Precise Null Pointer Analysis Through Global Value Numbering

Precise analysis of pointer information plays an important role in many static analysis techniques and tools today. The precision, however, must be balanced against the scalability of the analysis. This paper focusses on improving the precision of standard context and flow insensitive alias analysis algorithms at a low scalability cost. In particular, we present a semantics-preserving program transformation that drastically improves the precision of existing analyses when deciding if a pointer can alias NULL. Our program transformation is based on Global Value Numbering, a scheme inspired from compiler optimizations literature. It allows even a flow-insensitive analysis to make use of branch conditions such as checking if a pointer is NULL and gain precision. We perform experiments on real-world code to measure the overhead in performing the transformation and the improvement in the precision of the analysis. We show that the precision improves from 86.56% to 98.05%, while the overhead is insignificant.Comment: 17 pages, 1 section in Appendi

Effect of okra plant resistance on transmission rate of okra enation leaf curl virus by its vector whitefly, Bemisia tabaci

The present study aimed to investigate the effect of age of the okra plants that showed varying whitefly resistance responses on the transmission rate of okra enation leaf curl virus (OELCV) by its vector whitefly Bemisia tabaci. The OELCV infected whitefly adults were collected from whitefly colonies and were challenged on the test okra accessions (Upl mona 2, Co 1, Arka anamika and AE 64) of differential ages which were individually caged (7, 10 and 15 d after germination) with glass chimney and the number of such whiteflies used were at the rate of 2, 4, 6, 8, 10, 12, 14 and 20 adults per plant. Observations were made on the virus symptom expression 30 d after challenge. The efficiency of transmission was determined. The efficiency of transmission of OELCV was the highest (maximum T and P*, 0.80, 1.00 and 0.08, 0.10) when 7 d old seedlings were inoculated (Arka anamika and AE 64 respectively) and transmission had decreased as the age of seedlings increased. The estimated transmission rate for single whitefly (P*) increased with an increase in the number of whiteflies used per plant. Okra plant resistance to B. tabaci significantly changed the transmission rates of OELCV on okra. Understanding the resistance mechanisms of the okra accessions and interactions between plant viruses and their insect host can pave the way for novel approaches to protect plants from virus infection

Faster Algorithms for Weighted Recursive State Machines

Pushdown systems (PDSs) and recursive state machines (RSMs), which are linearly equivalent, are standard models for interprocedural analysis. Yet RSMs are more convenient as they (a) explicitly model function calls and returns, and (b) specify many natural parameters for algorithmic analysis, e.g., the number of entries and exits. We consider a general framework where RSM transitions are labeled from a semiring and path properties are algebraic with semiring operations, which can model, e.g., interprocedural reachability and dataflow analysis problems. Our main contributions are new algorithms for several fundamental problems. As compared to a direct translation of RSMs to PDSs and the best-known existing bounds of PDSs, our analysis algorithm improves the complexity for finite-height semirings (that subsumes reachability and standard dataflow properties). We further consider the problem of extracting distance values from the representation structures computed by our algorithm, and give efficient algorithms that distinguish the complexity of a one-time preprocessing from the complexity of each individual query. Another advantage of our algorithm is that our improvements carry over to the concurrent setting, where we improve the best-known complexity for the context-bounded analysis of concurrent RSMs. Finally, we provide a prototype implementation that gives a significant speed-up on several benchmarks from the SLAM/SDV project

Rapid production of therapeutic proteins using plant system

Plant molecular farming is simply defined as the production of proteins therapeutics (PT) in plants, which involves transient gene expression in plants and purification of expressed protein to a great scale for diagnosis, treatment and other applications.  This is therapid,economical, safe and reproducible approach for the production of PTas compared to bacterial and mammalian systems. Protein yield and post-translational modifications are the major roadblocks that can be overcome byhigh expression strategies includes over expression constructs, suitable plant host systems and glycoengineering of proteins. The inherent ability of ideally producing safe, functional protein is the most striking phenomenon recognized by the pharmaceutical industries and developed many therapeutic products within few weeks to meet escalating demands during pandemic/epidemic outbreaks recentl

Safety verification of asynchronous pushdown systems with shaped stacks

In this paper, we study the program-point reachability problem of concurrent pushdown systems that communicate via unbounded and unordered message buffers. Our goal is to relax the common restriction that messages can only be retrieved by a pushdown process when its stack is empty. We use the notion of partially commutative context-free grammars to describe a new class of asynchronously communicating pushdown systems with a mild shape constraint on the stacks for which the program-point coverability problem remains decidable. Stacks that fit the shape constraint may reach arbitrary heights; further a process may execute any communication action (be it process creation, message send or retrieval) whether or not its stack is empty. This class extends previous computational models studied in the context of asynchronous programs, and enables the safety verification of a large class of message passing programs

Accuracy of Femoral Tunnel Placement between Anteromedial and Anterolateral Visualisation Portals in Anterior Cruciate Ligament Reconstruction - Outcomes of a CT based Cross-Sectional Study

Introduction: Anatomical femoral tunnel placement is critical for anterior cruciate ligament reconstruction (ACLR). Tunnel placement may vary with different surgical techniques. The aim of this study was to compare the accuracy of femoral tunnel placement between the Anteromedial (AM) and Anterolateral (AL) visualisation portals on post-operative CT scans among a cohort of ACLR patients. Materials and methods: This cross-sectional study was conducted from January 2018 to March 2020 after obtaining ethics clearance. Patients who went for arthroscopic ACLR in our institute were divided into an AM (group 1) and an AL (group 2) based on the visualisation portal for creating the femoral tunnel and a 3D CT scan was done. The femoral tunnel position was calculated in deep to shallow and high to low direction using the Bernard Hertel grid. Femoral tunnel angle was measured in the 2D coronal image. Statistical analysis was done with the data collected. Results: Fifty patients with an average age of 26.36 (18-55) years ±7.216 SD were enrolled in the study. In this study, the AM technique was significantly more accurate (p<0.01) than the AL technique in terms of femoral tunnel angle. Furthermore, the deep to the shallow position was significantly (p= 0.018) closer to normative values, as determined by the chi-square test. The chances of error in tunnel angle in femoral condyle are 2.6 times greater in the AL technique (minimal clinical difference). Conclusion: To conclude, in ACLR the anteromedial visualisation portal can facilitate accurate femoral tunnel placement compared to the anterolateral visualisation portal

Investigation on topology-optimized compressor piston by metal additive manufacturing technique: Analytical and numeric computational modeling using finite element analysis in ANSYS

Air compressors are widely used in factories to power automation systems and store energy. Several studies have been conducted on the performance of reciprocating and screw compressors. Advancements in design and manufacturing techniques, such as generative design and topology optimization, are leading to improved performance and turbomachinery growth. This work presents a methodology to design and manufacture air compressor pistons using topology optimization and metal additive manufacturing. The existing piston is converted to 3D CAD data and topology optimization is conducted to reduce material in stress concentration regions. Thermal and mechanical loads are considered in boundary conditions. The results show reduced material and improved efficiency, which is validated using ANSYS fluent. The optimized 3D model of the piston is too complex for conventional subtractive manufacturing, so laser sintering 3D printing is proposed. Honeycomb pattern infill patterns are used in 3D printing. This investigation is a step toward researching similar methods in other reciprocating compressor components such as cylinder, cylinder head, piston pins, crankshaft, and connecting rods, which will ultimately lead to improved compressor efficiency. © 2023 the author(s), published by De Gruyter.Khon Kaen University, KKU: R.G.P.1/349/43; Deanship of Scientific Research, King Khalid UniversityFunding information: This research was funded by the Deanship of Scientific Research at King Khalid University (KKU) through the Research Group Program Under the Grant Number: (R.G.P.1/349/43).The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University (KKU) for funding this research through the Research Group Program Under the Grant Number: (R.G.P.1/349/43)

Distinct Levels of Sox9 Expression Mark Colon Epithelial Stem Cells that Form Colonoids in Culture

Sox9 is an high-mobility group box transcription factor that is expressed in the stem cell zone of the small intestine and colon. We have previously used a Sox9EGFP mouse model to demonstrate that discrete levels of Sox9 expression mark small intestine epithelial stem cells that form crypt/villus-like structures in a three-dimensional culture system (Formeister EJ, Sionas AL, Lorance DK, Barkley CL, Lee GH, Magness ST. Am J Physiol Gastrointest Liver Physiol 296: G1108–G1118, 2009; Gracz AD, Ramalingam S, Magness ST. Am J Physiol Gastrointest Liver Physiol 298: G590–G600, 2010). In the present study, we hypothesized that discrete levels of Sox9 expression would also mark colonic epithelial stem cells (CESCs). Using the Sox9EGFP mouse model, we show that lower levels of Sox9 mark cells in the transit-amplifying progenitor cell zone, while higher levels of Sox9 mark cells in the colonic crypt base. Furthermore, we demonstrate that variable SOX9 levels persist in cells of colonic adenomas from mice and humans. Cells expressing lower Sox9 levels demonstrate gene expression profiles consistent with more differentiated populations, and cells expressing higher Sox9 levels are consistent with less differentiated populations. When placed in culture, cells expressing the highest levels of Sox9 formed “colonoids,” which are defined as bodies of cultured colonic epithelial cells that possess multiple cryptlike structures and a pseudolumen. Cells expressing the highest levels of Sox9 also demonstrate multipotency and self-renewal in vitro, indicating functional stemness. These data suggest a dose-dependent role for Sox9 in normal CESCs and cells comprising colon tumors. Furthermore, distinct Sox9 levels represent a new biomarker to study CESC and progenitor biology in physiological and disease states