Ultra-thin Si-padded Si3N4 waveguides for low-loss photonics.

We proposed an ultra-thin Si-padded Si3N4 waveguide consisting of a very thin Si slab underneath a Si3N4 strip separated by a SiO2 layer. The Si slab and the Si3N4 strip form a hybrid waveguide mode, where the mode field is confined in these two structures. The measured waveguide propagation loss is 0.055 dB/cm, and the bending loss is 0.09 dB per 90° bend, depending on the bending radius. Because part of the waveguide mode is distributed in the Si slab, this waveguide structure has potential for implementing low-loss and high-speed photonic integrated circuits.

New cycloartanes and new iridoids from Dolichandrone spathacea collected in the mangrove forest of Soc Trang province, Vietnam.

Two new cycloartanes, named dolichandrone A (1) and dolichandrone B (2), as well as two new iridoids, named [6-O-[(E)-4-methoxycinnamoyl]-1ß-hydroxy-dihydrocatalpolgenin (3) and 6-O-[(E)-4-methoxycinnamoyl]-1α-hydroxy-dihydrocatalpolgenin (4), together with four known iridoids (5-8), were isolated from the leaves and barks of Dolichandrone spathacea. Their structures were elucidated by means of extensive analysis of their HRESIMS, 1D and 2D NMR spectroscopic data. All of these compounds have been isolated for the first time from this plant. Compounds 1, 2, 5, and 7 were evaluated for their cytotoxic activity in vitro against four human cancer cell lines KB, Lu, HepG2, and MCF7. The results showed that only compound 2 exhibited a good cytotoxicity against KB cell line with IC50 of 18.77 µM.

Coherent emission at 537 nm from IR-pumped erbium-doped silica microspheres.

Low pump threshold upconversion narrowband emission at 537 nm in a simple system of erbium-doped silica microsphere at the tip of a fiber is reported. The emission comes out radially (not from whispering gallery modes) and is strongly enhanced by a thin metal coating, in particular with platinum. This enhancement seems to be related to the coupling with surface plasmons. The emission wavelength does not correspond to any energy level differences of erbium in silica, and is the same that was reported earlier in a coated fiber.

Heptaellipside A, a rare new 2,28-bidesmosidic lupane-type saponin from the leaves of Heptapleurum ellipticum.

For the first time, phytochemical constituents of the leaves of Heptapleurum ellipticum were investigated. One rare new 2,28-bidesmosidic lupane-type saponin, named heptaellipside A (1), along with four other lupane-type analogs (2-5) were purified by combining differently chromatographic methods. All of the separated compounds (1-5) were communicated for the first time from H. ellipticum. The structures of them were definitely illustrated following extensive and comprehensive UV/VIS, FTIR, HRMS/ESI, and NMR techniques. Further, all isolated compounds were evaluated for their α-glucosidase and α-amylase inhibition. As the results, compound 3 respectively exhibited stronger in both inhibitory activities against α-glucosidase and α-amylase (IC50 values of 15.53 and 26.93 µM), than the acarbose standard (IC50 values of 214.50 and 143.48 µM).

Contrast-Enhanced Ultrasound Molecular Imaging in Atherosclerosis Research.

The management of cardiovascular conditions will likely be improved by noninvasive in vivo molecular imaging technologies that can provide earlier or more accurate diagnosis. These techniques are already having a positive impact in preclinical research by providing insight into disease pathobiology or efficacy of new therapies. Contrast enhanced ultrasound (CEU) molecular imaging is a technique that relies on the ultrasound detection of targeted microbubble contrast agents to examine molecular or cellular events that occur at the blood pool-endothelial interface. For the most part, targeted contrast agents are composed of encapsulated gas microbubbles (MBs) that are 2-4 µm in diameter, or other acoustically active micro- or nanoparticles. These agents bear several tens of thousands of binding molecules per particle. Because nonadhered agent is cleared rapidly, CEU molecular imaging can be performed in a matter of minutes. MBs are detected using contrast-specific techniques that generate and receive nonlinear signals produced by MB cavitation, thereby increasing signal-to-noise ratio. Dedicated kinetic models for molecular imaging have been generated that permit the elimination of signal from nonadherent agent.

Lymphangioma of Colon Presenting as an Intramural Tumor.

Lymphangiomas are rare and benign vascular malformations of the lymphatic system. They may arise in any location and at all ages and have variable presentation. These lesions in the intestinal wall are reported very rarely. In the case of colonic lymphangiomas, it is more common in late adulthood and old age, which, in this age group is thought to be associated with local disturbances of lymphatic circulation secondary to inflammation, degeneration, surgical procedure, trauma or radiation. The clinical presentation of colonic lymphangiomas varies from incidental findings on imaging to presenting with acute abdomen. The imaging features are usually multilocular cyst in intramural colon and submucosal mass on endoscopy. However, in the case of symptomatic lesions with atypical image findings, and the fact that the disease is rare, preoperative diagnosis is often difficult. On the other hand, although these cystic tumors do not transform into malignancy, they can be locally invasive or complicated, and often require resection. We report a 53-year-old male who had a cystic lymphangioma of the transverse colon illustrated by imaging modalities and recognized via postoperative histopathological examination.

Cost of postoperative sepsis in Vietnam.

Despite improvements in medical care, the burden of sepsis remains high. In this study, we evaluated the incremental cost associated with postoperative sepsis and the impact of postoperative sepsis on clinical outcomes among surgical patients in Vietnam. We used the national database that contained 1,241,893 surgical patients undergoing seven types of surgery. We controlled the balance between the groups of patients using propensity score matching method. Generalized gamma regression and logistic regression were utilized to estimate incremental cost, readmission, and reexamination associated with postoperative sepsis. The average incremental cost associated with postoperative sepsis was 724.1 USD (95% CI 553.7-891.7) for the 30 days after surgery, which is equivalent to 28.2% of the per capita GDP in Vietnam in 2018. The highest incremental cost was found in patients undergoing cardiothoracic surgery, at 2,897 USD (95% CI 530.7-5263.2). Postoperative sepsis increased patient odds of readmission (OR = 6.40; 95% CI 6.06-6.76), reexamination (OR = 1.67; 95% CI 1.58-1.76), and also associated with 4.9 days longer of hospital length of stay among surgical patients. Creating appropriate prevention strategies for postoperative sepsis is extremely important, not only to improve the quality of health care but also to save health financial resources each year.

Echocardiographic Molecular Imaging of the Effect of Anticytokine Therapy for Atherosclerosis.

BACKGROUND: Echocardiographic molecular imaging techniques are beginning to be applied to evaluate preclinical efficacy of new drugs. In a large clinical trial, anti-interleukin-1ß (IL-1ß) immunotherapy reduced atherosclerotic events, yet treatment effects were modest, and the mechanisms of action were not fully elucidated. We tested the hypothesis that echocardiographic molecular imaging can assess changes in vascular thromboinflammatory status in response to anti-IL-1ß therapy. METHODS: In wild-type and atherosclerotic mice deficient for the low-density lipoprotein-receptor and Apobec-1, closed-chest myocardial infarction (MI) was performed to mimic high-risk clinical cohorts. Control animals had sham surgery. Post-MI animals were randomized to either no therapy or anti-IL-1ß immunotherapy, which was continued weekly. At post-MI day 3 or 21, in vivo ultrasound molecular imaging of aortic VCAM-1, P-selectin, von Willebrand factor A1-domain, and platelet GPIbα in the thoracic aorta was performed. Aortic histology and NF-κB activity were assessed in atherosclerotic mice. RESULTS: In both atherosclerotic and wild-type mice, MI produced a several-fold increase (P < .05) in aortic molecular signals for P-selectin, VCAM-1, von Willebrand factor, and GPIbα. In atherosclerotic mice, signal remained elevated at day 21. Anti-IL-1ß therapy completely abolished the post-MI increase in signal for all endothelial targets (P < .05 vs nontreated) at day 3 and 21. In atherosclerotic mice, MI triggered an increase in aortic plaque growth and macrophage content, a decrease in plaque collagen, and elevated aortic NF-κB (P < .05 for all changes). All of these remote plaque adverse changes were inhibited by anti-IL-1ß therapy. CONCLUSIONS: Echocardiographic molecular imaging of the vascular endothelium can quantify the beneficial effects of therapies designed to suppress the proatherosclerotic arterial thromboinflammatory effects of alarmins such as IL-1ß. This approach could potentially be used to evaluate the biologic variables that influence response in preclinical studies, and possibly to select patients most likely to benefit from therapy.

Myocardial Infarction Complications After Surgery in Vietnam: Estimates of Incremental Cost, Readmission Risk, and Length of Hospital Stay.

Myocardial infarction is a considerable burden on public health. However, there is a lack of information about its economic impact on both the individual and national levels. This study aims to estimate the incremental cost, readmission risk, and length of hospital stay due to myocardial infarction as a post-operative complication. We used data from a standardized national system managed by the Vietnam Social Insurance database. The original sample size was 1,241,893 surgical patients who had undergone one of seven types of surgery. A propensity score matching method was applied to create a matched sample for cost analysis. A generalized linear model was used to estimate direct treatment costs, the length of stay, and the effect of the complication on the readmission of surgical patients. Myocardial infarction occurs most frequently after vascular surgery. Patients with a myocardial infarction complication were more likely to experience readmission within 30 and 90 days, with an OR of 3.45 (95%CI: 2.92-4.08) and 4.39 (95%CI: 3.78-5.10), respectively. The increments of total costs at 30 and 90 days due to post-operative myocardial infarction were 4,490.9 USD (95%CI: 3882.3-5099.5) and 4,724.6 USD (95%CI: 4111.5-5337.8) per case, while the increases in length of stay were 4.9 (95%CI: 3.6-6.2) and 5.7 (95%CI: 4.2-7.2) per case, respectively. Perioperative myocardial infarction contributes significantly to medical costs for the individual and the national economy. Patients with perioperative myocardial infarction are more likely to be readmitted and face a longer treatment duration.

Arterial Platelet Adhesion in Atherosclerosis-Prone Arteries of Obese, Insulin-Resistant Nonhuman Primates.

Background Platelet-endothelial interactions are thought to contribute to early atherogenesis. These interactions are potentiated by oxidative stress. We used in vivo molecular imaging to test the hypothesis that platelet-endothelial interactions occur at early stages of plaque development in obese, insulin-resistant nonhuman primates, and are suppressed by NADPH-oxidase-2 inhibition. Methods and Results Six adult rhesus macaques fed a Western-style diet for a median of 4.0 years were studied at baseline and after 8 weeks of therapy with the NADPH-oxidase-2-inhibitor apocynin (50 mg/kg per day). Six lean control animals were also studied. Measurements included intravenous glucose tolerance test, body composition by dual-energy X-ray absorptiometry, carotid intimal medial thickness, carotid artery contrast ultrasound molecular imaging for platelet GPIbα (glycoprotein- Ibα) and vascular cell adhesion molecule-1, and blood oxidative markers on mass spectrometry. Compared with lean controls, animals on a Western-style diet were obese (median body mass: 16.0 versus 8.7 kg, P=0.003; median truncal fat: 49% versus 20%, P=0.002), were insulin resistant (4-fold higher insulin-glucose area under the curve on intravenous glucose tolerance test, P=0.002), had 40% larger carotid intimal medial thickness (P=0.004), and exhibited oxidative signatures on proteomics. In obese but not lean animals, signal enhancement on molecular imaging was significantly elevated for GPIbα and vascular cell adhesion molecule-1. The signal correlated modestly with intimal medial thickness but not with the degree of insulin resistance. Apocynin significantly (P<0.01) reduced median signal for GPIbα by >80% and vascular cell adhesion molecule-1 signal by 75%, but did not affect intimal medial thickness, body mass, or intravenous glucose tolerance test results. Conclusion In nonhuman primates, diet-induced obesity and insulin resistance leads to platelet-endothelial adhesion at early atherosclerotic lesion sites, which is associated with the expression of pro-inflammatory adhesion molecules. These responses appear to be mediated, in part, through oxidative pathways.

Spitzenkörper assembly mechanisms reveal conserved features of fungal and metazoan polarity scaffolds.

The Spitzenkörper (SPK) constitutes a collection of secretory vesicles and polarity-related proteins intimately associated with polarized growth of fungal hyphae. Many SPK-localized proteins are known, but their assembly and dynamics remain poorly understood. Here, we identify protein-protein interaction cascades leading to assembly of two SPK scaffolds and recruitment of diverse effectors in Neurospora crassa. Both scaffolds are transported to the SPK by the myosin V motor (MYO-5), with the coiled-coil protein SPZ-1 acting as cargo adaptor. Neither scaffold appears to be required for accumulation of SPK secretory vesicles. One scaffold consists of Leashin-2 (LAH-2), which is required for SPK localization of the signalling kinase COT-1 and the glycolysis enzyme GPI-1. The other scaffold comprises a complex of Janus-1 (JNS-1) and the polarisome protein SPA-2. Via its Spa homology domain (SHD), SPA-2 recruits a calponin domain-containing F-actin effector (CCP-1). The SHD NMR structure reveals a conserved surface groove required for effector binding. Similarities between SPA-2/JNS-1 and the metazoan GIT/PIX complex identify foundational features of the cell polarity apparatus that predate the fungal-metazoan divergence.

Field evaluation of a prototype paper-based point-of-care fingerstick transaminase test.

Monitoring for drug-induced liver injury (DILI) via serial transaminase measurements in patients on potentially hepatotoxic medications (e.g., for HIV and tuberculosis) is routine in resource-rich nations, but often unavailable in resource-limited settings. Towards enabling universal access to affordable point-of-care (POC) screening for DILI, we have performed the first field evaluation of a paper-based, microfluidic fingerstick test for rapid, semi-quantitative, visual measurement of blood alanine aminotransferase (ALT). Our objectives were to assess operational feasibility, inter-operator variability, lot variability, device failure rate, and accuracy, to inform device modification for further field testing. The paper-based ALT test was performed at POC on fingerstick samples from 600 outpatients receiving HIV treatment in Vietnam. Results, read independently by two clinic nurses, were compared with gold-standard automated (Roche Cobas) results from venipuncture samples obtained in parallel. Two device lots were used sequentially. We demonstrated high inter-operator agreement, with 96.3% (95% C.I., 94.3-97.7%) agreement in placing visual results into clinically-defined "bins" (<3x, 3-5x, and >5x upper limit of normal), >90% agreement in validity determination, and intraclass correlation coefficient of 0.89 (95% C.I., 0.87-0.91). Lot variability was observed in % invalids due to hemolysis (21.1% for Lot 1, 1.6% for Lot 2) and correlated with lots of incorporated plasma separation membranes. Invalid rates <1% were observed for all other device controls. Overall bin placement accuracy for the two readers was 84% (84.3%/83.6%). Our findings of extremely high inter-operator agreement for visual reading-obtained in a target clinical environment, as performed by local practitioners-indicate that the device operation and reading process is feasible and reproducible. Bin placement accuracy and lot-to-lot variability data identified specific targets for device optimization and material quality control. This is the first field study performed with a patterned paper-based microfluidic device and opens the door to development of similar assays for other important analytes.