Mobile Efficient Diagnostics of Infectious Diseases via On-Chip RT-qPCR: MEDIC-PCR.

The COVID-19 outbreak has caused public and global health crises. However, the lack of on-site fast, reliable, sensitive, and low-cost reverse transcription polymerase chain reaction (RT-PCR) testing limits early detection, timely isolation, and epidemic prevention and control. Here, the authors report a rapid mobile efficient diagnostics of infectious diseases via on-chip -RT-quantitative PCR (RT-qPCR): MEDIC-PCR. First, the authors use a roll-to-roll printing process to accomplish low-cost carbon-black-based disposable PCR chips that enable rapid LED-induced photothermal PCR cycles. The MEDIC-PCR can perform RT (3 min), and PCR (9 min) steps. Further, the cohort of 89 COVID-19 and 103 non-COVID-19 patients testing is completed by the MEDIC-PCR to show excellent diagnostic accuracy of 97%, sensitivity of 94%, and specificity of 98%. This MEDIC-PCR can contribute to the preventive global health in the face of a future pandemic.

Protein redox by a piezoelectric acousto-nanodevice.

Protein redox is responsible for many crucial biological processes; thus, the ability to modulate the redox proteins through external stimuli presents a unique opportunity to tune the system. In this work, we present an acousto-nanodevice that is capable of oxidizing redox protein under ultrasonic irradiation via surface-engineered barium titanate (BTO) nanoparticles with a gold half-coating. Using cytochrome c as the model protein, we demonstrate nanodevice-mediated protein oxidation. BINased on our experimental observations, we reveal that the electron transfer occurs in one direction due to the alternating electrical polarization of BTO under ultrasound. Such unique unidirectional electron transfer is enabled by modulating the work function of the gold surface with respect to the redox center. The new class of ultrasonically powered nano-sized protein redox agents could be a modulator for biological processes with high selectivity and deeper treatment sites.

Combined Effects of Focused Ultrasound and Photodynamic Treatment for Malignant Brain Tumors Using C6 Glioma Rat Model.

PURPOSE: Glioblastoma (GBM) is an intractable disease for which various treatments have been attempted, but with little effect. This study aimed to measure the effect of photodynamic therapy (PDT) and sonodynamic therapy (SDT), which are currently being used to treat brain tumors, as well as sono-photodynamic therapy (SPDT), which is the combination of these two. MATERIALS AND METHODS: Four groups of Sprague-Dawley rats were injected with C6 glioma cells in a cortical region and treated with PDT, SDT, and SPDT. Gd-MRI was monitored weekly and 18F-FDG-PET the day before and 1 week after the treatment. The acoustic power used during sonication was 5.5 W/cm² using a 0.5-MHz single-element transducer. The 633-nm laser was illuminated at 100 J/cm². Oxidative stress and apoptosis markers were evaluated 3 days after treatment using immunohistochemistry (IHC): 4-HNE, 8-OhdG, and Caspase-3. RESULTS: A decrease in tumor volume was observed in MRI imaging 12 days after the treatment in the PDT group (p<0.05), but the SDT group showed a slight increase compared to the 5-Ala group. The high expression rates of reactive oxygen species-related factors, such as 8-OhdG (p<0.001) and Caspase-3 (p<0.001), were observed in the SPDT group compared to other groups in IHC. CONCLUSION: Our findings show that light with sensitizers can inhibit GBM growth, but not ultrasound. Although SPDT did not show the combined effect in MRI, high oxidative stress was observed in IHC. Further studies are needed to investigate the safety parameters to apply ultrasound in GBM.

Totally Implantable Oxygen Generator (TIOG) for Hypoxia and Hypoxemia.

Hypoxia and hypoxemia are the conditions when oxygen is depleted from the cell due to, for example, respiratory failure, cancer, etc. While the current therapy brought reasonable clinical outcomes, its systematic nature of oxygen delivery can be compromised by a significant dropout and side effects. This paper presents a totally implantable oxygen generator (TIOG) for localized, highly controllable, real-time, and targeted oxygen delivery. METHODS: The TIOG system, an ultra-low power implantable wireless platform, is built using off-the-shelf components. The TIOG can be remotely operated to enable a tailored oxygen delivery based on electrolysis with a precisely controlled electrical signal (i.e., current level, frequency, and duty cycle). RESULTS: The in vitro experiments demonstrate that the TIOG could deliver oxygen with a rate of 9.27 ± 1.9 µmol/L/min with the pulsed electrical current (800 µA, 600 µs pulse or 6% duty cycle with 10 ms period). The system could also suppress chlorine generation under the safety guideline (5 mg/L). Operating at 433 MHz ISM band, the TIOG could be wirelessly controlled from up to 600 cm distance with a 0%-bit error rate (BER) and 0%-packet error rate (PER). A single charge of the battery could operate the system for up to 3.3 hr, which can be wirelessly recharged for long-term operation. CONCLUSION: The longevity of the TIOG system enables ambulatory oxygen therapy in a much longer-term than current practice.

Light responsive plasmonic silicone elastomer/hydrogel soft actuator.

Soft robots offer unique advantages in their ability to interact with fragile organisms. Light responsive soft actuators are promising for the development of the untethered soft robots. However, this requires a mechanism for converting the externally applied light into mechanical actuation. We designed, fabricated, and tested a light responsive soft actuator consist of silicone elastomer with plasmonic metal nanoparticle embedment and temperature sensitive hydrogel. We found that the selection of the carrier solvent for the metal nanoparticle embedment in silicone elastomer to be crucial. The fabricated soft actuator showed a relatively fast response time (< 5 min) under light illumination.

Dual Sensing Acousto-electric Sensor.

Simultaneous monitoring of multiple physiological parameters are highly desirable for disease diagnosis and management. However, simultaneous interrogations of parameters from miniaturized sensors can be difficult; to overcome this difficulties, we present the dual sensing acousto-electric sensor capable of simultaneously measuring pressure and pH. The dual sensing is achieved by two electrically decoupled LC tanks emitting RF signal at their respective resonant frequencies under ultrasonic excitation. We designed, fabricated, and tested the dual sensing acousto-electric sensor.

Formulation of a Gastroretentive In Situ Oral Gel Containing Metformin HCl Based on DoE.

A gastroretentive in situ oral gel containing metformin hydrochloride (Met HCl) was prepared based on sodium alginate (Sod ALG), calcium carbonate, and hydroxyethylcellulose (HEC). The optimal composition of the formulation was explored based on the design of experiments (DoE). First, a 32 full factorial design was used for formulation E1 to determine proper composition of Sod ALG and calcium carbonate. Second, a circumscribed central composite design was employed to add HEC as a thickening agent (formulation E2). The dissolution rates at 15, 30, 60, 120, and 240 min were used as responses. Partial least squares regression analysis indicated the effect of each component in delaying the release of Met HCl in the oral gel formulation. The optimized formulation E2-08 consisting of 1.88% Sod ALG, 0.63% HEC, and 1.00% calcium carbonate and two more formulations, E2-10 and E2-12 conformed to USP monograph for extended release. Other physicochemical properties, including floating lag time and duration, viscosity, and pH, measured for each batch and FT-IR spectrometry analysis showed no unexpected interaction between Met HCl and excipients. The current study suggests the potential use of a gastroretentive in situ oral gel for Met HCl helping patient compliance. This study highlights that a systematic approach based on DoE allows the formulation optimization.

Implantable Cisplatin Synthesis Microdevice for Regional Chemotherapy.

Cisplatin, the first platinum chemotherapy agent to obtain Food and Drug Administration (FDA) approval in 1978, is widely used for a number of cancers. However, the painful side effects stemming from systemic delivery are the inevitable limitation of cisplatin. A possible solution is regional chemotherapy using various drug delivery systems, which reduces the systemic toxicity and increases drug accumulation in the tumor. In this paper, a rice-grain sized, ultrasonically powered, and implantable microdevice that can synthesize cisplatin in situ is presented. The microdevice produces 0.7 mg of cisplatin within 1 h under ultrasonic irradiation (400 mW cm-2 ). The effect of the microdevice-synthesized cisplatin is evaluated using in vitro murine breast cancer cells and ex vivo liver tissue. The results suggest that cytotoxic activities of the microdevice-mediated cisplatin delivery are significantly higher in both in vitro and ex vivo experiments. Overall, the proposed cisplatin synthesis microdevice represents a strong alternative treatment option for regional chemotherapy.

A Hydrogel-Based Ultrasonic Backscattering Wireless Biochemical Sensing.

Wireless monitoring of the physio-biochemical information is becoming increasingly important for healthcare. In this work, we present a proof-of-concept hydrogel-based wireless biochemical sensing scheme utilizing ultrasound. The sensing system utilizes silica-nanoparticle embedded hydrogel deposited on a thin glass substrate, which presents two prominent interfaces for ultrasonic backscattering (tissue/glass and hydrogel/glass). To overcome the effect of the varying acoustic properties of the intervening biological tissues between the sensor and the external transducer, we implemented a differential mode of ultrasonic back-scattering. Here, we demonstrate a wireless pH measurement with a resolution of 0.2 pH level change and a wireless sensing range around 10 cm in a water tank.

Hydrogel-Fractal Piezoelectric Bilayer Transducer for Wireless Biochemical Sensing.

This paper reports on a novel transducer for wireless biochemical sensing. The bilayer transducer consists of a fractal piezoelectric membrane and pH-sensitive chemo-mechanical hydrogel, which overcomes many shortcomings in the chemical and biochemical sensing. The fractal design on the piezoelectric membrane enhances frequency response and linearity by employing periodically repeated pore architecture. As a basis of the pore, a Hilbert space-filling curve with modifications is used. On the surface of the fractal piezoelectric membrane, the hydrogel is laminated. When the bilayer transducer is introduced to a pH environment (e.g., pH = 4, 8, and 12), the hydrogel swells (or shrinks) and induces the curling of the bilayer transducer (10.47°/pH). The curvature then exhibits various ultrasound responses when the bilayer transducer was excited. The measured voltage outputs using an ultrasonic receiver were 0.393, 0.341, 0.250 mV/cm2 when curvature angles were 30°, 60°, and 120°, respectively. Overall pH sensitivity was 0.017 mV/cm2/pH. Ultimately, the biochemical sensing principle using a novel bilayer ultrasound transducer suggests a simple, low-cost, battery-less, and long-range wireless readout system as compared to traditional biochemical sensing.

Complications associated with volar locking plate fixation for distal radius fractures in 1955 cases: A multicentre retrospective study.

PURPOSE: Since volar locking plates (VLPs) have the benefits of more stable fixation and fewer complications, VLP osteosynthesis is now the preferred osteosynthesis method in the operative management of distal radius fractures (DRF). Along with the increases in operative management of VLP, the character and frequency of complications have changed. Thus, this multicentre study aimed to identify the characteristics of patients with DRFs who were treated with VLP fixation, describe the complication types and rates related to the procedure, and compare the results with those found in the literature. MATERIAL AND METHODS: This retrospective multicentre study was conducted between January 2008 and December 2017. In total, data from 2225 patients over 17 years old who underwent VLP fixation for DRF were screened. Patients with closed reduction and pinning, external fixation, dorsal plate fixation, and screw-only fixation were excluded. Finally, 1955 wrists from 1921 patients (86.3%) were included. The following types of complications were investigated: (1) tendon injury, (2) nerve-related, (3) fixation- and instrument-related, (4) osteosynthesis-related, (5) infection, and (6) others. RESULTS: The mean age of the patients was 60.3 ± 14.6 years with 587 males (30.6%). Distal ulnar fractures were found in 940 wrists (48.1%). The mean interval between fracture and surgery was 6.2 days, while the mean operative time was 68.3 ± 30.3 minutes. The following complications were found: (1) nine (0.46%) and 12 (0.61%) cases of flexor pollicis longus and complete extensor pollicis longus tears, respectively; (2) nine cases (0.46%) of palmar sensory median nerve branch damage, 15 cases (0.77%) of complex regional pain syndrome, and 36 cases (1.84%) of carpal tunnel syndrome; (3) five cases (0.26%) of fracture displacement even after plate fixation, six cases (0.31%) of screw breakage, 26 cases (1.33%) of radiocarpal joint screw penetration, and 511 cases (26.14%) of implant removal; (4) five cases (0.26%) of delayed union and three cases (0.15%) of non-union; (5) 83 (4.25%) and two (0.1%) cases of superficial and deep infection, respectively; and (6) two cases (0.1%) of compartment syndrome and three cases (0.15%) of radial artery damage. CONCLUSIONS: After 10 years of experience performing VLP fixation for DRFs in a multicentre setting, the results regarding complication types and rates support its use as a reasonable treatment option with low rates of complication.

How Clean Is Clean? Recipes for van der Waals Heterostructure Cleanliness Assessment.

Van der Waals (vdW) heterostructures, artificial stacks of two-dimensional materials, present an exciting platform to explore new physical phenomena and unique applications. An important and increasingly recognized factor limiting the electrical and optical performance of heterostructure samples is the presence of interfacial contamination. In published work reporting various heterostructure fabrication methods, evidence for the cleanliness of samples is often presented as optical and atomic force microscopy images, typically exhibiting a completely flat topography. In this work, we demonstrate that such samples may nonetheless contain a uniformly thin layer of contaminants at the heterostructure interface. As alternatives, we propose two robust visualization methods that are highly sensitive to such residues, based on photoluminescence mapping and on selective solvent diffusion. The detection capability and straightforward implementation of these two imaging techniques make them powerful tools to assess and improve the cleanliness of a wide variety of fabrication techniques for heterostructures comprising any combination of vdW materials.

Untethered Actuation of Hybrid Hydrogel Gripper via Ultrasound.

Stimuli-responsive hydrogels that exhibit reversible volume changes in response to stimulus cues such as heat, pH, and light have been utilized in soft robotics, microfluidics, electronics, and biomedical surgical tools. While the development of the soft robotics has widely expanded, most external triggering systems still have limited utilities due to the low selectivity. We present a hybrid gripper capable of undergoing preprogrammed shape transformation utilizing ultrasound energy on-off processes as the external triggering system, which can be utilized in invisible and nonselective environments. Furthermore, we describe the magnetic locomotion of the soft gripper enabled by the introduction of iron oxide (Fe2O3) ferrogel. By integrating these dual ultrasonic and magnetic control systems, we demonstrate the soft gripper could actively and safely perform pick-and-place tasks on a biological salmon roe in the aqueous maze environment. We expect that this study can provide the groundwork for the further important advances to the creation of ultrasound-responsive shape programmable and multifunctional smart soft robots.

An Implantable Ultrasonically-Powered Micro-Light-Source (µLight) for Photodynamic Therapy.

Photodynamic therapy (PDT) is a promising cancer treatment modality that can selectively target unresectable tumors through optical activation of cytotoxic agents, thus reducing many side effects associated with systemic administration of chemotherapeutic drugs. However, limited light penetration into most biological tissues have so far prevented its widespread adoption beyond dermatology and a few other oncological applications in which a fiber optic can be threaded to the desired locations via an endoscopic approach (e.g., bladder). In this paper, we introduce an ultrasonically powered implantable microlight source, µLight, which enables in-situ localized light delivery to deep-seated solid tumors. Ultrasonic powering allows for small receiver form factor (mm-scale) and power transfer deep into the tissue (several centimeters). The implants consist of piezoelectric transducers measuring 2 × 2 × 2 mm3 and 2 × 4 × 2 mm3 with surface-mounted miniature red and blue LEDs. When energized with 185 mW/cm2 of transmitted acoustic power at 720 kHz, µLight can generate 0.048 to 6.5 mW/cm2 of optical power (depending on size of the piezoelectric element and light wavelength spectrum). This allows powering multiple receivers to a distance of 10 cm at therapeutic light output levels (a delivery of 20-40 J/cm2 light radiation dose in 1-2 hours). In vitro tests show that HeLa cells irradiated with µLights undergo a 70% decrease in average cell viability as compared to the control group. In vivo tests in mice implanted with 4T1-induced tumors (breast cancer) show light delivery capability at therapeutic dose levels. Overall, results indicate implanting multiple µLights and operating them for 1-2 hours can achieve cytotoxicity levels comparable to the clinically reported cases using external light sources.

Analysis of the Changes in the Clinical Outcomes According to Time After Arthroscopic Microfracture of Osteochondral Lesions of the Talus.

BACKGROUND:: Arthroscopic microfracture can effectively treat osteochondral lesions of the talus (OLTs). However, very few studies have reported on symptomatic improvement duration and time when symptomatic improvement ceases. This study aimed to investigate the clinical outcome changes after arthroscopic microfracture in patients with OLT. METHODS:: Among patients who underwent arthroscopic microfracture for OLT, 70 patients were available for follow-up for more than 3 years. Of these, 6 patients who showed worsening or no improvement in the 6 months after surgery were excluded, and a total of 64 patients were included in the analysis. To analyze and compare the clinical outcome changes according to time, the visual analog scale (VAS) and American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scores were evaluated every 3 months up to 1 year postoperatively and every 1 year thereafter. The clinical outcome differences based on the lesion size, lesion location, lesion containment, presence of cyst and bone marrow edema, age, sex, and obesity were analyzed. RESULTS:: The preoperative and final follow-up VAS scores significantly improved from 6.2 ± 1.1 to 1.2 ± 1.1 ( P< .05) and the AOFAS score from 63.1 ± 7.3 to 91.0 ± 7.3 ( P< .05). The overall success rate for arthroscopic microfracture in this study was 88.6%. The postoperative VAS and AOFAS scores at 3, 6, 9, 12, 24, and 36 months were 3.7 ± 1.4, 2.5 ± 1.3, 2.0 ± 1.1, 1.6 ± 1.2, 1.2 ± 1.2, and 1.3 ± 1.2 and 74.7 ± 10.3, 80.5 ± 8.9, 84.3 ± 7.4, 88.3 ± 7.3, 91.1 ± 7.2, and 90.8 ± 7.5, respectively, showing significant improvements up to 2 years. After 2 years, the symptoms did not improve but were maintained at a certain level up to 3 years. No clinical outcome differences based on the lesion size, lesion containment, presence of cyst and bone marrow edema, age, sex, and obesity were observed. CONCLUSION:: Symptomatic improvement early after arthroscopic microfracture for OLT was observed continuously for up to 2 years postoperatively. Symptom improvement was maintained without worsening for up to 3 years after surgery. Determining the final outcome of microfracture at least after 2 years would be reasonable. LEVEL OF EVIDENCE:: Level IV, case series.

Performance of thyristor memory device formed by a wet etching process.

Thyristor random access memory without a capacitor has been highlighted for its significant potential to replace current dynamic random access memory. We fabricated a two-terminal (2-T) thyristor by wet chemical etching techniques on n+-p-n-p+ silicon epitaxial layers, which have the proper thicknesses and carrier concentrations, as provided by technology computer-aided design simulation. The etched features such as etch rate, surface roughness, and morphologies, in a potassium hydroxide (KOH) and an isotropic etchant, were compared. The type of silicon etchant strongly affected the etched shapes of the side wall and therefore critically influenced the device performance with varying turn-on voltages. The turn-on voltage of thyristor fabricated with a KOH solution showed a consistent tendency of operation voltage in the range of 2.2-2.5 V regardless of the cell size, while the thyristor formulated with isotropic etchant had an operation voltage which increased from about 2.3-4.4 V as the device dimension decreased from 200 µm to 10 µm. The optimized 2-T thyristor showed a memory window of about 2 V, a nearly zero-subthreshold swing, and a current on-off ratio of about 104-105.

Assessment of Ankle Mortise Instability After Isolated Supination-External Rotation Lateral Malleolar Fractures.

BACKGROUND: The diagnosis of clinically important instability following isolated supination-external rotation (SER) distal fibular fractures is a challenge. The purpose of this study was to investigate the accuracy of clinical findings including medial tenderness, swelling, and ecchymosis, combined with the gravity stress test and magnetic resonance imaging (MRI), in the assessment of ankle mortise stability in association with isolated SER-type lateral malleolar fractures. The external rotation (ER) stress test was used as the reference with which the methods of assessment were compared. METHODS: Thirty-seven patients were enrolled prospectively. Using the ER stress test as a reference, we evaluated the sensitivity, specificity, likelihood ratio (LR), and post-test probability of instability when using clinical examination, the gravity stress test, and MRI for diagnosing ankle mortise instability after an isolated SER lateral malleolar fracture. RESULTS: The positive LR for clinical findings ranged from 1.45 to 2.54, and the negative LR ranged from 0.25 to 0.70, shifting the pre-test probability to a rarely important degree. In contrast, the positive LR for the gravity stress test was 5.71 with a 95% confidence interval (CI) of 1.52 to 21.48, a moderate shift from the pre-test probability, and the negative LR was 0.33 (95% CI = 0.16 to 0.66), indicating a small shift. In cases with a deep deltoid ligament disruption identified on MRI, the positive LR was 3.05 (95% CI = 1.03 to 9.02) and the negative LR was 0.53 (95% CI = 0.31 to 0.91), demonstrating a small but sometimes important shift. CONCLUSIONS: The gravity stress test is a reliable method for diagnosing ankle mortise instability in patients with an isolated SER lateral malleolar fracture. Nevertheless, this test alone would not qualify as a replacement for the ER stress test. However, when the gravity stress test result is consistent with the clinical or MRI findings, its diagnostic value is almost equivalent to that of the ER stress test. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Following the correction of varus deformity of the knee through total knee arthroplasty, significant compensatory changes occur not only at the ankle and subtalar joint, but also at the foot.

PURPOSE: This study aimed to assess radiological changes of the ankle joint, subtalar joint and foot following the correction of varus deformity of the knee with total knee arthroplasty (TKA). It was hypothesized that following the correction of varus deformity by TKA, compensatory reactions would occur at the subtalar joint in accordance with the extent of the correction. METHODS: For this prospective study, 375 knees of patients who underwent TKA between 2011 and 2012 were enrolled. The varus angle of the knee, talar tilt of the ankle joint (TT), ground-talar dome angle of the foot (GD), anterior surface angle of the distal tibia and lateral surface angle of the distal tibia, heel alignment ratio (HR), heel alignment angle (HA), and heel alignment distance (HD) were measured on radiographs obtained pre-operatively and at post-operative 6 months. RESULTS: The mean correction angle in varus deformity of the knee was 10.8 ± 4.1°. TT and GD changed significantly from 0.4 ± 1.9° and 6.5 ± 3.1° pre-operatively to 0.1 ± 1.8° and 0.2 ± 2.1°, respectively (p = 0.007, p < 0.001). No correlation was found between the preop-postop variance in mechanical axis of the lower extremity (MA) and TT, but there was a strong correlation between the preop-postop variance in MA and GD (r = 0.701). HR, HA and HD also changed significantly post-operatively, and the preop-postop variance in MA showed correlations with the preop-postop variances in HR, HA and HD (r = 0.206, - 0.348, and - 0.418). TT and the three indicators of hindfoot alignment all shifted to varus whereas GD was oriented in valgus. CONCLUSION: Following the correction of varus deformity of the knee through TKA, significant compensatory changes occurred not only at the ankle and subtalar joints, but also at the foot. The findings of this study are useful in predicting the orientation of changes in the ankle and subtalar joints and the foot following TKA, and in determining the sequence of surgery when both the ankle and knee have a problem. In other words, changes in the parts of the lower extremity below the ankle joint following the correction of varus deformity of the knee must be considered when TKA is planned and performed. Patients who have problems at the ankle, subtalar, and foot joints in addition to varus deformity of the knee are recommended to undergo knee joint correction first. LEVEL OF EVIDENCE: II.

Heated wire humidification circuit attenuates the decrease of core temperature during general anesthesia in patients undergoing arthroscopic hip surgery.

BACKGROUND: Intraoperative hypothermia is common in patients undergoing general anesthesia during arthroscopic hip surgery. In the present study, we assessed the effect of heating and humidifying the airway with a heated wire humidification circuit (HHC) to attenuate the decrease of core temperature and prevent hypothermia in patients undergoing arthroscopic hip surgery under general anesthesia. METHODS: Fifty-six patients scheduled for arthroscopic hip surgery were randomly assigned to either a control group using a breathing circuit connected with a heat and moisture exchanger (HME) (n = 28) or an HHC group using a heated wire humidification circuit (n = 28). The decrease in core temperature was measured from anesthetic induction and every 15 minutes thereafter using an esophageal stethoscope. RESULTS: Decrease in core temperature from anesthetic induction to 120 minutes after induction was lower in the HHC group (-0.60 ± 0.27℃) compared to the control group (-0.86 ± 0.29℃) (P = 0.001). However, there was no statistically significant difference in the incidence of intraoperative hypothermia or the incidence of shivering in the postanesthetic care unit. CONCLUSIONS: The use of HHC may be considered as a method to attenuate intraoperative decrease in core temperature during arthroscopic hip surgery performed under general anesthesia and exceeding 2 hours in duration.

Probing defect dynamics in monolayer MoS2 via noise nanospectroscopy.

Monolayer molybdenum disulfide (MoS2) has received intense interest as a strong candidate for next-generation electronics. However, the observed electrical properties of monolayer MoS2 exhibit several anomalies: samples universally exhibit unexpectedly low mobilities, n-type characteristics, and large contact resistances regardless of contact metal work function. These anomalies have been attributed to the presence of defects, but the mechanism behind this link has been elusive. Here we report the ionization dynamics of sulfur monovacancy defects in monolayer MoS2 probed via noise nanospectroscopy, realized by combining noise-current analysis with atomic force microscopy. Due to the nanoscale dimension of the in situ channel defined by the tip size, we probe a few monovacancy defects at a time. Monovacancy defects exhibit switching between three distinct ionization configurations, corresponding to charge states 0, -1, and -2. The most probable charge configurations are 0 and -1, providing a plausible mechanism to explain the observed anomalies of MoS2 monolayers.