Solid Electrolytic Substrates for High Performance Transistors and Circuits

Ionic liquids/gels have been used to realize field-effect-transistors (FETs) with two dimensional (2D) transition metal dichalcogenides (TMDs) [1]. Although near ideal gating has been reported with this biasing scheme, it suffers from several issues such as, liquid nature of the electrolyte, its humidity dependency and freezing at low temperatures [2]. Recently, air-stable solid electrolytes have been developed, thanks to the advancement in battery technology [3]. Although insulator-to-metal transition has been reported, the realization of 2D TMD FETs on solid electrolytic substrate has not been reported so far to the best of our knowledge [4]. In this work, we demonstrate a lithium ion (Liion) solid electrolytic substrate based TMD transistor and a CMOS amplifier, with near ideal gating efficiency reaching 60 mV/dec subthreshold swing, and amplifier gain ~34, the highest among comparable inverte

Lithium-ion electrolytic substrates for sub-1V high-performance transition metal dichalcogenide transistors and amplifiers

Electrostatic gating of two-dimensional (2D) materials with ionic liquids (ILs), leading to the accumulation of high surface charge carrier densities, has been often exploited in 2D devices. However, the intrinsic liquid nature of ILs, their sensitivity to humidity, and the stress induced in frozen liquids inhibit ILs from constituting an ideal platform for electrostatic gating. Here we report a lithium-ion solid electrolyte substrate, demonstrating its application in high-performance back-gated n-type MoS2 and p-type WSe2 transistors with sub-threshold values approaching the ideal limit of 60 mV/dec and complementary inverter amplifier gain of 34, the highest among comparable amplifiers. Remarkably, these outstanding values were obtained under 1 V power supply. Microscopic studies of the transistor channel using microwave impedance microscopy reveal a homogeneous channel formation, indicative of a smooth interface between the TMD and underlying electrolytic substrate. These results establish lithium-ion substrates as a promising alternative to ILs for advanced thin-film devices

Shelf Life Study and Quality Attributes of Cocoyam Chips

The study was carried out to determine changes in the quality indices (levels of peroxides values, acid values, pH and colour) of cocoyam chips and microbiological safety (bacterial, yeast and mould counts) of cocoyam chips as influenced by temperature during storage period of fried cocoyam chips. Cocoyam tubers were processed into chips of 3mm thickness; the slices were then fried at a frying temperature of 170°C in a shallow pot for 7 minutes and was packaged in polyethylene bags and stored under room and refrigerator temperature. The results showed that there was significant difference (p≤0.05) between quality indices, microbiological safety and storage temperature and packaging materials. From week 0-5, peroxide values of samples stored under refrigeration temperature were found to be low, ranged from 3.39 - 11.58 meq kg-1, while the samples stored in the room temperature were found to be higher 3.81 - 12.87 meq kg-1. Acid values were also found to be low in the samples stored in the refrigerator, ranged from 5.79 - 16 3.34mg/g and the samples that were stored in the room temperature ranged from 9.94 - 24.05mg/g. The samples stored under refrigeration temperature had low bacterial counts ranged from 5.0 x 101 - 6.2 x 101 cfu/ml while samples stored in the room temperature had higher bacterial counts, ranged from 9.0 x 101 – 74 x 101 cfu/ml. Yeast and mould counts in samples stored under refrigeration temperature ranged from 4.0 x 101 - 32 x 10 cfu/ml while the samples that were stored in room temperature had higher counts, ranged from 3.0 x 10 – 38 x 10 cfu/ml. pH ranged between 6.88 - 7.02 for both samples during storage period. The results showed that storage temperature and properly sealed packaging material has effect on the above parameters that were determined. There were also colour changes during the storage period

Primary breast lymphoma: a consideration in an HIV patient when a mass is discovered by screening mammography: a case report

Primary Breast lymphoma is a rare lesion that has been reported in patients without HIV. However, Primary Breast lymphoma occurring in a patient with HIV has rarely been reported despite the fact that HIV infection is known to increase the propensity to develop certain types of lymphoma. We report a case of an HIV patient with breast lymphoma that was discovered by screening mammography while presenting our argument for more cautionary management in this patient population

Uniform wafer-scale synthesis of graphene on evaporated Cu (111) film with quality comparable to exfoliated monolayer

Monolayer graphene has been grown on crystallized Cu (111) films on standard oxidized Si 100 mm wafers. The monolayer graphene demonstrates high uniformity (>97% coverage), with immeasurable defects (>95% defect-negligible) across the entire wafer. Key to these results is the phase transition of evaporated copper films from amorphous to crystalline at the growth temperature as corroborated by X-ray diffraction and electron backscatter diffraction. Noticeably, phase transition of copper film is observed on technologically ubiquitous oxidized Si wafer where the oxide is a standard amorphous thermal oxide. Ion mass spectroscopy indicates that the copper films can be purposely hydrogen-enriched during a hydrogen anneal which subsequently affords graphene growth with a sole carbonaceous precursor for low defect densities. Owing to the strong hexagonal lattice match, the graphene domains align to the Cu (111) domains, suggesting a pathway for increasing the graphene grains by maximizing the copper grain sizes. Fabricated graphene transistors on a flexible polyimide film yield a peak carrier mobility ~4,930 cm2/Vs

Direct growth of MoS 2 on electrolytic substrate and realization of high-mobility transistors

Although electrostatic gating with liquid electrolytes has been thoroughly investigated to enhance electrical transport in two-dimensional (2D) materials, solid electrolyte alternatives are now actively being researched to overcome the limitations of liquid dielectrics. Here, we report direct growth of few-layer (3-4 L) molybdenum disulfide (MoS2), a prototypical 2D transition metal dichalcogenide (TMD), on lithium-ion solid electrolyte substrate by chemical vapor deposition (CVD), and demonstrate a transfer-free device fabrication method. The growth resulted in 5-10 µm sized triangular MoS2 single-crystals as confirmed by Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. Field-effect transistors (FETs) fabricated on the as-grown few-layer crystals show near-ideal gating performance with room temperature subthreshold swings around 65 mV/dec while maintaining an ON/OFF ratio around 10 5. Field-effect mobility in the range of 42-49 cm2V-1s-1 and current densities as high as 120 µA/µm with 0.5 µm channel length has been achieved, back-gated by the solid electrolyte. This is the highest reported mobility among comparable FETs on as-grown single/few-layer CVD MoS2. This growth and transfer-free device fabrication method on solid electrolyte substrates can be applied to other 2D TMDs for studying advanced thin-film transistors, interesting physics, and is amenable to diverse surface science experiments, otherwise difficult to realize with liquid electrolytes.D.A. acknowledges the PECASE award from the Army Research Office (ARO) grant #W911NF-16-1-0277, and the National Science Foundation (NSF) MRSEC Center (DMR- 1720595). S.K.B. acknowledges support from ARO grant #W911NF-17-1-0312 (MURI), and the NSF NASCENT ERC. The work was partly done at the Texas Nanofabrication Facility supported by NSF grant #NNCI-1542159.Center for Dynamics and Control of Material

Popliteal block with transfibular approach in ankle arthrodesis: a case series

<p>Abstract</p> <p>Introduction</p> <p>Ankle arthrodesis is primarily undertaken to control severe pain in the ankle joint. Immediate postoperative pain is usually treated using oral analgesics, intravenous opiates and regional anaesthesia. The outcomes of ankle fusion, including patient satisfaction studies, are well documented in the literature. However, the advantage of popliteal block in the management of early postoperative pain after ankle fusion for osteoarthritis has not been widely reported. This study aims to determine the role of popliteal block using ankle fusion in the management of ankle osteoarthritis.</p> <p>Case presentation</p> <p>Ankle arthrodeses were performed in 27 patients over a five-year period. Eighteen patients were males (one had bilateral arthrodesis) and eight were females. Their mean age was 56 years and they were all Caucasians. The notes and radiographs of the patients were reviewed in retrospect for the duration of their hospital admission, time to union and complications.</p> <p>Conclusion</p> <p>Popliteal block is a safe and effective technique for postoperative analgesia in ankle arthrodesis. By using this technique, we achieved a significant reduction in the duration of hospital stay for our patients after ankle arthrodesis. The resultant cost saving was GBP717 for each patient.</p

Cryoablation of low-flow vascular malformations

PURPOSEWe aimed to evaluate the safety and effectiveness of cryoablation in the treatment of low-flow malformations, specifically venous malformation (VM) and fibroadipose vascular anomaly (FAVA).METHODSWe conducted a retrospective review of 11 consecutive patients with low-flow malformations (14 lesions; 9 VM, 5 FAVA), median lesion volume 10.8 cm3, (range, 1.8–55.6 cm3) with a median age of 19 years (range, 10–50 years) who underwent cryoablation to achieve symptomatic control. Average follow-up was at a median of 207 days postprocedure (range, 120–886 days). Indications for treatment included focal pain and swelling. Technical success was achieved if the cryoablation ice ball covered the region of the malformation that corresponded to the patient’s symptoms. Clinical success was considered complete if all symptoms resolved and partial if some symptoms persisted but did not necessitate further treatment.RESULTSThe technical success rate was 100%. At 1-month follow-up, 13 of 14 lesions (93%) had a complete response and one (7%) had a partial response. At 6-month follow-up 12 of 13 (92%) had a complete response and 1 (8%) had a partial response. A total of 6 patients underwent primary cryoablation. Out of 9 VM cases, 7 had prior sclerotherapy and 2 had primary cryoablation. Out of the 5 FAVA cases, 1 had prior sclerotherapy and the remaining 4 cases underwent primary cryoablation. There were 3 minor complications following cryoablation including 2 cases of skin blisters and 1 case of transient numbness. These complications resolved with conservative management.CONCLUSIONCryoablation is safe and effective in the treatment of low-flow vascular malformations, either after sclerotherapy or as primary treatment