bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of Ideal Mild Steel Weld Properties Using the Simple Additive Weighting (SAW) Method
Authors: Nweze S. , Achebo J.
Published: February 2021

Weld deformation which directly contributes to failures of welded components, has been a real time challenge in the manufacturing industry. To resolve this challenges, subtle manipulation of input process parameters is recommended by Researchers. This manipulation of input process parameters is done through the application of optimization methods hence this study.

In this study, the Simple Additive Weighting (SAW) method was used. This method was categorized into four groups, which are namely, linear scale transformation-Max method; linear scale transformation-Sum method; Vector normalization method and linear scale transformation-Max Min method. Each of these SAW methods was used to optimize the output parameters, which were classified as maximum criteria. It was noticed from the analysis, that the higher the values of the mechanical properties, the better the weldquality obtained and from using the linear scale transformation maximum method, weldment 7 was found to possess the best mechanical properties with ultimate tensile strength (UTS) of 395MPa, Impact energy (CVN) of 250J, Bead Height(BH) of 1.98 mm and Bead Width (BW) of4.82mmwas found to possess the best input and output parameters.
Basic Aerosol Science
Authors: Reist Parker C. , Zhu Yifang
Published: February 2021

An aerosol is a two‐phase system, consisting of particles and the gas in which they are suspended. Since airborne particles have been linked to various adverse health effects, it is essential to understand the behavior and properties of the aerosol. Health effects caused by aerosols depend on particle size and size distribution as well as on the composition of the particles. Other aerosol behavior including light scattering and coagulation can also vary markedly with particle size. This chapter focuses on various properties of the aerosol particles which influence their behavior, such as Stokes law, Reynolds number, Cunningham correction factor, particle motion, isokinetic sampling, electrical properties, and optical properties.
Heat Stress
Authors: Larrañaga Michael D.
Published: February 2021

Heat stress is known as the aggregate of external heat from the environment, internal heat generated by the human body through physical activity and metabolism, and the insulating effects of the clothing worn, which collectively impose a thermal load on a person. Heat strain is the human response to heat stress. This chapter presents an in‐depth review of the development and current status of heat stress standards and guidelines; the physiology of human thermal exchange with the environment; the measurement and interpretation of the thermal environment; and the assessment of heat stress and heat strain; and the application of controls for the prevention of heat stress and heat strain.
Occupational Microbiological Biohazards – Exposure, Detection, and Disease
Authors: Reponen Tiina
Published: February 2021

In this book chapter, sources and characteristics of airborne microbiological contaminants including, bacteria, viruses, and fungi, are discussed in relation to their detection and health effects associated with personal exposure in the occupational environment. The impacts of microorganisms including protists and protozoans and other botanically sourced bioaerosols such as pollen are not reviewed in this book chapter. The potential exposures to microbial bioaerosols and the aerodynamic behavior of these contaminants are reviewed as well as their respiratory and dermal health effects. Direct and indirect sampling methods are presented along with methods of analysis. Methods to prevent personal exposure are also provided.
Control of Biohazards
Authors: Burton Nancy C.
Published: February 2021

This chapter describes methods and guidelines for controlling biohazards at workplaces. The term biosafety describes a complete program of administrative controls, medical surveillance, vaccination (when available), and containment strategies for reducing the risk of disease among laboratory workers and other persons with potential exposure to biohazards.
Respiratory Protective Equipment
Authors: Colton Craig E.
Published: February 2021

Respirators have been used for almost 2000 years, and the genesis of their technical development is actually the mid‐nineteenth century. The Bureau of Mines in 1919 initiated the first respirator certification program based in the United States and certified their first respirator based on laboratory testing. In 1995, NIOSH promulgated new certification regulations. This chapter notes that respiratory protective equipment (RPE) should be used only when all higher priority control steps are not technically or financially feasible. Thus, RPE continues to be an important component in many respiratory exposure control plans. This chapter also addresses the performance of RPE and its evaluation in the laboratory and the more recent reliance on testing in the workplace. A respirator program ensures that the RPE selected can provide adequate protection under the conditions of intended use by implementing a respiratory protection program.
The History and Biological Basis of Occupational Exposure Limits for Chemical Agents
Authors: Paustenbach Dennis J. , Cyrs William D.
Published: February 2021

The history and biological basis for setting occupational exposure limits (OELs) for chemical agents are presented in this chapter. Baetjer reported that the first list of standards for chemical exposures in industry was the United States, known as maximum allowable concentrations (MAC), and that they were prepared in 1939 and 1940. Since then, more than 1000 occupational exposure limits (OELs) have been set for different chemicals in the United States and nearly 5000 limits are available in more than 10 countries. A considerable amount of information about the early history of OELs is presented here and about 300 different references are provided. The methods for setting limits based on the primary toxic effect are discussed (e.g. neurotoxicants, irritants, sensitizers, carcinogens, etc.). The topic of uncertainty factors received considerable attention given its importance to risk assessment. Methods for adjusting OELs for unusual work shifts are offered. The limitations inherent in various OELs are addressed in some detail. Modern approaches for incorporating additional insight into these factors are discussed. There is a brief discussion about the differences in OELs among different countries. The author's views about the future of OELs are provided.
Biological Monitoring of Exposure to Industrial Chemicals
Authors: Hopf Nancy B. , Fustinoni Silvia
Published: February 2021

Human biological monitoring is a powerful tool for scientists, policy makers, and occupational health‐care professionals, such as physicians and occupational hygienists, to assess and manage health risks associated with chemical exposures among the general population as well as at the workplace. This chapter will focus on using biological monitoring in occupational exposure assessments. It includes biological monitoring sampling strategies and practical approaches. Relevant biomarkers used in biomonitoring are derived based on fundamental understanding of absorption, distribution, metabolism, and excretion (ADME) of chemicals. Therefore, ADME will be discussed along with toxicokinetics and toxicodynamics. Individual susceptibility is a topic associated with biological monitoring as opposed to air monitoring. Monitoring variability associated with air and biological monitoring is compared. The biomonitoring strategy choice is dependent on the purpose, selected biomarker, matrix (urine, blood, saliva, hair, exhaled breath, exhaled breath condensate), sampling time, which is determined based on the selected biomarkers apparent elimination half‐life, and variability but also on the purpose of the biomonitoring program. Biological limit values are established on available scientific data. Their historic development and concepts are country specific. Biomonitoring of metals and inorganic compounds as well as organic compounds are extensively covered. Emerging biomarker fields as well as new chemical analytical methods are briefly discussed. Future trends in human biological monitoring are discussed as it is a current topic in public health policies, in occupational and environmental health and in science in general.
Characterizing Air Contaminant Emission Sources
Authors: Burton D. Jeff , Harris Robert L. , Arp Earl W.
Published: February 2021

All worker over‐exposures to air contaminants result from poorly controlled emissions of the contaminants into the work environment. The chapter focuses mainly on the emission inventory and how to implement cost‐effective emission and exposure controls. The role of industrial hygiene is also addressed in identifying and characterizing emission sources, which contribute to exposure.
Airborne and Emerging Infectious Diseases
Authors: Chiang Augusto Dulanto , Palmore Tara N.
Published: February 2021

Airborne transmission of infections pathogens can occur in a wide range of occupational settings. Tuberculosis is a particular concern for personnel in health care and allied fields. The risk from exposure to infectious aerosols or droplet nuclei depends in part on characteristics of the source, the pathogen, and the aerosol droplets, as well as host susceptibility. The movement of infectious droplets is determined by their size and the flow of air. Many pathogens that are not classically airborne can be transmitted via aerosols under certain circumstances. Special consideration should be given to workers with immune impairment, who may be at higher risk of infection. Emerging pathogens that are not airborne but have had recent and significant public health consequences are also discussed.
Emergency and Disaster: Preparedness, Response, and Recovery
Authors: Laszcz‐Davis Chris , Massey Mary , Leibowitz Alan J. , Hardt Daniel , Woessner Herman , Jabara Jim , Lebourgeois Fabrice , Villarreal Vicki , McHaney Ron R. , Otum Peggy , Barnes David , Pereira Steven P.
Published: February 2021

Emergency and disaster: preparedness, response, and recovery is an ongoing process of planning for and responding effectively to the occurrence of an event (planned or unplanned), as well as addressing the issue of recovery and restoration of operations and lives following an event. This chapter reflects a new paradigm which is being approached through increased awareness, preventive measures, and robust preparedness.

Emergency planning and disaster preparedness is not a new concept or philosophy. The inherent dangers and complex threats following the 11 September 2001 New York Twin Towers event, international wars, and dissemination of biological insults globally have raised the public's awareness level and need for quick response and recovery, dictating a new paradigm for incident management. The new paradigm for incident management is not designed to deal with only specific types of contingencies but is anchored by a National Incident Management System (NIMS), part of the National Response Framework (NRF), emphasizing unity of effort among all levels of government, flexible enough to accommodate “all hazards” and covering all disciplines required for conducting activities throughout the “full cycle” of an incident. Under this Framework, Federal, State, and local governments, along with private organizations and the American public, work as partners to manage domestic contingencies effectively and efficiently.
Health Care Industry: Contemporary Considerations
Authors: Emery Robert J. , Charlton Michael A. , Brown Bruce J. , Patlovich Scott J.
Published: February 2021

Individuals seek health care to preserve or improve their health status, so there may be the presumption that the health care workplace is inherently safe and relatively free from possible hazards. But intertwined with the provision of modern medical care is possible exposures to a wide variety of potentially hazardous conditions and agents. Industrial hygienists providing services to this unique work environment must develop a thorough understanding of the variety of risks present to effectively anticipate, recognize, evaluate, and control the hazards. The types of hazards possibly present in the typical health care work setting (whether in‐patient, out‐patient, or home delivery) are discussed along with suggested concurrent prudent control measures, all within the context of providing quality health care for patients, while protecting workers.
Fire Safety in the Workplace
Authors: Custer, Richard L.P. , Powell Pamela A.
Published: February 2021

The present study provides an overview of the terminology and concepts of fire safety with emphasis on the workplace setting. Various issues, such as fire protection codes, standards, and regulations, fire safety fundamentals, features of building construction related to fire protection, and employee response to emergencies have been examined. The topic of fire safety concerns of lithium‐ion batteries is introduced.
Ethics in Industrial Hygiene
Authors: Townsend Nina , Brown Garrett , Katchen Mark
Published: February 2021

Industrial hygienists have a moral responsibility, and, if certified or a member of an OHS professional organization, a professional obligation to act and perform their work in an ethical manner. According to ethicist Rushworth Kidder, the single largest problem in ethics is the inability to recognize ethical issues. Ethical challenges for individual industrial hygienists and the companies that employ them grew substantially with the development of the global economy starting in the 1990s. The growth of corporate social responsibility has not improved working conditions around the world; however, a handful of examples of worker‐driven social responsibility show potential. A code of ethics provides for a common understanding and minimum expectations. A professional code of ethics also provides evidence to those outside of the organization or discipline of the members' value and repute. The American Board of Industrial Hygiene code is enforceable among CIH candidates and diplomats. American Industrial Hygiene Association (AIHA) has a Code of Conduct, AIHA and the American Conference of Governmental Industrial Hygienists have joint ethical principles and the International Commission on Occupational Health has the more comprehensive International Code of Ethics for Occupational Health Professionals. Case studies provide an opportunity to work through common and complex ethical issues faced by industrial hygienists.
Industrial Hygiene Issues in Construction
Authors: Lippy Bruce , West Gavin H. , Gillen Matthew , Betit Eileen , Goldenhar Linda M. , Memarian Babak , Rinehart Richard , Barlet Grace , Fletcher M.K. , Brooks Sara , Le Jean Christophe
Published: February 2021

Construction is unique. Unlike other sectors, construction workplaces regularly involve multiple employers with a mix of trades that changes over the life of a project. Construction firms are predominantly small with the overwhelming number having less than 20 employees. Smaller contractors incur a disproportionate percentage of injuries and fatalities, which has led to construction consistently having the highest number of deaths of any sector. Most fatal construction injuries are caused by falls to a lower level, being struck by an object or a vehicle, contact with electric current, or being caught‐in or between objects or equipment. Health hazards are not given the prominence of safety hazards in construction because their effects may not be felt for decades and their causes may be unclear. Safety hazards are easier to identify. Seven percent of all OSHA construction inspections are for health hazards. Industrial hygienists should focus on task‐based personal monitoring, rather than time‐weighted averages, to better protect construction workers. Episodic exposures are more common in construction and can be quite elevated. Bystander exposures from nearby trades must also be considered as part of any hazard assessment. Dermal exposures are significant in construction because of the widespread use of cement, adhesive, solvents, abrasive cleaners, spray insulation, and paints. Engineering controls like local exhaust ventilation and wet methods can clearly reduce exposures to construction workers, if made available and maintained. New technological advances, like drones and nanomaterials, are appearing in construction. Industrial hygienists will be instrumental in navigating the benefits and risks of these technologies.
Decision Making in Managing Risk
Authors: Redinger Charles F. , Boelter Fred W. , O'Reilly Mary V. , Howard John , Barbi Glenn J.
Published: February 2021

Risk is a ubiquitous part of life and work, and decision making is at the heart of any consideration about what to do, if anything about risk. Whether our decision making about risk is framed in qualitative terms – good versus bad, acceptable versus unacceptable – or quantitative terms – permissible exposure limit, recommended exposure limit, we are always engaged in making decisions about risk. Decision making in managing risk is rife with complexity, tension, and paradox which arise from this arena's values‐dependent, and subjective nature. A central question is, “to whom or what is something a risk?” Depending upon the context and the “who or what,” a risk may be acceptable or not.

This chapter is purposefully not titled “risk management” or “risk analysis” or some variation, even though much of its content is about understanding and managing risks. Rather, the focus is on decision making in risk management because of decision making's central role in this arena, and the lens it provides to leverage advances in cognitive and organizational science to improve the success of risk management outcomes.

A goal with this chapter is to increase your risk awareness beyond occupational health and safety's (OHS) traditional roots. While OHS is the foundational focus, it is suggested, if not urged that OHS professionals need to expand their risk perspective as risk profiles get more complex and interconnected. It is also suggested that there is an imperative to look at health more broadly than just work‐related injury or illness, and to consider organization, community, personal, and environmental health, as well as how a worker's employment, or lack of, impacts their total health profile.
DNA methylation markers have universal prognostic value for anal cancer risk in HIV‐negative and HIV‐positive individuals
Authors: van der Zee Ramon P. , van Noesel Carel J.M. , Martin Ivonne , ter Braak Timo J. , Heideman Daniëlle A.M. , de Vries Henry J.C. , Prins Jan M. , Steenbergen Renske D.M.
Published: February 2021

Anal cancer has increasing incidence and is preceded by high‐grade anal intraepithelial neoplasia (HGAIN; AIN2–3). Previously, we identified and validated several methylation markers for accurate detection of anal cancer and HGAIN with cancer risk in HIV‐positive (HIV+) men who have sex with men (MSM). This study aimed to evaluate these markers in HIV‐negative risk groups. A cross‐sectional series of 176 tissue samples of anal cancer, AIN3, AIN2, AIN1 and control biopsies obtained in HIV‐negative women and men was tested for six methylation markers (ASCL1, LHX8, SST, WDR17, ZIC1andZNF582). Accuracy for detection of AIN3 and cancer (AIN3+) was determined by univariable and multivariable mixed‐effect ordinal logistic regression. Methylation levels of all markers increased with increasing severity of disease (P < 0.0001) and were comparable to results in HIV+ MSM. All markers showed high accuracy for AIN3+ detection [area under the curve (AUC): 0.83–0.86]. The optimal marker panel (ASCL1andZIC1; AUC = 0.85 for AIN3+) detected 98% of cancers at 79% specificity. In conclusion, DNA methylation markers show a high diagnostic performance for AIN3+ detection in HIV+ and HIV‐negative risk groups, justifying broad application of methylation analysis for anal cancer prevention programmes.
Development of Thermoinks for 4D Direct Printing of Temperature‐Induced Self‐Rolling Hydrogel Actuators
Authors: Podstawczyk Daria , Nizioł Martyna , Szymczyk‐Ziółkowska Patrycja , Fiedot‐Toboła Marta
Published: February 2021

4D printing has emerged as an important technique for fabricating 3D objects from programmable materials capable of time‐dependent reshaping. In the present investigation, novel 4D thermoinks composed of laponite (LAP), an interpenetrating network of poly(N‐isopropylacrylamide) (PNIPAAm), and alginate (ALG) are developed for direct printing of shape‐morphing structures. This approach consists of the design and fabrication of 3D honeycomb‐patterned hydrogel discs self‐rolling into tubular constructs under the stimulus of temperature. The shape morphing behavior of hydrogels is due to shear‐induced anisotropy generated via 3D printing. The compositionally tunable hydrogel discs can be programmed to exhibit different actuation behaviors at different temperatures. Upon immersion in 12 °C water, singly crosslinked sheets roll up into a tubular construct. When transferred to 42 °C water, the tubes first rapidly unfold and then slightly curve up in the opposite direction. Through a dual photocrosslinking of PNIPAAm, it is possible to inverse temperature‐dependent shape morphing and induce self‐folding at higher and unrolling at lower temperatures. The extensive self‐assembling motion is essential to developing thermal actuators with broad applications in, e.g., soft robotics and active implantology, whereas controllable self‐rolling of planar hydrogels is of the highest interest to biomedical engineering as it allows for effective fabrication of hollow tubes.
High‐Performance All‐Polymer Solar Cells with a Pseudo‐Bilayer Configuration Enabled by a Stepwise Optimization Strategy
Authors: Wu Qiang , Wang Wei , Wu Yao , Chen Zeng , Guo Jie , Sun Rui , Guo Jing , Yang Yang (Michael) , Min Jie
Published: February 2021

In this work, an efficiency of 15.17% in the PBDB‐T/PYT all‐PSCs fabricated by a layer‐by‐layer (LbL) deposition technique is achieved by synergistically controlling additive dosages, which is not only higher than that (14.06%) of the corresponding bulk heterojunction (BHJ) device, but also the top efficient for all‐PSCs. Through the studies of physical dynamics and morphological characteristics, it is found that the LbL film can effectively improve optical and electronic properties, ensure exciton separation, charge generation and extraction, reduce trap‐assisted recombination, and facilitate hole transfer in LbL blends, thus achieving higher performance compared to its BHJ counterpart. Notably, the synergistic regulation of additive dosages in donor and acceptor solutions is also confirmed in the other three photovoltaic systems. Of particular note is that over 15% device performance is also achieved in the PBDB‐T/PYT LbL all‐PSCs fabricated via a blade‐coating technique, further demonstrating the great significance of this synergistic additive‐doping strategy for the printing fabrication of organic photovoltaics.
Extreme‐Angle Silicon Infrared Optics Enabled by Streamlined Surfaces
Authors: Zhang Fei , Pu Mingbo , Li Xiong , Ma Xiaoliang , Guo Yinghui , Gao Ping , Yu Honglin , Gu Min , Luo Xiangang
Published: February 2021

Infrared optical systems are indispensable in almost all domains of society, but their performances are often restricted by bulky size, small field of view, large thermal sensitivity, high fabrication cost, etc. Here, based on the concept of catenary optics, a novel isophase streamline optimization approach is leveraged to design silicon complementary metal–oxide–semiconductor (CMOS)‐compatible metasurfaces with broadband, wide‐angle, and high‐efficiency performances, which breaks through the glass ceiling of traditional optical technologies. By using the truly local geometric phase, a maximum diffraction efficiency approaching 100% is obtained in ultrawide spectral and angular ranges. Somewhat surprising results are shown in that wide‐angle diffraction‐limited imaging and laser beam steering can be realized with a record field of view up to 178°. This methodology is scalable to the entire optical band and other materials, enabling unprecedented compact infrared systems for surveillance, unmanned vehicles, medical science, etc.
Achieving High Power Density and Long‐Term Stable Flexible Triboelectric Nanogenerators through Surface Functionalization of High Work‐Function Electrode with Cationic Thiol‐Based Self‐Assembled Monolayer
Authors: Cheng Yu‐Hsuan , Lee Chia‐Jung , Chang Chih‐Yu
Published: February 2021

In this study, a reliable strategy is demonstrated to improve performance and stability of a triboelectric nanogenerator (TENG) by using cationic (11‐mercaptoundecyl)‐N,N,N‐trimethylammonium bromide (MUTAB) self‐assembled monolayer (SAM) as the surface modification layer for high work‐function (WF) Ag electrode. The thiol head group of MUTAB can form covalent bond to Ag surface, while the positively charged ammonium group can induce favorable surface dipole moment to lower the WF of Ag layer, enabling efficient charge transfer from Ag electrode to polydimethylsiloxane (PDMS) dielectric layer. This strategy is highly compatible with large‐area flexible TENG based on solution‐processed Ag nanoparticle layer, affording open‐circuit voltage (Voc) of 1008 V, short‐circuit current (Isc) of 124.9 µA, and power density of 39.4 W m−2. To the best of our knowledge, such remarkable power density represents the highest value ever reported for SAM‐modified TENG. Taking advantage of high output characteristics of flexible TENG, 328 light‐emitting diodes can be lit up instantaneously. More encouragingly, the resulting TENG also possesses good stability, maintaining ≈96% of its original Voc after 300 000 cycles of continuous testing. The present findings highlight the importance of surface modification with SAM for efficient and long‐term stable TENG, which can advance the development of intelligent self‐powered systems.
Elucidating the Structure and Photophysics of Layered Perovskites through Cation Fluorination
Authors: Tekelenburg Eelco K. , Kahmann Simon , Kamminga Machteld E. , Blake Graeme R. , Loi Maria A.
Published: February 2021

Optoelectronic devices based on layered perovskites containing fluorinated cations display a well‐documented improved stability and enhanced performance over non‐fluorinated cations. The effect of fluorination on the crystal structure and photophysics, however, has received limited attention up until now. Here, 3‐fluorophenethylammonium lead iodide ((3‐FPEA)2PbI4) single crystals are investigated and their properties to the non‐fluorinated ((PEA)2PbI4) variant are compared. The bulkier 3‐FPEA cation increases the distortion of the inorganic layers, resulting in a blue‐shifted absorbance and photoluminescence. Temperature‐dependent photoluminescence spectroscopy reveals an intricate exciton substructure in both cases. The fluorinated variant shows hot‐exciton resonances separated by 12 to 15 meV, values that are much smaller than the 40 to 46 meV found for (PEA)2PbI4. In addition, high‐resolution spectra show that the emission at lower energies consists of a substructure, previously thought to be a single line. With the analysis on the resolved photoluminescence, a vibronic progression is excluded as the origin of the emission at lower energies. Instead, part of the excitonic substructure is proposed to originate from bound excitons. This work furthers the understanding of the photophysics of layered perovskites that has been heavily debated lately.
Multiband Photonic Topological Valley‐Hall Edge Modes and Second‐Order Corner States in Square Lattices
Authors: Kim Kwang‐Hyon , Om Kwang‐Kwon
Published: February 2021

Robust multiband photonic topological edge states are of great importance for photonic applications, including nonlinear wavelength conversion. In particular, higher‐order photonic topological states provide the realizability of photonic nanoresonators with high robustness against structural disorder of photonic crystals. This work reveals that multiband photonic topological valley‐Hall edge states and second‐order corner states can be observed in square lattice photonic crystals consisting of triangular dielectric rods. For small sizes of the triangles, multiband gapless edge modes propagate through the photonic topological waveguide. Their transmission characteristics and robustness against the structural defects have been evaluated for linear and Z‐shaped interfaces. When the size of the triangles increases, most of edge bands become gapped and one can obtain disorder‐immune multiband second‐order topological corner states, which is the core result of this report. The results obtained in this work can find important applications for nonlinear topological frequency conversion.
Blue Emissive fac/mer‐Iridium (III) NHC Carbene Complexes and their Application in OLEDs
Authors: Idris Muazzam , Kapper Savannah C. , Tadle Abegail C. , Batagoda Thilini , Muthiah Ravinson Daniel Sylvinson , Abimbola Opeoluwa , Djurovich Peter I. , Kim Jongchan , Coburn Caleb , Forrest Stephen R. , Thompson Mark E.
Published: February 2021

The photophysical and electrochemical properties of N‐heterocyclic carbene complexes of Iridium (III) (Ir(C^C:)3, where C^C: = N‐phenyl,N‐methyl‐pyrazinoimidazol‐2‐yl (pmpz), N,N‐di‐p‐tolyl‐pyrazinoimidazol‐2‐yl (tpz)) are reported. Facial and meridional isomers of Ir(pmpz)3 are prepared, but only the facial isomer can be isolated for Ir(tpz)3. The fac‐Ir(pmpz)3 and fac‐Ir(tpz)3 complexes have emission maxima at 465 nm in polystyrene, whereas the emission maximum of mer‐Ir(pmpz)3 is redshifted to 495 nm. The emission energies and photoluminescent quantum yield (ΦPL) in solution decrease on going from nonpolar to polar solvents; however, all the complexes are efficient emitters in polystyrene at room temperature (ΦPL = 88–96%) and 77 K. Blue phosphorescent organic light emitting diodes employing fac‐Ir(tpz)3 as an emissive dopant achieves a high external electroluminescence efficiency (≈18 ± 1%) and brightness (29 000 cd m−2) at low current density.
Theoretical Evidence of the Singlet Predominance in the Intramolecular Energy Transfer in Ruhemann's Purple Tb(III) Complexes
Authors: Moura Renaldo T. , Oliveira Jhulie A. , Santos Inácio A. , de Lima Ewerton M. , Carlos Luís D. , Aguiar Eduardo C. , Neto Albano N. Carneiro
Published: February 2021

This work presents a theoretical study on the geometries and intramolecular energy transfer (IET) process of Tb3+‐complexes based on the Ruhemman's purple (RP) as ligands. Density functional theory and its time‐dependent extension are performed to examine the coordination energies and excited states using the ωB97X‐D3/MWB54/def2‐TZVP/polarizable continuum model level of theory. The inclusion of solvent effect causes a blueshift in all excitation energies, which is crucial for a better description of the electronic situations of RP isomers and coordination compounds. The IET rates are assessed for 18 Tb‐RP different compounds, each one with 44 IET pathways, also, it is obtained that the main energy transfer channel comes from the singlet state, in complete agreement with previous experimental data. The energy transfer from the singlet state is mainly composed of the nonradiative absorptions7F6→5G6and7F5→5G5, representing together 97% of the total IET rate. As far as it is known, this is the first time that the solvent effect is included in the IET rates calculation, registering a step toward the development of IET analysis without any experimental or phenomenological input data.
Minimizing the Thickness of Ethoxylated Polyethylenimine to Produce Stable Low‐Work Function Interface for Nonfullerene Organic Solar Cells
Authors: Zeng Wenwu , Zhou Xianmin , Du Baocai , Hu Lu , Xie Cong , Wang Wen , Jiang Youyu , Wang Tao , Zhou Yinhua
Published: February 2021

Selection of interfacial layer is critical for nonfullerene active layers to obtain high performance due to high chemical reactivity with base or amines. So far, alcohol‐processed ethoxylated polyethylenimine (PEIE) interfacial layer has not been successfully used in high‐performance nonfullerene solar cells. Herein, findings are reported as follows: 1) alcohol‐processed PEIE as an interfacial layer can deliver high‐performance (15.3%) Y6‐based nonfullerene solar cells if its thickness is reduced to about 1.2 nm rather than 5–10 nm that is generally used in fullerene solar cells. That is comparable with the reference cells with ZnO interlayer. Slightly thicker PEIE (5 nm) would significantly reduce the power conversion efficiency down to 7.5%. This is completely different from the fullerene‐based solar cells. 2) The ultrathin thickness strategy is not universal for other nonfullerene acceptors. Even though the PEIE thickness is about 1.2 nm, the IT‐4F‐based nonfullerene solar cells exhibit lower performance than reference cells with ZnO interlayer. That is because the IT‐4F is more chemically reactive than Y6 with the PEIE. The observation suggests the proper selection and optimization of the interfacial layer is critical to the solar cells with different nonfullerene electron acceptors.
Assessing Dysferlinopathy Patients Over Three Years With a New Motor Scale
Authors: Jacobs Marni B. , James Meredith K. , Lowes Linda P. , Alfano Lindsay N. , Eagle Michelle , Muni Lofra Robert , Moore Ursula , Feng Jia , Rufibach Laura E. , Rose Kristy , Duong Tina , Bello Luca , Pedrosa‐Hernández Irene , Holsten Scott , Sakamoto Chikako , Canal Aurélie , Sanchez‐Aguilera Práxedes Nieves , Thiele Simone , Siener Catherine , Vandevelde Bruno , DeWolf Brittney , Maron Elke , Guglieri Michela , Hogrel Jean‐Yves , Blamire Andrew M. , Carlier Pierre G. , Spuler Simone , Day John W. , Jones Kristi J. , Bharucha‐Goebel Diana X. , Salort‐Campana Emmanuelle , Pestronk Alan , Walter Maggie C. , Paradas Carmen , Stojkovic Tanya , Mori‐Yoshimura Madoka , Bravver Elena , Díaz‐Manera Jordi , Pegoraro Elena , Mendell Jerry R. ,   The Jain COS Consortium, Mayhew Anna G. , Straub Volker
Published: February 2021

Objective

Dysferlinopathy is a muscular dystrophy with a highly variable clinical presentation and currently unpredictable progression. This variability and unpredictability presents difficulties for prognostication and clinical trial design. The Jain Clinical Outcomes Study of Dysferlinopathy aims to establish the validity of the North Star Assessment for Limb Girdle Type Muscular Dystrophies (NSAD) scale and identify factors that influence the rate of disease progression using NSAD.

Methods

We collected a longitudinal series of functional assessments from 187 patients with dysferlinopathy over 3 years. Rasch analysis was used to develop the NSAD, a motor performance scale suitable for ambulant and nonambulant patients. Generalized estimating equations were used to evaluate the impact of patient factors on outcome trajectories.

Results

The NSAD detected significant change in clinical progression over 1 year. The steepest functional decline occurred during the first 10 years after symptom onset, with more rapid decline noted in patients who developed symptoms at a younger age (p = 0.04). The most rapidly deteriorating group over the study was patients 3 to 8 years post symptom onset at baseline.

Interpretation

The NSAD is the first validated limb girdle specific scale of motor performance, suitable for use in clinical practice and clinical trials. Longitudinal analysis showed it may be possible to identify patient factors associated with greater functional decline both across the disease course and in the short‐term for clinical trial preparation. Through further work and validation in this cohort, we anticipate that a disease model incorporating functional performance will allow for more accurate prognosis for patients with dysferlinopathy. ANN NEUROL 2021;89:967–978
Redox Donor–Acceptor Conjugated Microporous Polymers as Ultralong‐Lived Organic Anodes for Rechargeable Air Batteries
Authors: Zhong Linfeng , Fang Zhengsong , Shu Chenhao , Mo Chunshao , Chen Xiaochuan , Yu Dingshan
Published: February 2021

Herein, we explore a new redox donor–acceptor conjugated microporous polymer (AQ‐CMP) by utilizing anthraquinone and benzene as linkers via C‐C linkages and demonstrate the first use of CMP as ultralong‐lived anodes for rechargeable air batteries. AQ‐CMP features an interconnected octupole network, which affords not only favorable electronic structure for enhanced electron transport and n‐doping activity compared to linear counterpart, but also high density of active sites for maximizing the formula‐weight‐based redox capability. This coupled with highly cross‐linked and porous structure endows AQ‐CMP with a specific capacity of 202 mAh g−1 (96 % of theoretical capacity) at 2 Ag−1 and ≈100 % capacity retention over 60000 charge/discharge cycles. The assembled CMP‐air full cell shows a stable and high capacity with full capacity recovery after only refreshing cathodes, while the decoupled electrolyte and cathode design boosts the discharge voltage and voltage efficiency to ≈1 V and 87.5 %.
CRISPR/Cas technology as a promising weapon to combat viral infections
Authors: Escalona‐Noguero Carmen , López‐Valls María , Sot Begoña
Published: February 2021

The versatile clustered regularly interspaced short palindromic repeats (CRISPR)/Cas system has emerged as a promising technology for therapy and molecular diagnosis. It is especially suited for overcoming viral infections outbreaks, since their effective control relies on an efficient treatment, but also on a fast diagnosis to prevent disease dissemination. The CRISPR toolbox offers DNA‐ and RNA‐targeting nucleases that constitute dual weapons against viruses. They allow both the manipulation of viral and host genomes for therapeutic purposes and the detection of viral nucleic acids in “Point of Care” sensor devices. Here, we thoroughly review recent advances in the use of the CRISPR/Cas system for the treatment and diagnosis of viral deleterious infections such as HIV or SARS‐CoV‐2, examining their strengths and limitations. We describe the main points to consider when designing CRISPR antiviral strategies and the scientific efforts to develop more sensitive CRISPR‐based viral detectors. Finally, we discuss future prospects to improve both applications. Also see the video abstract here: https://www.youtube.com/watch?v=C0z1dLpJWl4
Design of synthetic promoters for controlled expression of therapeutic genes in retinal pigment epithelial cells
Authors: Johari Yusuf B. , Mercer Andrew C. , Liu Ye , Brown Adam J. , James David C.
Published: February 2021

Age‐related macular degeneration (AMD) associated with dysfunction of retinal pigment epithelial (RPE) cells is the most common cause of untreatable blindness. To advance gene therapy as a viable treatment for AMD there is a need for technologies that enable controlled, RPE‐specific expression of therapeutic genes. Here we describe design, construction and testing of compact synthetic promoters with a pre‐defined transcriptional activity and RPE cell specificity. Initial comparative informatic analyses of RPE and photoreceptor (PR) cell transcriptomic data identified conserved and overrepresented transcription factor regulatory elements (TFREs, 8–19 bp) specifically associated with transcriptionally active RPE genes. Both RPE‐specific TFREs and those derived from the generically active cytomegalovirus‐immediate early (CMV‐IE) promoter were then screened in vitro to identify sequence elements able to control recombinant gene transcription in model induced pluripotent stem (iPS)‐derived and primary human RPE cells. Two libraries of heterotypic synthetic promoters varying in predicted RPE specificity and transcriptional activity were designed de novo using combinations of up to 20 discrete TFREs in series (323–602 bp) and their transcriptional activity in model RPE cells was compared to that of the endogenous BEST1 promoter (661 bp, plus an engineered derivative) and the highly active generic CMV‐IE promoter (650 bp). Synthetic promoters with a highpredicted specificity, comprised predominantly of endogenous TFREs exhibited a range of activities up to 8‐fold that of the RPE‐specific BEST1 gene promoter. Moreover, albeit at a lower predicted specificity, synthetic promoter transcriptional activity in model RPE cells was enhanced beyond that of the CMV‐IE promoter when viral elements were utilized in combination with endogenous RPE‐specific TFREs, with a reduction in promoter size of 15%. Taken together, while our data reveal an inverse relationship between synthetic promoter activity and cell‐type specificity, cell context‐specific control of recombinant gene transcriptional activity may be achievable.
Trace element alterations in Alzheimer's disease: A review
Authors: Cilliers Karen
Published: February 2021

Dyshomeostasis of trace elements have been implicated in the progression of Alzheimer's disease (AD), which is characterized by amyloid‐β (Aβ) plaques. Trace elements are particularly associated with the Aβ plaques. Metal‐protein attenuating compounds have been developed to inhibit metals from binding to Aβ proteins, which result in Aβ termination, in the hope of improving cognitive functioning. However, there are still some contradicting reports. This review aims to first establish which trace elements are increased or decreased in the brains of Alzheimer's patients, and secondly, to review the effectiveness of clinical trials with metal‐protein attenuating compounds for AD. Studies have consistently reported unchanged or increased iron, contradicting reports for zinc, decreased copper, unchanged or decreased manganese, inconsistent results for calcium, and magnesium seems to be unaffected. However, varied results have been reported for all trace elements. Clinical trials using metal‐protein attenuating compounds to treat AD have also reported varied results. Copper chelators have repeatedly been used in clinical trials, even though few studies report increased brain copper levels in AD patients. Homeostasis of copper levels is important since copper has a vital role in several enzymes, such as cytochrome c, Cu/Zn superoxide dismutase and ceruloplasmin. Dyshomeostasis of copper levels can lead to increased oxidative stress and neuronal loss. Future studies should assess a variety of trace element levels in moderately and severely affected AD patients since there are contradicting reports. This review thus provides some insight into trace element alterations in the brains of individuals with AD.
Morphological alterations of the cornea following crosslinking treatment (CXL)
Authors: Subasinghe Sandeepani K. , Ogbuehi Kelechi C. , Mitchell Logan , Dias George J.
Published: February 2021

Introduction

Corneal crosslinking (CXL) has revolutionized the treatment of keratoconus during the past decade. In the present study, the morphological changes in the corneal collagen fibrils (CFs) following crosslinking treatment are described.

Materials and Methods

Ten pairs of porcine and rabbit corneas were retrieved. In each pair, one cornea was the control and the other underwent CXL treatment. The central corneal thickness (CCT) was measured before and after CXL treatment. Each treated and control cornea was examined with light microscopy and by transmission electron microscopy.

Results

(a) The mean CCT was significantly reduced following treatment. (b) CFs were more closely packed in the anterior region and loosely packed in the posterior region. (c) CF diameter increased significantly in the anterior and intermediate regions but declined gradually towards the deeper regions. (d) There was a statistically significant decrease in the interfibrillar distance over the different regions of the cornea, except for the posterior region in porcine corneas, where there was no change. (e) The distance between adjacent collagen lamellae was significantly decreased in all regions of treated rabbit corneas. There was no change in porcine corneas.

Conclusion

CXL treatment resulted in increased the CF diameter and decreased interfibrillar distance in the anterior and intermediate regions, while its effects on the posterior region differed among species. The effect on interlamellar distance was more prominent in the rabbit model than the porcine model. CXL treatment stiffened the corneas by increasing CF diameter and decreasing interfibrillar distance in both rabbit and pig corneas.
William Hunter's aristocratic post mortems
Authors: McDonald Stuart W.
Published: February 2021

William Hunter's writings, lectures and his collection of circa 1,400 pathological specimens at the University of Glasgow show that, within the scientific limitations of the 18th Century, he had a sound grasp of the significance of morbid anatomical appearances. Unlike John Hunter's collection at the Royal College of Surgeons of England, few of the Hunterian specimens at Glasgow have an accompanying case history. Within the Special Collections at the Glasgow University Library are a small number of post mortem reports, including four involving William Hunter's aristocratic patients. This article explores these patient cases, and also the only instance recorded by John Hunter of William working with him on a post mortem of an aristocrat, that of the Marquis of Rockingham, Prime Minister, who died in 1782. The study aims to better understand William Hunter's medical practice and his professional connections with other practitioners. The post mortem examinations were carried out by a surgeon/anatomist and observed by the patient's physician(s). For aristocratic post mortems, those attending were senior and well‐established practitioners. The notes made were not particularly detailed. The reports show clearly that William Hunter's practice, in the 1760s at least, was not confined to midwifery.
Daily provision of instrumental and emotional support to friends is associated with diurnal cortisol during adolescence
Authors: Armstrong‐Carter Emma , Telzer Eva H.
Published: February 2021

This study investigates how adolescents' daily prosocial behaviors to friends are related to diurnal cortisol using between‐ and within‐subject analyses. Further, we examine whether role fulfillment (i.e., feeling like a good friend) moderates links between prosocial behaviors and cortisol. Ethnically diverse adolescents (N = 370; ages 11–18) reported whether they provided instrumental and emotional support to friends for 5 days, and provided four saliva samples/day for 4 days. On the daily level, providing emotional support predicted lower cortisol awakening response the next day, and providing instrumental assistance to friends was associated with a flatter cortisol slope the same day (a cardiovascular risk factor). Adolescents also provided more emotional support on days they had lower CAR and steeper cortisol slopes. On the average level, providing more instrumental support was associated with steeper cortisol slopes among adolescents who felt high levels of role fulfillment, but not among adolescents who felt low levels of role fulfillment. Providing instrumental support may be physiologically taxing from day to day but, across the long term, linked to lower cardiovascular risk for adolescents who experience helping as highly fulfilling.