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.

People with Type Diabetes Mellitus (T1DM) self-reported views on their own condition management reveal links to potentially improved outcomes and potential areas for service improvement

BACKGROUND

The self-management of type 1 diabetes (T1DM) has moved forward in many areas over the last 40 years. Our study asked people with T1DM what is their experience of blood glucose (BG) monitoring day to day and how this influences decisions about insulin dosing.

METHODS

An on-line self-reported questionnaire containing 44 questions prepared after consultation with clinicians and patients was circulated to people with T1DM 116 responders provided completed responses. Fixed responses were allocated specific values (e.g. not confident = 0 fairly confident = 1). Multivariate regression analysis was carried out. Only those 5 factors with p-value <0.05 were retained.

RESULTS

59% of respondents were >50 years old and 66% had diabetes for >20 years, with 63% of patients reporting HbA1c results ≤8% or 64 mmol/mol. Findings included; 75% used only 1 m; 56% had used the same meter for ≥3 years; 10% had tried flash monitors; 47% were concerned about current BG level; 85% were concerned about long-term impact of higher BG. 72% of respondents keep BG level high to avoid hypoglycaemia; 25% used ≥7 mmol/L as pre-meal BG target to calculate dose; 65% were concerned they might be over/under-dosing; 83% did not discuss accuracy when choosing meter. However 85% were confident in their meter's performance. The factors that linked to LOWER HbA1c included LESS units of basal insulin (p < 0.001), HIGHER number of daily BG tests (p = 0.008), LOWER bedtime blood glucose (p = 0.009), HIGHER patient's concern over long-term impact of high BG (BG) (p < 0.009 but LOWER patient's concern over current BG values (p = 0.009). The final statistical model could explain 41% of the observed variation in HbA1c.

CONCLUSION

Many people still run their BG high to avoid hypoglycaemia. Concern about the longer-term consequences of suboptimal glycaemic control was associated with a lower HbA1c and is an area to explore in the future when considering how to help people with T1DM.

Efficacy and safety of expectant management in the treatment of tubal ectopic pregnancy: a systematic review and meta-analysis

STUDY QUESTION

Is expectant management (EM) of tubal ectopic pregnancy (EP) an effective and safe treatment strategy when compared to alternative interventions?

SUMMARY ANSWER

There is insufficient evidence to conclude EM yields a difference in the resolution of tubal EP, the avoidance of surgery or time to resolution of tubal EP when compared to intramuscular methotrexate in stable patients with β-hCG <1500 IU/l.

WHAT IS ALREADY KNOWN

The utilisation of medical and surgical management for EP is well established. EM aims to allow spontaneous resolution of the EP without intervention.

STUDY DESIGN SIZE AND DURATION

We performed a systematic review and meta-analysis, searching Ovid MEDLINE, Embase, PsycINFO, CINAHL, Web of Science, OpenGrey.eu, Google Scholar, cross-referencing citations and trial registries to 15 December 2019. There were no limitations placed on language or publication date. Search terms included tubal EP and EM as well as variations of these terms.

PARTICIPANTS/MATERIALS SETTING AND METHOD

We considered studies that included patients with tubal EP, EM as a comparator, and that were randomised controlled trials (RCTs). The primary outcome was resolution of tubal EP. Secondary outcomes included avoidance of surgery and the time to resolution of EP. Two reviewers independently selected the studies, assessed bias and extracted data. Relative risk (RR) and mean difference with 95% CI were assessed using a random effects model. The certainty of evidence was scored according to Grading of Recommendations Assessment, Development and Evaluation guidelines.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 920 studies were screened. Five studies were eligible for inclusion in the systematic review. Two RCTs comparing methotrexate to EM were identified as being eligible for inclusion in meta-analysis. No RCTs comparing surgery to EM were identified. Compared with EM, there was insufficient evidence that methotrexate yields a difference on resolution of tubal EP (RR 1.04, 95% CI 0.88-1.23, P = 0.67; two RCTs, moderate-certainty evidence), avoiding surgery (RR 1.10, 95% CI 0.94-1.29, P = 0.25; two RCTs, low-certainty evidence) or the time to resolution of tubal EP (-2.56 days (favouring EM), 95% CI -7.93-2.80, P = 0.35; two RCTs, low-certainty evidence).

LIMITATIONS REASONS FOR CAUTION

Only two RCTs with a total of 103 patients were eligible for inclusion in this meta-analysis. Further RCTs comparing EM to medical and surgical management are needed and these should also report adverse events. Patient preference should also be evaluated.

WIDER IMPLICATIONS OF THE FINDINGS

We found insufficient evidence of differences in terms of resolution, avoidance of surgery and time to resolution between expectant and medical management. Given the imprecision in the effect estimates as demonstrated by the wide CIs, resulting in the downgrading of certainty of evidence for all outcomes in this meta-analysis, larger RCTs comparing interventions for tubal EP are needed. Caution should be exercised when trying to decide between EM and methotrexate to treat tubal EP.

STUDY FUNDING/COMPETING INTERESTS

There was no funding for this study. NICM receives funding from various sources; none specifically supported this research. M.L. reports grants from Australian Women and Children's Research Foundation, outside the submitted work. M.A.: As a medical research institute, NICM Health Research Institute receives research grants and donations from foundations, universities, government agencies and industry. Sponsors and donors provide untied and tied funding for work to advance the vision and mission of the Institute. This systematic review was not specifically supported by donor or sponsor funding to NICM. M.A. reports a partnership grant with Metagenetics outside the submitted work. G.C. reports grants from Australian Women and Children's Research Foundation, personal fees from Roche and GE Healthcare, outside the submitted work. The remaining authors report no conflicts of interest.

PROSPERO REGISTRATION NUMBER

CRD42020142736.

Phosphatidylinositol 4-kinase IIIβ mediates contraction-induced GLUT4 translocation and shows its anti-diabetic action in cardiomyocytes

In the diabetic heart, long-chain fatty acid (LCFA) uptake is increased at the expense of glucose uptake. This metabolic shift ultimately leads to insulin resistance and a reduced cardiac function. Therefore, signaling kinases that mediate glucose uptake without simultaneously stimulating LCFA uptake could be considered attractive anti-diabetic targets. Phosphatidylinositol-4-kinase-IIIβ (PI4KIIIβ) is a lipid kinase downstream of protein kinase D1 (PKD1) that mediates Golgi-to-plasma membrane vesicular trafficking in HeLa-cells. In this study, we evaluated whether PI4KIIIβ is involved in myocellular GLUT4 translocation induced by contraction or oligomycin (an F₁F₀-ATP synthase inhibitor that activates contraction-like signaling). Pharmacological targeting, with compound MI14, or genetic silencing of PI4KIIIβ inhibited contraction/oligomycin-stimulated GLUT4 translocation and glucose uptake in cardiomyocytes but did not affect CD36 translocation nor LCFA uptake. Addition of the PI4KIIIβ enzymatic reaction product phosphatidylinositol-4-phosphate restored oligomycin-stimulated glucose uptake in the presence of MI14. PI4KIIIβ activation by PKD1 involves Ser294 phosphorylation and altered its localization with unchanged enzymatic activity. Adenoviral PI4KIIIβ overexpression stimulated glucose uptake, but did not activate hypertrophic signaling, indicating that unlike PKD1, PI4KIIIβ is selectively involved in GLUT4 translocation. Finally, PI4KIIIβ overexpression prevented insulin resistance and contractile dysfunction in lipid-overexposed cardiomyocytes. Together, our studies identify PI4KIIIβ as positive and selective regulator of GLUT4 translocation in response to contraction-like signaling, suggesting PI4KIIIβ as a promising target to rescue defective glucose uptake in diabetics.

Transport and concentration of wealth: Modeling an amenities-based-theory

We derive a reaction-advection-diffusion equation based framework for analyzing the movement of wealth in urban environments. Gentrification is a core issue that affects many urban areas, and the dynamics of such are not fully understood. To understand the process using a few physically relevant variables, we develop an approach to model the interplay between local amenities and wealth from existing analyses of factors influencing gentrification. We conduct a linear stability analysis on model parameters that results in spatially homogeneous solutions and determine directions for parameter changes to induce instabilities. From these parameters, we determine quantities that lead to the formation of areas of wealth and amenity concentration in the long term on bounded and unbounded domains. We present a global bifurcation result in two dimensions, leading to the existence and stability of non-constant equilibrium solutions, which represents solutions with wealth and amenity hotspots. Finally, we present a theory for discerning the one-dimensional pattern formation in the transition between stability and instability and verify numerically through a weakly nonlinear analysis. The analysis provides a promising framework for further verification using publicly available geospatial data on the relevant variables.

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.

Liquid Chromatographic Method for the Determination of Nine Phenolic Antioxidants in Butter Oil: Collaborative Study

Ten laboratories collaboratively studied a liquid chromatographic (LC) method for the determination of propyl, octyl, and dodecyl gallate (PG, OG, and DG, respectively), 2,4,5-trihydroxybutyrophenone (THBP), ferf-butylhydroquinone (TBHQ), nordihydroguaiaretic acid (NDGA), 2- and 3-tert-butyl-4- hydroxyanisole (BHA), 2,6-di-ferf-butyl-4-hydroxymethylphenol (lonox-100), and 3,5-di-terf-butyl-4- hydroxytoluene (BHT) in butter oil. The 10 samples analyzed were spiked in matched pairs at about 100,50, and 10 μg/g. In the method studied, antioxidants are extracted as in AOAC LC method 983.15, but different LC eluants are used to separate the 9 antioxidants. Results from 1 laboratory were rejected as not valid and were not included in any calculations. For the remaining 9 laboratories, the overall mean recoveries for PG, THBP, TBHQ, NDGA, BHA, OG, lonox, BHT, and DG were 100.9, 97.8,103.4,95.4, 97.4,93.6,95.5,79.0, and 96.2%, respectively. The overall reproducibility relative standard deviations were 8.55,17.4,25.6,14.5,6.60, 9.64,10.8,11.4, and 7.35%, respectively. The method was adopted first action by AOAC International as a modification of AOAC method 983.15.

Determination of Low-Level Glucose and Fructose in Raw and Refined Crystalline Sugar by High-Performance Anion-Exchange Chromatography: Collaborative Study

A method was developed and a collaborative study was performed under the auspices of the International Commission of Uniform Methods for Sugar Analysis. The collaborators used high-performance anion-exchange chromatography (HPAEC) to determine trace amounts of glucose and fructose in 3 raw and 3 refined sugar samples provided as blind duplicates. Fourteen laboratories participated in the study. Although difficulties were experienced by a few analysts, 10 laboratories reported positive results. Average repeatabilities and reproducibilities for glucose and fructose in raw sugar were slightly above 5 and 10%, respectively, and the average Horwitz ratios were well under 2. Average repeatabilities and reproducibilities for glucose and fructose in refined sugar were 10 and 22%, respectively; although the Horwitz ratios were &gt;2, they were marginal (2.8). The HPAEC results agreed with results obtained by gas chromatography in an independent laboratory. Because the method was collaboratively studied according to the protocol of the International Union of Pure and Applied Chemistry for collaborative studies, and the results meet its criteria, it is recommended that the method be adopted Official First Action by AOAC INTERNATIONAL.

Connected diagnostics: linking digital rapid diagnostic tests and mobile health wallets to diagnose and treat brucellosis in Samburu, Kenya

BACKGROUND

Despite WHO guidelines for testing all suspected cases of malaria before initiating treatment, presumptive malaria treatment remains common practice among some clinicians and in certain low-resource settings the capacity for microscopic testing is limited. This can lead to misdiagnosis, resulting in increased morbidity due to lack of treatment for undetected conditions, increased healthcare costs, and potential for drug resistance. This is particularly an issue as multiple conditions share the similar etiologies to malaria, including brucellosis, a rare, under-detected zoonosis. Linking rapid diagnostic tests (RDTs) and digital test readers for the detection of febrile illnesses can mitigate this risk and improve case management of febrile illness.

METHODS

This technical advance study examines Connected Diagnostics, an approach that combines the use of point-of-care RDTs for malaria and brucellosis, digitally interpreted by a rapid diagnostic test reader (Deki Reader) and connected to mobile payment mechanisms to facilitate the diagnosis and treatment of febrile illness in nomadic populations in Samburu County, Kenya. Consenting febrile patients were tested with RDTs and patient diagnosis and risk information were uploaded to a cloud database via the Deki Reader. Patients with positive diagnoses were provided digital vouchers for transportation to the clinic and treatment via their health wallet on their mobile phones.

RESULTS

In total, 288 patients were tested during outreach visits, with 9% testing positive for brucellosis and 0.6% testing positive for malaria. All patients, regardless of diagnosis were provided with a mobile health wallet on their cellular phones to facilitate their transport to the clinic, and for patients testing positive for brucellosis or malaria, the wallet funded their treatment. The use of the Deki Reader in addition to quality diagnostics at point of care also facilitated geographic mapping of patient diagnoses in relation to key risk areas for brucellosis transmission.

CONCLUSIONS

This study demonstrates that the Connected Dx approach can be effective even when addressing a remote, nomadic population and a rare disease, indicating that this approach to diagnosing, treatment, and payment for healthcare costs is feasible and can be scaled to address more prevalent diseases and conditions in more populous contexts.

Faecal Calprotectin and Magnetic Resonance Enterography in Ileal Crohn's Disease: Correlations Between Disease Activity and Long-Term Follow-Up

BACKGROUND AND AIMS

Magnetic resonance enterography [MRE] is the gold standard for assessing ileal inflammation in Crohn's disease [CD]. The aim of the present study was to correlate faecal calprotectin [FC] to MRE via a simple score in an exclusive ileal cohort with long-term follow-up for association with time to surgery or biologic therapy.

METHODS

In total, 150 MRE studies with matched FC [±30 days] were identified from the Edinburgh FC Register [2008-12; n = 18138]. Scans were re-read blinded to clinical data, independently, by two expert gastrointestinal radiologists, to generate a simple MRE score [range 0-10] from assessment of the worst intestinal segment plus total disease extent.

RESULTS

In total, 119 MRE scans were evaluated from 104 patients with ileal CD [L1 or L3 with panproctocolectomy]. Receiver operating characteristic analysis showed an area under the curve of 0.77 [0.67-0.87, p < 0.0001] for FC and MRE score >1, with an optimal cut-off of 145 μg/g for severe inflammation on MRE with 69.3% [57.6-79.5] sensitivity and 71.4% [53.7-85.4] specificity. Long-term follow-up over a median [interquartile range] of 2086 days [1786-2353] revealed FC ≥ 145 μg/g was associated with reduced biologic-free survival until 3 years following MRE, whereas MRE score [severe vs absent] was associated with reduced surgery- and biologic-free survival throughout follow-up. Backwards stepwise logistic regression revealed that length of ileal disease (odds ratio [OR] 3.8, 1.1-13.2, p = 0.034) and increased bowel wall thickness at MRE [OR 4.2, 1.6-10.7, p < 0.0001] or female sex [OR 5.2, 1.5-18.7, p = 0.011] increased the risk of biologic use or surgery, respectively.

CONCLUSIONS

FC correlates well with MRE assessment of ileal CD with MRE parameters associated with long-term biologic- and surgery-free remission.