A Novel 4H-SiC SGT MOSFET with Improved P+ Shielding Region and Integrated Schottky Barrier Diode.

A silicon carbide (SiC) SGT MOSFET featuring a ""-shaped P+ shielding region (PSR), named SPDT-MOS, is proposed in this article. The improved PSR is introduced as a replacement for the source trench to enhance the forward performance of the device. Its improvement consists of two parts. One is to optimize the electric field distribution of the device, and the other is to expand the current conduction path. Based on the improved PSR and grounded split gate (SG), the device remarkably improves the conduction characteristics, gate oxide reliability, and frequency response. Moreover, the integrated sidewall Schottky barrier diode (SBD) prevents the inherent body diode from being activated and improves the reverse recovery characteristics. As a result, the gate-drain capacitance, gate charge, and reverse recovery charge (Qrr) of the SPDT-MOS are 81.2%, 41.2%, and 90.71% lower than those of the DTMOS, respectively. Compared to the double shielding (DS-MOS), the SPDT-MOS exhibits a 20% reduction in on-resistance and an 8.1% increase in breakdown voltage.

The Application of Sesamoid Position in Diagnosing Thumb Metacarpophalangeal Joint Dorsal Dislocation: A Retrospective Study.

OBJECTIVES: The position of sesamoid of thumb metacarpophalangeal (MCP) joint changed clearly when the joint was dislocated dorsally. However, the significance of sesamoid location in diagnosing joint dislocation was unclear. The present study aimed to explore the positional relationship between sesamoid bone and thumb metacarpophalangeal joint in normal and dorsal dislocation joints. METHODS: Between January 2018 and August 2023, we collected 60 isometric plain films from sixty outpatients and reviewed 56 anisometric plain films from twenty-eight emergency patients with dorsal dislocation of thumb MCP joint at Tianjin Hospital, then took measurements on the hand X-ray images. The sesamoid length on its longitudinal axis was defined as DP, the distance between the distal edge of sesamoid and thumb MCP joint was defined as DJ, and the ratio of DJ and DP was R. An independent-samples t-test and paired-samples t-test was utilized to analyze difference among data groups. RESULTS: The 60 isometric images were from 30 male and 30 female outpatients with normal bone structure in their hands, and the 56 anisometric images of the 28 emergency patients included both preoperative and postoperative materials. Among the outpatients, the actual distance between the distal edge of sesamoid and thumb MCP joint space (DJ) was 2.09 mm and 1.40 mm in males and females, respectively. The authentic average length of sesamoid (DP) was 4.46 mm in males and 4.22 mm in females. The average value of R (the ratio of DJ and DP) in males and females was 0.49 and 0.34, respectively. There were gender-related statistical differences in DJ (p < 0.01) and R (p=0.01), but no statistical difference in DP (p > 0.05). For the 28 emergency patients, the mean value of R was -0.47 before joint reduction and 0.58 after joint reduction, with statistical difference between them (p < 0.01). CONCLUSIONS: There was significant difference in the relative position between sesamoid and thumb MCP joint when joint dislocation and joint reduction. The distal edge of sesamoid beyond thumb MCP joint could be an evidence in diagnosing joint dorsal dislocation. The distal edge of sesamoid below thumb MCP joint could be an evidence of joint reduction.

Diagnosing suspected scaphoid fractures: a systematic review and meta-analysis.

UNLABELLED: Imaging protocols for suspected scaphoid fractures among investigators and hospitals are markedly inconsistent. We performed a systematic review and meta-analysis to assess and compare the diagnostic performance of bone scintigraphy, MRI, and CT for diagnosing suspected scaphoid fractures. Twenty-six studies were included. Sensitivity, specificity, and diagnostic odds ratio were pooled separately and summary receiver operating characteristic curves were fitted for each modality. Meta-regression analyses were performed to compare these modalities. We obtained likelihood ratios derived from the pooled sensitivity and specificity and, using Bayes' theorem, calculated the posttest probability by application of the tests. The pooled sensitivity, specificity, natural logarithm of the diagnostic odds ratio, and the positive and negative likelihood ratios were, respectively, 97%, 89%, 4.78, 8.82, and 0.03 for bone scintigraphy; 96%, 99%, 6.60, 96, and 0.04 for MRI; and 93%, 99%, 6.11, 93, and 0.07 for CT. Bone scintigraphy and MRI have equally high sensitivity and high diagnostic value for excluding scaphoid fracture; however, MRI is more specific and better for confirming scaphoid fracture. We believe additional studies are needed to assess diagnostic performance of CT, especially paired design studies or randomized controlled trials to compare CT with MRI or bone scintigraphy. LEVEL OF EVIDENCE: Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

[Reconstruction of ankle and foot with combination of free perforator flaps and skin graft].

Objective: To evaluate the clinical outcomes of free perforator flaps combined with skin graft for reconstruction of ankle and foot soft tissue defects. Methods: Between June 2014 and October 2015, 20 cases of ankle and foot soft tissue defects were treated. There were 16 males and 4 females, aged from 19 to 61 years (mean, 43.3 years). Injury was caused by traffic accident in 7 cases, by crashing in 9 cases, and machine twist in 4 cases. The locations were the ankle in 6 cases, the heel in 3 cases, the dorsum pedis in 4 cases, and the plantar forefoot in 7 cases of avulsion injury after toes amputation. The size of wound ranged from 15 cm×10 cm to 27 cm×18 cm. The time from injury to treatment was from 11 to 52 days (mean, 27 days). The anterolateral thigh perforator flap was used in 11 cases, thoracodorsal antery perforator flap in 3 cases, medial sural artery perforator flap in 4 cases, deep inferior epigastric perforator flap in 1 case, and anteromedial thigh perforator flap in 1 case, including 5 chimeric perforator flaps, 5 polyfoliate perforator flaps, 3 flow-through perforator flaps, and 3 conjoined perforator flaps. The size of the perforator flap ranged from 10.0 cm×6.5 cm to 36.0 cm×8.0 cm, the size of skin graft from 5 cm×3 cm to 18 cm×12 cm. Results: Venous crisis occurred in 2 flaps which survived after symptomatic treatment; 18 flaps survived successfully and skin grafting healed well. The follow-up time ranged 4-18 months (mean, 8.3 months). The flaps had good appearance, texture and color, without infection. The patients could walk normally and do daily activities. Only linear scars were observed at the donor sites. Conclusion: Free perforator flap can be used to reconstruct defects in the ankle and foot, especially in the weight-bearing area of the plantar forefoot. A combination of free perforator flap and skin graft is ideal in reconstruction of great soft tissue defects in the ankle and foot.

Cost-Effectiveness of Diagnostic Strategies for Suspected Scaphoid Fractures.

OBJECTIVES: The aim of this study was to assess the cost effectiveness of multiple competing diagnostic strategies for suspected scaphoid fractures. METHODS: With published data, the authors created a decision-tree model simulating the diagnosis of suspected scaphoid fractures. Clinical outcomes, costs, and cost effectiveness of immediate computed tomography (CT), day 3 magnetic resonance imaging (MRI), day 3 bone scan, week 2 radiographs alone, week 2 radiographs-CT, week 2 radiographs-MRI, week 2 radiographs-bone scan, and immediate MRI were evaluated. The primary clinical outcome was the detection of scaphoid fractures. The authors adopted societal perspective, including both the costs of healthcare and the cost of lost productivity. The incremental cost-effectiveness ratio (ICER), which expresses the incremental cost per incremental scaphoid fracture detected using a strategy, was calculated to compare these diagnostic strategies. Base case analysis, 1-way sensitivity analyses, and "worst case scenario" and "best case scenario" sensitivity analyses were performed. RESULTS: In the base case, the average cost per scaphoid fracture detected with immediate CT was $2553. The ICER of immediate MRI and day 3 MRI compared with immediate CT was $7483 and $32,000 per scaphoid fracture detected, respectively. The ICER of week 2 radiographs-MRI was around $170,000. Day 3 bone scan, week 2 radiographs alone, week 2 radiographs-CT, and week 2 radiographs-bone scan strategy were dominated or extendedly dominated by MRI strategies. The results were generally robust in multiple sensitivity analyses. CONCLUSIONS: Immediate CT and MRI were the most cost-effective strategies for diagnosing suspected scaphoid fractures. LEVEL OF EVIDENCE: Economic and Decision Analyses Level II. See Instructions for Authors for a complete description of levels of evidence.

Treatment of acute scaphoid fractures: systematic review and meta-analysis.

Whether operative treatment is a better option than nonoperative treatment for acute nondisplaced or minimally displaced fractures of the scaphoid is controversial. The type of cast that should be used for nonoperative treatment is not known. We performed a systematic review and meta-analysis of randomized and quasirandomized trials to evaluate the effect of operative versus nonoperative treatment and the effect of different casting methods for nonoperative treatment of acute scaphoid fractures on nonunion rate, return to work, grip strength, range of wrist motion, complications, patient evaluation, and incidence of osteoarthritis. Two investigators assessed trial quality and extracted data. Operative treatment of acute nondisplaced or minimally displaced fractures of the scaphoid waist does not provide greater benefits regarding nonunion rate, return to work, grip strength, range of wrist motion, or patient satisfaction than cast immobilization; however, it causes more complications and, perhaps, a higher risk of scaphotrapezial osteoarthritis. There is no evidence from randomized trials to determine whether operative treatment is superior to nonoperative treatment for an acute proximal pole fracture of scaphoid bones. There is insufficient evidence to determine which type of cast should be used in nonoperative treatment of nondisplaced scaphoid fractures.