Evolution of Vibrational Spectra in the Manganese-Silicon Clusters Mn2Sin, n = 10, 12, and 13, and Cationic [Mn2Si13].

A comparison of DFT-computed and measured infrared spectra reveals the ground state structures of a series of gas-phase silicon clusters containing a common Mn2 unit. Mn2Si12 and [Mn2Si13]+ are both axially symmetric, allowing for a clean separation of the vibrational modes into parallel (a1) and perpendicular (e1) components. Information about the Mn-Mn and Mn-Si bonding can be extracted by tracing the evolution of these modes as the cluster increases in size. In [Mn2Si13]+, where the antiprismatic core is capped on both hexagonal faces, a relatively simple spectrum emerges that reflects a pseudo-D6d geometry. In cases where the cluster is more polar, either because there is no capping atom in the lower face (Mn2Si12) or the capping atom is present but displaced off the principal axis (Mn2Si13), the spectra include additional features derived from vibrational modes that are forbidden in the parent antiprism.

Mn2 Dimers Encapsulated in Silicon Cages: A Complex Challenge to MC-SCF Theory.

MC-SCF wavefunctions for three endohedral Mn/Si clusters, Mn2Si10, Mn2Si12, and [Mn2Si13]+, show evidence for strong static correlation, both in the Mn-Si bonds ('in-out correlation') and between the two Mn centers ('up-down correlation'). We use both Restricted and Generalized Active Spaces (RAS and GAS) to place constraints on the configurations included in the trial wavefunction, showing that, particularly in the high-symmetry cases, the GAS approach captures more of the static correlation. The important correlating pairs are similar across the series, indicating that the electronic structure of the endohedral Mn2 unit is, to a first approximation, independent of the size of the silicon cage in which it is embedded.

Future and training of craniofacial surgery in India.

Craniofacial surgery, in the strictest sense, is the surgery of structures above and behind the maxilla. Craniofacial surgery is not new to India and has been around for more than 4 decades now since the 1970s. Keeping in mind the promotion of the specialty in India, an Indian Craniofacial Foundation was launched in the year 2012 at the Annual Meeting of the Association of Plastic Surgeons of India. To develop a craniofacial center in India, the primary requirement is a source of funding. Several craniofacial centers, which are already running successfully in India, have amply demonstrated that this can be done in several ways. We would like to discuss here the 2 models of craniofacial service delivery and training that the authors have seen and experienced firsthand.

Functional reconstruction of complex tendo Achilles defect by free latissimus dorsi muscle flap.

Managing the complex tendo Achilles defect involves reconstructing the Achilles tendon as well as providing soft tissue cover to the heel area. The advent of microsurgery has revolutionised the reconstruction of this difficult defect providing a number of options to the reconstructive surgeon. We present a case of complex tendo Achilles defect reconstructed by the latissimus dorsi free flap.

RetiSurge - Enabling "Dry Lab" vitreoretinal surgical training during COVID-19 pandemic.

The COVID-19 pandemic has resulted in reduction of patient volumes in Ophthalmology. With only emergency surgical procedures being performed with few elective surgical procedures, surgical volumes are at an all-time low. This has resulted in decreased surgical training opportunities for trainee surgeons. We developed a simple, cost-effective, 3D printed model eye - RetiSurge - for "Dry Lab" vitreoretinal surgery training. The model incorporates a retinal film that can be changed, making it suitable for multiple uses. The RetiSurge model can be used to practice visualization, instrument manipulation and endolaser photocoagulation. RetiSurge can be sterilized by ethylene oxide and is safe for use inside the operating room. RetiSurge is a simple, cost-effective, and reusable model eye for early training in Vitreoretinal surgery.

Profile of patients receiving intravitreal anti-vascular endothelial growth factor injections during COVID-19-related lockdown.

PURPOSE: The aim of this study was to analyze the impact on vision due to delay in presentation of patients requiring intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections, consequent to COVID-19-related travel restrictions. METHODS: Data were collected retrospectively of patients who received anti-VEGF injections during four months of the COVID-19 pandemic. Visual acuities, indication for treatment were noted along with basic demographic characteristics. RESULTS: Data were analyzed for 303 eyes of 263 patients. The indication for treatment was age-related macular degeneration (AMD) in 60 eyes (19.8%), while 162 eyes (53.5%) had Diabetic Macular Edema, 71 eyes (23.4%) had Retinal Vein Occlusion and 10 eyes (3.3%) had other diagnosis. The visual acuity in the treatment naïve eyes (Group A, n = 168) was significantly worse (P <0.001) than those who presented for retreatment (Group B, n = 135). In Group B, there was a significant decline in vision for the entire cohort (P = 0.009) and those with AMD (P = 0.036). Those in Group B presented at a mean interval of 19.1 ± 10.6 (range, 4-64) weeks for retreatment. CONCLUSION: The COVID-19 pandemic has led to a delay in patients receiving anti-VEGF injections. The visual acuity is worse in both treatment naïve as well as those requiring retreatment. This could have long-term impact on vision of patients requiring this vision preserving treatment.

Alveolar bone graft with Platelet Rich Plasma in cleft alveolus.

INTRODUCTION: Cleft of the lip, palate and alveolus are the commonest congenital anomaly to affect the orofacial region. Currently, there is great interest in the alveolar bone grafting procedures that involve use of platelet-rich-plasma (PRP), to enhance bone formation and specifically to promote bone graft healing. MATERIALS AND METHODS: 20 patients with residual alveolar cleft, in the age group of 9-29 years, having unilateral or bilateral cleft lip and palate were selected. They were randomly assigned in either group A (with PRP) or group B (without PRP). RESULTS: Primary healing was observed in 90% patients in group A. Secondary healing was seen in 30% patients in group B. There was no graft rejection in group A but was seen in one patient (10%) in group B. Pain and swelling persisted longer in group B then group A. Bone grafts with added PRP presented with increased bone density (1028.00 ± 11.30 HU) in comparison to grafts without PRP (859.50 ± 27.73 HU) at end of 6-month postoperative. However, the mean bone density (as determined by the Dentascan image analyzer software) was 1.04 times more in the PRP group than non PRP group at 3-month and 1.2 times more at 6 months. CONCLUSION: We conclude that on preliminary investigations, PRP seems to enhance bone formation in alveolar clefts when admixed with autologous cancellous bone harvested from the iliac crest.

The transversely split gracilis twin free flaps.

The gracilis muscle is a Class II muscle that is often used in free tissue transfer. The muscle has multiple secondary pedicles, of which the first one is the most consistent in terms of position and calibre. Each pedicle can support a segment of the muscle thus yielding multiple small flaps from a single, long muscle. Although it has often been split longitudinally along the fascicles of its nerve for functional transfer, it has rarely been split transversely to yield multiple muscle flaps that can be used to cover multiple wounds in one patient without subjecting him/her to the morbidity of multiple donor areas.