RESUMEN

Unravelling the perplexing nature of negative differential resistance (NDR) in 2D transition metal dichalcogenide (2D TMD) devices, especially regarding intrinsic properties, is hindered by experiments conducted in ambient environments. A thorough investigation is essential for unveiling the actual mechanism. In this study, we provide compelling evidence of the NDR effect with a remarkably high peak-to-valley current ratio and proton-diffused superionic conductivity in quantum-confined water molecules anchored to a thin film of 2D TMDs. Our investigation underscores the crucial role of ambient moisture for this robust NDR effect independent of underlying materials used. The bonding of water molecules to the existing sulfur defect sites on 2D TMD nanoflakes facilitates the formation of bridges between two planar metal electrodes, thus enabling superionic in-plane protonic conduction. During electrolysis of chemisorbed water, protons are liberated at the anode and migrate toward the cathode during bias voltage sweeping. Nevertheless, proton diffusion encounters increasing impedance beyond a certain applied bias, thereby restricting current flow even with higher biasing voltages, which is attributed to the interfacial Schottky energy barrier influenced by the Fermi level pinning effect. Our DFT simulations corroborate this mechanism, revealing minimal intermolecular interaction of H+ ions compared to OH- ions at distinct atomic sites on 2D TMD nanoflakes.

RESUMEN

With the advent of the modern era, there is a huge demand for memristor-based neuromorphic computing hardware to overcome the von Neumann bottleneck in traditional computers. Here, we have prepared two-dimensional titanium carbide (Ti3C2Tx) MXene following the conventional HF etching technique in solution. After confirmation of Ti3C2Tx properties by Raman scattering and crystallinity measurements, high-quality thin-film deposition is realized using an immiscible liquid-liquid interfacial growth technique. Following this, the memristor is fabricated by sandwiching a Ti3C2Tx layer with a thickness of 70 nm between two electrodes. Subsequently, current-voltage (I-V) characteristics are measured, revealing a nonvolatile resistive switching property characterized by a swift switching speed of 30 ns and an impressive current On/Off ratio of approximately 103. Furthermore, it exhibits endurance through 500 cycles and retains the states for at least 1 × 104 s without observable degradation. Additionally, it maintains a current On/Off ratio of about 102 while consuming only femtojoules (fJ) of electrical energy per reading. Systematic I-V results and conductive AFM-based current mapping image analysis are converged to support the electroforming mediated filamentary conduction mechanism. Furthermore, our Ti3C2Tx memristor was found to be truly versatile as an all-in-one device for demonstrating edge computation, logic gate operation, and classical conditioning of learning by the brain in Psychology.

RESUMEN

Memristors have gained significant attention recently due to their unique ability to exhibit functionalities for brain-inspired neuromorphic computing. Here, we demonstrate a high-performance multifunctional memristor using a thin film of liquid-phase exfoliated (LPE) 2D MoS2 pinched between two electrodes. Nanoscale inspection of a solution-processed MoS2 thin film using scanning electron and scanning probe microscopies revealed the high-quality and defect-free nature. Systematic current-voltage (I-V) characterizations depict a facile, nonvolatile resistive switching behavior of our 2D MoS2 thin film device with a current On/Off ratio of 103 and energy cost of only a few picojoules. Excellent performance metrics, including at least 103 cycle endurance, 104 s retention, and switching speed down to a few nanoseconds, reflect robust high-performance data storage capability. Charge carriers trapping and detrapping at the sulfur vacancy defect sites in MoS2 nanosheets mainly display the resistive switching property, supported by the impedance analysis and theoretical fitting results. Multifunctionality is leveraged through implementing two-input logic gate operations, edge computation, and crucial adaptive learning via a Pavlov's dogs experiment. Overall, our solution-processed MoS2 memristor has the potential for tremendous future opportunities in integrated circuits and different computing paradigms, including energy-efficient neuromorphic computing hardware in artificial intelligence.

RESUMEN

Echinococcus granulosus causes a zoonotic infection called cystic echinococcosis (CE) or more commonly known as hydatid disease. Although the two most common locations of hydatid cyst are liver and lung, it may also appear in other parts of the body. Clinical presentation of the hydatid disease depends on the site and size of the lesion. A retrospective study was done in Medical College and Hospital, Kolkata, from January 2012 to June 2014, to find the site of involvement, distribution, clinical features, history of contact, mode of presentation, laboratory diagnosis, and treatment modalities of the cases of hydatid cyst. The cases were identified by radiological and laboratory methods, the data were entered in Excel spreadsheet, and analysis was done. Among the 21 cases of hydatid cyst included in the study, solitary hepatic involvement was seen in 11 (52.38%), pulmonary involvement in 4 (19%), and 6 (28.71%) were in unusual locations such as liver cyst extending as retroperitoneal, omental cyst, choledochal cyst, splenic cyst, and in hepatorenal pouch. History of contact with dog was seen in 15 (71.43%). All the patients were treated with surgery and albendazole and were discharged in healthy condition. CE may be present in usual and unusual locations with a lot of variations in the clinical features. Hence, proper radiological and laboratory diagnosis is required for accurate diagnosis and appropriate management of these cases.

RESUMEN

Mucormycosis is a severe fungal infection which is rare in clinical practice. This infection is usually acquired by inhalation; other portals of entry are ingestion and traumatic implantation, especially in immuno-compromised patients. Here, we present a case of mucormycosis in a 44-year-old diabetic woman. The patient had collection of fluid in the Pouch of Douglas (POD) and history of bleeding per vagina. Hysterectomy was done which showed a blackish serosal surface of the posterior uterus. Subsequent investigations revealed mycormycosis caused by Rhizopus oryzae (R. arrhizus) affecting the POD. Patient was treated with liposomal amphotericin B and is now keeping well.

RESUMEN

Chyluria is the passage of chyle into urine, and develops as a result of communication between the lymphatic system and the urinary system. It is an unusual manifestation of lymphatic filariasis reported mainly from South Asian countries. We report the case of a 38-year-old man from an endemic area who presented with passage of milky urine. Physical examination did not reveal any lymphadenopathy or lymph oedema. Urine tests revealed nephrotic range proteinuria. A 99m technetium sulphur colloid lymphoscintigraphy confirmed connection between lymphatic vessels and the urinary tract. Predominant chyluria with no overt lymphatic filariasis remains an enigma.

Asunto(s)

Quilo , Filariasis/complicaciones , Síndrome Nefrótico/etiología , Proteinuria/etiología , Wuchereria bancrofti/aislamiento & purificación , Adulto , Animales , Cistoscopía , Diagnóstico Diferencial , Filariasis/parasitología , Filariasis/orina , Humanos , Masculino , Síndrome Nefrótico/diagnóstico , Síndrome Nefrótico/orina , Proteinuria/diagnóstico , Proteinuria/orina

RESUMEN

Nocardia brasiliensis is a rare human pathogen that is usually associated with localised cutaneous infections. We report a case of primary cutaneous Nocardia brasiliensis infection causing delayed wound healing that developed after ovarian cystectomy in an otherwise healthy 32-year-old woman. The patient was initially treated with cotrimoxazole, however due to intolerance intravenous amikacin was given and gradually the wound healed. The diagnosis was confirmed by demonstrating the causative organism in exudates, and cultures. Early diagnosis as well as early institution of chemotherapy is effective in most patients, and antimicrobial susceptibility testing of the isolate should be performed to identify the best treatment options.