming sunlight in the porous microstructure of the cellulose FP. Additionally, the low thermal conductivity of the IFCS effectively localizes the photothermally generated heat at the IFCS/FP surface, thereby significantly suppressing the conduction heat losses to the underlying bulk water. Meanwhile, the capillary action of the FP supplies an adequate amount of water to the heated surface for accelerating the evaporation process. Benefitting from the synergistic effect of these characteristics, the IFCS/FP achieves high evaporation rates of ∼1.16 and ∼4.09 kg m-2 h-1 and their corresponding efficiencies of ∼75.1 and 90.9% under one and three sun illumination, respectively. Moreover, the IFCS/FP device presents an excellent longevity owing to the persistent performance over 15 repeated cycles under one and three sun illumination. Hence, the facile fabrication, fine mechanical strength, desalination, and the salt-resistance ability of our IFCS/FP make it a suitable candidate for practical applications.

15.
ACS Appl Mater Interfaces ; 13(43): 50911-50919, 2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34551516

RESUMO

Effectively utilizing eco-friendly solar energy for desalination and wastewater purification has immense potential to overcome the global water crisis. Herein, we demonstrate a highly efficient solar vapor generator (SVG) developed via a simple morphological alteration, from a two-dimensional (2D) TiO2 film (TF) to one-dimensional (1D) TiO2 nanorods (TNRs) grown on a glassy carbon foam (CF). Given that evaporation is primarily a surface physical phenomenon, the 1D morphology of TNRs provides a higher evaporation surface area compared to their 2D counterpart. Additionally, the superhydrophilic nature of TNRs ensures an adequate supply of water to the evaporation surface via effective capillary action. Consequently, the 1D TNRs properly utilize photothermal heat, which results in a significant reduction in the convection heat loss. Owing to the synergistic effect of these characteristics, TNRs/CF acquires a high evaporation rate of ∼2.23 kg m-2 h-1 and an energy utilization efficiency of ∼67.1% under one sun irradiation. Moreover, the excellent stability, desalination, self-cleaning capabilities, and the facile fabrication method make TNRs/CF suitable for cost-effective, large-scale device application.

16.
Front Chem ; 9: 711190, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34976944

RESUMO

A new bisbenzylisoquinoline named as chondrofolinol (1) and four reported compounds (2-5) were isolated and characterized from the roots of Berberis glaucocarpa Stapf. Anti-inflammatory, anti-pyretic, and leishmanicidal studies were performed against carrageenan-induced paw edema, yeast-induced pyrexia, and the promastigotes of Leishmania tropica, respectively. The new compound significantly reduced the paw volume in carrageenan-induced paw edema and rectal temperature in yeast-induced pyrexia at 10 and 20 mg/ kg of body weight. Chondrofolinol caused almost 100% inhibition of the promastigotes of Leishmania tropica. All the compounds displayed minimal cytotoxicity against THP-1 monocytic cells. In order to ascertain the potential macromolecular targets of chondrofolinol responsible for the observed anti-inflammatory and anti-leishmanial activities, a molecular docking study was carried out on relevant protein targets of inflammation and Leishmania. Protein targets of human endoplasmic reticulum aminopeptidase 2 (ERAP2) and human matrix metalloproteinase-1 (MMP-1) for inflammation and protein targets of N-myristoyltransferase (NMT), tyrosyl-tRNA synthetase (TyrRS), and uridine diphosphate-glucose pyrophosphorylase (UGPase) for Leishmania major were selected after thorough literature search about protein targets responsible for inflammation and Leishmania major. Chondrofolinol showed excellent docking to ERAP2 and to MMP-1. The Leishmania major protein targets with the most favorable docking scores to chondrofolinol were NMT, TyrRS, and UGPase. The study indicated that bisbenzylisoquinoline and isoquinoline alkaloids possess anti-pyretic, anti-inflammatory, and anti-leishmanial properties with minimal cytotoxicity and therefore, need to be further explored for their therapeutic potential.

17.
ACS Appl Mater Interfaces ; 13(13): 15783-15790, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33769783

RESUMO

The spin Seebeck effect (SSE) has attracted renewed interest as a promising phenomenon for energy harvesting systems. A noteworthy effort has been devoted to improving the SSE voltage by inserting ultrathin magnetic layers including Fe70Cu30 interlayers in Pt/Y3Fe5O12 (Pt/YIG) systems with increased spin-mixing conductance at the interfaces. Nevertheless, the responsible underlying physics associated with the role of the interlayer in Pt/YIG systems in the SSE is still unknown. In this paper, we demonstrate that with a monolayer tungsten diselenide (ML WSe2) interlayer in the Pt/YIG bilayer system, the longitudinal SSE (LSSE) voltage is significantly increased by the increased spin accumulation in the Pt layer; the spin fluctuation in ML WSe2 amplifies the spin current transmission because the in-plane-aligned WSe2 spins are coupled to thermally pumped spins under nonequilibrium magnetization conditions in the LSSE configuration at room temperature. The thermopower (VLSSE/ΔT) improves by 323% with respect to the value of the reference Pt/YIG bilayer sample in the LSSE at room temperature. In addition, the induced ferromagnetic properties of the ML WSe2 flakes on YIG increase the LSSE voltage (VLSSE) of the sample; the ferromagnetic properties are a result of the improved magnetic moment density in the ML WSe2 flakes and their two-dimensional (2D) ML nature in the LSSE under nonequilibrium magnetization conditions. The results can extend the application range of the materials in energy harvesting and provide important information on the physics of the LSSE with a transition metal dichalcogenide intermediate layer in spin transport.

18.
ACS Appl Mater Interfaces ; 13(48): 57588-57596, 2021 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-34797625

RESUMO

Noncentrosymmetric transition-metal dichalcogenides, particularly their 3R polymorphs, provide a robust setting for valleytronics. Here, we report on the selective growth of monolayers and bilayers of MoS2, which were acquired from two closely but differently oriented substrates in a chemical vapor deposition reactor. It turns out that as-grown bilayers are predominantly 3R-type, not more common 2H-type, as verified by microscopic and spectroscopic characterization. As expected, the 3R bilayer showed a significantly higher valley polarization compared with the centrosymmetric 2H bilayer, which undergoes efficient interlayer scattering across contrasting valleys because of their vertical alignment of the K and K' points in momentum space. Interestingly, the 3R bilayer showed even higher valley polarization compared with the monolayer counterpart. Moreover, the 3R bilayer reasonably maintained its valley efficiency over a very wide range of excitation power density from ∼0.16 kW/cm2 to ∼0.16 MW/cm2 at both low and room temperatures. These observations are rather surprising because valley dephasing could be more efficient in the bilayer via both interlayer and intralayer scatterings, whereas only intralayer scattering is allowed in the monolayer. The improved valley polarization of the 3R bilayer can be attributed to its indirect-gap nature, where valley-polarized excitons can relax into the valley-insensitive band edge, which otherwise scatter into the contrasting valley to effectively cancel out the initial valley polarization. Our results provide a facile route for the growth of 3R-MoS2 bilayers that could be utilized as a platform for advancing valleytronics.

19.
Cureus ; 12(6): e8494, 2020 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-32656012

RESUMO

Hyperplastic polyps are the second most common type of gastric polyp in the United States with equal incidence in both genders, usually found incidentally during endoscopic examinations. It is a well-known fact that they are associated with iron-deficiency anemia due to chronic blood loss. We present a case of a 69-year-old man with a relatively small hyperplastic gastric polyp with acute upper gastrointestinal bleeding, presenting with melena and acute blood loss anemia requiring admission to intensive care unit and urgent endoscopic intervention with hot snare removal of the polyp and cautery of surrounding area with excellent hemostasis. The pathology revealed focal intestinal metaplasia and low-grade dysplasia with no evidence of malignancy. He was subsequently discharged with outpatient follow-up with gastroenterology.

20.
Cureus ; 12(6): e8823, 2020 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-32742837

RESUMO

Pyogenic liver abscess can be a major diagnostic and therapeutic challenge despite advances in cutting edge technologies. A patient presented with fever, right upper quadrant pain and diarrhea. CT revealed multiple hypodensities in both lobes of liver. The largest lesion was in the left lobe of liver and was multiloculated with thick septations. The causative organism was identified to be Fusobacterium nucleatum by Karius testing. The patient was discharged on six weeks of ertapenem therapy, which resulted in complete resolution. This is the first case of liver abscess where Karius testing was used to identify microorganism. It also highlights that multiloculated and difficult to drain liver abscesses caused by highly sensitive organisms can potentially be treated by intravenous antibiotics alone in immunocompetent patients.

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