Anatomical and Radiological Assessments of Injectate Spread Stratified by the Volume of the Pericapsular Nerve Group Block.

BACKGROUND: The pericapsular nerve group (PENG) block was recently suggested as a regional technique for managing acute pain after hip surgery. However, few anatomical studies have confirmed the spread of injectate during the PENG block. This cadaver study aimed to analyze injectate spread to the target nerves during single-injection ultrasound-guided PENG block. METHODS: Ultrasound-guided PENG block with 3 different injectate volumes (10, 20, or 30 mL) was performed in 18 cadavers. Injectate spread by the volume was first evaluated on computed tomography, followed by cadaver dissection. The spread of the dye over the pelvis and lower limb was evaluated. RESULTS: The articular branches of the femoral nerve were stained nearly sufficiently with 20- and 30-mL specimens. The femoral nerve itself was stained simultaneously in six of 12 (50%) 20-mL specimens and 12 of 12 (100%) 30-mL specimens. The accessory obturator nerve was observed only in three (9%) of 36 specimens. The articular branches of the obturator nerve were rarely affected, regardless of injectate volume (1/12, 10 mL specimens; 2/12, 20 mL specimens; 1/12, 30 mL specimens; P > .999). Rather, the obturator nerve was affected. However, the obturator nerve was not stained consistently even with 30 mL of injectate (50%). CONCLUSIONS: After combining the dissection and radiological findings, the single-injection ultrasound-guided PENG blocks with volumes of 10, 20, and 30 mL do not support motor sparing or selective anterior hip capsule innervation in a clinical setting. If early rehabilitation is needed, high-volume PENG block might not be the ideal option, and persisting pain after PENG block might be attributed in part to the lack of obturator nerve articular branches blockade.

Delayed Adverse Events after Procedural Sedation in Pediatric Patients with Hematologic Malignancies.

Background and objectives: Procedural sedation for bone marrow examination (BME) and intrathecal chemotherapy (ITC) is necessary for pediatric patients with hematological malignancies. There has been no report on adverse events after discharge from the recovery room. This retrospective study evaluated the types and incidences of delayed adverse events among pediatric patients scheduled for BME or ITC under deep sedation in a single center for 3 years. Materials and Methods: The patients were divided into two groups: inpatients (group I) and outpatients (group O). All patients were managed during the procedures and the recovery period. In total, 10 adverse events were assessed; these occurred 2 h (T1, acute), 12 h (T2, early), and 24 h (T3, delayed) after the procedure. The duration of each adverse event was also recorded and was classified as 2 h (D1), 12 h (D2), or 24 h (D3). The data of 263 patients (147 inpatients and 116 outpatients) who met the inclusion criteria were analyzed. Results: The overall incidence of adverse events was statistically significant difference: 48.3% in group I and 33.6% in group O (p = 0.011). The rates of adverse events at T1 and T2 were significantly different between groups I and O (42.8% vs. 11.2% and 7.5% vs. 20.7%, respectively) (p < 0.001). The adverse events were mostly of D1 or D2 duration in both groups. Patients with a higher proportion of ketamine in a propofol−ketamine mixture had a significantly higher proportion of adverse events at T1 (34.6%), as compared with those with a mixture with a lower proportion of ketamine (21.1%) or propofol alone (17.9%) (p = 0.012). Conclusions: The most common adverse events were dizziness or headache; typically, they did not last longer than 12 h. The propofol-ketamine combination with a higher proportion of ketamine seems to produce more adverse events within 2 h after the procedure. Nevertheless, all sedative types appear safe to use without additional management.

The Effect of Opioid-Free Anesthesia on the Quality of Recovery After Gynecological Laparoscopy: A Prospective Randomized Controlled Trial.

Purpose: Opioid-free anesthesia (OFA) is an emerging technique that eliminates intraoperative use of opioids and is associated with lower postoperative opioid consumption and reduced adverse postoperative events. The present study investigated the effect of OFA on the quality of recovery in patients undergoing gynecological laparoscopy. Patients and Methods: Seventy-five adult patients undergoing elective gynecological laparoscopy were randomly assigned to the OFA group with dexmedetomidine and lidocaine or the remifentanil-based anesthesia (RA) group with remifentanil. Patients, surgeons, and medical staff members providing postoperative care and assessing outcomes were blinded to group allocation. The anesthesiologist performing general anesthesia could not be blinded due to the different drug administration protocols by groups. The primary outcome was the quality of recovery measured using the Quality of Recovery-40 (QoR-40) questionnaire. Secondary outcomes were postoperative pain score, intraoperative and postoperative adverse events, and stress hormones levels. Results: The patients in both groups had comparable baseline characteristics. The QoR-40 score on postoperative day 1 was significantly higher in the OFA group than in the RA group (155.9 ± 21.2 in the RA group vs 166.9 ± 17.8 in the OFA group; mean difference: -11.0, 95% confidence interval: -20.0, -2.0; p = 0.018). The visual analog scale score at 30 min after surgery was significantly lower in the OFA group than in the RA group (6.3 ± 2.3 in the RA group vs 4.1 ± 2.1 in the OFA group; p < 0.001). The incidences of nausea and shivering in the post-anesthetic care unit were also significantly lower in the OFA group (p = 0.014 and 0.025; respectively). Epinephrine levels were significantly lower in the OFA group (p = 0.002). Conclusion: OFA significantly improved the quality of recovery in patients undergoing gynecological laparoscopy.

Ferroelastic-Ferroelectric Multiferroicity in van der Waals Rhenium Dichalcogenides.

2D multiferroics with combined ferroic orders have gained attention owing to their novel functionality and underlying science. Intrinsic ferroelastic-ferroelectric multiferroicity in single-crystalline van der Waals rhenium dichalcogenides, whose symmetries are broken by the Peierls distortion and layer-stacking order, is demonstrated. Ferroelastic switching of the domain orientation and accompanying anisotropic properties is achieved with 1% uniaxial strain using the polymer encapsulation method. Based on the electron localization function and bond dissociation energy of the Re-Re bonds, the change in bond configuration during the evolution of the domain wall and the preferred switching between the two specific orientation states are explained. Furthermore, the ferroelastic switching of ferroelectric polarization is confirmed using the photovoltaic effect. The study provides insights into the reversible bond-switching process and potential applications based on 2D multiferroicity.

Impact of H-Doping on n-Type TMD Channels for Low-Temperature Band-Like Transport.

Band-like transport behavior of H-doped transition metal dichalcogenide (TMD) channels in field effect transistors (FET) is studied by conducting low-temperature electrical measurements, where MoTe2 , WSe2 , and MoS2 are chosen for channels. Doped with H atoms through atomic layer deposition, those channels show strong n-type conduction and their mobility increases without losing on-state current as the measurement temperature decreases. In contrast, the mobility of unintentionally (naturally) doped TMD FETs always drops at low temperatures whether they are p- or n-type. Density functional theory calculations show that H-doped MoTe2 , WSe2 , and MoS2 have Fermi levels above conduction band edge. It is thus concluded that the charge transport behavior in H-doped TMD channels is metallic showing band-like transport rather than thermal hopping. These results indicate that H-doped TMD FETs are practically useful even at low-temperature ranges.

Impact of Organic Molecule-Induced Charge Transfer on Operating Voltage Control of Both n-MoS2 and p-MoTe2 Transistors.

Since transition metal dichalcogenide (TMD) semiconductors are found as two-dimensional van der Waals materials with a discrete energy bandgap, many TMD based field effect transistors (FETs) are reported as prototype devices. However, overall reports indicate that threshold voltage ( Vth) of those FETs are located far away from 0 V whether the channel is p- or n-type. This definitely causes high switching voltage and unintended OFF-state leakage current. Here, a facile way to simultaneously modulate the Vth of both p- and n-channel FETs with TMDs is reported. The deposition of various organic small molecules on the channel results in charge transfer between the organic molecule and TMD channels. Especially, HAT-CN molecule is found to ideally work for both p- and n-channels, shifting their Vth toward 0 V concurrently. As a proof of concept, a complementary metal oxide semiconductor (CMOS) inverter with p-MoTe2 and n-MoS2 channels shows superior voltage gain and minimal power consumption after HAT-CN deposition, compared to its initial performance. When the same TMD FETs of the CMOS structure are integrated into an OLED pixel circuit for ambipolar switching, the circuit with HAT-CN film demonstrates complete ON/OFF switching of OLED pixel, which was not switched off without HAT-CN.

Interband Transitions in Monolayer and Few-Layer WSe2 Probed Using Photoexcited Charge Collection Spectroscopy.

Transition-metal dichalcogenides are currently under rigorous investigation because of their distinct layer-dependent physical properties originating from the corresponding evolution of the band structure. Here, we report the highly resolved probing of layer-dependent band structure evolution for WSe2 using photoexcited charge collection spectroscopy (PECCS). Monolayer, few-layer, and multilayer WSe2 can be probed in top-gate field-effect transistor platforms, and their interband transitions are efficiently observed. Our theoretical calculations show a great coincidence with the PECCS results, proving that the indirect Γ-K and Γ-Λ transitions as well as the direct K-K transition are clearly resolved in multilayer WSe2 by PECCS.

Vertical and In-Plane Current Devices Using NbS2/n-MoS2 van der Waals Schottky Junction and Graphene Contact.

A van der Waals (vdW) Schottky junction between two-dimensional (2D) transition metal dichalcogenides (TMDs) is introduced here for both vertical and in-plane current devices: Schottky diodes and metal semiconductor field-effect transistors (MESFETs). The Schottky barrier between conducting NbS2 and semiconducting n-MoS2 appeared to be as large as ∼0.5 eV due to their work-function difference. While the Schottky diode shows an ideality factor of 1.8-4.0 with an on-to-off current ratio of 103-105, Schottky-effect MESFET displays little gate hysteresis and an ideal subthreshold swing of 60-80 mV/dec due to low-density traps at the vdW interface. All MESFETs operate with a low threshold gate voltage of -0.5 ∼ -1 V, exhibiting easy saturation. It was also found that the device mobility is significantly dependent on the condition of source/drain (S/D) contact for n-channel MoS2. The highest room temperature mobility in MESFET reaches to approximately more than 800 cm2/V s with graphene S/D contact. The NbS2/n-MoS2 MESFET with graphene was successfully integrated into an organic piezoelectric touch sensor circuit with green OLED indicator, exploiting its predictable small threshold voltage, while NbS2/n-MoS2 Schottky diodes with graphene were applied to extract doping concentrations in MoS2 channel.

Homogeneous 2D MoTe2 p-n Junctions and CMOS Inverters formed by Atomic-Layer-Deposition-Induced Doping.

Recently, α-MoTe2 , a 2D transition-metal dichalcogenide (TMD), has shown outstanding properties, aiming at future electronic devices. Such TMD structures without surface dangling bonds make the 2D α-MoTe2 a more favorable candidate than conventional 3D Si on the scale of a few nanometers. The bandgap of thin α-MoTe2 appears close to that of Si and is quite smaller than those of other typical TMD semiconductors. Even though there have been a few attempts to control the charge-carrier polarity of MoTe2 , functional devices such as p-n junction or complementary metal-oxide-semiconductor (CMOS) inverters have not been reported. Here, we demonstrate a 2D CMOS inverter and p-n junction diode in a single α-MoTe2 nanosheet by a straightforward selective doping technique. In a single α-MoTe2 flake, an initially p-doped channel is selectively converted to an n-doped region with high electron mobility of 18 cm2 V-1 s-1 by atomic-layer-deposition-induced H-doping. The ultrathin CMOS inverter exhibits a high DC voltage gain of 29, an AC gain of 18 at 1 kHz, and a low static power consumption of a few nanowatts. The results show a great potential of α-MoTe2 for future electronic devices based on 2D semiconducting materials.

Coupling Two-Dimensional MoTe2 and InGaZnO Thin-Film Materials for Hybrid PN Junction and CMOS Inverters.

We report the fabrication of hybrid PN junction diode and complementary (CMOS) inverters, where 2D p-type MoTe2 and n-type thin film InGaZnO (IGZO) are coupled for each device process. IGZO thin film was initially patterned by conventional photolithography either for n-type material in a PN diode or for n-channel of top-gate field-effect transistors (FET) in CMOS inverter. The hybrid PN junction diode shows a good ideality factor of 1.57 and quite a high ON/OFF rectification ratio of ∼3 × 104. Under photons, our hybrid PN diode appeared somewhat stable only responding to high-energy photons of blue and ultraviolet. Our 2D nanosheet-oxide film hybrid CMOS inverter exhibits voltage gains as high as ∼40 at 5 V, low power consumption less than around a few nW at 1 V, and ∼200 µs switching dynamics.

Low Power Consumption Complementary Inverters with n-MoS2 and p-WSe2 Dichalcogenide Nanosheets on Glass for Logic and Light-Emitting Diode Circuits.

Two-dimensional (2D) semiconductor materials with discrete bandgap become important because of their interesting physical properties and potentials toward future nanoscale electronics. Many 2D-based field effect transistors (FETs) have thus been reported. Several attempts to fabricate 2D complementary (CMOS) logic inverters have been made too. However, those CMOS devices seldom showed the most important advantage of typical CMOS: low power consumption. Here, we adopted p-WSe2 and n-MoS2 nanosheets separately for the channels of bottom-gate-patterned FETs, to fabricate 2D dichalcogenide-based hetero-CMOS inverters on the same glass substrate. Our hetero-CMOS inverters with electrically isolated FETs demonstrate novel and superior device performances of a maximum voltage gain as ∼27, sub-nanowatt power consumption, almost ideal noise margin approaching 0.5VDD (supply voltage, VDD=5 V) with a transition voltage of 2.3 V, and ∼800 µs for switching delay. Moreover, our glass-substrate CMOS device nicely performed digital logic (NOT, OR, and AND) and push-pull circuits for organic light-emitting diode switching, directly displaying the prospective of practical applications.