Dynamics and phase behavior of metallo-dielectric rod-shaped microswimmers driven by alternating current electric field.

The ability to move and self-organize in response to external stimuli is a fascinating feature of living active matter. Here, the metallo-dielectric rod-shaped microswimmers are shown to have a similar behavior in the presence of an AC electric field. The silica-copper Janus microrods were fabricated using the physical vapor deposition-based glancing angle deposition technique (GLAD). When the aqueous solution of the microrods was under the influence of an external AC electric field, they were found to exhibit different phases such as clustering, swimming, and vertical standing in response to variation of the applied frequency. The swimming behavior (5-90 kHz) of the rods is attributed to the induced-charge electrophoresis (ICEP) phenomenon, whereas the dynamic clustering (<5 kHz) could be explained in terms of the electrohydrodynamic (EHD) interaction. Interestingly, the rods flip to attain the vertically standing position when responding to the applied electric field above 90 kHz. The reorientation and switching of the major axis of the rod along the field direction is attributed to the electro-orientation phenomenon. This is basically due to the dominance of the electric torque above the upper limit of the characteristic frequency, where the strength of slip flows around the microrods is predicted to be poor. The present study not only offers insight into the fundamental aspects of the dynamics and the phase behavior of rod-shaped microswimmers, but also opens an avenue to design reconfigurable active matter systems with features inspired by biological systems.

Effectiveness and Safety of EUS Rendezvous After Failed Biliary Cannulation With ERCP: A Systematic Review and Proportion Meta-analysis.

BACKGROUND: Endoscopic ultrasound-guided rendezvous (EUS-RV) endoscopic retrograde cholangiopancreatography (ERCP) is an alternative to interventional radiology-guided rendezvous ERCP in patients who failed biliary cannulation with conventional ERCP. However, there is significant variation in reported rates of success and adverse events associated with EUS-RV-assisted ERCP. We performed a systematic review and a proportion meta-analysis to reliably assess the effectiveness and safety of the EUS-RV-assisted ERCP. MATERIALS AND METHODS: We conducted a comprehensive search of multiple electronic databases and conference proceedings (from inception through August 2020) to identify studies reporting EUS-RV-assisted ERCP in patients who failed biliary cannulation with conventional ERCP techniques. Using the random-effects model described by DerSimonian and Laird, we calculated the pooled rates of technical success, clinical success, and adverse events of EUS-RV-assisted ERCP. RESULTS: Twelve studies reporting a total of 342 patients were included in the meta-analysis. The pooled rate of technical success (12 studies reporting a total of 342 patients) was 86.1% [95% confidence interval (CI): 78.4-91.3]. The pooled rate of clinical success (4 studies reporting a total of 94 patients) was 80.8% (95% CI: 64.1-90.8). The pooled rate of overall adverse events (12 studies; 42 events in 342 patients) was 14% (95% CI: 10.5-18.4). Low to moderate heterogeneity was noted in the analyses. CONCLUSIONS: EUS-RV-assisted ERCP appears to be effective and safe in patients who failed biliary cannulation with conventional ERCP. Given the risk of adverse events, it should be performed in centers with expertise in therapeutic endoscopic ultrasound.

Biliary Sphincterotomy Alone versus Biliary Stent with or without Biliary Sphincterotomy for the Management of Post-Cholecystectomy Bile Leak: A Systematic Review and Meta-Analysis.

BACKGROUND: Endoscopic therapy with endoscopic retrograde cholangiopancreatography is considered the first-line treatment in the management of post-cholecystectomy bile leak (PCBL). Currently, there is no consensus on the most effective endoscopic intervention for PCBL. Hence, we performed a systematic review and meta-analysis to compare the effectiveness and safety of the two interventional groups (biliary sphincterotomy [BS] alone vs. biliary stent ± BS) in management of PCBL. METHODS: We conducted a comprehensive search of multiple electronic databases and conference proceedings (from inception through January 2021). The primary outcome was to compare the pooled rate of clinical success between the 2 groups. The secondary outcome was to estimate the pooled rate of adverse events. RESULTS: The pooled rate of clinical success with BS alone (5 studies, 299 patients) was 88% (95% confidence interval (CI): 84-92%, I2: 0%) and for biliary stent ± BS (5 studies, 864 patients) was 97% (CI: 93-100%, I2: 79%). The rate of clinical success in biliary stent ± BS group was significantly higher than BS alone group (OR: 3.91 95% CI: 2.29-6.69, p < 0.001, I2: 13%). The rate of adverse events was numerically lower in biliary stent ± BS group compared to BS alone (3 studies; OR: 0.65 95% CI: 0.41-1.03, p = 0.07) without statistical significance. Low heterogeneity was noted in the analysis. CONCLUSIONS: Biliary stent ± BS is more effective in endoscopic management of PCBL compared to BS alone. This may be related to inter-endoscopist variation in completeness of sphincterotomy and post-sphincterotomy edema, which can influence the preferential trans-papillary flow of bile.

Determining age and sex-specific distribution of pancreatic whole-gland CT attenuation using artificial intelligence aided image segmentation: Associations with body composition and pancreatic cancer risk.

BACKGROUND & AIMS: Increased intrapancreatic fat is associated with pancreatic diseases; however, there are no established objective diagnostic criteria for fatty pancreas. On non-contrast computed tomography (CT), adipose tissue shows negative Hounsfield Unit (HU) attenuations (-150 to -30 HU). Using whole organ segmentation on non-contrast CT, we aimed to describe whole gland pancreatic attenuation and establish 5th and 10th percentile thresholds across a spectrum of age and sex. Subsequently, we aimed to evaluate the association between low pancreatic HU and risk of pancreatic ductal adenocarcinoma (PDAC). METHODS: The whole pancreas was segmented in 19,456 images from 469 non-contrast CT scans. A convolutional neural network was trained to assist pancreas segmentation. Mean pancreatic HU, volume, and body composition metrics were calculated. The lower 5th and 10th percentile for mean pancreatic HU were identified, examining the association with age and sex. Pre-diagnostic CT scans from patients who later developed PDAC were compared to cancer-free controls. RESULTS: Less than 5th percentile mean pancreatic HU was significantly associated with increase in BMI (OR 1.07; 1.03-1.11), visceral fat (OR 1.37; 1.15-1.64), total abdominal fat (OR 1.12; 1.03-1.22), and diabetes mellitus type 1 (OR 6.76; 1.68-27.28). Compared to controls, pre-diagnostic scans in PDAC cases had lower mean whole gland pancreatic HU (-0.2 vs 7.8, p = 0.026). CONCLUSION: In this study, we report age and sex-specific distribution of pancreatic whole-gland CT attenuation. Compared to controls, mean whole gland pancreatic HU is significantly lower in the pre-diagnostic phase of PDAC.

Outcomes of Radiofrequency Ablation versus Endoscopic Surveillance for Barrett's Esophagus with Low-Grade Dysplasia: A Systematic Review and Meta-Analysis.

BACKGROUND: Endoscopic therapy using radiofrequency ablation (RFA) is a recommended treatment for Barrett's esophagus with high-grade dysplasia (BE-HGD) without a visible lesion which is managed by resection. However, currently, there is no consensus on the management of BE with low-grade dysplasia (BE-LGD) - RFA versus endoscopic surveillance. Hence, we performed a systematic review and meta-analysis of these comparative studies to compare the risk of progression to HGD or esophageal adenocarcinoma (EAC) among patients with BE-LGD treated with RFA versus endoscopic surveillance. METHODS: The primary outcome was to compare the risk of progression to HGD or EAC among patients with BE-LGD treated with RFA versus endoscopic surveillance. RESULTS: Four comparative studies reporting a total of 543 patients with BE-LGD were included in the meta-analysis (234 in RFA and 309 in endoscopic surveillance). The progression of BE-LGD to either HGD or EAC was significantly lower in patients treated with RFA compared to endoscopic surveillance (OR: 0.17, 95% confidence interval [CI]: 0.04-0.65, p = 0.01). The progression to HGD alone was significantly lower in patients treated with RFA versus endoscopic surveillance (OR: 0.23, 95% CI: 0.08-0.61, p = 0.003). The progression to EAC alone was numerically lower in RFA than endoscopic surveillance without statistical significance (OR: 0.44, 95% CI: 0.17-1.16, p = 0.09). Moderate heterogeneity was noted in the analysis. CONCLUSIONS: Based on our meta-analysis, there was a significant reduction in the risk of progression to HGD or EAC among patients with BE-LGD treated with RFA compared with those undergoing endoscopic surveillance. Endoscopic eradication therapy with RFA should be the preferred management approach for BE-LGD.

Significance of peripheral eosinophilia for diagnosis of IgG4-related disease in subjects with elevated serum IgG4 levels.

OBJECTIVES: In this study, we aim to assess the diagnostic utility of elevated serum IgG4 (sIgG4) concentration alone and in combination with peripheral eosinophilia (PE) for IgG4-related disease (IgG4-RD). METHODS: From the Mayo Clinic, Rochester electronic medical record database we identified 409 patients with above normal levels of sIgG4 (reference range 121-140 mg/dL) who had sIgG4 measured to differentiate IgG4-RD from another disease. RESULTS: Among 409 patients with any elevation in sIgG4 levels, 129 (31.5%) had a definite diagnosis of IgG4-RD. The prevalence of PE increased with increasing sIgG4 levels and was more likely to be seen in subjects with IgG4-RD vs. non-IgG4-RD at ≥1X (n = 35/120, 29.2% vs. n = 23/258, 8.9%; p < 0.001), ≥2X (n = 23/64, 35.9% vs. n = 5/54,9.3%; p = 0.001) and ≥3X (n = 18/42, 42.9% vs. n = 0/9, 0%; p = 0.015) of sIgG4 upper limit of normal (ULN), respectively. After adjusting for gender and age, sIgG4 levels ≥ 2X ULN with PE as a predictor, had a higher positive predictive value in predicting IgG4-RD (72.2% vs. 65.9%) with an Area Under the Receiver Operatic Characteristic Curve (AUC) of 0.776, compared to sIgG4 ≥ 2X ULN without PE predictor (AUC = 0.74), p = 0.016. PE, sIgG4≥2X ULN, male gender, and age independently predicted the disease with odds ratio of 4.89 (95% CI:2.51-9.54), 3.78 (95% CI:2.27-6.28), 2.78 (95% CI:1.55-4.97), and 1.03 (95% CI:1.02-1.05), respectively. CONCLUSION: Even in subjects in whom IgG4-RD is suspected, only a minority (∼30%) with elevated sIgG4 levels have IgG4-RD. sIgG4 by itself is more specific at higher levels, though never diagnostic. PE increases with increasing sIgG4 and adds diagnostic value at higher sIgG4 levels.

Computerized tomography scan in pre-diagnostic pancreatic ductal adenocarcinoma: Stages of progression and potential benefits of early intervention: A retrospective study.

BACKGROUND: The frequency, nature and timeline of changes on thin-slice (≤3 mm) multi-detector computerized tomography (CT) scans in the pre-diagnostic phase of pancreatic ductal adenocarcinoma (PDAC) are unknown. It is unclear if identifying imaging changes in this phase will improve PDAC survival beyond lead time. METHODS: From a cohort of 128 subjects (Cohort A) with CT scans done 3-36 months before diagnosis of PDAC we developed a CTgram defining CT Stages (CTS) I through IV in the radiological progression of pre-diagnostic PDAC. We constructed Cohort B of PDAC resected at CTS I and II and compared survival in CTS I and II in Cohort A (n = 22 each; control natural history cohort) vs Cohort B (n = 33 and 72, respectively; early interception cohort). RESULTS: CTs were abnormal in 16% and 85% at 24-36 and 3-6 months respectively, before PDAC diagnosis. The PDAC CTgram stages, findings and median lead times (months) to clinical diagnosis were: CTS I: Abrupt duct cut-off/duct dilatation (-12.8); CTS II: Low density mass confined to pancreas (-9.5), CTS III: Peri-pancreatic infiltration (-5.8), CTS IV: Distant metastases (only at diagnosis). PDAC survival was better in cohort B than in cohort A despite inclusion of lead time in Cohort A: CTS I (36 vs 17.2 months, p = 0.03), CTS II (35.2 vs 15.3 months, p = 0.04). CONCLUSION: Starting 12-18 months before PDAC diagnosis, progressive and increasingly frequent changes occur on CT scans. Resection of PDAC at the time of pre-diagnostic CT changes is likely to provide survival benefit beyond lead time.

ERCP with overtube-assisted enteroscopy in patients with Roux-en-Y gastric bypass anatomy: a systematic review and meta-analysis.

BACKGROUND: Endoscopic retrograde cholangiopancreatography (ERCP) in patients with Roux-en-Y gastric bypass (RYGB) anatomy is challenging. Overtube-assisted enteroscopy (OAE) is usually needed to perform ERCP in these patients. There is significant variation in the reported rates of success and adverse events across published studies. We performed a systematic review and meta-analysis to reliably estimate the pooled rates of success and adverse events. METHODS: We performed a systematic search of multiple electronic databases through February 2020 to identify studies reporting outcomes of OAE-ERCP in post-RYGB patients. The pooled rates of enteroscopy success, technical success, and adverse events were estimated for OAE-ERCP. The pooled rates of success and adverse events were also estimated for ERCP using double-balloon enteroscopes (DBE) alone. RESULTS: 10 studies reporting a total of 398 procedures were included in the meta-analysis. The pooled rates of enteroscopy and technical success of OAE-ERCP were 75.3 % (95 % confidence interval [CI] 64.5 - 83.6) and 64.8 % (95 %CI 53.1 - 74.9) respectively. The pooled rate of adverse events was 8.0 % (95 %CI 5.2 - 12.2). The pooled rates of enteroscopy and technical success of DBE-ERCP (four studies) were 83.5 % (95 %CI 68.3 - 92.2) and 72.5 % (95 %CI 52.3 - 86.4), respectively. The pooled rate of adverse events with DBE-ERCP was 9.0 % (95 %CI 5.4 - 14.5). Substantial heterogeneity was noted. CONCLUSIONS: OAE-ERCP appears to be effective and safe in post-RYGB patients. Among the currently available techniques, OAE-ERCP is the least invasive approach in this challenging group of patients. Future studies comparing the effectiveness and safety of alternative novel techniques, such as endosonography-directed transgastric ERCP, with OAE-ERCP are needed.

EUS-guided versus endoscopic transpapillary gallbladder drainage in high-risk surgical patients with acute cholecystitis: a systematic review and meta-analysis.

BACKGROUND: In patients with acute cholecystitis who are deemed high risk for cholecystectomy, percutaneous cholecystostomy (PC) was historically performed for gallbladder drainage (GBD). There are several limitations associated with PC. Endoscopic GBD [Endoscopic transpapillary GBD (ET-GBD) and EUS-guided GBD (EUS-GBD)] is an alternative to PC. We performed a systematic review and meta-analysis to compare the effectiveness and safety of EUS-GBD versus ET-GBD. METHODS: We performed a systematic search of multiple databases through May 2019 to identify studies that compared outcomes of EUS-GBD versus ET-GBD in the management of acute cholecystitis in high-risk surgical patients. Pooled odds ratios (OR) of technical success, clinical success and adverse events between EUS-GBD and ET-GBD groups were calculated. RESULTS: Five studies with a total of 857 patients (EUS-GBD vs ET-GBD: 259 vs 598 patients) were included in the analysis. EUS-GBD was associated with higher technical [pooled OR 5.22 (95% CI 2.03-13.44; p = 0.0006; I2 = 20%)] and clinical success [pooled OR 4.16 (95% CI 2.00-8.66; p = 0.0001; I2 = 19%)] compared to ET-GBD. There was no statistically significant difference in the rate of overall adverse events [pooled OR 1.30 (95% CI 0.77-2.22; p = 0.33, I2 = 0%)]. EUS-GBD was associated with lower rate of recurrent cholecystitis [pooled OR 0.33 (95% CI 0.14-0.79; p = 0.01; I2 = 0%)]. There was low heterogeneity in the analyses. CONCLUSION: EUS-GBD has higher rate of technical and clinical success compared to ET-GBD. While the rates of overall adverse events are statistically similar, EUS-GBD has lower rate of recurrent cholecystitis. Hence, EUS-GBD is preferable to ET-GBD for endoscopic management of acute cholecystitis in select high-risk surgical patients.

Optical and Thermophoretic Control of Janus Nanopen Injection into Living Cells.

Devising strategies for the controlled injection of functional nanoparticles and reagents into living cells paves the way for novel applications in nanosurgery, sensing, and drug delivery. Here, we demonstrate the light-controlled guiding and injection of plasmonic Janus nanopens into living cells. The pens are made of a gold nanoparticle attached to a dielectric alumina shaft. Balancing optical and thermophoretic forces in an optical tweezer allows single Janus nanopens to be trapped and positioned on the surface of living cells. While the optical injection process involves strong heating of the plasmonic side, the temperature of the alumina stays significantly lower, thus allowing the functionalization with fluorescently labeled, single-stranded DNA and, hence, the spatially controlled injection of genetic material with an untethered nanocarrier.

Beyond O&P Times Three.

Although examination of the stool for ova and parasites times three (O&P ×3) is routinely performed in the United States (US) for the evaluation of persistent and/or chronic diarrhea, the result is almost always negative. This has contributed to the perception that parasitic diseases are nearly non-existent in the country unless there is a history of travel to an endemic area. The increasing number of immigrants from third-world countries, tourists, and students who present with symptoms of parasitic diseases are often misdiagnosed as having irritable bowel syndrome or inflammatory bowel disease. The consequences of such misdiagnosis need no explanation. However, certain parasitic diseases are endemic to the US and other developed nations and affect both immunocompetent and immunocompromised patients. Testing for parasitic diseases either with O&P or with other diagnostic tests, followed by the recommended treatment, is quite rewarding when appropriate. Most parasitic diseases are easily treatable and should not be confused with other chronic gastrointestinal (GI) disorders. In this review, we critically evaluate the symptomatology of luminal parasitic diseases, their differential diagnoses, appropriate diagnostic tests, and management.

Chiral Plasmonic Hydrogen Sensors.

In this article, a chiral plasmonic hydrogen-sensing platform using palladium-based nanohelices is demonstrated. Such 3D chiral nanostructures fabricated by nanoglancing angle deposition exhibit strong circular dichroism both experimentally and theoretically. The chiroptical properties of the palladium nanohelices are altered upon hydrogen uptake and sensitively depend on the hydrogen concentration. Such properties are well suited for remote and spark-free hydrogen sensing in the flammable range. Hysteresis is reduced, when an increasing amount of gold is utilized in the palladium-gold hybrid helices. As a result, the linearity of the circular dichroism in response to hydrogen is significantly improved. The chiral plasmonic sensor scheme is of potential interest for hydrogen-sensing applications, where good linearity and high sensitivity are required.

Diabetes confers in vitro calcific potential on serum which associates with in vivo vascular calcification.

Although vascular calcification (VC) is prevalent in Type 2 diabetes mellitus (T2DM), underlying mechanisms remain unclear. Neither is it known whether T2DM confers calcific potential (CP) on serum, enabling it to induce VC outside the disease milieu. We, therefore, investigated the CP of serum from controls and subjects with T2DM with and without in vivo VC. Samples from 20 healthy controls and 44 age- and sex-matched patients with T2DM with modification of diet in renal disease estimated glomerular filtration rate (MDRD-4 eGFR) > 60 ml·min-1 were analysed for CP using rat aortic smooth muscle cells in vitro CT scans of femoral arteries identified individuals with in vivo calcification. Serum from subjects with T2DM revealed significantly greater CP than controls. This was further enhanced in the presence of in vivo VC. Addition of ß-glycerophosphate (ß-GP) plus CaCl2 increased the CP of T2DM serum but not of controls. Along with age, CP was an independent predictor of the presence of VC. In receiver operator curve (ROC) analysis, CP was a significant predictor of femoral arterial VC (C-statistic 0.70: P=0.009). The distribution of CP was bimodal around a cutoff of 100 nmoles of Ca2+ protein mg-1, with a higher proportion of Type 2 diabetes subjects with in vivo calcification (T2DM+) sera above the cutoff value. This group also showed elevated levels of osteoprotegerin (OPG) and matrix Gla protein (MGP). Diabetes confers CP on the serum which is enhanced by the presence of in vivo VC. The CP acquired may be dependent on levels of OPG and MGP. These findings may be clinically relevant for early identification of individuals at risk of VC and for informing therapeutic strategies.

Spatially graded TiO2-SiO2 Bragg reflector with rainbow-colored photonic band gap.

A simple single-step method to fabricate spatially graded TiO2-SiO2 Bragg stack with rainbow colored photonic band gap is presented. The gradation in thickness of the Bragg stack was accomplished with a modified glancing angle deposition (GLAD) technique with dynamic shadow enabled by a block attached to one edge of the rotating substrate. A linear gradation in thickness over a distance of about 17 mm resulted in a brilliant colorful rainbow pattern. Interestingly, the photonic band gap position can be changed across the whole visible wavelength range by linearly translating the graded Bragg stack over a large area substrate. The spatially graded Bragg stack may find potential applications in the tunable optical devices, such as optical filters, reflection gratings, and lasers.

Light-driven micromotors for on-demand and local pH sensing applications.

In recent years, self-propelled light-driven micromotors have gained significant attention due to their capabilities for a wide range of applications, including cargo delivery, chemical sensing, environmental monitoring, etc. Here, we demonstrate the design of light-driven micromotors for local pH sensing applications. The micromotors are spherical Janus particles with multiple functional coatings that provide them with interesting features, like a dual optical response, i.e., controlled swimming under UV light (320-400 nm) and pH-dependent fluorescence signal emission when excited with blue light (450 nm), and moving path guidance using a weak external uniform magnetic field (50 G). All of these features allow the micromotors to sense the pH of the medium on-demand and locally or of a target location by guiding them to swim to the target location. The pH-dependent change in the fluorescence signal intensity is used for the measurement of the local pH of the medium. It is observed that the careful measurement of small pH changes requires a spectrometer that precisely measures the intensity change. However, the fluorescence signal of the micromotors was good enough to provide a clear visual demarcation for large pH changes. Systematic experimental studies supported by controlled experiments are performed to optimize the system as well as to calibrate the micromotors for local pH sensing applications. The characteristics like easy-to-design structure, light activation, directional swimming, and ability to measure the pH on-demand and locally prove that micromotors have the potential to revolutionize pH monitoring in various domains, including lab-on-a-chip devices, biomedical research, environmental monitoring, quality control in industrial processes, etc.

Human uraemic serum displays calcific potential in vitro that increases with advancing chronic kidney disease.

Vascular calcification (VC) strongly correlates with declining renal function and contributes to the high morbidity and mortality of patients with CKD (chronic kidney disease). It is closely regulated by circulating factors but little is known about the capacity of serum from patients to induce calcification outside the disease setting, which we now define as the calcific potential of serum. We have therefore examined the ability of serum from age- and sex-matched subjects with and without advancing CKD to induce calcification of cultured SMCs (smooth muscle cells). Samples from patients with CKD induced significant calcification compared with controls. More importantly, samples from patients on haemodialysis induced significantly higher calcification than those with moderate or advanced CKD. The calcification induced by the latter two but not those on haemodialysis could be enhanced with calcium chloride and ß-GP (ß-glycerophosphate). A positive correlation was evident between measured serum creatinine, phosphate, PTH (parathyroid hormone), OPG (osteoprotegerin) and the degree of calcification in vitro. eGFR (estimated glomerular filtration rate), DBP (diastolic blood pressure), haemoglobin and serum albumin correlated negatively. Stepwise multivariate analysis of log-transformed calcific potential data highlighted serum creatinine, albumin and OPG as significant predictors, explaining approximately 50% of the variation. Thus, other regulators, either not investigated or as yet unidentified, may contribute to the calcification potential of serum in vitro. Furthermore, uraemic serum can induce graded calcification outside of the disease milieu that reflects the degree of kidney impairment in vivo. These findings could have important clinical relevance in terms of developing novel diagnostic and/or therapeutic strategies for subjects with CKD.

pH-Responsive swimming behavior of light-powered rod-shaped micromotors.

Micromotors have emerged as promising devices for a wide range of applications e.g., microfluidics, lab-on-a-chip devices, active matter, environmental monitoring, etc. The control over the activity of micromotors with the ability to exhibit multimode swimming is one of the most desirable features for many of the applications. Here, we demonstrate a rod-shaped light-driven micromotor whose activity and swimming behavior can easily be controlled. The rod-shaped micromotors are fabricated through the dynamic shadowing growth (DSG) technique, where a 2 µm long arm of titanium dioxide (TiO2) is grown over spherical silica (SiO2) particles (1 µm diameter). Under low-intensity UV light exposure, the micromotors exhibit self-propulsion in an aqueous peroxide medium. When activated, the swimming behavior of micromotors greatly depends on the pH of the medium. The swimming direction, i.e., forward or backward movement, as well as swimming modes like translational or rotational motion, can be controlled by changing the pH values. The observed dynamics has been rationalized using a theoretical model incorporating chemical activity, hydrodynamic flow, and the effect of gravity for a rod-shaped active particle near a planar wall. The pH-dependent translational and rotational dynamics of micromotors provide a versatile platform for achieving controlled and responsive behaviors. Continued research and development in this area hold great promise for advancing micromotors and enabling novel applications in microfluidics, micromachining, environmental sciences, and biomedicine.

COVID-19 Related Predisposition to Diabetic Ketoacidosis.

Background and aims Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can exacerbate hyperglycemia and can cause life-threatening diabetic ketoacidosis (DKA) in patients with diabetes mellitus (DM). The objective of this study is to compare the characteristics of diabetic COVID-19 patients with and without DKA and to determine the predictors of mortality in the setting of COVID-19 and DKA. Methods This is a retrospective single-center cohort study including patients admitted to our hospital with COVID-19 and DM from March 2020 to June 2020. Patients with DKA were filtered as per the diagnostic criteria set by the American Diabetes Association (ADA). Patients with hyperosmolar hyperglycemic state (HHS) were excluded. A retrospective analysis was performed, which included those who developed DKA and those with neither DKA nor HHS. The primary outcome measurement was mortality rate and predictors of mortality for DKA. Results Out of 301 patients with COVID-19 and DM, 30 (10%) had DKA and five (1.7%) had HHS. Mortality was significantly higher in the DKA group compared to the non-DKA/HHS group (36.6% vs 19.5%; OR: 2.38; p=0.03). After adjusting for parameters used for multivariate logistic model for mortality, DKA was no longer associated with mortality (OR: 2.08, p=0.35). The independent predictors for mortality were age, platelet count, serum creatinine, C-reactive protein, hypoxic respiratory failure, need for intubation, and need for vasopressors. Conclusion Our study demonstrates higher mortality rate in diabetic COVID-19 patients with DKA. Though direct and independent statistical association of mortality with DKA could not be proven in our multivariate logistic model, physicians must be vigilant in risk-stratifying and managing these patients in a timely manner.

Light-driven microrobots: capture and transport of bacteria and microparticles in a fluid medium.

The design of simple microrobotic systems with capabilities to address various applications like cargo transportation, as well as biological sample capture and manipulation in an individual unit, provides a novel route for designing advanced multifunctional microscale systems. Here, we demonstrate a facile approach to fabricate such multifunctional and fully controlled light-driven microrobots. The microrobots are titanium dioxide-silica Janus particles that are propelled in aqueous hydroquinone/benzoquinone fuel when illuminated by low-intensity UV light. The application of light provides control over the speed as well as activity of the microrobots. When modified with additional thin film coatings of nickel and gold, the microrobots exhibit the capturing and transportation of silica microparticles and E. coli bacteria. While transporting, they also show guided swimming under an external uniform magnetic field, which is interesting for deciding their moving path or the start/end positions. The fluorescent dye-based live/dead tests confirm that in the microrobot system almost no bacteria were harmed during the capturing or transportation. The simplistic design and steerable swimming with the ability to capture and transport are the important features of the microrobots. These features make them an ideal candidate for in vitro or lab-on-a-chip based studies, e.g., drug delivery, bacterial sensing, cell treatment, etc., where the capturing and transport of microscopic entities play a crucial role.

Analytical quality goals for 25-vitamin D based on biological variation.

BACKGROUND: Measurement of 25-hydroxyvitamin D, (25D) is central in the investigation of pathologies of bone and mineral ion metabolism and in determining a patient's vitamin D status. More recently much research interest has lead to investigating the role it can play in decreasing the risk of many chronic illnesses, including common cancers, autoimmune diseases, infectious diseases, and cardiovascular disease. Knowledge of the biological variation of an analyte forms an essential part of evaluating a new analyte enabling the objective assessment of the changes in serial results, the utility of reference intervals as well as establishing laboratory quality specifications. METHODS: This study determined the biological variation of 25D in 20 healthy individuals that was calculated according to the familiar methods outlined by Fraser and Harris. RESULTS: The within-subject variation was 12.1% and the between subject variation was 40.3%. The critical difference for sequential values significant at P<0.05 was calculated as 38.4%. The within-subject variation forms a relatively small part of the reference interval shown by the low index of individuality of 0.3. Objective analytical quality goals have also been established which have shown achievable minimum performance for imprecision of ∼6%. The desirable analytical bias goal was ∼10%. CONCLUSION: This study has objectively shown that the analytical precision of current instruments is being achieved contrary to the known problems surrounding the analytical bias for 25D assays. The limitations of using reference intervals for 25D, both in diagnoses and monitoring are shown.