Battery-Electric Powertrain System Design for the HorizonUAM Multirotor Air Taxi Concept

The work presented herein has been conducted within the DLR internal research project HorizonUAM, which encompasses research within numerous areas related to urban air mobility. One of the project goals was to develop a safe and certifiable onboard system concept. This paper aims to present the conceptual propulsion system architecture design for an all-electric battery-powered multirotor electric Vertical Takeoff and Landing (eVTOL) vehicle. Therefore, a conceptual design method was developed that provides a structured approach for designing the safe multirotor propulsion architecture. Based on the concept of operation the powertrain system was initially predefined, iteratively refined based on the safety assessment and validated through component sizing and simulations. The analysis was conducted within three system groups that were developed in parallel: the drivetrain, the energy supply and the thermal management system. The design process indicated that a pure quadcopter propulsion system can merely be designed reasonably for meeting the European Union Aviation Safety Agency (EASA) reliability specifications. By adding two push propellers and implementing numerous safety as well as passivation measures the reliability specifications defined by EASA could finally be fulfilled. The subsequent system simulations also verified that the system architecture is capable of meeting the requirements of the vehicle concept of operations. However, further work is required to extend the safety analysis to additional system components as the thermal management system or the battery management system and to reduce propulsion system weight.Comment: 38 pages, 27 figures, CEAS Aeronautical Journal Special Issue "HorizonUAM - Opportunities and Challenges of Urban Air Mobility

Systematic Multi-Domain Alzheimer's Risk Reduction Trial (SMARRT): Study Protocol.

This article describes the protocol for the Systematic Multi-domain Alzheimer's Risk Reduction Trial (SMARRT), a single-blind randomized pilot trial to test a personalized, pragmatic, multi-domain Alzheimer's disease (AD) risk reduction intervention in a US integrated healthcare delivery system. Study participants will be 200 higher-risk older adults (age 70-89 years with subjective cognitive complaints, low normal performance on cognitive screen, and ≥ two modifiable risk factors targeted by our intervention) who will be recruited from selected primary care clinics of Kaiser Permanente Washington, oversampling people with non-white race or Hispanic ethnicity. Study participants will be randomly assigned to a two-year Alzheimer's risk reduction intervention (SMARRT) or a Health Education (HE) control. Randomization will be stratified by clinic, race/ethnicity (non-Hispanic white versus non-white or Hispanic), and age (70-79, 80-89). Participants randomized to the SMARRT group will work with a behavioral coach and nurse to develop a personalized plan related to their risk factors (poorly controlled hypertension, diabetes with evidence of hyper or hypoglycemia, depressive symptoms, poor sleep quality, contraindicated medications, physical inactivity, low cognitive stimulation, social isolation, poor diet, smoking). Participants in the HE control group will be mailed general health education information about these risk factors for AD. The primary outcome is two-year cognitive change on a cognitive test composite score. Secondary outcomes include: 1) improvement in targeted risk factors, 2) individual cognitive domain composite scores, 3) physical performance, 4) functional ability, 5) quality of life, and 6) incidence of mild cognitive impairment, AD, and dementia. Primary and secondary outcomes will be assessed in both groups at baseline and 6, 12, 18, and 24 months

Ex Vivo Expansion of Human CD8+ T Cells Using Autologous CD4+ T Cell Help

Background: Using in vivo mouse models, the mechanisms of CD4+ T cell help have been intensively investigated. However, a mechanistic analysis of human CD4+ T cell help is largely lacking. Our goal was to elucidate the mechanisms of human CD4+ T cell help of CD8+ T cell proliferation using a novel in vitro model. Methods/Principal Findings: We developed a genetically engineered novel human cell-based artificial APC, aAPC/mOKT3, which expresses a membranous form of the anti-CD3 monoclonal antibody OKT3 as well as other immune accessory molecules. Without requiring the addition of allogeneic feeder cells, aAPC/mOKT3 enabled the expansion of both peripheral and tumor-infiltrating T cells, regardless of HLA-restriction. Stimulation with aAPC/mOKT3 did not expand Foxp3+ regulatory T cells, and expanded tumor infiltrating lymphocytes predominantly secreted Th1-type cytokines, interferon-γ and IL-2. In this aAPC-based system, the presence of autologous CD4+ T cells was associated with significantly improved CD8+ T cell expansion in vitro. The CD4+ T cell derived cytokines IL-2 and IL-21 were necessary but not sufficient for this effect. However, CD4+ T cell help of CD8+ T cell proliferation was partially recapitulated by both adding IL-2/IL-21 and by upregulation of IL-21 receptor on CD8+ T cells. Conclusions: We have developed an in vitro model that advances our understanding of the immunobiology of human CD4+ T cell help of CD8+ T cells. Our data suggests that human CD4+ T cell help can be leveraged to expand CD8+ T cells in vitro

The Impact of Pandemic-Related Restrictions on Dementia Risk Factors in Older Adults.

Adults aged 65+ are at highest risk for severe COVID-19 outcomes, and prior to the distribution of vaccines in the U.S., were strongly advised to quarantine at home to reduce risk of infection. This study examines how COVID-19 restrictions impacted various dementia risk factors and social determinants of health among older adults. Data came from the Systematic Multi-Domain Alzheimers Risk Reduction Trial, a randomized controlled trial of a multi-domain intervention in higher-risk older adults (aged 70-89). A questionnaire was administered to participants (n = 156; 90.7% response rate) between May 2020 and March 2021. The data show a significant decline in social activity, physical activity, and mood among respondents. Compared to living with others, living alone was associated with worsened physical activity, diet, and subjective memory/thinking, adjusted for sex and age. These results suggest that the COVID-19 pandemic exacerbated several risk factors for dementia in older adults, particularly in those living alone

Conceptual Design of a Safety-critical Battery-electric Powertrain System for the HorizonUAM Air Taxi Concept

Within the DLR internal research project HorizonUAM the department of Safety-Critical Systems and Systems Engineering focused on developing a safe and certifiable onboard system concept for an intra-city eVTOL multicopter. This poster presents the conceptual design steps of the propulsion system that was aligned to meet the EASA special Condition for Vertical Take-Off and Landing Aircraft (EASA SC-VTOL) [1] safety & reliability requirements. Initially, several studies were conducted analyzing the powertrain technologies. Then, the battery-electric propulsion system architecture was iteratively developed based on the safety assessment and validated through component sizing and simulations

Incremental circle transform and eigenvalue analysis for object recognition: an integrated approach

In this paper, a new method to recognize two-dimensional objects by combining the concept of incremental circle transform (ICT) and eigenvalue analysis is presented. The algorithm has two stages. In the first stage, the shape of an object is preserved by the use of ICT (Bein et al. Proc. ICARCV, 1990, 851-855), which maps the boundary of an object into a circle with constant radius. In the second stage, the eigenvalues of the variance and covariance matrix of the computed ICT vector are found and are used to represent compactly the set of objects. Apart of realizing memory reduction, the proposed integrated method is shown to be rotation and translation invariant. Experimental results have been highly encouraging in terms of accuracy in the recognition of target objects. (C) 2000 Elsevier Science B.V. All rights reserved

1,4-Disilacyclohexa-2,5-diene : a molecular building block that allows for remarkably strong neutral cyclic cross-hyperconjugation

2,3,5,6-Tetraethyl-1,4-disilacyclohexa-2,5-dienes with either four chloro (1a), methyl (1b), or trimethylsilyl (TMS) (1c) substituents at the two silicon atoms were examined in an effort to design rigid compounds with strong neutral cross-hyperconjugation between pi- and sigma-bonded molecular segments arranged into a cycle. Remarkable variations in the lowest electronic excitation energies, lowest ionization energies, and the first oxidation potentials were observed upon change of substituents, as determined by gas phase ultraviolet (UV) absorption spectroscopy, ultraviolet photoelectron spectroscopy (UPS), and cyclic voltammetry. A particularly strong neutral cyclic cross-hyperconjugation was observed in 1c. Its lowest electron binding energy (7.1 eV) is distinctly different from that of 1b (8.5 eV). Molecular orbital analysis reveals a stronger interaction between filled pi(C=C) and pi(SiR2) group orbitals in 1c than in 1a and 1b. The energy shift in the highest occupied molecular orbital is also reflected in the first oxidation potentials as observed in the cyclic voltammograms of the respective compounds (1.47, 0.88, and 0.46 V for 1a, 1b and 1c, respectively). Furthermore, 1,4-disilacyclohexadiene 1c absorbs strongly at 273 nm (4.55 eV), whereas 1a and 1b have no symmetry allowed excitations above 215 nm (below 5.77 eV). Thus, suitably substituted 1,4-disilacyclohexa-2,5-dienes could represent novel building blocks for the design of larger cross-hyperconjugated molecules as alternatives to traditional purely cross-p-conjugated analogues, and could allow for design of molecules with properties that are not accessible to those that are exclusively pi-conjugated

Systematic Multi-Domain Alzheimer's Risk Reduction Trial (SMARRT): Study Protocol.

This article describes the protocol for the Systematic Multi-domain Alzheimer's Risk Reduction Trial (SMARRT), a single-blind randomized pilot trial to test a personalized, pragmatic, multi-domain Alzheimer's disease (AD) risk reduction intervention in a US integrated healthcare delivery system. Study participants will be 200 higher-risk older adults (age 70-89 years with subjective cognitive complaints, low normal performance on cognitive screen, and ≥ two modifiable risk factors targeted by our intervention) who will be recruited from selected primary care clinics of Kaiser Permanente Washington, oversampling people with non-white race or Hispanic ethnicity. Study participants will be randomly assigned to a two-year Alzheimer's risk reduction intervention (SMARRT) or a Health Education (HE) control. Randomization will be stratified by clinic, race/ethnicity (non-Hispanic white versus non-white or Hispanic), and age (70-79, 80-89). Participants randomized to the SMARRT group will work with a behavioral coach and nurse to develop a personalized plan related to their risk factors (poorly controlled hypertension, diabetes with evidence of hyper or hypoglycemia, depressive symptoms, poor sleep quality, contraindicated medications, physical inactivity, low cognitive stimulation, social isolation, poor diet, smoking). Participants in the HE control group will be mailed general health education information about these risk factors for AD. The primary outcome is two-year cognitive change on a cognitive test composite score. Secondary outcomes include: 1) improvement in targeted risk factors, 2) individual cognitive domain composite scores, 3) physical performance, 4) functional ability, 5) quality of life, and 6) incidence of mild cognitive impairment, AD, and dementia. Primary and secondary outcomes will be assessed in both groups at baseline and 6, 12, 18, and 24 months

Long-Term Outcomes of Hairy Cell Leukemia Treated With Purine Analogs: A Comparison With the General Population

Hairy cell leukemia (HCL) is a rare hematologic malignancy with high response rates and long progression-free survival (PFS) after treatment with purine nucleoside analogs (PNAs; Pentostatin/Cladribine). However, treatment is not curative, and subsequent treatment at relapse is often required. Rechallenge with a purine analog is commonly implemented despite limited data regarding the efficacy of this approach. We retrospectively analyzed 61 consecutive patients with HCL diagnosed between 1995 and 2013 at Cleveland Clinic. Median follow-up was 72 months (3-193). Cladribine as first-line therapy was administered to 59 patients (97%). Overall response rate (ORR) was 97%, with 78% of patients achieving complete remission (CR). PFS after response was significantly improved for patients who achieved CR compared with those with a partial remission (PR) (5-year PFS 71% vs. 39%, respectively [P = .004]). Of the 19 patients who relapsed, 12 received PNAs as second-line treatment with an ORR (83%) comparable to what these patients had with first-line treatment (ORR 92%). Overall survival of all 61 patients was excellent and superior to that of age-, sex-, and race-matched controls from the general population, possibly due to selection bias. In an analysis of a larger cohort of unselected patients in the Surveillance, Epidemiology, and End Results (SEER) database, we found that mortality rates for patients with HCL were similar to those of the general population approximately 5 years after diagnosis. These data confirm the excellent prognosis for patients with HCL after first- and second-line PNA therapy