Morphological Phase Separation in Unstable Thin Films: Pattern Formation and Growth

We present results from a comprehensive numerical study of {\it morphological phase separation} (MPS) in unstable thin liquid films on a 2-dimensional substrate. We study the quantitative properties of the evolution morphology via several experimentally relevant markers, e.g., correlation function, structure factor, domain-size and defect-size probability distributions, and growth laws. Our results suggest that the late-stage morphologies exhibit dynamical scaling, and their evolution is self-similar in time. We emphasize the analogies and differences between MPS in films and segregation kinetics in unstable binary mixtures.Comment: 17 pages, 6 figures; Accepted for publication in Physical Chemistry Chemical Physic

Spinodal Phase Separation in Liquid Films with Quenched Disorder

We study spinodal phase separation in unstable thin liquid films on chemically disordered substrates via simulations of the thin-film equation. The disorder is characterized by immobile patches of varying size and Hamaker constant. The effect of disorder is pronounced in the early stages (amplification of fluctuations), remains during the intermediate stages and vanishes in the late stages (domain growth). These findings are in contrast to the well-known effects of quenched disorder in usual phase-separation processes, viz., the early stages remain undisturbed and domain growth is slowed down in the asymptotic regime. We also address the inverse problem of estimating disorder by thin-film experiments.Comment: 12 pages, 7 figure

Kinetics of Spinodal Phase Separation in Unstable Thin Liquid Films

We study universality in the kinetics of spinodal phase separation in unstable thin liquid films, via simulations of the thin film equation. It is shown that in addition to morphology and free energy,the number density of local maxima in the film profile can also be used to identify the early, intermediate and late stages of spinodal phase separation. A universal curve between the number density of local maxima and rescaled time describes the kinetics of early stage in d = 2, 3. The Lifshitz-Slyozov exponent of -1/3 describes the kinetics of the late stage in d = 2 even in the absence of coexisting equilibrium phases.Comment: 5 figure

Outcome of operative intervention in intramedullary spinal cord tumours

Objective: The authors analysed the outcome of intramedullary spinal cord tumour surgery, focusing on the preoperative & postoperative neurological status and influence of preoperative gait status on postoperative gait.Methods: Retrospective analysis of medical records of 53 intramedullary tumour patients, operated at our institute between Jan 2006 and July 2012 was done. Pre - and postoperative neurological status was determined. Preoperative MRI was done. Ambulatory status were evaluated using the modified McCormick Scale. All the patients were operated using standard microsurgical techniques. Extent of resection was quantified by direct visualization with microscope as: gross resection, subtotal resection, partial resection, and biopsy.Results: 73.5% of the patients were in 40-60 years of age group (age range, 5-81 years; mean age 41 years). Region most commonly affected was thoracic (40%). The preoperative McCormick grade was I in 20 (37.7%), II in 16 (30.1%), III in 7 (13.2%), IV in 9 (16.9%), and V in 1 (1.88%) patients. Gross resection was possible in 54.7% of cases. Gross resection rate was significantly higher in good preoperative gait (grade - I). Histologically 41.5% of the lesions were ependymomas. Overall postoperative neurological status improved in 16 (30.3%) of the patients, remained unchanged in 27 (50.9%) of cases, and deteriorated in 10 (18.8%) patients.Conclusions: Better final outcome of walking ability correlated with good preoperative gait. Higher Gross resection rate was found in cases at an early stage. We favor early and optimal resection of tumour to give least morbidity and better quality of life

Outcome of operative intervention in intramedullary spinal cord tumours

Objective: The authors analysed the outcome of intramedullary spinal cord tumour surgery, focusing on the preoperative & postoperative neurological status and influence of preoperative gait status on postoperative gait.Methods: Retrospective analysis of medical records of 53 intramedullary tumour patients, operated at our institute between Jan 2006 and July 2012 was done. Pre - and postoperative neurological status was determined. Preoperative MRI was done. Ambulatory status were evaluated using the modified McCormick Scale. All the patients were operated using standard microsurgical techniques. Extent of resection was quantified by direct visualization with microscope as: gross resection, subtotal resection, partial resection, and biopsy.Results: 73.5% of the patients were in 40-60 years of age group (age range, 5-81 years; mean age 41 years). Region most commonly affected was thoracic (40%). The preoperative McCormick grade was I in 20 (37.7%), II in 16 (30.1%), III in 7 (13.2%), IV in 9 (16.9%), and V in 1 (1.88%) patients. Gross resection was possible in 54.7% of cases. Gross resection rate was significantly higher in good preoperative gait (grade - I). Histologically 41.5% of the lesions were ependymomas. Overall postoperative neurological status improved in 16 (30.3%) of the patients, remained unchanged in 27 (50.9%) of cases, and deteriorated in 10 (18.8%) patients.Conclusions: Better final outcome of walking ability correlated with good preoperative gait. Higher Gross resection rate was found in cases at an early stage. We favor early and optimal resection of tumour to give least morbidity and better quality of life

Influence of tyre transience on anti-lock braking

Transient tyre characteristics can have significant influence in vehicle handling, particularly in anti-lock braking system (ABS), which involves wheel speed oscillations as a result of rapid changes in wheel brake pressure. Hitherto, ABS studies have been conducted mostly with straight-line motion. Relatively simple vehicle models have been used which cannot capture the interactions between non-linear handling dynamics and tyre behaviour. This article takes such interactions into account, using a non-linear 14-degrees-of-freedom vehicle model in combination with three different single-point contact tyre models with transient characteristics. They include a stretched-string-based model, a modified stretched-string model, and a contact mass model. The particularly demanding situation of combined cornering/ABS braking is investigated. It is shown that although all tyre models are of similar bandwidth (maximum frequency ≈ 15 Hz), the simple string tyre model fails to cope with the non-linearities involved in combined braking/cornering and predicts greater braking distances than the two more enhanced tyre models

A multi-body dynamics approach for the study of critical handling manoeuvres on surfaces with uneven friction

The study of the dynamic behaviour of vehicles using computer simulation has been one of the major areas of research for many years. Based on the application area, the models used for performing these studies vary greatly in their capability, complexity and amount of data required. The multi-body approach is most preferred when it comes to iterative design optimization, whereas relatively simple models are mostly used for studying basic handling characteristics and vehicle stability. However, for studies involving critical handling manoeuvres, it is imperative to include certain amount of detail in the vehicle model, which accounts for the influence of suspension geometry and tyre characteristics on handling behaviour. The aim of the present research is to develop a vehicle model, based on Newton-Euler formulation of equations, incorporating sufficient degrees of freedom and adequate non linear characteristics for the realistic simulation of severe handling manoeuvres. The model is verified against experimental vehicle data and is finally used for the investigation of critical handling manoeuvres on surfaces with uneven friction. During this procedure, the tendency of the vehicle to rollover is assessed, together with other dynamic outputs such as yaw velocity and lateral acceleration

Transdural herniated lumbar disc disease with muscle patch for closure of durotomy – A Brief review of literature

Purpose Intradural migration of disc (IDMD) is a rare clinical entity accounting for 0.27–0.33% of all herniated disc diseases. Flimsy or dense adhesion between the ventral dural surface and the opposing posterior longitudinal ligament (PLL) is the principal pathology for intradural migrated disc. The most commonly affected lumbar segments are L4-5 (55%), L3-4 (16%), L5-S1 (10%) and less commonly L2L3 and L1L2. No imaging feature is characteristic and the management protocol of durotomy via an endoscopic method is unclear. Methods An L5S1 disc disease was operated by endoscopic method. Difficulty in separating the dural sac from PLL, dense adhesions prompting sharp dissection at this location and a calcified disc are the earliest evidence of intradural migration. MRI features of an intradural location are loss of continuity of posterior longitudinal ligament, beak-like appearance also known as “Hawk-beak sign”, peripheral enhancement around an intradural disc, fluid-filled intradural cyst. Magnification either by Microscope or Endoscope is of importance when dissecting the intradural disc so as to avoid the nerve root injury. Liberal use of fibrin glue and augmentation with muscle patch was performed. Results Ambulated by 48h and discharged by 5th day. Two and 9 months follow up showed no evidence of pseudomeningocoele. Conclusion Autologous muscle patch with fibrin glue for dural rent closure is a simple and effective method which can be performed by endoscopic or minimally invasive approaches. Suturing the dura, being a tedious and cumbersome procedure can be avoided

Correlation between prolactin, thyroid, LH, FSH, estradiol and progesterone in the infertile women

Background: An important global health issue, infertility affects a couple’s social, psychological, economic, and sexual well-being. A variety of issues stemming from abnormal hypothalamus pituitary ovarian axis dysfunction make up the hormonal diseases of the female reproductive system. The aim of the study was to find correlation between prolactin, thyroid, LH, FSH, estradiol and progesterone in the infertile women. Methods: Present study was hospital based descriptive, cross-sectional study. 150 infertile women were required in sample size. Serum LH, FSH, estradiol was measured on day 2 of menstrual cycle and also serum TSH and serum progesterone on day 21. Results: Around one third (38%) of the cases was married since more than 10 years. Majority 108 (72%) had primary infertility and 50% of the women had history of irregular menstrual cycles. There was significant positive correlation between TSH and prolactin (p value <0.05) and significant negative correlation of TSH with FSH and LH (p value <0.05) and there was insignificant negative correlation of TSH with estrogen (D2) and progesterone (D21). The mean value of TSH in our study was 7.47±1.82 μIU/ml. Conclusions: TSH has strong positive co-relation between prolactin, FSH and LH indicating role in female infertility. These hormonal evaluations allow a routine etiological approach to the diagnosis of infertility.