Correction: Integrated silicon photonic MEMS

[This corrects the article DOI: 10.1038/s41378-023-00498-z.].

Integrated silicon photonic MEMS

Silicon photonics has emerged as a mature technology that is expected to play a key role in critical emerging applications, including very high data rate optical communications, distance sensing for autonomous vehicles, photonic-accelerated computing, and quantum information processing. The success of silicon photonics has been enabled by the unique combination of performance, high yield, and high-volume capacity that can only be achieved by standardizing manufacturing technology. Today, standardized silicon photonics technology platforms implemented by foundries provide access to optimized library components, including low-loss optical routing, fast modulation, continuous tuning, high-speed germanium photodiodes, and high-efficiency optical and electrical interfaces. However, silicon's relatively weak electro-optic effects result in modulators with a significant footprint and thermo-optic tuning devices that require high power consumption, which are substantial impediments for very large-scale integration in silicon photonics. Microelectromechanical systems (MEMS) technology can enhance silicon photonics with building blocks that are compact, low-loss, broadband, fast and require very low power consumption. Here, we introduce a silicon photonic MEMS platform consisting of high-performance nano-opto-electromechanical devices fully integrated alongside standard silicon photonics foundry components, with wafer-level sealing for long-term reliability, flip-chip bonding to redistribution interposers, and fibre-array attachment for high port count optical and electrical interfacing. Our experimental demonstration of fundamental silicon photonic MEMS circuit elements, including power couplers, phase shifters and wavelength-division multiplexing devices using standardized technology lifts previous impediments to enable scaling to very large photonic integrated circuits for applications in telecommunications, neuromorphic computing, sensing, programmable photonics, and quantum computing.

Puckering the planar landscape of fragments: design and synthesis of a 3D cyclobutane fragment library

Fragment‐based drug discovery (FBDD) has a growing need for unique screening libraries. The cyclobutane moiety was identified as an underrepresented yet attractive three‐dimensional (3D) scaffold. Synthetic strategies were developed via a key 3‐azido‐cyclobutanone intermediate, giving potential access to a range of functional groups with accessible growth vectors. A focused set of 33 novel 3D cyclobutane fragments was synthesised, comprising three functionalities: secondary amines, amides, and sulfonamides. This library was designed using Principal Component Analysis (PCA) and an expanded version of the rule of three (RO3), followed by Principal Moment of Inertia (PMI) analysis to achieve both chemical diversity and high 3D character. Cis and trans ring isomers of library members were generated to maximise the shape diversity obtained, while limiting molecular complexity through avoiding enantiomers. Property analyses of the cyclobutane library indicated that it fares favourably against existing synthetic 3D fragment libraries in terms of shape and physicochemical properties.

Synthesis and crystal structure of a zinc(II) coordination polymer: N-(2-pyridylmethyl)- L-alanine)isothiocyanate Zn(II)

The title compound, N-(2-pyridylmethyl)-L-alanine) zinc(II), [Zn(C10H11N3O2S)], a coordination polymer derived from the mixed ligands, N-(2-pyridylmethyl)-L-alanine (HL1) and ammonium thiocyanide (L2) has been synthesized and characterized by IR spectroscopy, 1H-NMR, elemental analysis, thermogravimetric analysis and single crystal x-ray structure determination.The single crystal X-ray structure analysis of the title compoundreveals a molecular polymeric compound that crystallizes in the orthorhombic crystal system and P2(1)2(1)2(1) space group. The ligand acts as a bridge between adjacent zinc(II) centres, each of which adopts a five-coordinate geometry.  Zinc bonds to two N atoms and one O atom of HL1, one N atom of L2 and one O atom of another HL1 ligand. This is confirmed by IR spectroscopy. Thermogravimetric analysis shows a one-step decomposition of the complex to leave a zinc sulfide residue.                     KEY WORDS: Zinc(II), N-(2-pyridylmethyl)-(L)-alanine) ligand, Isothiocyanate, Coordination polymer, Single crystal structure   Bull. Chem. Soc. Ethiop. 2020, 34(2), 285-293 DOI: https://dx.doi.org/10.4314/bcse.v34i2.7

Silicon photonics-based laser Doppler vibrometer array for carotid-femoral pulse wave velocity (PWV) measurement

Pulse wave velocity (PWV) is a reference measure for aortic stiffness, itself an important biomarker of cardiovascular risk. To enable low-cost and easy-to-use PWV measurement devices that can be used in routine clinical practice, we have designed several handheld PWV sensors using miniaturized laser Doppler vibrometer (LDV) arrays in a silicon photonics platform. The LDV-based PWV sensor design and the signal processing protocol to obtain pulse transit time (PTT) and carotid-femoral PWV in a feasibility study in humans, are described in this paper. Compared with a commercial reference PWV measurement system, measuring arterial pressure waveforms by applanation tonometry, LDV-based displacement signals resulted in more complex signals. However, we have shown that it is possible to identify reliable fiducial points for PTT calculation using the maximum of the 2^nd derivative algorithm in LDV-based signals, comparable to those obtained by the reference technique, applanation tonometry.

Bioluminescent flashes drive nighttime schooling behavior and synchronized swimming dynamics in flashlight fish

Schooling fishes, like flocking birds and swarming insects, display remarkable behavioral coordination. While over 25% of fish species exhibit schooling behavior, nighttime schooling has rarely been observed or reported. This is due to vision being the primary modality for schooling, which is corroborated by the fact that most fish schools disperse at critically low light levels. Here we report on a large aggregation of the bioluminescent flashlight fish Anomalops katoptron that exhibited nighttime schooling behavior during multiple moon phases, including the new moon. Data were recorded with a suite of low-light imaging devices, including a high-speed, high-resolution scientific complementary metal-oxide-semiconductor (sCMOS) camera. Image analysis revealed nighttime schooling using synchronized bioluminescent flashing displays, and demonstrated that school motion synchrony exhibits correlation with relative swim speed. A computer model of flashlight fish schooling behavior shows that only a small percentage of individuals need to exhibit bioluminescence in order for school cohesion to be maintained. Flashlight fish schooling is unique among fishes, in that bioluminescence enables schooling in conditions of no ambient light. In addition, some members can still partake in the school while not actively exhibiting their bioluminescence. Image analysis of our field data and model demonstrate that if a small percentage of fish become motivated to change direction, the rest of the school follows. The use of bioluminescence by flashlight fish to enable schooling in shallow water adds an additional ecological application to bioluminescence and suggests that schooling behavior in mesopelagic bioluminescent fishes may be also mediated by luminescent displays.

Mapping recovery in simple and complex tibial plateau fracture fixation

Aims

The aim of this study was to determine the trajectory of recovery following fixation of tibial plateau fractures up to five-year follow-up, including simple (Schatzker I-IV) versus complex (Schatzker V-VI) fractures.

Patients and Methods

Patients undergoing open reduction and internal fixation (ORIF) for tibial plateau fractures were enrolled into a prospective database. Functional outcome, using the 36-Item Short Form Health Survey Physical Component Summary (SF-36 PCS), was collected at baseline, six months, one year, and five years. The trajectory of recovery for complex fractures (Schatzker V and VI) was compared with simple fractures (Schatzker I to IV). Minimal clinically important difference (MCID) was calculated between timepoints. In all, 182 patients were enrolled: 136 (74.7%) in simple and 46 (25.3%) in complex. There were 103 female patients and 79 male patients with a mean age of 45.8 years (15 to 86).

Results

Mean SF-36 PCS improved significantly in both groups from six to 12 months (p < 0.001) and one to five years (simple, p = 0.008; complex, p = 0.007). In both groups, the baseline scores were not reached at five years. The SF-36 PCS was significantly higher in the simple group compared with the complex group at both six months (p = 0.007) and 12 months (p = 0.01), but not at five years (p = 0.17). Between each timepoint, approximately 50% or more of the patients in each group achieved an MCID in their score change, indicating a significant clinical change in condition. The complex group had a much larger drop off in the first six months, with comparable proportions achieving MCID at the subsequent time intervals.

Conclusion

Tibial plateau fracture recovery was characterized overall by an initial decline in functional outcome from baseline, followed by a steep improvement from six to 12 months, and ongoing recovery up to five years. In simple patterns, patients tended to achieve a higher functional score by six months compared with the complex patterns. However, comparable functional scores between the groups achieved only at the five-year point suggest later recovery in the complex group. Function does not improve to baseline by five years in either group. This information is useful in counselling patients about the course of prospective recovery. Cite this article: Bone Joint J 2019;101-B:1009–1014.

Randomized Trial of Systemic Therapy After Involved-Field Radiotherapy in Patients With Early-Stage Follicular Lymphoma: TROG 99.03

Purpose

Follicular lymphoma (FL) is curable by involved-field radiotherapy (IFRT) in < 50% of patients with stage I to II disease. We hypothesized that adding systemic therapy to IFRT would improve long-term progression-free survival (PFS).

Patients and Methods

A multicenter randomized controlled trial enrolled patients with stage I to II low-grade FL after staging computed tomography scans and bone marrow biopsies. 18F-labeled fluorodeoxyglucose–positron emission tomography (PET) was not mandatory. Patients were randomly assigned to either arm A (30 Gy IFRT alone) or arm B (IFRT plus six cycles of cyclophosphamide, vincristine, and prednisolone [CVP]). From 2006, rituximab was added to arm B (R-CVP).

Results

Between 2000 and 2012, 150 patients were enrolled, 75 per arm. In arm B, 44 patients were allocated to receive CVP and 31 were allocated to receive R-CVP. At randomization, 75% had stage I, the median age was 57 years, 52% were male, and 48% were PET staged. With a median follow-up of 9.6 years (range, 3.1 to 15.8 years), PFS was superior in arm B (hazard ratio, 0.57; 95% CI, 0.34 to 0.95; P = .033). Ten-year PFS rates were 59% (95% CI, 46% to 74%) and 41% (95% CI, 30% to 57%) for arms B and A, respectively. Patients in arm B who received R-CVP had markedly superior PFS compared with contemporaneous patients in arm A (hazard ratio, 0.26; 95% CI, 0.07 to 0.97; P = .045). Fewer involved regions ( P = .047) and PET staging ( P = .056) were associated with better PFS. Histologic transformation occurred in four and 10 patients in arms B and A, respectively ( P = .1). Ten deaths occurred in arm A versus five in arm B, but overall survival was not significantly different ( P = .40; 87% and 95% at 10 years, respectively).

Conclusion

Systemic therapy with R-CVP after IFRT reduced relapse outside radiation fields and significantly improved PFS. IFRT followed by immunochemotherapy is more effective than IFRT in early-stage FL.

Impact of Regionalization of ST-Segment–Elevation Myocardial Infarction Care on Treatment Times and Outcomes for Emergency Medical Services–Transported Patients Presenting to Hospitals With Percutaneous Coronary Intervention

Background:

Regional variations in reperfusion times and mortality in patients with ST-segment–elevation myocardial infarction are influenced by differences in coordinating care between emergency medical services (EMS) and hospitals. Building on the Accelerator-1 Project, we hypothesized that time to reperfusion could be further reduced with enhanced regional efforts.

Methods:

Between April 2015 and March 2017, we worked with 12 metropolitan regions across the United States with 132 percutaneous coronary intervention–capable hospitals and 946 EMS agencies. Data were collected in the ACTION (Acute Coronary Treatment and Intervention Outcomes Network)-Get With The Guidelines Registry for quarterly Mission: Lifeline reports. The primary end point was the change in the proportion of EMS-transported patients with first medical contact to device time ≤90 minutes from baseline to final quarter. We also compared treatment times and mortality with patients treated in hospitals not participating in the project during the corresponding time period.

Results:

During the study period, 10 730 patients were transported to percutaneous coronary intervention–capable hospitals, including 974 in the baseline quarter and 972 in the final quarter who met inclusion criteria. Median age was 61 years; 27% were women, 6% had cardiac arrest, and 6% had shock on admission; 10% were black, 12% were Latino, and 10% were uninsured. By the end of the intervention, all process measures reflecting coordination between EMS and hospitals had improved, including the proportion of patients with a first medical contact to device time of ≤90 minutes (67%–74%; P <0.002), a first medical contact to device time to catheterization laboratory activation of ≤20 minutes (38%–56%; P <0.0001), and emergency department dwell time of ≤20 minutes (33%–43%; P <0.0001). Of the 12 regions, 9 regions reduced first medical contact to device time, and 8 met or exceeded the national goal of 75% of patients treated in ≤90 minutes. Improvements in treatment times corresponded with a significant reduction in mortality (in-hospital death, 4.4%–2.3%; P =0.001) that was not apparent in hospitals not participating in the project during the same time period.

Conclusions:

Organization of care among EMS and hospitals in 12 regions was associated with significant reductions in time to reperfusion in patients with ST-segment–elevation myocardial infarction as well as in in-hospital mortality. These findings support a more intensive regional approach to emergency care for patients with ST-segment–elevation myocardial infarction.

Neutrophil Proteases Can Inactivate Human PAR3 and Abolish the Co-receptor Function of PAR3 on Murine Platelets

Three members of the protease-activated receptor family, PAR1, PAR3 and PAR4, are activated when thrombin cleaves the receptor N-terminus, exposing a tethered ligand. Proteases other than thrombin can also cleave PAR family members and, depending upon whether this exposes or removes the tethered ligand, either activate or disable the receptor. For example, on human platelets PAR1 is disabled by cathepsin G, although aggregation still occurs because cathepsin G can activate PAR4. The present studies examine the interaction of cathepsin G and a second neutrophil protease, elastase, with PAR3 using two model systems: COS-7 cells transfected with human PAR3 and mouse platelets, which express PAR3 and PAR4, but not PAR1. In contrast to human platelets, cathepsin G did not aggregate murine platelets, and prevented their activation only at low thrombin concentrations. Elastase had no effect on thrombin responses in mouse platelets, but when added to COS cells expressing human PAR3, both cathepsin G and elastase prevented activation of phospholipase C by thrombin. Notably, this inhibition occurred without loss of the binding sites for two monoclonal antibodies that flank the tethered ligand on human PAR3. We therefore conclude that 1) exposure to cathepsin G disables signaling through human PAR3, and prevents murine PAR3 from serving its normal role, which is to facilitate PAR4 cleavage at low thrombin concentrations, 2) elastase disables human, but not murine, PAR3, 3) in contrast to human PAR4, mouse PAR4 will not support platelet aggregation in response to cathepsin G, and 4) the inactivation of human PAR3 by cathepsin G and elastase involves a mechanism other than amputation of the tethered ligand domain. These results extend the range of possible interactions between PAR family members and proteases, and provide further support for species-specific differences in the interaction of these receptors with proteases other than thrombin.

High magnetic relaxivity in a fluorescent CdSe/CdS/ZnS quantum dot functionalized with MRI contrast molecules

Fluorescent quantum dots functionalized with Gd(iii) MRI contrast agents produce an unprecedentedly high T₁ relaxivity per particle (6800 mM⁻¹ s⁻¹).

Evaluation of Techniques for Measuring Microbial Hazards in Bathing Waters: A Comparative Study

Recreational water quality is commonly monitored by means of culture based faecal indicator organism (FIOs) assays. However, these methods are costly and time-consuming; a serious disadvantage when combined with issues such as non-specificity and user bias. New culture and molecular methods have been developed to counter these drawbacks. This study compared industry-standard IDEXX methods (Colilert and Enterolert) with three alternative approaches: 1) TECTA™ system for E. coli and enterococci; 2) US EPA’s 1611 method (qPCR based enterococci enumeration); and 3) Next Generation Sequencing (NGS). Water samples (233) were collected from riverine, estuarine and marine environments over the 2014–2015 summer period and analysed by the four methods. The results demonstrated that E. coli and coliform densities, inferred by the IDEXX system, correlated strongly with the TECTA™ system. The TECTA™ system had further advantages in faster turnaround times (~12 hrs from sample receipt to result compared to 24 hrs); no staff time required for interpretation and less user bias (results are automatically calculated, compared to subjective colorimetric decisions). The US EPA Method 1611 qPCR method also showed significant correlation with the IDEXX enterococci method; but had significant disadvantages such as highly technical analysis and higher operational costs (330% of IDEXX). The NGS method demonstrated statistically significant correlations between IDEXX and the proportions of sequences belonging to FIOs, Enterobacteriaceae, and Enterococcaceae. While costs (3,000% of IDEXX) and analysis time (300% of IDEXX) were found to be significant drawbacks of NGS, rapid technological advances in this field will soon see it widely adopted.

Molecular mechanism of 17α-ethinylestradiol cytotoxicity in isolated rat hepatocytes

17α-Ethinylestradiol (17-EE) is used in formulations of contraceptives and hormone replacement therapy because it is an estradiol derivative. However, it has been associated with an increase in the risk of liver cancers and injury. The carcinogenic properties of 17-EE are similar to that of other estrogens, but the molecular mechanism of liver injury is still unclear. It is important to identify any secondary toxic mechanisms that can be used to prevent or treat the toxicity. The LC50 of 17-EE toward isolated rat hepatocytes was determined to be 150 ± 8 μmol/L. Accelerated cytotoxicity mechanism screening (ACMS) techniques using isolated rat hepatocytes showed that CYP1A inhibitors decreased cytotoxicity, whereas tyrosinase increased toxicity; this suggests that the toxic mechanism involved is the oxidation of 17-EE. A hepatocyte inflammation model also increased 17-EE-induced mitochondrial toxicity, as well as the formation of ROS and H2O2. Cytotoxicity was increased when inhibitors of quinone reduction, catechol-O-methylation, glucuronidation, glutathione conjugation, and sulfation were co-incubated with 17-EE. The hepatocytes could be rescued with antioxidants and quinone trapping agents, thereby suggesting a role for quinoid moiety induced oxidative stress in 17-EE induced cytotoxicity. These mechanisms for 17-EE hepatotoxicity could provide a new perspective for the treating 17-EE-induced liver injury.

Passivation of lanthanide surface sites in sub-10 nm NaYF(4):Eu(3+) nanocrystals

We examined in detail the optical properties of NaYF(4):Eu(3+) nanocrystals of ~9 nm in diameter. For such small nanocrystals roughly 17 % of Y(3+) ions occupy surface sites and can be efficiently substituted by optically active Eu(3+) ions. In order to determine the influence of surface Eu(3+) on the optical properties of the whole nanocrystal, small β-NaYF(4):Eu(3+) nanocrystals with homogenous size distribution were prepared using trioctylphosphine oxide as a coordinating solvent. In order to passivate the surface sites, a thin β-NaYF(4) shell was further deposited on nanocrystals core and the optical properties were investigated. For this purpose absorption, photoluminescence, photoluminescence excitation, and photoluminescence decays were recorded and analyzed. The optical characteristics of surface Eu(3+) significantly diminish for surface passivated nanocrystals. We calculated the increase of quantum yield to the value of 64 % when NaYF(4):Eu(3+) core was capped by undoped shell. The optical spectroscopy techniques were shown to be sufficient in determination of surface passivation of nanocrystals with high surface to volume ratio.

Synthesis of the azaphilones (+)-sclerotiorin and (+)-8-O-methylsclerotiorinamine utilizing (+)-sparteine surrogates in copper-mediated oxidative dearomatization

Enantioselective syntheses of the azaphilone natural products (+)-sclerotiorin and (+)-8-O-methylsclerotiorinamine that possess the natural R-configuration at the quaternary center are reported. The syntheses were accomplished using copper-mediated asymmetric dearomatization employing bis-μ-oxo copper complexes prepared from readily available (+)-sparteine surrogates. Of note, site-selective O-methylation of a vinylogous pyridone was used to access the isoquinolin-6(7H)-one core of (+)-8-O-methylsclerotiorinamine.

Best Practices for Clinical Pathology Testing in Carcinogenicity Studies

The Society of Toxicologic Pathology (STP) and American Society for Veterinary Clinical Pathology (ASCVP) convened a Clinical Pathology in Carcinogenicity Studies Working Group to recommend best practices for inclusion of clinical pathology testing in carcinogenicity studies. Regulatory guidance documents and literature were reviewed, and veterinary pathologists from North America, Japan, and Europe were surveyed regarding current practices, perceived value, and recommendations for clinical pathology testing in carcinogenicity studies. For two-year rodent carcinogenicity studies, the Working Group recommends that clinical pathology testing be limited to collection of blood smears at scheduled and unscheduled sacrifices to be examined only if indicated to aid in the diagnosis of possible hematopoietic neoplasia following histopathologic evaluation. Additional clinical pathology testing is most appropriately used to address specific issues from prior toxicity studies or known test article–related class effects. Inadequate data were available to make a recommendation concerning clinical pathology testing for alternative six-month carcinogenicity assays using genetically modified mice, although the Working Group suggests that it may be appropriate to use the same approach as for two-year carcinogenicity studies since the study goal is the same.