Detecting non-secure memory deallocation with CBMC

2021 Fall.Includes bibliographical references.Scrubbing sensitive data before releasing memory is a widely recommended but often ignored programming practice for developing secure software. Consequently, sensitive data such as cryptographic keys, passwords, and personal data, can remain in memory indefinitely, thereby increasing the risk of exposure to hackers who can retrieve the data using memory dumps or exploit vulnerabilities such as Heartbleed and Etherleak. We propose an approach for detecting a specific memory safety bug called Improper Clearing of Heap Memory Before Release, referred to as Common Weakness Enumeration 244. The CWE-244 bug in a program allows the leakage of confidential information when a variable is not wiped before heap memory is freed. Our approach uses the CBMC model checker to detect this weakness and is based on instrumenting the program using (1) global variable declarations that track and monitor the state of the program variables relevant for CWE-244, and (2) assertions that help CBMC to detect unscrubbed memory. We develop a tool, SecMD-Checker, implementing our instrumentation based algorithm, and we provide experimental validation on the Juliet Test Suite that the tool is able to detect all the CWE-244 instances present in the test suite. The proposed approach has the potential to work with other model checkers and can be extended for detecting other weaknesses that require variable tracking and monitoring, such as CWE-226, CWE-319, and CWE-1239

Random Walks in Polytopes and Negative Dependence

We present a Gaussian random walk in a polytope that starts at a point inside and continues until it gets absorbed at a vertex. Our main result is that the probability distribution induced on the vertices by this random walk has strong negative dependence properties for matroid polytopes. Such distributions are highly sought after in randomized algorithms as they imply concentration properties. Our random walk is simple to implement, computationally efficient and can be viewed as an algorithm to round the starting point in an unbiased manner. The proof relies on a simple inductive argument that synthesizes the combinatorial structure of matroid polytopes with the geometric structure of multivariate Gaussian distributions. Our result not only implies a long line of past results in a unified and transparent manner, but also implies new results about constructing negatively associated distributions for all matroids

Optimization of Work Zone Segments on Urban Roads Using Cellular Automata Model in Mixed Traffic

Increased delays and reduced speeds in work zones leads to congestion. This can be improved by optimizing the work zone length. The focus of this study is to model work zones using cellular automata model and to find the effects of work zones on traffic flow. The methodology adopted in the study involved creating work-zone on the road by blocking some of the cells and then determining traffic characteristics such as delay and queue lengths for model validation. For this the lateral movement rules of the existing Cellular Automata model were modified in order to replicate the traffic movement near work zones. This model is calibrated and validated using data from work zone observed near a metro rail station in Delhi. From the analysis it was evident that the queue length increased with increase in the length of work zone. Several relationships were tried between delay and work zone length. Among them the rational form was found suitable

Current scenario and challenges for bone retrieval for allograft use in North India

Bone grafts are the second most common tissue transplanted. With advances in the treatment of musculoskeletal tumors, limb salvage surgery, with its concomitant demand for bone graft, has increased significantly. This study aims to evaluate current scenario for bone donation in north India. This study was done in bone bank, Government Medical College, Kota, Rajasthan. Inclusion and exclusion criteria of bone donors were followed as per the APASTB standards of tissue banking. Bone was retrieved from deceased donor and live donors after proper consent and counselling in this institute during period 01 January 2021 to 31 January 2022. During the period of study bones were retrieved from 26 donors – 24 live donors and 2 cadavers. Out of 24 live donors 20 were femoral head, 2 tibia and fibula and 2 hemi-radius and hemi-ulna. All donors were between 28-71-year age group and mean age was 56 years. 18 males and 8 females participated in study. There is huge difference between demand and supply of bone allograft in this region of country. There is lack of initiative from government for encouraging people to donate bone along with other organ and tissue donations. Lack of infrastructure for to and fro transport of bone retrieval from deceased and live donors to storage unit results in loss of bone samples. Less trained personnel and sufficiently low coordination between various institutes. Concerns of family members and misconceptions to be addressed properly to reduce morbidity burden in society

Association of clinical features, comorbidities and laboratory profile with outcomes among dengue patients admitted in a tertiary care hospital, Delhi NCR

Background: Dengue fever is an endemic disease across multiple countries. Dengue infection results in a wide spectrum of non-specific clinical manifestations with unpredictable clinical course and outcome. Objective of the study was to understand the association of different clinical features, comorbidities and laboratory profile with outcomes (ICU use, ventilation use and blood transfusion) among dengue patients admitted in a tertiary care hospital in Delhi, National Capital Region.Methods This cross-sectional study included 75 dengue patients with fever <1 week confirmed based on NS-1 antigen and/or IgM antibody positivity. Descriptive analysis was used.Results: Gender was not significantly associated with the outcomes. The duration of fever was significantly higher among those with ICU use (median: 6 versus 4 days; p=0.005), ventilator use (median: 5.5 versus 4.0 days; p=0.049] and blood transfusion (median: 6 versus 4 days; p=0.013). Dengue patients with co-morbidities (diabetes, hypertension, or chronic obstructive pulmonary disease) or co-infection had a significantly higher odds of the outcomes. The platelet level was significantly lower while liver enzymes were significantly higher among those with the outcomes.Conclusions: The clinical features, comorbidities and laboratory profile can help in identifying critical patients for ICU admission and timely intervention to improve outcome

Multiferroicity and magnetoelastic coupling in alpha-Mn2O3: A binary perovskite

Multiferroics where at least two primary ferroic orders are present and coupled in a single system constitute an important class of materials. They attracted special consideration as they present both intriguing fundamental physics problems and technological importance for potential multifunctional devices. Here, we present the evidence of multiferroicity and magnetoelectric (ME) coupling in alpha-Mn2O3; a unique binary perovskite. Corresponding to the antiferromagnetic (AFM) ordering around 80K, a clear frequency independent transition is observed in the dielectric permittivity. We showed that electric polarization emerges near AFM regime that can be modulated with magnetic field. The detailed structural analysis using synchrotron radiation X-ray diffraction demonstrates the increase in structural distortion with decreasing temperature, as well as changes in the unit cell parameters and bond lengths across the ferroelectric and magnetic ordering temperatures. This observation of multiferroicity and magnetoelastic coupling in alpha-Mn2O3 provides insights for the exploration of ME coupling in related materials.Comment: Page 20 and 6 figure

Yoga Intervention as a Potential Countermeasure for Polar T3 Syndrome

Polar T3 syndrome is a common ailment for polar sojourners. It is characterised by abnormal fluctuations of thyroid hormones during extended polar winter. A randomised controlled study was conducted on 14 winter expedition members of Indian Scientific Expedition (2016) to Antarctica by introducing customised yoga module. Blood samples were collected during January to October, 2016 at different intervals for the estimation of total thyroxine (TT4), total triiodothyronine (TT3), thyroid stimulating hormone and noradrenaline (NA) by ELISA. In October yoga group showed significant (p = 0.04) higher TT3 values (2.1 ng/ml ± 0.9; mean ± SD) as compared to the control (0.7 ng/ml ± 0.6). In October a significant difference (p=0.0085) was observed between yoga and control group for NA values (47.0 pg/ml ± 22.0 and 107 pg/ml ± 46.0). Thyroid response of control group at the end of the study revealed presence of polar T3 syndrome in control group. Results indicate that regular yoga practice helped mitigating polar T3 syndrom

Preparation and evaluation of mouth dissolving tablets of meloxicam

The aim of the present study was to develop evaluate mouth dissolving tablet of meloxicam. Drug delivery systems became sophisticated as pharmaceutical scientists acquire a better understanding of the physicochemical and biochemical parameters pertinent to their performance. Over the past three decades, mouth dissolving or orally disintegrating tablets have gained considerable attention as a preferred alternative to conventional tablets due to better patient compliance. The most preferrable route of drug administration (e.g. oral) is limited to drug candidate that show poor permeability across the gastric mucosa and those, which are sparingly soluble. A large majority of the new chemical entities and many new existing drug molecules are poorly soluble, thereby limiting their potential uses and increasing the difficulty of formulating bioavailable drug products,so lastlly the purpose of this study was to grow mouth dissolve tablets of Meloxicam. Meloxicam is a newer selective COX-1 inhibitor. These tablets were prepared by wet granulation procedure. The tablets were evaluated for % friability, wetting time and disintegration time. Sublimation of camphor from tablets resulted in better tablets as compared to the tablets prepared from granules that were exposing to vacuum. The systematic formulation approach helped in understanding the effect of formulation processing variables.Keywords: Mouth dissolving tablet; Maloxicam; Bioavailability; NSAI

Preparation and evaluation of mouth dissolving tablets of meloxicam

The aim of the present study was to develop evaluate mouth dissolving tablet of meloxicam. Drug delivery systems became sophisticated as pharmaceutical scientists acquire a better understanding of the physicochemical and biochemical parameters pertinent to their performance. Over the past three decades, mouth dissolving or orally disintegrating tablets have gained considerable attention as a preferred alternative to conventional tablets due to better patient compliance. The most preferrable route of drug administration (e.g. oral) is limited to drug candidate that show poor permeability across the gastric mucosa and those, which are sparingly soluble. A large majority of the new chemical entities and many new existing drug molecules are poorly soluble, thereby limiting their potential uses and increasing the difficulty of formulating bioavailable drug products,so lastlly the purpose of this study was to grow mouth dissolve tablets of Meloxicam. Meloxicam is a newer selective COX-1 inhibitor. These tablets were prepared by wet granulation procedure. The tablets were evaluated for % friability, wetting time and disintegration time. Sublimation of camphor from tablets resulted in better tablets as compared to the tablets prepared from granules that were exposing to vacuum. The systematic formulation approach helped in understanding the effect of formulation processing variables.Keywords: Mouth dissolving tablet; Maloxicam; Bioavailability; NSAI