bluuebunny/crossref_metadata_2025 huggingface dataset:
An overview of indoor environmental conditions in work-from-home settings
Authors: Manu Sanyogita , Rysanek Adam
Published: June 2023

During the last week of March 2020, about 4.7 million workers in Canada transitioned to working from home due to the pandemic. A similar transition occurred at a global scale. Few studies have evaluated the WFH setting from a perspective that’s been a significant public concern during the COVID-19 pandemic: indoor environmental quality (IEQ). The objective of this paper is to present an analysis of the IEQ conditions in WFH settings based on a field study of 95 WFH sites during May-July 2022 in the Pacific Northwest region. The IEQ variables of air temperature, relative humidity, CO2, total volatile organic compounds, PM2.5, ambient light and noise were measured continuously at 10-minute intervals for the duration of the study. A preliminary analysis of the IEQ data shows the indoor air temperature in WFH settings within the study sample, ranged between 15.7-32°C, with a mean value of 22.7°C (SD = 2.3°C). The mean indoor concentrations of CO2, TVOCs and PM2.5 were 674 ppm (SD = 324 ppm), 288 ppb (SD = 515 ppb) and 4.7 μ/m3 (SD = 20.5 μ/m3) respectively. The mean values for relative humidity, light and noise were 53% (SD = 7%), 174 lux (SD = 349 lux) and 53 dB (SD = 5 dB). Associations between type of residence and most of the IEQ variables were found.
Analysis of gravity effect on human blood flow and skin temperature through postural change
Authors: Azemachi Hiroya , Oomae Taro , Ito Tsubasa , Nagano Hideaki , Shiratori Suguru , Shimano Kenjiro
Published: June 2023

The blood flow of human body has much impact on the thermo-physiological response. When person change the posture, the gravity acts changes its direction and thus the blood flow can be changed. It is hypothesized that the gravitational effects of postural changes affect blood flow and skin temperature, which in turn affect comfort. To verify this, in the present study, a subject experiment focusing on postural changes was conducted for two conditions (Case 1 and Case 2). In the Case 1 experiment, the subjects were asked to raise their hands for 10 minutes after 30 minutes of rest in the chair-sitting position. As a result, significant skin temperature change were observed in the upper arm, forearm, and hand. The largest skin temperature change was observed in the hands, which showed a decrease in skin temperature of approximately 1.2 °C. The change had influence on the whole-body average value. In Case 2, the subjects were placed in the supine position for 10 minutes after 30 minutes of rest in the chair position. As a result, a decrease in skin temperature of approximately 1 °C was observed on the hands and 0.5 °C in the foot was observed.
Analysis of the influence of pressure difference across building envelope on indoor particulate matter concentration
Authors: Park Soyi , Choi Suji , Jo Jaehun
Published: June 2023

Outdoor PM2.5, penetrated by infiltration, has a continuous and important effect on indoor environments. To determine the infiltration rate, it is important to consider the airtightness level and pressure difference across an envelope. This study investigated the influence of pressure difference and airtightness on indoor PM2.5 in a residential building with natural ventilation. Field measurements were conducted in eight residential households. The indoor and outdoor PM2.5 concentrations and pressure differences across the envelope were measured simultaneously. The airtightness of each unit was determined via a blower door test. As a result, the indoor PM2.5 concentration exhibited a significant correlation with airtightness and envelope pressure difference. However, the correlation between the PM2.5 I/O ratio and the pressure difference was found to weaken as the airtightness decreased. This appears to be influenced more by other external factors in addition to pressure under loose airtightness conditions. Thus, the influence of the factors on the penetration of PM2.5 can vary depending on the airtightness of the envelope.
Comparison of resistance improvement to Aspergillus brasiliensis growth on recycled building materials by nano-metal impregnation and ozone treatment
Authors: Lin Chi-Chi , Xiao Pei-Chen
Published: June 2023

This study explores the potential of nanometal and ozone treatment to improve the Aspergillus brasiliensis resistance of recycled building materials (RBMs). RBMs include gypsum board (GB), waterproof gypsum board (WGB), calcium silicate board (CSB), and fiber cement board (FCB). The A. brasiliensis was inoculated on each sample, and their growth was visually evaluated according to ASTM G21-09. The results show that the effect of the treatment with nano-silver of 0.015 g/L and 0.03 g/L solution by impregnation was similar to that of the treatment with 60 ppb concentration of ozone for 4 hours: rating 3 on GB, rating 1 on WGB, rating 1 on CSB, and rating 1 on FCB. The antifungal effects of different building materials treated with different types and concentrations of nanometals or ozone are different. All the tested nanometals or ozone of the selected concentrations failed to provide complete protection against fungal growth on the four tested BMs. However, it is supposedly confirmed that the higher the nanometal concentration was, the longer the lag period until fungi growth began, and fewer fungi grew on the materials.
Digital Twin for biological safety cabinet to reproduce performance and field certification test specified by NSF/ANSI 49 - 2019
Authors: Muta Ryota , Ito Kazuhide
Published: June 2023

The airflow balance test to confirm the physical performance of biological safety cabinets (BSC) is standardized by JIS K 3800 in accordance with NSF/ANSI 49 in Japan. In the test, Bacillus atrophaeus spores are used as an evaluation index, which poses a few limitations, such as their dependence on the environmental conditions to be tested. The aim of this study is to develop BSC digital twins and discuss reasonable alternatives for performance evaluation tests while maintaining the accuracy of the bacterial test performance. Herein, we provide the outline of a digital twin model for BSCs and the results of a numerical analysis, where a passive scalar is used as an alternative pollutant in the evaluation index.
The Effect of Avoiding Closed Spaces on the Indoor Environment of Nursery School Rooms during COVID-19 winter
Authors: Ito Ryosuke , Aoki Tetsu , Taguchi Sachiko , Honda Kosei
Published: June 2023

This study aimed to clarify the effect of the policy of avoiding closed spaces with poor ventilation for preventing COVID-19 on the indoor environment of nursery school rooms during winter. The measurement survey was conducted in 23 rooms of nine nursery schools in the Tokai region of Japan. We measured the CO2 concentration, temperature, and humidity in 10 min intervals during the winter in 2022. The data collected from 9 a.m. to 3 p.m. on weekdays when the rooms were occupied were analyzed. The results showed that the mean value of the CO2 concentration in the nursery school rooms was below 1000 ppm in 22 of 23 rooms. Besides, we estimated the ventilation rate and found that most rooms exceeded the value per person required to keep the concentration below 1000ppm. The results suggest that the nursery school teachers actively used mechanical and window-opening ventilation. On the other hand, the mean temperature was below 18 °C in 12 rooms and the mean relative humidity was below 40% in 22 rooms. We found that increasing the ventilation volume to avoid closed spaces during winter significantly decreased the relative humidity in the nursery school rooms.
Effects of Indoor Air Curtain and Fan on Cross-Infection Risk for a Space with Displacement Ventilation
Authors: Robinson Austin , Zhai Zhiqiang (John)
Published: June 2023

Air curtain is an effective control for separating air spaces and reducing the cross-transfer of air, heat, and contaminant between different zones. Studies show that displacement ventilation is better for indoor air quality than mixed ventilation. However, displacement ventilation may be susceptible to a phenomenon called lock-up, whereby contaminants are held in a lower stratified portion of the space and increase infection potential. This study investigates whether indoor air curtain and circulation fan can reduce the lock-up phenomenon for spaces with displacement ventilation and thus reduce infection risk across the breathing zone. Specially, numerical test is conducted to explore if a side-wall diffuser-integrated vertical slot air curtain would be sufficient for reducing infection risk. Additionally, circulation fans above the occupants are applied to explore if they would reduce the lock-up phenomenon. The conclusions are that neither a side air curtain slot nor circulation fans is/are adequate to reduce infection risk. In fact, all methods tested increased infection risk. This increase in infection risk is contrary to previous research and is due to changing air flow patterns throughout the space that disrupted thermal plumes and created contaminant leakage from one side of the room to the other. Circulation fans provided the promising results while further optimization should be conducted in terms of the ideal quantity, location, flow rate, orientation, and size of fans throughout a given space.
Design factors affecting the passive release of tracer gas for ventilation measurements
Authors: Ahmed Jalal , Altamirano-Medina Hector , Rovas Dimitrios , Allinson David , Mawditt Ian
Published: June 2023

The ventilation rate is an important parameter for assessing indoor air quality and energy efficiency. In occupied buildings, ventilation measurements utilising passive methods are preferable to active methods due to their simplicity and less intrusive nature. The perfluorocarbon tracer method can be used to measure long-term ventilation rates for this purpose. This method requires the passive release of a tracer gas which is often a liquid chemical diffusing out of a vial. The tracer gas emission rate is a key parameter of the vial design as if it is too low, the sampler will not be able to detect the tracer gas. If the emission rate is too high, the sampler can become saturated. Both scenarios will lead to inaccurate ventilation results. There is wide variability in vial design but little information about the relative impact of each design factor. Thus, the aim of this study was to compare the emission rate of a common tracer gas, perfluoromethylcyclohexane, using different vials designs i.e. capping styles, septa materials, and fill levels. Samples were kept in an incubator and gravimetric analysis was carried out using a semi-microbalance (resolution: 0.01 mg). The results demonstrate that the emission rate is significantly affected by capping style but not by fill level.
Reduced personal exposure to airborne cross-infection using wearable exhaust ventilation
Authors: Bivolarova Mariya P. , Kierat Wojciech , Hvidkjær Signe , Stengade Kathrine-Amalie , Illum Trine , Boe Gad Stine , Melikov Arsen K.
Published: June 2023

This study aimed to explore an alternative solution for protection against cross-infection. Exposure reduction to exhaled airborne contaminants by wearing an exhaust nozzle was studied. Experiments were performed in a full-scale test room (64.8 m3) equipped with a small section of a stadium tribune with six seats. Two breathing thermal manikins and four heated dummies were placed on the tribune. The manikins were equipped with artificial lungs simulating a realistic breathing cycle and respiratory flow. One of the breathing manikins was used to mimic a sick person having an infectious respiratory disease. The exhaled air of the “infecting person” was mixed with tracer gas to imitate pathogens. Four types of air exhaust nozzles were studied for their efficiency to reduce exposure to exhaled contaminants. The nozzle was positioned in front of the mouth of the infecting person. The test room was ventilated with mixing background ventilation. The use of the exhaust nozzle resulted in cleaner air in the room and at the breathing zone of the simulated occupants compared to only using dilution by the background ventilation. The novel device has the potential to capture exhaled air and reduce airborne cross-infection in densely occupied sitting areas.
A training dataset for machine learning-based prediction of window opening position in a naturally ventilated building
Authors: Wong Jeremy , Donges Julian , Gasparella Andrea , Rysanek Adam
Published: June 2023

Window operation is the main strategy used by building occupants to naturally ventilate buildings. However, common approaches to measure window operation for energy and comfort assessments are still technically complex or insufficient; typical window open/close sensors often provide only binary information about the opening state of a window, not the extent to which the window is open. This paper is the first outcome of a research project that seeks to use photo imagery and machine learning to predict the variable opening state of windows on a real multi-family residential passive house located in Vancouver, Canada. The employed windows are European-style in that they can be opened in tilt or turn mode. To eventually train the algorithm, a ground-truth dataset is constructed by manually changing the opening state of sixteen windows every minute over a 15-hour test period spanning three days and taking a photo of the windows at each instance, measuring the angle each time. This paper documents the first outcome of the overall project: the publication of the training dataset itself, with over 10,000+ images of a building fac¸ade taken, under variable-but-known window opening state, and under various light conditions. The paper presents the testing methodology undertaken for generation of the dataset and provides instructions for how to access the dataset. In the future, these images will be used to calibrate a machine learning model to estimate window opening/closing state of the tested building. The dataset can also be extended for semantic segmentation in support of other machine learning problems.
Experimental and numerical analysis of a new wind tunnel for building and mechanical ventilation components performance assessment
Authors: El Mahiba Ghizlane , Mélois Adeline , El Mankibi Mohamed
Published: June 2023

Aeraulic, air movement, and wind effects studies are of high importance when assessing building performances. Indeed, several studies have been conducted using wind tunnels to better understand aerodynamics inside and around buildings. The objective of this study is to accurately characterize the air velocity field inside the test chamber of a wind tunnel at different locations using the Hot-Wire-Anemometry technique and propose an experimental protocol to extend the use of wind tunnels to study mechanical ventilation systems’ performances. To this end, a first intercomparing protocol involving six hot-wire anemometers was carried out to verify the accuracy of measurements. In addition, we have developed a CFD numerical model of the wind tunnel under the Ansys Fluent environment. Several turbulence models, numerical schemes, and mesh types were studied to analyze the air velocity distribution and identify the appropriate model fitting experimental results. As a result, the CFD model uses the Quadrilateral Structured Fine Mapped mesh, Standard k−ε as a turbulence model, and MUSCL as a discretization scheme with a relative error of 5.21% to experiment values. Both wind tunnel and its numerical model are designated to establish on-demand building and ventilation components performance assessment using a hybrid approach, numerical and experimental.
CFD simulation of pollutant dispersion in a street canyon: Impact of idealized and realistic sources
Authors: Qin Peng , Ricci Alessio , Blocken Bert
Published: June 2023

Pollutant dispersion is of great relevance for people living in urban areas. High levels of pollutant can usually result from the combination of poor natural ventilation and high-traffic volumes of vehicles. Idealized point and line sources are commonly used to reproduce traffic emissions in simplified portions of urban areas, as street canyons. However, a limited number of studies focuses on the usage of realistic sources, as real car geometries which can influence the flow characteristics and the pollutant distribution inside the canyon. This is also the goal of the present paper for which Computational Fluid Dynamics (CFD) simulations were performed by means of scale-adaptive simulation (SAS) on a street canyon to investigate the impact of idealized and realistic sources. In stage 1, SAS simulations were performed with idealized line sources by reproducing reduced-scale wind-tunnel (WT) experiments. In stage 2, SAS simulations were carried out on a street canyon using idealized line sources and realistic sources with different levels of simplification. The results showed that the use of realistic sources can result in an increased concentration of 1.03 - 6.76 (at z = 0.33 m above the ground), with respect to the use of idealized line sources. Overall, at the lower level of the street canyon (e.g. z < 1.5 m), the concentration can be strongly affected by the presence of the car bodies. The results of the present study are expected to help urban planners as well as governmental institutions to reduce pollutant concentrations in the street canyon.
A study on dedicated outdoor air handling unit systems regarding the widespread of ZEB
Authors: Suzuki Shogo , Yoon Gyuyoung
Published: June 2023

ZEB has been promoted in the building sector to realize energy conservation and carbon neutrality. This has caused changes such as a decrease in the room sensible heat load factor and an increase in the outdoor air load ratio. In this study, the systems with a dedicated outdoor air handling unit (OAHU) are evaluated as air conditioning systems that can flexibly respond to a changing heat load, and guidelines for rational design and operation are given. A case study is conducted to evaluate the indoor environment and energy performance of a conventional air handling unit (AHU) system and an OAHU system under the assumption of a reduction in internal heat gain intensity. The study results showed that the OAHU processed latent heat and reduced the number of uncomfortable hours by 78% compared to those for the AHU system during the cooling season for cases with reduced internal heat gain. Regarding system energy consumption, the OAHU system consumed 17% more energy than the AHU-system. Thus, the OAHU system maintained a better indoor environment than the AHU system at the cost of increased energy use. Based on these results, measures for reducing the energy consumption of the OAHU system are discussed.
The BeTOP facility for performance testing of building systems
Authors: Berardi Umberto
Published: June 2023

Proposing new materials and systems to improve buildings' performance and energy efficiency often requires testing their performance in the field. Experimental performance characterization of new and existing building systems is crucial to understanding their behaviour. Full-scale experimental test cell facilities have been at the forefront of experimental performance evaluation in building-related research, as they provide a realistic representation of buildings, including environmental conditions, assembling challenges, and operational characteristics. In this paper, trends in the design and construction of outdoor testing facilities are first discussed. Then, based on the current literature and the knowledge gained through visits to multiple facilities, the new test cell facility “BeTOP”, located in Toronto (Ontario), is described. BeTOP is a full-scale experimental facility with the capacity to perform multiple experimental tests simultaneously. This paper describes its characteristics, including structure details, testing capabilities, system details, current monitoring campaigns, and future testing potential. The paper concludes by showing that the design of a full-scale testing facility is crucial to observe the long-term performance of new systems under variable boundary conditions in a continental climate with cold winters and hot and humid summers.
Characterization and energy performance of flexible photochromic window films
Authors: Khaled Khaled , Berardi Umberto
Published: June 2023

Windows are considered the weakest components in the building envelope, driven by their low thermal resistance and static transmittance to solar gains. Consequently, innovative coatings are often proposed to promote energy saving performance of windows. This article investigates several flexible photochromic window films capable of reversibly modulating solar gains based on the abundance of ultraviolet radiation. The peel-and-stick films are applied to the internal glazing surface, making them suitable for window retrofits without interrupting building occupancy. The optical properties of the photochromic films are experimentally characterized at various solar radiation intensities. The results are then used to numerically evaluate the energy-saving potential of the different films for a representative room in a high-rise office building located in Tokyo’s warm climate. The results of the experimental and numerical investigations are discussed to show the potential of photochromic films for window-retrofit applications.
Study of vertical solar irradiance and local scale climate to assess passive cooling potential in Tangerang of Indonesia
Authors: Putra I. Dewa Gede Arya , Nimiya Hideyo , Kubota Tetsu , Lee Han Soo , Iketani Fuga , Trihamdani Andhang Rakhmat , Sopaheluwakan Ardhasena , Alfata Muhammad Nur Fajri , Permana Donaldi Sukma , Pradana Radyan Putra
Published: June 2023

Solar radiation information is very important in green building design, namely for the daylighting, solar heat gain prevention as well for solar energy utilization. This study uses solar radiation data from six pyranometer sensors for measuring the horizontal component (global horizontal irradiance (GHI) and infrared irradiance) and the vertical component (pyranometer sensors to the north, south, east, and west) located in Tangerang, Indonesia. Measurements have been filtered for one year from January 2021 to December 2021. The solar radiation observation is complemented with other measurement of climate elements, such as wind speed and direction, dew point temperature, relative humidity, and air temperature. The diurnal and seasonal patterns of solar irradiance and other climatic elements have been observed using the visualization technique of heat maps. The results show that sensors pointing north experience an increase in solar intensity in May, June, July, and August. Meanwhile, sensors that point to the south experience the increases in solar intensity in November, December, January, and February. The increase in radiation intensity towards the east occurs from 07.00 to 10.00 local time (LT), while the increase in sensor intensity towards the west occurs from 14.00 to 16.00 LT. The results of solar radiation analysis in horizontal and vertical surfaces are combined with other climate elements to create a bio-climatic design guideline suitable for buildings in the hot and humid climate.
Development of an integrated index to quantify thermal comfort and walkability in urban areas
Authors: Alnimer Mona , Mirzaei Parham A. , Riffat Saffa
Published: June 2023

Although outdoor thermal comfort is extensively investigated in urban areas, the measures are barely focused to determine the walkability through these spaces. Therefore, a space with a high level of thermal comfort can experience a low level of pedestrian agglomeration while a space with a low level of thermal comfort can be massively used by inhabitants. Therefore, the solution to urban design and planning can be significantly altered if both dimensions are simultaneously taken into the account. This study investigates the relationship between spatial configuration and thermal comfort potential to evaluate the effect of spatial configuration on outdoor environmental quality. For this purpose, a framework is developed to understand the impact of built urban areas on thermal comfort and space syntax performance using a high-resolution spatial model to simulate the correlation of thermal comfort and betweenness centrality of a case study neighbourhood in the hot and humid climate area of Al-Khobar in Saudi Arabia. The mixed-use neighbourhood is analysed by the universal thermal comfort index and several space syntax metrics. The presented study uses Grasshopper environment and Ladybug and Decoding Spaces tools. The simulation study expressed that significant changes in orientation and buildings heights have a remarkable effect on improving OTC and space syntax in the urban neighbourhood.
Improving outdoor thermal comfort of a kindergarten by optimizing its building shape with genetic algorithm
Authors: Sun Rui , Chen Di , Xu Yulun , Lai Dayi , Liu Wei
Published: June 2023

Thermally comfortable mircoclimate is essential for creating high-quality outdoor spaces that attract citizens and boost city vitality. Previous design efforts to improve outdoor thermal comfort were usually conducted at large scales, such as city scale, neighborhood scale, urban block scale. Few researchers focused on the building scale. This study proposes an optimization framework based on genetic algorithm to determine the building shape, orientation, and location during early design stage that reduces the overall thermal stress in the target outdoor space. Solar radiation and wind fields were simulated to obtain the outdoor Universal Thermal Climate Index (UTCI) as the performance indicator. The simulations were validated against the experimental data. This investigation applied the proposed optimization framework to design the outdoor space for a kindergarten under the climate of Tianjin and Shanghai, respectively. The results showed that optimization reduced the overall thermal stress. The most favourable kindergarten forms were suggested through optimization. This study supplements the inverse design of outdoor thermal comfort at building scale and provides suggestions to create comfortable urban outdoor spaces.
The evolving structure of the global mining industry,
Authors: Ericsson Magnus
Published: June 2023

The green energy transition has been called a transition from a fossil fuel dependency to a metal and mineral dependency. Concerns about the security of future supplies are raised mainly in the EU and the USA with the Critical Raw Materials Act and the Inflation Reduction Act. The perspectives of these policies are centred on the demands created in the industrialised countries. The need for metals to lift billions of poor people out of poverty and to cater for the population growth is often, if not always, left out of the equation. While demand undoubtedly is increasing, the opposition to new mines and new renewable energy supply is strong and perhaps even increasing. It is necessary to find new ways to create a recognition that mining plays a key role for the green transition.
Can We Still Afford Innovative Surgical Procedures?
Authors: Lux Michael Patrick , Untch Michael , Kolberg Hans-Christian , Friedrich Michael , Thill Marc , Schütz Florian
Published: June 2023

Introduction Hospitals are currently facing major financial challenges. Due to the high incidence of breast cancer and the complex range of associated services, surgical treatment of breast cancer is a particular case in point when it comes to the question of cost coverage for innovative versus established procedures by the service providers. The aim of this study is to shed light from a healthcare economics perspective on the current situation of hospitals in Germany with regard to their different structures and processes for breast-conserving therapy.

Materials and methods An online questionnaire with 46 questions was developed and made available to hospitals that are members of the AGO [German Working Group for Gynecological Oncology] Breast Committee and AWOgyn [German Working Group for Cosmetic, Plastic and Reconstructive Surgery in Gynecology], as well as AG-certified breast centers. The questions cover various parameters for health economics analysis, including primary case numbers, structures, and questions about tumor and sentinel marking and surgical procedures.

Results 142 hospitals or breast centers took part in the survey. 93% of the hospitals were certified. The average number of primary cases was 264.6 per year. In over 60% of the hospitals, the surgical procedure and surgery planning were influenced by capacity limitations of cooperation partners. “Targeted axillary dissection” was performed in 83.5% of the hospitals, and radioactive markers were most commonly used for sentinel lymph node marking. Over 60% of participating hospitals were highly satisfied with the marking method used.

Conclusion This structure and process analysis now makes it possible to reflect on the costs involved for hospitals of different sizes, in different regions, and with different funding models, and to use this as a basis for the economic evaluation of new surgical procedures within an overall context. In general, it is possible to make savings through innovative procedures in the surgical treatment of breast cancer.
Das Blutungsrisiko unter Antidepressiva verstehen und einschätzen
Authors: Seifert Johanna , Eckermann Gabriel , Heck Johannes , Bleich Stefan , Dabbert Dominik , Grohmann Renate , Toto Sermin
Published: June 2023

Antidepressiva, insbesondere die selektiven Serotoninwiederaufnahmehemmer (SSRI),
sind die meistverordnete psychopharmakologische Arzneistoffgruppe, weshalb eine
genaue Kenntnis der zu erwartenden unerwünschten Arzneimittelwirkungen
unabdingbar ist. Das erhöhte Risiko für Blutungsereignisse ist
vor allem bei Patienten, die mit SSRI behandelt werden, gut belegt. Mit wenigen
Ausnahmen können jedoch auch die anderen antidepressiven
Arzneistoffgruppen Einfluss auf die Blutgerinnung nehmen und somit das
Blutungsrisiko erhöhen. In der nachfolgenden Übersichtsarbeit
wird das thrombozytäre Serotoninsystem vorgestellt und die
Angriffspunkte der unterschiedlichen Antidepressiva erläutert.
Anschließend wird die zur Verfügung stehende Literatur zu
Blutungen unter den jeweiligen Antidepressivaklassen bzw. einzelnen Substanzen
vorgestellt, wobei hier nach Möglichkeit jeweils Daten aus Meta-Analysen
herangezogen werden. Neben dem allgemeinen Blutungsrisiko werden zudem einzelne
Blutungsentitäten betrachtet, wie gastrointestinale und Hirnblutungen.
Zuletzt werden die Auswirkungen von anderen blutgerinnungsfördernden
Arzneistoffen (Nichtsteroidale Antirheumatika, Thrombozytenaggregationshemmer
und Antikoagulanzien) in Kombination mit Antidepressiva diskutiert. Mit dem
vorgestellten Wissen soll es Behandlern in Zukunft leichter fallen
Entscheidungen hinsichtlich einer geeigneten antidepressiven Pharmakotherapie
anhand der patientenindividuellen Risikokonstellation zu treffen.
Applications of Viscoelastic Testing in Breast Cancer Patients: A Systematic Review Focusing on Hypercoagulability and Free Flap Thrombosis
Authors: Pamulapati Saagar , Conroy Meghan , Madireddy Sathwik , Kamaraju Sailaja , Cortina Chandler , Moore Hunter , Hartmann Jan
Published: June 2023

Viscoelastic testing is a clinically available method to assess hypercoagulability. This systematic review aims to provide a comprehensive overview of the existing literature and the potential use of such testing in patients with breast cancer. A systematic literature search for studies investigating the application of viscoelastic testing for patients with breast cancer was conducted. Studies were included as long as they were original, peer-reviewed, and in the English language. Studies were excluded if they were review articles, did not include breast cancer patients, or if the full text was unavailable. This review identified 10 articles that met the inclusion criteria. Two of the studies utilized rotational thromboelastometry, and an additional four studies used thromboelastography, to assess hypercoagulability in patients with breast cancer. Three of the identified articles discussed the use of thromboelastometry in free flap breast reconstruction for patients with breast cancer. One study was a retrospective chart review looking at thromboelastography and microsurgical breast reconstruction. Current literature regarding the application of viscoelastic testing in breast cancer and free flap breast reconstruction is limited, with no randomized trials thus far. However, some studies suggest that there may be potential utility in viscoelastic testing to assess risk for thromboembolism in breast cancer patients, and future research in this area is warranted.
Using “dirty” precursors to develop ultra-clean crystals
Authors: Ikenson Ben
Published: June 2023

Organometallic elemental precursors promise potential for improved molecular beam epitaxy.
All-electron APW+lo calculation of magnetic molecules with the SIRIUS domain-specific package
Authors: Zhang Long , Kozhevnikov Anton , Schulthess Thomas , Trickey S. B. , Cheng Hai-Ping
Published: June 2023

We report APW+lo (augmented plane wave plus local orbital) density functional theory (DFT) calculations of large molecular systems using the domain specific SIRIUS multi-functional DFT package. The APW and FLAPW (full potential linearized APW) task and data parallelism options and the advanced eigen-system solver provided by SIRIUS can be exploited for performance gains in ground state Kohn–Sham calculations on large systems. This approach is distinct from our prior use of SIRIUS as a library backend to another APW+lo or FLAPW code. We benchmark the code and demonstrate performance on several magnetic molecule and metal organic framework systems. We show that the SIRIUS package in itself is capable of handling systems as large as a several hundred atoms in the unit cell without having to make technical choices that result in the loss of accuracy with respect to that needed for the study of magnetic systems.
Effects of the inhomogeneous vertical structure of an internal solitary wave on the force exerted on a horizontal transverse cylinder
Authors: Wang Shaodong , Du Hui , Wei Gang , Peng Pai , Xuan Pu , Xu Junnan
Published: June 2023

The vertical inhomogeneous structure of an internal solitary wave (ISW) in a continuous density pycnocline and its force exerted on a horizontal transverse cylinder are investigated theoretically and experimentally. The Dubreil–Jacotin–Long equation is used to describe the inhomogeneous vertical structure of the ISW, and a formula for calculating the vertical force on the cylinder in the inhomogeneous vertical structure is proposed. The inhomogeneous vertical structure of the ISW and its vertical force on a horizontal transverse cylinder are experimentally measured in a large stratified fluid flume. It is shown that the inhomogeneous vertical structure of the ISW is characterized by both inhomogeneous vertical distributions of ISW envelopes and amplitudes. The inhomogeneous vertical structure of the flow field is characterized by the shear distribution of the horizontal velocity above and below the continuous density pycnocline, as well as the reversed distribution of the vertical velocity on the windward and leeward sides of the ISW. The vertical force characteristics on the cylinder in the continuous density pycnocline, as well as the physical mechanism of the influence of the ISW inhomogeneous vertical structure on the vertical force, are obtained. The peak value of the vertical force on the cylinder situated at the pycnocline increases with the increase in ISW amplitude, and also, it increases and then decreases with the increase in submerged depth. Considering the inhomogeneous vertical structure characteristics of the ISW in an actual ocean environment, the average relative error in the vertical force calculation can be more effectively reduced by using the continuous density pycnocline force model than the strict two-layer fluid force model. The actual characteristics of ISWs in a stratified ocean environment can be objectively described, and the estimation accuracy of the vertical force on underwater objects can be greatly improved.
NV-doped microstructures with preferential orientation by growth on heteroepitaxial diamond
Authors: Weippert Jürgen , Engels Jan , Quellmalz Patricia , Giese Christian , Luo Tingpeng , Mathes Niklas , Lindner Lukas , Jeske Jan , Knittel Peter , Kirste Lutz , Kustermann Jan , Lebedev Vadim
Published: June 2023

For the wafer-scale fabrication of diamond devices, the growth of diamond substrates by heteroepitaxial chemical vapor deposition is the most promising option currently available. However, the transfer of growth and also structuring processes from small homoepitaxial to larger heteroepitaxial samples is not straightforward and requires adaptation. In this study, we present an approach for the fabrication of functional microstructures including pyramids and mesas as well as more complex structures with hollow centers. The associated methods were previously demonstrated by homoepitaxial growth and are now evaluated on heteroepitaxially grown diamond films. After optimizing the growth procedures to ensure a sufficient quality of the bare diamond substrates, precursor structures for overgrowth were fabricated by e-beam lithography and plasma etching. In the overgrowth of nanopillars, a truncated pyramidal shape was achieved. The characterization with scanning electron microscopy revealed the growth of higher-index facets. Nevertheless, photoluminescence spectroscopy reveals localized doping on the sides of the microstructures. In addition, optically detected magnetic resonance reaches a contrast of 6% of one preferred nitrogen vacancy orientation per facet and a transverse relaxation time T2∗ of 96 ns.
Metal–insulator transition of vanadium dioxide and the role of grain boundaries
Authors: Zhang Xuewei , Guo Yuzheng , Chu Daping , Robertson John
Published: June 2023

The metal–insulator transition (MIT) in polycrystalline vanadium dioxide (VO2) is less sharp than in single-crystal VO2 due to the presence of grain boundaries (GBs). The MIT causes a resistivity change (Ron/Roff) across the MIT to decline from the single-crystal value of ∼104 and also causes a larger hysteresis across the transition. The properties of GBs in VO2 are studied as a function of GB tilt angle. We find that V–V site pairing, which causes a monoclinic phase VO2 to be semiconducting in bulk, also controls bandgap opening at GBs, thus influencing the overall metal–insulator behavior. The almost linear relationship between the ratio of adhesion energy divided by two times the surface energy and the GB energy indicates that the GB energy of twin GBs is primarily determined by re-binding across the GB rather than by the corresponding surface energy. Moreover, a steeper linear fit, characterized by a slope of 0.62, observed in the monoclinic phase VO2 suggests that the GB energy and stability have a higher tolerance to interfacial distortion at the boundary, compared to the rutile phase VO2 and TiO2.
Self-consistent simulations of intracavity terahertz comb difference frequency generation by mid-infrared quantum cascade lasers
Authors: Popp Johannes , Seitner Lukas , Schreiber Michael A. , Haider Michael , Consolino Luigi , Sorgi Alessia , Cappelli Francesco , De Natale Paolo , Fujita Kazuue , Jirauschek Christian
Published: June 2023

Portable terahertz (THz) frequency comb sources are highly desired for applications in rotational molecular spectroscopy and sensing. To date, direct THz quantum cascade laser (QCL) frequency comb generation is not achievable at room temperature. However, THz comb generation based on intracavity difference frequency generation (DFG) in mid-infrared (mid-IR) QCLs is a promising alternative. Here, we present a numerical study of THz DFG-QCL comb formation in mid-IR QCLs based on a self-consistent multi-domain simulation approach. The dynamical simulations are performed using our open-source software tool mbsolve, which provides a flexible and efficient codebase for solving the generalized full-wave Maxwell–Bloch equations. Here, DFG in the active region of a dual-wavelength mid-IR QCL is considered for the generation of THz radiation. The mixing process and, thus, THz generation require a high second-order intersubband nonlinear susceptibility in the QCL active region and can be obtained by targeted quantum engineering. The associated nonlinear effects are included in the Hamiltonian of our Maxwell–Bloch simulation approach. All necessary input parameters for the description of the quantum system are determined self-consistently using our in-house ensemble Monte Carlo software tool for stationary carrier transport simulations. Notably, such simulations require a full-wave Maxwell–Bloch solver that does not employ the common rotating wave approximation, as a broadband optical field extending from the THz to the mid-IR region is investigated. Our modeling approach and the obtained simulation results for two THz DFG-QCL comb setups are validated against experimental data, showing reasonable agreement. Furthermore, we obtain a locked frequency modulated comb state for mid-IR and THz regimes.
Temperature dependence of avalanche breakdown in 4H-SiC devices
Authors: Steinmann Philipp , Hull Brett , Ji In-Hwan , Lichtenwalner Daniel , Van Brunt Edward
Published: June 2023

We report new data on the temperature coefficient of the avalanche breakdown voltage (BV) in 4H-SiC devices. We compare avalanche in different device types (MOSFETs/Schottky diodes), different measurement types [Id(Vd)-sweeps and unclamped inductive switching stress], and avalanche directions (vertical and lateral) for a wide range of avalanche voltages. We fit the measured BV(T)-curves to the one-sided abrupt junction model and extract values for the temperature coefficients of impact ionization coefficients in their Chynoweth and Thornber forms for both holes and electrons.
Photodissociation dynamics of methylamine in the blue edge of the A-band. I. The H-atom elimination channel
Authors: Recio Pedro , Cachón Javier , Zanchet Alexandre , Marggi Poullain Sonia , Bañares Luis
Published: June 2023

The photodissociation dynamics of methylamine (CH3NH2) upon excitation in the blue edge of the first absorption A-band, in the 198–203 nm range, are investigated by means of nanosecond pump–probe laser pulses and velocity map imaging combined with H(2S)-atom detection through resonance enhanced multiphoton ionization. The images and corresponding translational energy distributions for the H-atoms produced show three different contributions associated with three reaction pathways. The experimental results are complemented by high-level ab initio calculations. The potential energy curves computed as a function of the N–H and C–H bond distances allow us to draw a picture of the different mechanisms. Major dissociation occurs through N–H bond cleavage and it is triggered by an initial geometrical change, i.e., from a pyramidal configuration of the C–NH2 with respect to the N atom to a planar geometry. The molecule is then driven into a conical intersection (CI) seam where three outcomes can take place: first, threshold dissociation into the second dissociation limit, associated with the formation of CH3NH(Ã), is observed; second, direct dissociation after passage through the CI leading to the formation of ground state products; and third, internal conversion into the ground state well in advance to dissociation. While the two last pathways were previously reported at a variety of wavelengths in the 203–240 nm range, the former had not been observed before to the best of our knowledge. The role of the CI and the presence of an exit barrier in the excited state, which modify the dynamics leading the two last mechanisms, are discussed considering the different excitation energies used.
In situ monitoring of initial plasma electrolytic oxidation process on 60 vol. % SiCp/2009 aluminum matrix composite by sound and vibration measurement techniques
Authors: Liao Yizhao , Zhou Qian , Gao Chuanli , Xu Chi , Jin Xiaoyue , Du Jiancheng , Xue Wenbin , Zhang Yongzhong
Published: June 2023

The initial discharge process of plasma electrolytic oxidation (PEO) on the 60 vol. % SiCP/2009 aluminum matrix composite in silicate solution was in situ monitored by sound and vibration measurement techniques. The underwater sound, airborne sound, and sample vibration signals were detected in the initial 120 s of the PEO process, and their generation mechanism was discussed. In terms of waveforms and spectrograms of the sound and vibration signals, the initial PEO process can be divided into five stages: conventional anodizing stage (I), glow discharge stage (Ⅱ), tiny spark discharge stage (Ⅲ), large spark discharge stage (Ⅳ), and strong spark discharge stage (Ⅴ). The sound and vibration signals during the PEO process are attributed to the evolution of bubbles, which are from the plasma discharge, electrochemical reactions, and vaporization of electrolyte under Joule heat. In stage I, these signals completely come from the bubbles produced by the evaporative electrolyte and electrochemical reactions. In stages Ⅱ–Ⅴ, the bubbles from the plasma discharge gradually become the main source of these signals with increasing discharge intensity. In addition, the spike peaks on the waveforms of these signals at stage Ⅴ are related to the strong discharge sparks. These results demonstrate that sound and vibration measurement techniques can effectively monitor the PEO discharge process.
Role of finite probe size in measuring growth exponent in film deposition
Authors: Amorim Pablo M. , Mozo Luis Edwin E. , Dall’Agnol Fernando F. , de Assis Thiago A.
Published: June 2023

We use computer simulations to investigate the effects of the tip diameter of an electrostatic force microscope (EFM) operating at a constant force on the extraction of the growth exponent β during film growing in a one-dimensional substrate. Laplace’s equation is solved in the EFM simulation using the finite element method to determine the electrostatic force between the tip and the film interface. Importantly, for EFM tips with sufficiently large apex diameters, the topographies calculated with EFM and those computed with the transformed mean height profile (TMHP) method, where the interface is divided into bins of the same tip diameter size and the average height within each bin is used to transform the original interface, are almost identical. This was shown in the context of lattice models of the Kardar–Parisi–Zhang (KPZ) and Villain–Lai–Das–Sarma (VLDS) classes. The global roughness of the film surface, W, scales with the diameter of the EFM tip, ε, as W/a=(ε/a)αg[Ψ], where a is the lattice parameter, α is the KPZ/VLDS roughness exponent, and g is a universal scaling function of the argument Ψ≡t/(ε/a)z, where t and z are the reduced time of deposition and the KPZ/VLDS dynamic exponent, respectively. These results provide a limit for ε from which a KPZ/VLDS growth exponent can be reliably determined with EFM at a constant force. When the EFM tip diameter is larger than the surface correlation length, a misleading effective growth exponent consistent with uncorrelated growth is found.
Attitude control of 3D soft pneumatic actuators based on BP neural
network
Authors: Zhang Chengpei , Zhou Wen , Zheng Tengfei , Wang Xudong , Wang Chaohui
Published: June 2023

Soft pneumatic robotics have attracted considerable attention in recent years due to their deformation capabilities, which far exceed those of conventional robotics. However, precise control of soft pneumatic actuators remains a challenge due to the lack of model-based control techniques. This work aims to employ a high-precision and low-cost backpropagation (BP) neural network-based model method to control a 3D soft pneumatic actuator. Experiments show that this BP neural network-based model control method performs well in terms of precision, in which the errors of bending angle and deflection angle are within 0.8° and 1.2°, respectively, and the end point position error of the soft actuator is less than 2.5 mm, which is significantly better than traditional modeling methods, demonstrating the application potential of soft robots for high-precision operations.