Heart Rate Variability: A possible machine learning biomarker for mechanical circulatory device complications and heart recovery

Cardiovascular disease continues to be the number one cause of death in the United States, with heart failure patients expected to increase to \u3e8 million by 2030. Mechanical circulatory support (MCS) devices are now better able to manage acute and chronic heart failure refractory to medical therapy, both as bridge to transplant or as bridge to destination. Despite significant advances in MCS device design and surgical implantation technique, it remains difficult to predict response to device therapy. Heart rate variability (HRV), measuring the variation in time interval between adjacent heartbeats, is an objective device diagnostic regularly recorded by various MCS devices that has been shown to have significant prognostic value for both sudden cardiac death as well as all-cause mortality in congestive heart failure (CHF) patients. Limited studies have examined HRV indices as promising risk factors and predictors of complication and recovery from left ventricular assist device therapy in end-stage CHF patients. If paired with new advances in machine learning utilization in medicine, HRV represents a potential dynamic biomarker for monitoring and predicting patient status as more patients enter the mechanotrope era of MCS devices for destination therapy

ASCE LRFD Method For Stainless Steel Structures

In recent years, probability-based load-and-resistance-factor-design (LRFD) method has been successfully applied to the design of hot-rolled steel sections and cold-formed steel members in the United States and foreign countries. In order to develop the LRFD criteria for the design of cold-formed stainless steel structural members and connections, a research project was conducted at the University of Missouri-Rolla since 1986 under the sponsorship of the American Society of Civil Engineers (ASCE). This newly developed LRFD Specification with Commentary has been adopted by ASCE as a new standard in 1990. It supersedes the 1974 edition of the Specification for the Design of Cold-Formed Stainless Steel Structural Members issued by the American Iron and Steel Institute. The basic theory of probability-based design approach and the development of the ASCE LRFD criteria for cold-formed stainless steel structural members are presented in this paper. © ASCE

Illustrative examples based on the ASCE standard specification for the design of cold-formed stainless steel structural members

PREFACE During the past four years, two methods were developed for the design of stainless steel structural members at the University of Missouri-Rolla with consultation of Professor T. V. Galambos at the University of Minnesota. One of the methods is based on the load and resistance factor design (LRFD) and the other is based on the allowable stress design (ASD). Both design methods are now included in the new ASCE Standard 8-90, Specification for the Design of Cold-Formed Stainless Steel Structural Members. At the September 21, 1990 meeting of the Control Group of the ASCE Stainless Steel Cold-Formed Section Standards Committee held in Washington, D.C., the urgent need for design examples using the new ASCE Standard was discussed at length. The University of Missouri-Rolla was asked to submit a proposal for preparation of such illustrative examples beginning October 1, 1990. During the period from October 1990 through December 1991, a total of 27 illustrative problems have been prepared as included herein. Most of the given data used for these examples are similar to those used in the 1986 edition of the AISI Cold-Formed Steel Manual except that for each problem, two examples are illustrated by using LRFD and ASD methods. The research work reported herein was conducted in the department of Civil Engineering at the University of Missouri-Rolla with the consulting work provided by Dr. Shin-Hua Lin and Professor T. V. Galambos. The financial assistance provided by the Nickel Development Institute and the Chromium Centre is gratefully acknowledged. Appreciation is also expressed to Dr. W. K. Armitage, Mr. J. P. Schade, Professor P. Van der Merwe and Professor G. J. Van den Berg for their technical review and suggested revisions

Load and resistance factor design of cold-formed stainless steel statistical analysis of material properties and development of the LRFD provisions

INTRODUCTION 1.1 General Remarks The Allowable Stress Design method has long been used for the design of steel structures in the United States. 1,2,3 Recently, the probability-based load and resistance factor design (LRFD) criteria have been successfully applied to the structural design of hot-rolled steel shapes and built-up members. 4,5,6 The AISI LRFD Specification is being developed as well for the design of structural members cold-formed from carbon and low alloy steels. 7-17 These design criteria can provide a more uniform degree of structural safety to achieve consistent reliability for different design situations. The probability-based design method is developed on the basis of the Limit States Design philosophy, 18-22 which is related to the ultimate strength and serviceability of the structural members and connections. In the United States, research work on probability-based design has focused primarily on the ultimate strength limit states because such limit states are clearly defined. In order to update the 1974 edition of the AISI Specification and to develop the new LRFD Specification for cold-formed stainless steel structural members. a research project entitled Load and Resistance Factor Design of Cold-Formed Stainless Steel was initiated in July 1986 at the University of Missouri-Rolla under the sponsorship of the American Society of Civil Engineers (ASCE). This study was conducted by Shin-Hua Lin under the direction of Dr. Wei-Wen Yu. Dr. Theodore V. Galambos of the University of Minnesota is the ASCE consultant for the project. The first phase of this study dealt with the revision of the 1974 edition of the AISI allowable stress design specification 3 for cold-formed stainless steel structural members and its commentary. Based on the reevaluation of previous test results obtained from the research projects conducted at Cornell University 23-27 and the current AISI specifications for the design of cold-formed stainless steel and carbon steel structural members, 2,3 a draft of the Proposed Allowable Stress Design Specification with Commentary has been prepared and published in the Third Progress Report. 30 This proposed ASCE Specification includes four types of austenitic stainless steels (annealed, 1/16-, 1/4-, and 1/2-Hard Types 201, 301, 304, and 316) and three types of ferritic stainless steels (annealed Types 409, 430, and 439). Following a careful review by the ASCE Steering Committee at its meeting held at the University of Missouri-Rolla on April 21, 1988, it was recommended that the proposed ASD Specification included in the Third Progress Report be submitted to the new ASCE Standard Committee for consideration. The second phase of this project is to develop the new LRFD criteria for cold-formed stainless steel structural members. These criteria are to be developed on the basis of the first-order probabilistic theory by using only the mean values and coefficients of variation of load effects, material factors, fabrication factors, and profess ional factors. The development of load and resistance factor design criteria for cold-formed stainless steel structural members is being carried out at the University of Missouri-Rolla. The initial work included statistical analyses of mechanical properties and material thicknesses together with the calibrations of the proposed LRFD provisions by using the available test data

Design of cold-formed stainless steel structural members proposed allowable stress design specification with commentary

INTRODUCTION This progress report on the design of cold-formed stainless steel structural members contains the following two parts: Part I: Proposed Specification for the Design of Cold-Formed Stainless Steel Structural Members (Third Draft). Part II: Commentary on the Proposed Specification for the Design of Cold-Formed Stainless Steel Structural Members (Second Draft). This project was sponsored by the American Society of Civil Engineers. The financial assistance provided by the Chromium Center, the Nickel Development Institute, and the Specialty Steel Industry of the United States is gratefully acknowledged. Special thanks are extended to members of the ASCE Steering Committee (Dr. Ivan M. Viest, Mr. Don S. Wolford, and Mr. John P. Ziemianski), Mr. Edwin Jones of the American Society of Civil Engineers, Dr. W. K. Armitage of the Chromium Center, and Mr. Johannes P. Schade of the Nickel Development Institute for their technical guidance. Appreciation is also expressed to Mr. Ziemianski and Professor van der Merwe for providing the technical information on Types 409, 430, and 439

Distributions.jl: Definition and Modeling of Probability Distributions in the JuliaStats Ecosystem

Random variables and their distributions are a central part in many areas of statistical methods. The Distributions.jl package provides Julia users and developers tools for working with probability distributions, leveraging Julia features for their intuitive and flexible manipulation, while remaining highly efficient through zero-cost abstractions

On the Concept of Similiarity in the Theory of Isotropic Turbulence

Much recent work has been done in the study of isotropic turbulence, particularly from the point of view of its spectrum. But the underlying concept is still the assumption of the similarity of the spectrum during the process of decay, which is equivalent to the idea of self-preservation of the correlation functions introduced by the senior author. It is however generally recognized that the correlation function does change its shape during the process of decay, and hence the concept of self-preservation or similarity must be interpreted with suitable restrictions. Under the limitation to low Reynolds numbers of turbulence, the original idea of Kármán-Howarth has been confirmed. Then the decay consists essentially of viscous dissipation of energy separately in each individual frequency interval. However, when turbulent diffusion of energy, i.e., transfer of energy between frequency intervals, occurs at a significant rate, the interpretation of the decay process and the spectral distribution is quite varied. This an be seen by a comparison of Heisenberg, Batchelor, Frenkiel, and the present authors. The purpose of the present paper is an attempt to clarify this situation

Cracking in hydrogen ion-implanted Si/Si0.8Ge0.2/Si heterostructures

We demonstrate that a controllable cracking can be realized in Si with a buried strain layer when hydrogen is introduced using traditional H-ion implantation techniques. However, H stimulated cracking is dependent on H projected ranges; cracking occurs along a Si0.8Ge0.2 strain layer only if the H projected range is shallower than the depth of the strained layer. The absence of cracking for H ranges deeper than the strain layer is attributed to ion-irradiation induced strain relaxation, which is confirmed by Rutherford-backscattering-spectrometry channeling angular scans. The study reveals the importance of strain in initializing continuous cracking with extremely low H concentrations

Reduced expression of alpha-1,2-mannosidase I extends lifespan in Drosophila melanogaster and Caenorhabditis elegans

Exposure to sub-lethal levels of stress, or hormesis, was a means to induce longevity. By screening for mutations that enhance resistance to multiple stresses, we identified multiple alleles of alpha-1,2-mannosidase I (mas1) which, in addition to promoting stress resistance, also extended longevity. Longevity enhancement is also observed when mas1 expression is reduced via RNA interference in both Drosophila melanogaster and Caenorhabditis elegans. The screen also identified Edem1 (Edm1), a gene downstream of mas1, as a modulator of lifespan. As double mutants for both mas1 and Edm1 showed no additional longevity enhancement, it appeared that both mutations function within a common pathway to extend lifespan. Molecular analysis of these mutants revealed that the expression of BiP, a putative biomarker of dietary restriction (DR), is down-regulated in response to reductions in mas1 expression. These findings suggested that mutations in mas1 may extend longevity by modulating DR