Effect of nano-scale surface roughness on transverse energy spread from GaAs photocathodes

High quantum yield, low transverse energy spread and prompt response time make GaAs activated to negative electron affnity, an ideal candidate for a photocathode in high brightness photoinjectors. Even after decades of investigation, the exact mechanism of electron emission from GaAs is not well understood. We show that a nanoscale surface roughness can affect the transverse electron spread from GaAs by nearly an order of magnitude and explain the seemingly controversial experimental results obtained so far. This model can also explain the measured dependence of transverse energy spread on the wavelength of incident light.Comment: 3pages, 3figure

Management of acetabulum fracture with contralateral neck of femur in an obese patient: a rare case report

Acetabular fractures are complex fractures that pose a challenge for orthopaedic trauma surgeons due to their extension into the hip joint. The simultaneous occurrence of contralateral neck of femur fracture in an obese patient makes postoperative wound healing and rehabilitation even challenging. Here, we report a case of management of acetabulum fracture with contralateral neck of femur fracture in an obese patient. We are reporting a case of a 50-year-old obese female from Chennai who presented to the Department of Orthopaedics, SRIHER, Chennai, with complaints of bilateral hip pain and inability to weight bear on bilateral lower limb, following a high-velocity road traffic accident. She was diagnosed to have left acetabulum fracture with right hip displaced neck of femur fracture. We managed her with right hip bipolar hemiarthroplasty and left acetabulum open reduction and internal fixation. 6 month follow up showed excellent radiological and functional outcome. This case report highlights how obesity alters the surgical and medical management in obese patients with contralateral acetabulum and neck of femur fracture and the importance of a multidisciplinary approach in such polytrauma patients

Electronic Structures of Group 9 Metallocorroles with Axial Ammines

The electronic structures of metallocorroles (tpfc)M(NH_3)_2 and (tfc)M(NH_3)_2 (tpfc is the trianion of 5,10,15-(tris)pentafluorophenylcorrole, tfc is the trianion of 5,10,15-trifluorocorrole, and M = Co, Rh, Ir) have been computed using first principles quantum mechanics [B3LYP flavor of Density Functional Theory (DFT) with Poisson−Boltzmann continuum solvation]. The geometry was optimized for both the neutral systems (formal M^(III) oxidation state) and the one-electron oxidized systems (formally M^(IV)). As expected, the M^(III) systems have a closed shell d^6 configuration; for all three metals, the one-electron oxidation was calculated to occur from a ligand-based orbital (highest occupied molecular orbital (HOMO) of B_1 symmetry). The ground state of the formal M^(IV) system has M^(III)-Cπ character, indicating that the metal remains d^6, with the hole in the corrole π system. As a result the calculated M^(IV/III) reduction potentials are quite similar (0.64, 0.67, and 0.56 V vs SCE for M = Ir, Rh and Co, respectively), whereas the differences would have been large for purely metal-based oxidations. Vertically excited states with substantial metal character are well separated from the ground state in one-electron-oxidized cobalt (0.27 eV) and rhodium (0.24 eV) corroles, but become closer in energy in the iridium (0.15 eV) analogues. The exact splittings depend on the chosen functional and basis set combination and vary by ~0.1 eV

Optical patterning of trapped charge in nitrogen-doped diamond

The nitrogen-vacancy (NV) centre in diamond is emerging as a promising platform for solid-state quantum information processing and nanoscale metrology. Of interest in these applications is the manipulation of the NV charge, which can be attained by optical excitation. Here we use two-color optical microscopy to investigate the dynamics of NV photo-ionization, charge diffusion, and trapping in type-1b diamond. We combine fixed-point laser excitation and scanning fluorescence imaging to locally alter the concentration of negatively charged NVs, and to subsequently probe the corresponding redistribution of charge. We uncover the formation of spatial patterns of trapped charge, which we qualitatively reproduce via a model of the interplay between photo-excited carriers and atomic defects. Further, by using the NV as a probe, we map the relative fraction of positively charged nitrogen upon localized optical excitation. These observations may prove important to transporting quantum information between NVs or to developing three-dimensional, charge-based memories

Evaluation of granisetron as an antiemetic in patients undergoing abdominal hysterectomy under spinal anaesthesia

Background: PONV most common complications related to surgery and anaesthesia despite major advances in spinal, epidural and combined spinal-epidural anesthesia techniques IONV are still present in a significant number of patients. Ondansetron, used for controlling PONV induced by chemotherapy or radiation. Recently 5HT3 receptor antagonist granisetron has more potent, selective and longer acting activity than ondansetron. Granisetron is more active for control of PONV in cisplatin induced vomiting than ondansetron. It also reduces PONV in strabismus repair, tonsillectomy, and general surgeries, it has less side effects as compared to ondansetron. Objective of the study was to study efficacy and safety of granisetron and compare it with ondansetron for prevention of IONV and PONV.Methods: 80 ASA grade I and II women undergoing abdominal hysterectomy under spinal anaesthesia were studied. Patients in group A received injection granisetron 2 mg and group B injection ondansetron 4 mg,10 minutes prior to induction of spinal anaesthesia. Main outcome measures were occurrence of nausea, retching or vomiting in intraoperative and postoperative period at 6, 12, 18 and 24 hours’ post-surgery. The response of patient to therapy and side effects were evaluated in both groups. The results were analyzed by ‘z’ test (p<0.5) considered significant.Results: Demographic characteristics of both groups were comparable patients in granisetron (80%) had more complete response as compared to ondansetron (47.5%). Adverse effects were lower in granisetron group.Conclusions: Granisetron 2 Mg has better efficacy and safety profile than ondansetron 4 Mg