Speed control with low armature loss for very small sensorless brushed DC motors

A method for speed control of brushed dc motors is presented. It is particularly applicable to motors with armatures of less than 1 cm3. Motors with very small armatures are difficult to control using the usual pulsewidth-modulation (PWM) approach and are apt to overheat if so driven. The technique regulates speed via the back electromotive force but does not require current-discontinuous drives. Armature heating in small motors under PWM drive is explained and quantified. The method is verified through simulation and measurement. Control is improved, and armature losses are minimized. The method can expect to find application in miniature mechatronic equipment

Neprilysin inhibition: A brief review of past pharmacological strategies for heart failure treatment and future directions

Heart failure (HF) is a manifestation of aberrant vascular responses and remains a public health concern with a worldwide prevalence of around 23 million and a 5-year mortality numerically equivalent to many cancers. Over the last two decades, mortality from HF reached a plateau with current pharmaceutical agents and mechanical cardiac support. In the last several years, various “novel” pharmaceutical agents have been tested in clinical trials and ultimately met with disappointment, showing only incremental benefit in the treatment of HF. Designing a HF drug with enhanced efficacy over existing agents seemed like a Sisyphean task. Yet again, pharmaceutical chemists have demonstrated their prowess in lateral thinking by developing a vasoactive agent which is a co-crystallized compound of valsartan and sacubitril in a one-to-one molar ratio; the former molecule belongs to a family of agents that are the current standard of care for HF and the latter molecule is a novel agent which inhibits neprilysin — a neutral endopeptidase found in human plasma which alters neurohumoral responses. In July of 2015, a drug which is a combination of valsartan and sacubitril was formally licensed by the United States Food and Drug Administration for the treatment of HF. This review describes the evolution of HF medications focusing on rational drug design with the first HF medication, the beta-adrenergic receptor antagonist. We then discuss the biochemical and physiological properties of sacubitril/valsartan which likely lead to its dramatic ability to ameliorate HF mortality

Reaching the Diffraction Limit - Differential Speckle and Wide-Field Imaging for the Gemini-N Telescope

Speckle imaging allows telescopes to achieve di raction limited imaging performance. The technique requires cameras capable of reading out frames at a very fast rate, e ectively `freezing out' atmospheric seeing. The resulting speckles can be correlated and images reconstructed that are at the di raction limit of the telescope. These new instruments are based on the successful performance and design of the Di erential Speckle Survey Instrument (DSSI) [2, 1]. The instruments are being built for the Gemini-N and WIYN telescopes and will be made available to the community via the peer review proposal process. We envision their primary use to be validation and characterization of exoplanet targets from the NASA K2 and TESS missions and RV discovered exoplanets. Such targets will provide excellent follow-up candidates for both the WIYN and Gemini telescopes [3]. Examples of DSSI data are shown in the gures below. We expect similar data quality in speckle imaging mode with the new instruments. Additionally, both cameras will have a wide- eld mode and standard SDSS lters. They will be highly versatile instruments and it is that likely many other science programs will request time on the cameras. The limiting magnitude for speckle observations, will remain around 13-14th at WIYN and 16-17th at Gemini, while wide- eld, normal CCD imaging operation should be able to go to much fainter, providing usual CCD imaging and photometric capabilities. The instruments will also have high utility as scoring cameras for telescope engineering purposes, or other applications where high time resolution is needed. Instrument support will be provided, including a software pipeline that takes raw speckle data to fully reconstructed images

Reaching the Diffraction Limit - Differential Speckle and Wide-Field Imaging for the WIYN Telescope

Speckle imaging allows telescopes to achieve diffraction limited imaging performance. The technique requires cameras capable of reading out frames at a very fast rate, effectively 'freezing out' atmospheric seeing. The resulting speckles can be correlated and images reconstructed that are at the diffraction limit of the telescope. These new instruments are based on the successful performance and design of the Differential Speckle Survey Instrument (DSSI).The instruments are being built for the Gemini-N and WIYN telescopes and will be made available to the community via the peer review proposal process. We envision their primary use to be validation and characterization of exoplanet targets from the NASA, K2 and TESS missions and RV discovered exoplanets. Such targets will provide excellent follow-up candidates for both the WIYN and Gemini telescopes. We expect similar data quality in speckle imaging mode with the new instruments. Additionally, both cameras will have a wide-field mode and standard SDSS filters. They will be highly versatile instruments and it is that likely many other science programs will request time on the cameras. The limiting magnitude for speckle observations will remain around 13-14th at WIYN and 16-17th at Gemini, while wide-field, normal CCD imaging operation should be able to go to much fainter, providing usual CCD imaging and photometric capabilities. The instruments will also have high utility as scoring cameras for telescope engineering purposes, or other applications where high time resolution is needed. Instrument support will be provided, including a software pipeline that takes raw speckle data to fully reconstructed images

Linked CSF reduction of phosphorylated tau and IL-8 in HIV associated neurocognitive disorder.

HIV-associated neurocognitive disorder (HAND) is a common condition in both developed and developing nations, but its cause is largely unknown. Previous research has inconsistently linked Alzheimer's disease (AD), viral burden, and inflammation to the onset of HAND in HIV-infected individuals. Here we simultaneously measured cerebrospinal fluid (CSF) levels of established amyloid and tau biomarkers for AD, viral copy numbers, and six key cytokines in 41 HIV-infected individuals off combination anti-retroviral therapy (14 with HAND) who underwent detailed clinical and neuropsychological characterization, and compared their CSF patterns with those from young healthy subjects, older healthy subjects with normal cognition, and older people with AD. HAND was associated with the lowest CSF levels of phosphorylated tau (p-Tau181) after accounting for age and race. We also found very high CSF levels of the pro-inflammatory interferon gamma-induced protein 10 (IP-10/CXCL10) in HIV regardless of cognition, but elevated CSF interleukin 8 (IL-8/CXCL8) only in HIV-NC but not HAND. Eleven HIV-infected subjects underwent repeat CSF collection six months later and showed strongly correlated longitudinal changes in p-Tau181 and IL-8 levels (R = 0.841). These data suggest reduced IL-8 relative to IP-10 and reduced p-Tau181 to characterize HAND

Academic Priority: Graduate/Doctoral Research

Overview Doctoral Education at UNO: Past, Present, and Future

Empirical relationships among oliguria, creatinine, mortality, and renal replacement therapy in the critically ill

Purpose: The observation periods and thresholds of serum creatinine and urine output defined in the Acute Kidney Injury Network (AKIN) criteria were not empirically derived. By continuously varying creatinine/urine output thresholds as well as the observation period, we sought to investigate the empirical relationships among creatinine, oliguria, in-hospital mortality, and receipt of renal replacement therapy (RRT). Methods: Using a high-resolution database (Multiparameter Intelligent Monitoring in Intensive Care II), we extracted data from 17,227 critically ill patients with an in-hospital mortality rate of 10.9 %. The 14,526 patients had urine output measurements. Various combinations of creatinine/urine output thresholds and observation periods were investigated by building multivariate logistic regression models for in-hospital mortality and RRT predictions. For creatinine, both absolute and percentage increases were analyzed. To visualize the dependence of adjusted mortality and RRT rate on creatinine, the urine output, and the observation period, we generated contour plots. Results: Mortality risk was high when absolute creatinine increase was high regardless of the observation period, when percentage creatinine increase was high and the observation period was long, and when oliguria was sustained for a long period of time. Similar contour patterns emerged for RRT. The variability in predictive accuracy was small across different combinations of thresholds and observation periods. Conclusions: The contour plots presented in this article complement the AKIN definition. A multi-center study should confirm the universal validity of the results presented in this articleNational Institute of Biomedical Imaging and Bioengineering (U.S.) (Grant R01 EB001659