Temperature Fluctuation Attenuation of Circulating Cooling Water Using Dynamic Thermal Filtering

The Demand for circulating cooling water (CCW) with high temperature stability and a quick response to temperature control is essential for precision engineering, so a dynamic thermal filtering method is proposed in this paper. Some CCW is bypassed, blocked, and used as a thermal capacity medium, and the temperature fluctuation of CCW is significantly reduced by heat exchanging with the medium. The temperature of the medium dynamically follows the set value of the CCW temperature by real time updating, and so realizes a quick CCW temperature control response. The attenuation ratio of temperature fluctuation was derived, theoretically validating the effectiveness of the method. The experimental results indicate that a CCW temperature fluctuation attenuation ratio of tens of dB (−3.47 dB, −6.91 dB, −10.97 dB and −15.28 dB corresponding to temperature fluctuation frequencies of 0.01 Hz, 0.025 Hz, 0.053 Hz and 0.105 Hz, respectively) is achieved by the proposed method. The updating time of thermal capacity medium is 82 s, which means that the temperature fluctuation attenuation remains functionally valid when the set value of CCW changes. The proposed method is low cost in operation and provides an effective approach to satisfy the challenging demand for CCW with high stability and a good dynamic temperature control performance

Ultraprecision Diameter Measurement of Small Holes with Large Depth-To-Diameter Ratios Based on Spherical Scattering Electrical-Field Probing

In order to solve the difficulty of precision measurement of small hole diameters with large depth-to-diameter ratios, a new measurement method based on spherical scattering electrical-field probing (SSEP) was developed. A spherical scattering electrical field with identical sensing characteristics in arbitrary spatial directions was formed to convert the micro gap between the probing-ball and the part being measured into an electrical signal. 3D non-contact probing, nanometer resolution, and approximate point probing—which are key properties for high measurement precision and large measurable depth-to-diameter ratios—were achieved. A specially designed hole diameter measuring machine (HDMM) was developed, and key techniques, including laser interferometry for macro displacement measurement of the probe, multi-degree-of-freedom adjustment of hole attitude, and measurement process planning, are described. Experiments were carried out using the HDMM and a probing sensor with a ϕ3-mm probing ball and a 150-mm-long stylus to verify the performance of the probing sensor and the measuring machine. The experimental results indicate that the resolution of the probing sensor was as small as 1 nm, and the expanded uncertainty of measurement result was 0.2 μm (k = 2) when a ϕ20-mm ring gauge standard was measured

Quantitative Investigation of Surface Charge Distribution and Point Probing Characteristics of Spherical Scattering Electrical Field Probe for Precision Measurement of Miniature Internal Structures with High Aspect Ratios

For precision measurement of miniature internal structures with high aspect ratios, a spherical scattering electrical field probe (SSEP) is proposed based on charge signal detection. The characteristics and laws governing surface charge distribution on the probing ball of the SSEP are analyzed, with the spherical scattering electrical field modeled using a 3D seven-point finite difference method. The model is validated with finite element simulation by comparing with the analysis results of typical situations, in which probing balls of different diameters are used to probe a grounded plane with a probing gap of 0.3 μm. Results obtained with the proposed model and finite element method (FEM) simulation indicate that 31% of the total surface charge on a ϕ1 mm probing ball concentrates in an area that occupies 1% of the total probing ball surface. Moreover, this surface charge concentration remains unchanged when the surface being measured varies in geometry, or when the probing gap varies in sensing range. Based on this, the SSEP has realized approximate point probing capability with a virtual “needle” of electrical effect. Together with its non-contact sensing characteristics and 3D isotropy, it can, therefore, be concluded that the SSEP has great potential to be an ideal solution for precision measurement of miniature internal structures with high aspect ratios

Effects of Low-Dose Recombinant Human Brain Natriuretic Peptide on Anterior Myocardial Infarction Complicated by Cardiogenic Shock

Abstract INTRODUCTION: The mortality due to cardiogenic shock complicating acute myocardial infarction (AMI) is high even in patients with early revascularization. Infusion of low dose recombinant human brain natriuretic peptide (rhBNP) at the time of AMI is well tolerated and could improve cardiac function. OBJECTIVE: The objective of this study was to evaluate the hemodynamic effects of rhBNP in AMI patients revascularized by emergency percutaneous coronary intervention (PCI) who developed cardiogenic shock. METHODS: A total of 48 patients with acute ST segment elevation myocardial infarction (STEMI) complicated by cardiogenic shock and whose hemodynamic status was improved following emergency PCI were enrolled. Patients were randomly assigned to rhBNP (n=25) and control (n=23) groups. In addition to standard therapy, study group individuals received rhBNP by continuous infusion at 0.005 µg kg−1 min−1 for 72 hours. RESULTS: Baseline characteristics, medications, and peak of cardiac troponin I (cTnI) were similar between both groups. rhBNP treatment resulted in consistently improved pulmonary capillary wedge pressure (PCWP) compared to the control group. Respectively, 7 and 9 patients died in experimental and control groups. No drug-related serious adverse events occurred in either group. CONCLUSION: When added to standard care in stable patients with cardiogenic shock complicating anterior STEMI, low dose rhBNP improves PCWP and is well tolerated

Behavioral and emotional difficulties and HIV treatment outcomes among HIV-infected children in rural southwestern China

Abstract Background Previous studies have not clearly demonstrated the impact of behavioral and emotional problems (BEDs) on treatment outcomes among HIV-infected children on antiretroviral therapy (ART). This study aimed to describe the prevalence of BEDs among this population and identify the factors associated with HIV treatment outcomes. Methods This cross-sectional study was conducted in Guangxi, China, between July and August 2021. HIV-infected children answered questionnaires about BEDs, physical health, social support, and whether they have missed doses in the past month. BEDs were assessed using the Chinese version of the self-reported Strengths and Difficulties Questionnaire (SDQ-C). The self-reported survey data were linked to participants’ HIV care information that was obtained from the national surveillance database. Univariate and multivariate logistic regression models were used to identify factors that were associated with missed doses in the past month and virological failure. Results The study sample was 325 HIV-infected children. HIV-infected children had a higher proportion of abnormal scores on SDQ-C total difficulties compared to their peers in the general population (16.9 vs 10.0%; P = 0.002). An abnormal SDQ-C total difficulties score (AOR = 2.06, 95%CI: 1.10–3.88) and infrequency of receiving assistance and support from parents over the past 3 months (AOR = 1.85, 95%CI: 1.12–3.06) were significantly associated with missed doses in the past month. Between the ages of 14–17 years (AOR = 2.66, 95% CI: 1.37–5.16), female (AOR = 2.21, 95% CI: 1.20–4.08), and suboptimal adherence (AOR = 2.45, 95% CI: 1.32–4.57) were significantly associated with virological failure. Conclusions Children’s mental health plays a role in HIV treatment outcomes. Psychological interventions should be promoted in pediatric HIV care clinics to improve children’s mental health status and HIV treatment outcomes

Correlation analysis between the static and the changed neutrophil-to-lymphocyte ratio and in-hospital mortality in critical patients with acute heart failure

Association between neutrophil-to-lymphocyte ratio (NLR) on admission and poor prognosis in patients with acute heart failure (AHF) has been well established. However, the relationship between dynamic changes in NLR and in-hospital mortality in AHF patients has not been studied. Our purpose was to determine if an early change in NLR within the first week after AHF patients was admitted to intensive care unit (ICU) was associated with in-hospital mortality. Data from the medical information mart for intensive care IV (the MIMIC-IV) database was analyzed. The effect of baseline NLR on in-hospital mortality in critical patients with AHF was evaluated utilizing smooth curve fitting and multivariable logistic regression analysis. Moreover, comparison of the dynamic change in NLR among survivors and non-survivors was performed using the generalized additive mixed model (GAMM). There were 1169 participants who took part in the present study, 986 of whom were in-hospital survivors and 183 of whom were in-hospital non-survivors. The smooth curve fitting revealed a positive relationship between baseline NLR and in-hospital mortality, and multivariable logistic regression analysis indicated that baseline NLR was an independent risk factor for in-hospital mortality (OR 1.04, 95% CI 1.02,1.07, P-value = 0.001). After adjusting for confounders, GAMM showed that the difference in NLR between survivors and non-survivors grew gradually during the first week after ICU admission, and the difference grew by an average of 0.51 per day (β = 0.51, 95% CI 0.45–0.56, P-value Baseline NLR was associated with poor prognosis in critical patients with AHF. Early rises in NLR were linked to higher in-hospital mortality, which suggests that keeping track of how NLR early changes might help identify short-term prognosis of critical patients with AHF.</p