A new preparation technology of structural- gradient materials without a brittle transition zone in a Mn-Si-Cr-B bainitic cast steel

In the present work, a unique gradient cooling heat treatment process(GCHT) for a Mn-Si-Cr-B bainitic cast steel was developed, and microstructure and mechanical properties were examined by OM, SEM, EBSD and a uniaxial tensile test. The results showed that the structural-gradient-material(SGM) with a gradient microstructure from granular bainite to martensite was successfully produced, and it exhibited a good ductility(~13.8%) at one end and an excellent ultimate strength(~1,720 MPa) at the other end. In between the bainite and martensite, a transition region with a superior combination of tensile strength and ductility(1,700 MPa and 11.1%) was obtained, which is different from the normal knowledge of a brittle transition region. Moreover, through changing the gradient of cooling rate, the optimized SGM with a new gradient microstructure from pearlite to martensite showed a more stable structural gradient and an improved ductility(22.8%) at one end. The microstructure variation in the sample was mainly related to the carbon diffusion rate during heat treatment, and the diffusion rate could be controlled by regulating the cooling velocity. Therefore, the SGMs with different gradient microstructures could be designed to meet the needs of different properties. As a result, this work provides a new approach for preparation of the gradient structured steel, which has potential for practical application for dual-property automobile parts.

Protective effect of sevoflurane on lung function of elderly chronic obstructive pulmonary disease patients undergoing total hip arthroplasty

BACKGROUND Chronic obstructive pulmonary disease(COPD)is a common respiratory disorder that affects the elderly population and increases the risk of postoperative pulmonary complications(PPCs)after major surgeries.Sevoflurane is a volatile anesthetic that has been shown to have anti-inflammatory and antioxidant properties and attenuate lung injury in animal models.AIM To evaluate the protective effect of sevoflurane on the lung function of elderly COPD patients undergoing total hip arthroplasty(THA).METHODS In this randomized controlled trial,we randomly assigned 120 elderly patients with COPD,who were scheduled for THA,to receive either sevoflurane(sevoflurane group)or propofol(propofol group)as the maintenance anesthetic.The primary outcome was the incidence of PPCs within seven days after surgery.The secondary outcomes were changes in the lung function parameters,inflammatory markers,oxidative stress markers,and postoperative pain scores.RESULTS The results showed that the incidence of PPCs was significantly lower in the sevoflurane group than in the propofol group(10%vs 25%,P=0.02).Furthermore,the decline in the forced expiratory volume in 1 s,forced vital capacity,and peak expiratory flow was significantly lesser in the sevoflurane group than in the propofol group at 24 h and 48 h after surgery(P<0.05).The interleukin-6,tumor necrosis factor-alpha,malondialdehyde,and 8-hydroxy-2α-deoxyguanosine levels were significantly lower in the sevoflurane group than in the propofol group at 24 h after surgery(P<0.05).The sevoflurane group showed significantly lower postoperative pain scores than the propofol group at 6 h,12 h,and 24 h after surgery(P<0.05).CONCLUSION Sevoflurane protects the lung function of elderly COPD patients undergoing THA under general anesthesia by reducing the incidence of PPCs,attenuating inflammatory and oxidative stress responses,and alleviating postoperative pain.

Skyway:Accelerate Graph Applications with a Dual-Path Architecture and Fine-Grained Data Management

Graph processing is a vital component of many AI and big data applications.However,due to its poor locality and complex data access patterns,graph processing is also a known performance killer of AI and big data applications.In this work,we propose to enhance graph processing applications by leveraging fine-grained memory access patterns with a dual-path architecture on top of existing software-based graph optimizations.We first identify that memory accesses to the offset,edge,and state array have distinct locality and impact on performance.We then introduce the Skyway architecture,which consists of two primary components:1)a dedicated direct data path between the core and memory to transfer state array elements efficiently,and 2)a data-type aware fine-grained memory-side row buffer hardware for both the newly designed direct data path and the regular memory hierarchy data path.The proposed Skyway architecture is able to improve the overall performance by reducing the memory access interference and improving data access efficiency with a minimal overhead.We evaluate Skyway on a set of diverse algorithms using large real-world graphs.On a simulated fourcore system,Skyway improves the performance by 23%on average over the best-performing graph-specialized hardware optimizations.

Notes,outline and divergence times of Basidiomycota

The Basidiomycota constitutes a major phylum of the kingdom Fungi and is second in species numbers to the Ascomycota.The present work provides an overview of all validly published,currently used basidiomycete genera to date in a single document.An outline of all genera of Basidiomycota is provided,which includes 1928 currently used genera names,with 1263 synonyms,which are distributed in 241 families,68 orders,18 classes and four subphyla.We provide brief notes for each accepted genus including information on classification,number of accepted species,type species,life mode,habitat,distribution,and sequence information.Furthermore,three phylogenetic analyses with combined LSU,SSU,5.8s,rpb1,rpb2,and ef1 datasets for the subphyla Agaricomycotina,Pucciniomycotina and Ustilaginomycotina are conducted,respectively.Divergence time estimates are provided to the family level with 632 species from 62 orders,168 families and 605 genera.Our study indicates that the divergence times of the subphyla in Basidiomycota are 406-430 Mya,classes are 211-383 Mya,and orders are 99-323 Mya,which are largely consistent with previous studies.In this study,all phylogenetically supported families were dated,with the families of Agaricomycotina diverging from 27-178 Mya,Pucciniomycotina from 85-222 Mya,and Ustilaginomycotina from 79-177 Mya.Divergence times as additional criterion in ranking provide additional evidence to resolve taxonomic problems in the Basidiomycota taxonomic system,and also provide a better understanding of their phylogeny and evolution.

Unit Test Data Generation for C Using Rule-Directed Symbolic Execution

Unit testing is widely used in software development. One important activity in unit testing is automatic test data generation. Constraint-based test data generation is a technique for automatic generation of test data, which uses symbolic execution to generate constraints. Unit testing only tests functions instead of the whole program, where individual functions typically have preconditions imposed on their inputs. Conventional symbolic execution cannot detect these preconditions, let alone converting these preconditions into constraints. To overcome these limitations, we propose a novel unit test data generation approach using rule-directed symbolic execution for dealing with functions with missing input preconditions. Rule-directed symbolic execution uses predefined rules to detect preconditions in the individual function, and generates constraints for inputs based on preconditions. We introduce implicit constraints to represent preconditions, and unify implicit constraints and program constraints into integrated constraints. Test data generated based on integrated constraints can explore previously unreachable code and help developers find more functional faults and logical faults. We have implemented our approach in a tool called CTS-IC, and applied it to real-world projects. The experimental results show that rule-directed symbolic execution can find preconditions (implicit constraints) automatically from an individual function. Moreover, the unit test data generated by our approach achieves higher coverage than similar tools and efficiently mitigates missing input preconditions problems in unit testing for individual functions.

Automated String Constraints Solving for Programs Containing String Manipulation Functions

The ability to solve various constraints is a principal factor of automatic constraint solvers. Most object-oriented languages treat a character string as a primitive data type which is manipulated by string library functions. Most constraint solvers have limitations on their input constraints, such as strong restrictions on the expressiveness of constraints or lack of the ability to solve hybrid constraints. These limitations hinder applying automated constraint solvers on program analysis techniques for programs containing strings and string manipulation functions. We propose an approach to automatically solve program constraints involving strings and string manipulation functions. Based on the character array model, we design a constraint language which contains primitive operations to precisely describe the constraints of commonly used string manipulation functions. The translated string constraints together with numeric constraints are then solved by a two- phase test generation procedure： firstly, a partial solution is obtained to satisfy the arithmetic constraints of the position variables, and the solution is utilized to simplify the string constraints into pure character array constraints; secondly, the pure array constraints are solved by an off-the-shelf array-specific theory based constraint solver. We integrate the approach into an automated testing tool to support the generation of string test cases, and then perform experiments. The results of the experiments prove that the integration of the proposed approach promotes the testing coverage of the existing testing tool, and the integrated tool has an advantage of handling specific string manipulation functions compared with an existing string solver.

An integrated supramolecular fungicide nanoplatform based on pH-sensitive metal–organic frameworks

The construction of an integrated nanoplatform with controlled fungicide delivery features in the specific microenvironment produced by fungal pathogens is a highly desirable strategy to improve the utilization of fungicides. Herein, we report a supramolecular fungicide delivery system based on benzimidazolemodified NH_(2)-MIL-101(Fe) metal–organic frameworks(B-MIL-101(Fe) MOFs) as carriers loaded with osthole(OS), and β-cyclodextrin(β-CD) as nanovalves to form β-CD@B-MIL-101(Fe)-OS. The nanoplatform can release the loaded OS for fungus control through self-degradation of the MOFs skeleton in an oxalic acid microenvironment produced by Botrytis cinerea. The experimental results exhibit that the constructed supramolecular fungicide delivery system could effectively inhibit mycelial growth and protect the tomatoes from infection by B. cinerea during the ripening stage. This strategy constructs a facile and integrated supramolecular drug delivery system for B. cinerea control and opens up a new avenue for the sustainable development of modern agriculture.