Impact of Level of Surgery on the Functional Outcomes in Patients with Lower Extremity Bone Tumors Undergoing Amputation Versus Limb Salvage Surgery.

Limb salvage surgery is the preferred treatment for bone tumors in the current surgical practice. The aim of this study was to compare the functional outcomes between amputation and limb salvage surgery based on the level of surgery at two levels: knee and hip. A single institutional analysis of 137 patients with lower extremity bone tumors was done between 2014 and 2020. Eighty-seven patients treated with amputation were compared with 50 patients treated with limb salvage surgery based on following variables: age, gender, histology, anatomic site, and MSTS score. The mean MSTS scores were fairly better in patients who underwent surgery at knee level compared to those who underwent surgery at hip level. The mean MSTS score at 1-year follow-up was 22.0 in amputation group compared to 22.4 in limb salvage group, whereas at 2-year follow-up was 24.1 in amputation group compared to 25.1 in limb salvage group. At knee level, functional outcomes were similar after amputation and limb salvage. At hip level, patients undergoing amputation had poorer MSTS scores compared to limb salvage surgery at 2-year follow-up (p = 0.04). The functional outcomes for patients undergoing surgery at knee level were similar irrespective of type of surgery. At longer follow-up, patients undergoing amputation at hip level had a poorer functional outcome compared to limb salvage surgery. Although limb salvage was associated with similar MSTS scores when compared with amputation, it produced a better functional outcome especially for proximally located tumors.

Electric Field and Strain Tuning of 2D Semiconductor van der Waals Heterostructures for Tunnel Field-Effect Transistors.

Heterostacks consisting of low-dimensional materials are attractive candidates for future electronic nanodevices in the post-silicon era. In this paper, using first-principles calculations based on density functional theory (DFT), we explore the structural and electronic properties of MoTe2/ZrS2 heterostructures with various stacking patterns and thicknesses. Our simulations show that the valence band (VB) edge of MoTe2 is almost aligned with the conduction band (CB) edge of ZrS2, and (MoTe2)m/(ZrS2)m (m = 1, 2) heterostructures exhibit the long-sought broken gap band alignment, which is pivotal for realizing tunneling transistors. Electrons are found to spontaneously flow from MoTe2 to ZrS2, and the system resembles an ultrascaled parallel plate capacitor with an intrinsic electric field pointed from MoTe2 to ZrS2. The effects of strain and external electric fields on the electronic properties are also investigated. For vertical compressive strains, the charge transfer increases due to the decreased coupling between the layers, whereas tensile strains lead to the opposite behavior. For negative electric fields a transition from the type-III to the type-II band alignment is induced. In contrast, by increasing the positive electric fields, a larger overlap between the valence and conduction bands is observed, leading to a larger band-to-band tunneling (BTBT) current. Low-strained heterostructures with various rotation angles between the constituent layers are also considered. We find only small variations in the energies of the VB and CB edges with respect to the Fermi level, for different rotation angles up to 30°. Overall, our simulations offer insights into the fundamental properties of low-dimensional heterostructures and pave the way for their future application in energy-efficient electronic nanodevices.

Accurate graphene quantum Hall arrays for the new International System of Units.

Graphene quantum Hall effect (QHE) resistance standards have the potential to provide superior realizations of three key units in the new International System of Units (SI): the ohm, the ampere, and the kilogram (Kibble Balance). However, these prospects require different resistance values than practically achievable in single graphene devices (~12.9 kΩ), and they need bias currents two orders of magnitude higher than typical breakdown currents IC ~ 100 µA. Here we present experiments on quantization accuracy of a 236-element quantum Hall array (QHA), demonstrating RK/236 ≈ 109 Ω with 0.2 part-per-billion (nΩ/Ω) accuracy with IC ≥ 5 mA (~1 nΩ/Ω accuracy for IC = 8.5 mA), using epitaxial graphene on silicon carbide (epigraphene). The array accuracy, comparable to the most precise universality tests of QHE, together with the scalability and reliability of this approach, pave the road for wider use of graphene in the new SI and beyond.

The Use of a New Device-Assisted Needle Guidance versus Conventional Approach to Perform Ultrasound Guided Brachial Plexus Blockade: A Randomized Controlled Study.

Purpose: Ultrasound guidance during nerve blockade poses the challenge of maintaining in-plane alignment of the needle tip. The needle guidance device maintains needle alignment and assists with in-plane needle visualization. The purpose of this study is to evaluate the utility of this device by comparing procedure performance during brachial plexus blockade with the conventional approach. Methods: After the Institutional Review Board approval and obtaining informed consent, 70 patients receiving either interscalene or supraclavicular nerve blocks were randomly assigned into 2 groups, a conventional approach versus utilizing the needle guidance device. An independent observer recorded: total procedure time; needle insertion time; number of unplanned redirections; and number of reinsertions. Additionally, physician satisfaction and ease of needle visualization were assessed. Results: Data from seventy patients were analyzed. The median [25th percentile-75th percentile] time to complete the block by the device assisted needle guidance group was 3 (2-3.75) minutes and 4 (3-6) minutes in the conventional approach group (p < 0.001). Additionally, subgroup analyses were performed in the supraclavicular block and interscalene block. Supraclavicular blockade, needle insertion time (median [25th percentile-75th percentile] in seconds) (106 [92-162] vs 197 [140-278]), total procedure time (3 [2-3] vs 4.5 [4-6] in minutes) and unplanned needle redirections (2 [1-5] vs 5.5 [3-9]) were significantly lower in needle guidance group (p < 0.001). With interscalene blockade, needle insertion time (86 [76-146] vs 126 [94-295]) and unplanned needle redirections (2 [1-3] vs 4 [2-8.5]) were significantly lower with needle guidance (p < 0.001), but total procedure time was similar. All the physicians reported that they would use the needle guidance again, and 90% would prefer it for in-plane blocks. Conclusion: Performing regional blocks using the needle guidance device reduces needle insertion time and unplanned needle redirections in brachial plexus blockade. Moreover, physician satisfaction also improved compared to the use of the conventional technique.

Postoperative Pediatric Cerebellar Mutism After Posterior Fossa Surgery: A Case Report.

Cerebellar mutism syndrome (CMS) is a common complication of posterior fossa surgery that can confound the postanesthetic examination and have long-lasting impacts. There is confusion surrounding its precise description, diagnostic features, and associated morbidity. Here, we discuss the most up-to-date knowledge of CMS drawing from a clinical case in the context of 3 new reports: (1) an international consensus paper presenting a new proposed working definition by the Iceland Delphi Group, (2) a knowledge update by Gadgil et al, (3) and a review of neuroimaging-based data elucidating the etiology of CMS by Patay.

Clinical study of Tinea capitis in Northern Karnataka: A three-year experience at a single institute.

BACKGROUND: Tinea capitis is a superficial fungal infection of the hair follicle of scalp. Most of the dermatophytosis do not have such age propensity as tinea capitis which almost invariably involves the paediatric age group. The exact incidence of tinea capitis is not known. This study is done in order to isolate the species variation in an area, to know the changing patterns of occurrence of different species and their association with clinical pattern MATERIALS AND METHODS: All clinically diagnosed cases of tinea capitis which presented to our out patient department over a period of one year were included in the study. RESULTS: 70 cases of Tinea capitis were studied. DISCUSSION: Tinea capitis is a disease of prepubertal children with common in age group of 5- 15 years. The incidence varies from 0.5% to 10%. Most common presenting feature was alopecia.