140 research outputs found
Nematic kink states in a laser field
We have investigated the nonlinear optical interaction of uniform and kink states of a nematic and a ferrofluid-doped nematic (ferronematic) liquid crystal with an incident laser field. We find that the transition between the permitted uniform oreintational states of these systems is of first order in the case of nematics, and of second order in the case of ferronematics. In the latter case we also find the phenomenon of reentrance. We find new kink states in a magnetic field with topological winding different from p in the case of nematics, and 2π in the case of ferronematics. In ferronematics, due to grain segregation the phase diagrams for uniform and kink states are entirely different. In these systems we find a first or second order structural transformation from a single kink into a pair of kinks. Further, we obtain a rich variety of kink states as the intensity of the laser field is varied
Prosthesis for a Case of Subtotal Orbital Exenteration
Aims and objectives: To rehabilitate a patient with subtotal orbital exenteration defect. Case description: A 32 year old male with history of carcinoma of ethmoid, treated surgically with subtotal orbital exenteration presented with a defect communicating with the pharynx. He was rehabilitated with a prosthetic eye. Conclusion: A two piece cast with a removable part containing the defect made it very easy to fabricate the prosthesis. Patient was happy with the appearance and expressed satisfaction. 
Occlusal Plane Determination Using Custom Made Broadrick Occlusal Plane Analyser: A Case Control Study
Proper occlusal plane is an essential consideration when multiple long span posterior restorations are designed. The determination of the occlusal plane can have a profound effect on the short and long term success of a restorative case. Purpose of Study. (1) To determine the appropriate occlusal curve for individual patients. (2) To compare the deviation of the clinical occlusal curve with the ideal ones. Materials and Methods. A total of 20 subjects were examined and study models were made of their maxillary and mandibular dentition. Inter-occlusal records were made and the casts were articulated in semiadjustable articulator. An ideal occlusal plane was created. The distance of the farthest cusp tip from the Broadrick curve was measured along the long axis of the tooth for each individual. Paired t-tests were used to compare the findings between subjects and controls. Results. A statistically significant difference P < 0.05 was found in the deviation from the Broadrick curve between patients who have lost posterior teeth and the control group who had a full dentition with no missing teeth. Conclusion. Proper utilization of the broadrick flag on a semi-adjustable articulator will allow for a correct determination of the occlusal plane
Trans-osseous intraoperative limb length measurement in hip replacement surgery
Background: Discrepancy of the limb length following total hip replacement is one of common complication. To reduce the occurrence, various modalities are used like pre-operative templating, navigation assisted measurements and intraoperative methods. This study was done using trans-osseous method of measurement using hip gauge which provides a faster, simpler assessment of limb length.Methods: A prospective study of 25 patients who underwent uncemented hip arthroplasty was taken in the study and the LLD was measured before and after the surgical procedure. Patient were re-assessed for limb length discrepancy after 6 months with functional Harris hip score and radiological analysis on weight bearing standard X-ray antero-posterior view of the pelvis with bilateral hip joint.Results: The results showed significant improvement in limb length discrepancy, and analysis of postoperative radiographs found the mean length difference of 2.44 mm and average Harris hip score was 95.5. No device related complications were reported, and none of them complained of the discomfort related to limb-length discrepancy after surgery. Conclusions: Trans-osseous fixed method using hip gauge provides a faster, reproducible and simpler method for the assessment of Limb length and aids with offset placement, acetabular anteversion for precise cup placement. This is a reliable method as it can be used both in the primary and revision hip surgery and most importantly doesn’t require any additional intraoperative imaging
Original Research Article Effect of Radiotherapy on Flexural Strength of Luting Cementsan In Vitro Study
Aim - The aim of this study was to evaluate changes in the flexural strength of luting cements due to radiotherapy. Methodology- Total of 90 rectangular specimens of 25×2×2 mm dimension were fabricated by utilizing the putty consistency polyvinyl siloxane rubber mould. They were grouped based on their type. Group A included 30 specimens made of zinc phosphate cement, Group B included 30 specimens fabricated using glass ionomer luting cement, and Group C consisted of 30 specimen’s fabricated using resin luting cement. Once the specimens were set, they were stored in distilled water between the experiments. After 24 hours, 15 from each group of the mentioned cements were subjected to irradiation fractionally upto 60 Gy by a Cobalt-60 external beam machine. Remaining specimens from each group were used as controls. After radiotherapy, the specimens were stored in distil water for 24 hours until performing the 3 point bend test. All the specimens were subjected to 3 point bend test on universal testing machine for checking flexural strength. Statistics- Kruskal Wallis Test followed by Mann Whitney test as post hoc analysis was used to compare the mean values of different parameters between three groups of Irradiated and controlled samples. The level of significance was set at P<0.05. Results- After exposure to fractional irradiation for 4 weeks, in the zinc phosphate luting cement (Group-A) and glass ionomer luting cement (Group-B), showed a slight decrease in flexural strength. The resin luting cement (Group-C) showed slight increase in flexural strength. Conclusion- Among all the groups, the resin luting cement showed a slight increase in flexural strength when compared to the other luting cement groups after fractional irradiatio
Silicon-lattice-matched boron-doped gallium phosphide: A scalable acousto-optic platform
The compact size, scalability, and strongly confined fields in integrated
photonic devices enable new functionalities in photonic networking and
information processing, both classical and quantum. Gallium phosphide (GaP) is
a promising material for active integrated photonics due to its high refractive
index, wide band gap, strong nonlinear properties, and large acousto-optic
figure of merit. In this work we demonstrate that silicon-lattice-matched
boron-doped GaP (BGaP), grown at the 12-inch wafer scale, provides similar
functionalities as GaP. BGaP optical resonators exhibit intrinsic quality
factors exceeding 25,000 and 200,000 at visible and telecom wavelengths
respectively. We further demonstrate the electromechanical generation of
low-loss acoustic waves and an integrated acousto-optic (AO) modulator.
High-resolution spatial and compositional mapping, combined with ab initio
calculations indicate two candidates for the excess optical loss in the visible
band: the silicon-GaP interface and boron dimers. These results demonstrate the
promise of the BGaP material platform for the development of scalable AO
technologies at telecom and provide potential pathways toward higher
performance at shorter wavelengths
Surviving streptococcal toxic shock syndrome: a case report
Streptococcal toxic shock syndrome and associated myositis caused by group A beta-hemolytic streptococcus pyogenes generally have a poor outcome despite aggressive operative treatment. Frequently the diagnosis is missed initially as the clinical features are non-specific. The progression to a toxic state is rapid and unless definitive treatment measures are initiated early, the end result can be catastrophic. We report a previously healthy patient who had features of toxic shock syndrome due to alpha haemolytic (viridans) streptococcus mitis which was treated successfully with antibiotics, aggressive intensive care support including the use of a 'sepsis care bundle', monitoring and continuous multidisciplinary review. Life and limb threatening emergencies due to streptococcus mitis in an immune-competent person are rare and to our knowledge, have not previously been described in the English scientific literature. Successful outcome is possible provided a high degree of suspicion is maintained and the patient is intensively monitored
GATA3 and MDM2 are synthetic lethal in estrogen receptor-positive breast cancers.
Synthetic lethal interactions, where the simultaneous but not individual inactivation of two genes is lethal to the cell, have been successfully exploited to treat cancer. GATA3 is frequently mutated in estrogen receptor (ER)-positive breast cancers and its deficiency defines a subset of patients with poor response to hormonal therapy and poor prognosis. However, GATA3 is not yet targetable. Here we show that GATA3 and MDM2 are synthetically lethal in ER-positive breast cancer. Depletion and pharmacological inhibition of MDM2 significantly impaired tumor growth in GATA3-deficient models in vitro, in vivo and in patient-derived organoids/xenograft (PDOs/PDX) harboring GATA3 somatic mutations. The synthetic lethality requires p53 and acts via the PI3K/Akt/mTOR pathway. Our results present MDM2 as a therapeutic target in the substantial cohort of ER-positive, GATA3-mutant breast cancer patients. With MDM2 inhibitors widely available, our findings can be rapidly translated into clinical trials to evaluate in-patient efficacy
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