Smoothing tool design and performance during subaperture glass polishing.

During subaperture tool grinding and polishing, overlaps of the tool influence function can result in undesirable mid-spatial frequency (MSF) errors in the form of surface ripples, which are often corrected using a smoothing polishing step. In this study, flat multi-layer smoothing polishing tools are designed and tested to simultaneously (1) reduce or remove MSF errors, (2) minimize surface figure degradation, and (3) maximize the material removal rate. A time-dependent convergence model in which spatial material removal varies with a workpiece-tool height mismatch, combined with a finite element mechanical analysis to determine the interface contact pressure distribution, was developed to evaluate various smoothing tool designs as a function of tool material properties, thicknesses, pad textures, and displacements. An improvement in smoothing tool performance is achieved when the gap pressure constant, h¯ (which describes the inverse rate at which the pressure drops with a workpiece-tool height mismatch), is minimized for smaller spatial scale length surface features (namely, MSF errors) and maximized for large spatial scale length features (i.e., surface figure). Five specific smoothing tool designs were experimentally evaluated. A two-layer smoothing tool using a thin, grooved IC1000 polyurethane pad (with a high elastic modulus, E p a d =360M P a), thicker blue foam (with an intermediate modulus, E f o a m =5.3M P a) underlayer, and an optimized displacement (d t=1m m) provided the best overall performance (namely, high MSF error convergence, minimal surface figure degradation, and high material removal rate).

Safety, Feasibility and Efficacy of Lokomat® and Armeo®Spring Training in Deconditioned Paediatric, Adolescent and Young Adult Cancer Patients.

BACKGROUND: Rehabilitation robotics is a field of study which aims to understand and augment rehabilitation through the use of robotics devices. OBJECTIVE: This proof of concept study aimed to test the safety (no. adverse events, incidence of infection), feasibility (program demand, adherence, participant satisfaction) and efficacy (Peak Oxygen uptake (VO2peak), 6-min walk test, gait speeds, Canadian Occupational Performance Measure, quality of life) of Lokomat® and Armeo®Spring training in children and adolescents and young adults (AYAs) during or soon after cancer treatment. METHOD: This was a 6-week single arm pre-post study. Cancer patients with significant musculoskeletal, neurological, gait and/or upper limb deficiency aged 5 to 25 years were recruited. The rehabilitation program included access to two robotic orthoses: the Lokomat® and/or Armeo®Spring. Robotic devices utilised real-time biofeedback and computer games to engage and guide participants through a repetitive functional range of movement aimed at improving functional deficiencies. Progressive increases in exercise intensity and duration were encouraged. RESULTS: Twentey-eight participants were approached for study; twenty-one consented. Seventy-six percent completed the six-week intervention with an overall adherence of 83%. The mean participant satisfaction score was 8.8/10. Forty-nine adverse events were recorded throughout the course of the study, forty-five grade 1, three grade 2 and one grade 3. No adverse events led to withdrawal from the study. Preliminary efficacy results indicate large beneficial effects on VO2peak (r = 0.63), 10 m comfortable pace walk (r = 0.51) and maximal pace walk (r = 0.60), 6-min walk test (r = 0.60), maximal back and leg strength (r = 0.71), trunk flexibility (r = 0.60), The European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ C30) (r = 0.61), Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT F) r = 0.53 and the Canadian Occupational Performance Measure, satisfaction (r = 0.88) and performance scores (r = 0.83), and moderate beneficial effects on Leisure Score Index (LSI) (r = 0.30). CONCLUSION: Our results suggest that Lokomat® and Armeo®Spring training is safe and feasible for use in children and AYAs who are currently undergoing or have recently completed cancer therapy. A larger controlled trial investigating the efficacy of robotics rehabilitation in this cohort is warranted.

Clinical Significance of Quantitative Viral Load in Patients Positive for SARS-CoV-2.

Cycle threshold (CT) refers to the number of cycles in a reverse transcriptase polymerase chain reaction (RT-PCR) assay needed to amplify viral RNA and can be used to indicate viral load. CT is inversely related to viral load, where lower CT values indicate higher viral levels. Data suggest lower CT scores are associated with worse outcomes in COVID; however, quantitative CT scores are not typically reported to patients. This retrospective analysis examined the use of CT scores in patient counseling for positive COVID results and suggests that higher viral loads were associated with greater need for prescription drug therapy in the outpatient setting. Patient perception of CT score was found to influence masking and quarantine behavior. We hypothesize that a quantitative threshold for viral load such as CT can be useful in patient counseling, estimating need for drug therapy, and influencing behavior toward public health concerns.

Understanding and reducing mid-spatial frequency ripples during hemispherical sub-aperture tool glass polishing.

During sub-aperture tool polishing of glass optics, mid-spatial surface ripples are generated because of material removal non-uniformities during tool linear translation (resulting in feed ripples) and tool pathway step overlaps (resulting in pitch ripples). A variety of tool influence function (TIF) spots, trenches, and patches were created to understand and minimize such ripples on fused silica workpieces after polishing with cerium oxide slurry using a rotating hemispherical pad-foam tool. The feed ripple amplitude can be decreased by reducing the non-uniformities in the pad texture and/or by minimizing a derived feed ripple metric (rf=Vmax0.5Vf/Rt) via adjustments in processing parameters. Pitch ripples can be minimized by reducing relative step distance to spot radius ratio (xs/at) and by achieving a flat bottom trench shape cross section or by reducing the material removal per pass. Using the combined methods, an overall ripple error of ∼1.2nm rms has been achieved.

Process evaluation and challenges in collecting data from an after-school sports and literacy program in a diverse, low-income community.

BACKGROUND: To understand how programs succeed we must evaluate them. The purpose of this paper was to examine the intervention and evaluation processes and identify areas of success and challenges in delivering and evaluating the Reflective Educational Approach to Character and Health (REACH) after-school program in a low SES community. METHODS: Sixty-six fifth and sixth graders from two schools participated. Data were collected at the intervention and control schools at four time points over the year. Data collected at baseline (Aug/Sep 2016), and Time 4 (May, 2017) were used for the analysis. Reach and fidelity to the intervention were assessed along with information on the process of data collection for variables of interest (e.g., accelerometer-measured physical activity level, FITNESSGRAM tests, vertical jump, and literacy). Missing data were imputed and a 2(School) by 2(Time) mixed factorial ANOVA was performed to examine the efficacy of the intervention. RESULTS: There were no significant time by school interactions for any of the outcomes assessed. There were several challenges in evaluating the program such as low compliance to wearing the accelerometer, lack of effort during literacy tests, peers affecting effort on physical tests, and missing data. CONCLUSIONS: We posit that research implementation be re-examined in community-based research that is conducted with students at the elementary level in low-income communities. Future research should engage with youth in the data collection process to make it a meaningful experience for them and to possibly reduce attrition from the program.

Effect of workpiece curvature on the tool influence function during hemispherical sub-aperture tool glass polishing.

The influence of workpiece curvature on the tool influence function spot during polishing of fused silica glass with cerium oxide slurry, while using a rotating hemispherical pad-foam tool for a wide variety of process conditions (tool displacement, inclination angle, and rotation rate), has been investigated. (Workpiece curvature ranged from 500 mm radius concave to 43 mm radius convex.) The TIF spot decreases in diameter and increases in the peak removal rate on more convex workpieces. In contrast, the TIF spot increases both in diameter and peak removal rate on more concave workpieces. For the range of workpiece curvatures investigated, both the spot size and the peak removal rate changed significantly, as much as 2 times. An elastic sphere-sphere contact mechanics model, which utilizes both a modified displacement (that leads to a change in the applied load) as well as a mismatch factor (that influences the pressure distribution shape), has been developed. The model was validated using both offline load-displacement measurements and finite-element analysis simulations. The model quantitatively describes the measured change in the relative contact diameter and relative pressure distribution, as well as semiquantitively describes the change in the relative volumetric removal rate on a large variety of TIF spots. The change in the volumetric removal rate for convex workpieces is a result of the balance between a decreasing spot size (reducing removal) and an increasing peak pressure (increasing removal), which usually results in relatively small changes in volumetric removal. In the case of concave workpieces, the volumetric removal rate change is also governed by a similar balance, but the spot size increase contribution dominates, resulting in a significant increase in volumetric removal rate. Understanding these trends can enable methods to add greater determinism during the fabrication of freeform optics by adjusting polishing parameters (such as dwell time) while the tool translates along a workpiece surface with different local curvatures.

Mechanisms influencing and prediction of tool influence function spots during hemispherical sub-aperture tool polishing on fused silica.

Sub-aperture tool polishing of precision optics requires a detailed understanding of the local material removal [tool influence function (TIF)] at the contact spot between the workpiece and tool to achieve high removal determinism and hence precision of the optic relative to the desired/design surface figure. In this study, the mechanisms influencing and the quantitative prediction of the removal rate and shape of TIF spots during polishing of fused silica glass with cerium oxide slurry using a rotating hemispherical pad-foam tool for a wide variety of process conditions (including tool properties, kinematics, and applied displacements) are investigated. The TIF volumetric removal rate can be estimated utilizing the average relative velocity and contact area using a simple analytical model. In addition, stability of the volumetric removal rate for fixed process conditions is shown to be greatly dependent on the pad preparation and amount of tool use (affecting both pad topography and slurry buildup), whose general behavior shows an increase in removal rate followed by stabilization with polishing time. The determination of the TIF removal shape is more complex. An extended version of the Preston removal model is developed to explain a comprehensive set of measured TIF removal shapes to within ∼22%. This model incorporates a number of phenomena impacting the TIF removal shape including: (a) temporal and spatial dependent relative velocity between the workpiece and tool; (b) an elastic mechanics based, as well as hydrodynamic, pressure distribution; (c) a spatially dependent friction coefficient possibly caused by both reduced slurry replenishment in low velocity regions and pad slurry islands (100 µm scale) and porosity (millimeter scale); and (d) a shear-based removal mechanism on the periphery of the contact spot.

Sapphire advanced mitigation process: wet etch to expose sub-surface damage and increase laser damage resistance and mechanical strength.

A novel, to the best of our knowledge, method of wet chemical etching of sapphire workpieces (such as optics, wafers, windows, and cones), called the sapphire advanced mitigation process (or sapphire AMP), has been developed that exposes sub-surface mechanical damage created during the optical fabrication process and significantly enhances the surface laser damage resistance ($ \gt {2{\times}}$>2×) and mechanical strength (up to $\sim{2.6{\times}}$∼2.6×). Sapphire AMP involves first treating the workpiece with a mixture of sulfuric and phosphoric acid $([{\rm H_{2}{\rm SO_{4}}}]:[{\rm H_{3}{\rm PO_{4}}}]=1:3)$([H2SO4]:[H3PO4]=1:3) at 220°C, followed with phosphoric acid at 160°C, then with sodium hydroxide base (NaOH) and surfactant at 40°C, and finally with a high-pressure deionized water spray rinse. Sapphire AMP has been demonstrated on both A- and C-plane sapphire workpieces. The mechanism of this etch process involves the reaction of the sapphire $({\rm Al_{2}}{\rm O_{3}})$(Al2O3) surface with sulfuric acid $({\rm H_{2}}{\rm SO_{4}})$(H2SO4) forming aluminum sulfate $[{{\rm Al}_2}{({{\rm SO}_4})_3}]$[Al2(SO4)3], which has low solubility. The high phosphoric acid content in the first and second steps of sapphire AMP results in the efficient conversion of ${{\rm Al}_2}{({{\rm SO}_4})_3}$Al2(SO4)3 to aluminum phosphate $({\rm AlPO_{4}})$(AlPO4), which is very soluble, greatly reducing reaction product redeposition on the workpiece surface. Sapphire AMP is shown to expose sub-surface mechanical damage on the sapphire surface created during the grinding and polishing processes, whose etched morphology has either isotropic or anisotropic evolution depending on the nature of the initial surface damage. Sapphire AMP was also designed to remove the key known surface, laser absorbing precursors (namely, foreign chemical impurities, the fracture surface layer of preexisting sub-surface damage, and reaction product or foreign species redeposition or precipitation). Static and sliding indention induced surface microfractures on sapphire are shown after sapphire AMP to have a significant decrease in the fast photoluminescence intensity (a known metric for measuring the degree of laser damaging absorbing precursors). In addition, the onset of laser damage (at 351 nm 3 ns) on sapphire AMP treated workpieces was shown to increase in fluence from $\sim{4}$∼4 to $ \gt {9}.{5}\;{{\rm J/cm}^2}$>9.5J/cm2. Finally, biaxial ball-on-ring mechanical tests on sapphire disks showed an increase in the failure stress from 340 MPa (with pre-existing 28 µm flaws) to $\sim{900}\;{\rm MPa}$∼900MPa after sapphire AMP, which is attributed to the blunting of the surface microfractures.

Students' Perceptions of Technology Integration During the F.I.T. Unit.

PURPOSE: This study sought to explore students' experiences of the Fitness Integrated with Technology (F.I.T.) unit and of their perceptions of using technology in physical education. METHOD: This manuscript is part of a larger mixed-methods study that measured student attitude and physical activity (PA) levels of 221 students in sixth, seventh, and eighth grades. Selected students (N = 13; seven girls) were observed and then interviewed after the unit through semistructured interviews. Students were identified based on their PA levels and attitude scores from a baseline measurement. The unit was designed to deliver fitness-based knowledge and used accelerometers as a tool to measure and teach students about PA. RESULTS: Three themes emerged from the data analysis: (a) technology and problems implementing it, (b) homework in PE, and (c) potential motivational effects of technology. The lack of access to technology at home and the design and utility of the accelerometers were perceived barriers. Additionally, homework was not well received. The accelerometer seemed to have a motivational effect on increasing students' PA levels but wore off during the unit. CONCLUSIONS: Results demonstrate that the use of technology for some students was a motivating factor to increase PA, and the use of accelerometers was a welcomed addition for students. Some students, however, raised concerns with the integration of technology such as the bulkiness of the accelerometer, not being able to wear it at sporting events, a novelty effect, and lack of access to technology at home that limited their interaction with their accelerometer data.

Role of Immune Cells and Cytokines for Immune Response in Kala-Azar.

Resolution of leishmanial infection is dependent on the coordinated interactions between components of cell mediated immune response, central to which is the activation of targeted T-cell populations for appropriate cytokine production and activation of infected cells. There is a correlation between the clinical outcome of Leishmania infection and the cytokine response profile. While a protective immune response against Leishmania has been clearly identified to be related to the influence of a type-l response and IFN-γ production, the precise role of T helper (TH) 2 cytokines in non-healing infections requires further exploration. Experimental evidence and clinical studies indicate multifaceted role of various factors leading to parasite survival and multiplication. In early stage of infection, generation of reactive oxygen and nitrogen intermediates play significant role in curtailing the parasite multiplication. In later phase, hepatic resistance is expressed by the dominant role played by nitric oxide synthase (NOS)-2 gene regulation and on the other hand, production of inhibitors of NOS-2 gene expression, interleukin 10 (IL-10) and transforming growth factor-ß (TGF-ß) correlate well with reduced parasite killing. The hepatic infection is usually self-limiting due to production of multiple cytokine responses including moderate level of tumour necrosis factor (TNF) but in spleen excess TNF mediates destructive pathology. CD8+ T cells appear to play multiple roles comprising both cytotoxic activity and secretion of cytokines and chemokines. A better understanding of the innate and acquired immune functioning of the host could aid in rational control and better therapeutic intervention of the disease.

EBS is a bivalent histone reader that regulates floral phase transition in Arabidopsis.

The ability of cells to perceive and translate versatile cues into differential chromatin and transcriptional states is critical for many biological processes1-5. In plants, timely transition to a flowering state is crucial for successful reproduction6-9. EARLY BOLTING IN SHORT DAY (EBS) is a negative transcriptional regulator that prevents premature flowering in Arabidopsis thaliana10,11. We found that EBS contains bivalent bromo-adjacent homology (BAH)-plant homeodomain (PHD) reader modules that bind H3K27me3 and H3K4me3, respectively. We observed co-enrichment of a subset of EBS-associated genes with H3K4me3, H3K27me3, and Polycomb repressor complex 2 (PRC2). Notably, EBS adopted an autoinhibition mode to mediate its switch in binding preference between H3K27me3 and H3K4me3. This binding balance was critical because disruption of either EBS-H3K27me3 or EBS-H3K4me3 interaction induced early floral transition. Our results identify a bivalent chromatin reader capable of recognizing two antagonistic histone marks, and we propose a distinct mechanism of interaction between active and repressive chromatin states.

Clinical Characteristics and Haematological Parameters Associated With Visceral Leishmaniasis in Bangladeshi Individuals.

Visceral leishmaniasis (VL) also known as kala-azar (KA) is the most severe form of leishmaniasis and can be fatal in the absence of treatment. KA is highly endemic in Mymensingh region of Bangladesh. Although estimating the true incidence of VL may be difficult. The objective of the study was to evaluate clinico-haematological parameters in different groups of leishmaniasis cases. It was a cross-sectional descriptive type of study and was conducted in a research centre of Mymensingh, Bangladesh from February 2016 to January 2017. A total of 90 cases who were rk-39 strip test positive from five divisions of Bangladesh admitted to Research Centre were included for clinical and haematological parameters. All the cases were categorized into five different groups depending on the clinical case definition and Real Time PCR (RT-PCR) was performed using buffy coat preparation. The age of the study subjects ranged from 3 to 80 years. Mymensingh was the highest affected division (60%) and primary kala azar (PKA) cases were more than half of the study subjects. Fever was the most common feature (100%) in PKA, relapse kala azar (R-KA) and treatment failure kala azar (TF-KA) followed by splenomegaly (70.2%) in PKA, loss of appetite (62.9%) in R-KA, and skin pigmentation was observed (100%) in PKDL cases. Anaemia was present in 62.7%, leucopenia in 57.6% and thrombocytopenia in 61.7% PKA cases. Pancytopenia was observed in a total of 33 cases from all groups. There were no significant changes in serum bilirubin, SGPT and serum creatinine level. RT-PCR was performed in all cases and found positive in 30 (63.8%) PKA, 16 (59.3%) R-KA, 2 (100%) TF-KA and 2 (50%) R-KA associated with PKDL cases. Overall, VL cases were positive in 62.5% (50/80) and no PKDL cases were detected by buffy-coat RT-PCR. In endemic areas, the magnitude of the problem and limited resources of a developing country like ours, clinical characteristics and hematological parameters may also play important role for diagnosis of the clinical cases.

Dual recognition of H3K4me3 and H3K27me3 by a plant histone reader SHL.

The ability of a cell to dynamically switch its chromatin between different functional states constitutes a key mechanism regulating gene expression. Histone mark "readers" display distinct binding specificity to different histone modifications and play critical roles in regulating chromatin states. Here, we show a plant-specific histone reader SHORT LIFE (SHL) capable of recognizing both H3K27me3 and H3K4me3 via its bromo-adjacent homology (BAH) and plant homeodomain (PHD) domains, respectively. Detailed biochemical and structural studies suggest a binding mechanism that is mutually exclusive for either H3K4me3 or H3K27me3. Furthermore, we show a genome-wide co-localization of SHL with H3K27me3 and H3K4me3, and that BAH-H3K27me3 and PHD-H3K4me3 interactions are important for SHL-mediated floral repression. Together, our study establishes BAH-PHD cassette as a dual histone methyl-lysine binding module that is distinct from others in recognizing both active and repressive histone marks.

Acute Kidney Injury in Patients with Acute Viral Hepatitis: A Study in a Tertiary Care Hospital.

This cross sectional observational study was done in the Department of Medicine, Mymensingh Medical College Hospital (MMCH), Mymensingh, Bangladesh from May 2013 to April 2014 to find out the proportion of acute kidney injury among patients with acute viral hepatitis and to identify risk factors associated with development of acute kidney injury (AKI). A total of 100 patients with acute viral hepatitis were included purposively as study subjects. Among them 61 were male and 39 were female. They were divided into AKI group (n=6) and non-AKI group (n=94) on the basis of development of AKI. There was no significant difference in mean age (39.0±13.1 years vs. 32.2±10.8 years, p=0.335) and sex (67% vs. 61% & 33.0% vs. 39.0%) p=0.769) between AKI group and non-AKI group. There were 27% acute viral hepatitis A, 21% acute viral hepatitis B and 52% acute viral hepatitis E but no case of acute viral hepatitis C was found in this study. Acute kidney injury (AKI) developed in 6 of 27 patients with acute viral hepatitis A. This study showed that 22.2% patients with acute viral hepatitis A developed acute kidney injury but patients with acute viral hepatitis B (HBV) and hepatitis E (HEV) did not develop acute kidney injury. Majority of the patients with acute kidney injury were smokers and hypertensive with elevated mean arterial pressure (p=0.0001) at presentation and had higher total bilirubin (p=0.0001), alanine aminotranseferase values (p=0.040), prolonged prothrombin time (INR) {p=0.0001}, lower albumin (p=0.0001), lower haematocrit level (p=0.0001), high CRP concentration (p=0.0001), leucocytosis (p=0.0001) and thrombocytopenia (p=0.0001) at presentation than patients without acute kidney injury. It is evident from the study that acute kidney injury is not a rare complication in patients with acute viral hepatitis.

Efficacy of Prophylactic use of Ciprofloxacin and Metronidazole in Mild and Moderately Severe Acute Pancreatitis.

INTRODUCTION: There are new concepts and developments in the diagnosis and management of acute pancreatitis. Current evidence suggests that there is no role of prophylactic antibiotics use in acute pancreatitis. However, it is still a common practice to administer prophylactic antibiotics in a country like Nepal. So, we have conducted a study in mild and moderately severe acute pancreatitis to study the efficacy of prophylactic antibiotics. METHODS: A case control study was conducted among 76 patients comparing efficacy of prophylactic antibiotics versus no antibiotics in patients with mild and moderately severe acute pancreatitis. RESULTS: The two most common etiology of acute pancreatitis in AG and NAG were alcohol 21 (55.2%) vs. 24 (63.1%) and biliary 10 (26.3%) vs. 4 (10.5%) respectively. Pancreatic necrosis was seen in five (13.1 %) in AG and four (10.5%) in NAG. Four (10.5%) developed extra pancreatic complications in AG and five (13.1%) in NAG. There was one (2.6%) death in AG and no death in NAG. Abdominal pain improvement seen in AG vs. NAG was 3.2 days vs. 2.4 days (P=0.002). The hospital stay was 7.7±2.23 days in AG and 7.5±1.85 days in NAG (P=0.65). CONCLUSIONS: The routine use of prophylactic antibiotics for mild and moderately severe acute pancreatitis is not associated with improvement in meaningful clinical outcomes.

Development of X-ray CCD camera based X-ray micro-CT system.

Availability of microfocus X-ray sources and high resolution X-ray area detectors has made it possible for high resolution microtomography studies to be performed outside the purview of synchrotron. In this paper, we present the work towards the use of an external shutter on a high resolution microtomography system using X-ray CCD camera as a detector. During micro computed tomography experiments, the X-ray source is continuously ON and owing to the readout mechanism of the CCD detector electronics, the detector registers photons reaching it during the read-out period too. This introduces a shadow like pattern in the image known as smear whose direction is defined by the vertical shift register. To resolve this issue, the developed system has been incorporated with a synchronized shutter just in front of the X-ray source. This is positioned in the X-ray beam path during the image readout period and out of the beam path during the image acquisition period. This technique has resulted in improved data quality and hence the same is reflected in the reconstructed images.