Broadband, silicon photonic, optical add-drop filters with 3 dB bandwidths up to 11 THz.

We present the designs, theory, and experimental demonstrations of ultra-broadband, optical add-drop filters on the silicon-on-insulator platform, realized using period-chirped contra-directional couplers. Our fabricated devices have ultra-broad 3 dB bandwidths of up to 11 THz (88.1 nm), with flat-top responses at their drop ports. All of our devices were fabricated using a commercial, CMOS-compatible, 193 nm deep-ultraviolet lithography process. By using lithography-prediction models, the measured bandwidths, insertion losses, central wavelengths, and extinction ratios of our devices are all in good agreement with our predicted, simulated results. Such filters are necessary for photonic integrated circuits to operate over multiple optical bands.

Broadband, silicon photonic, optical add-drop filters with 3 dB bandwidths up to 11 THz: publisher's note.

This publisher's note contains corrections to Opt. Lett.46, 2738 (2021)OPLEDP0146-959210.1364/OL.423745.

Automated control algorithms for silicon photonic polarization receiver.

We demonstrate greedy linear descent-based, basic gradient descent-based, two-point step size gradient descent-based, and two-stage optimization method-based automated control algorithms and examine their performance for use with a silicon photonic polarization receiver. With an active feedback loop control process, time-varying arbitrary polarization states from an optical fiber can be automatically adapted and stabilized to the transverse-electric (TE) mode of a single-mode silicon waveguide. Using the proposed control algorithms, we successfully realize automated adaptations for a 10 Gb/s on-off keying signal in the polarization receiver. Based on the large-signal measurement results, the control algorithms are examined and compared with regard to the iteration number and the output response. In addition, we implemented a long-duration experiment to track, adapt, and stabilize arbitrary input polarization states using the two-point step size gradient descent-based and two-stage optimization method-based control algorithms. The experimental results show that these control algorithms enable the polarization receiver to achieve real-time and continuous polarization management.

Sub-wavelength grating-assisted polarization splitter-rotators for silicon-on-insulator platforms: erratum.

An erratum is presented to correct the caption of Fig. 1 and the citation number in Fig. 7(d) in the original article [Opt. Express 27, 17581 (2019)].

Triglyceride is independently correlated with insulin resistance and islet beta cell function: a study in population with different glucose and lipid metabolism states.

BACKGROUND: Previous studies on the effects of lipotoxicity and oxidative stress on islet beta cell function mainly focused on patients with diabetes, whereas studies on normal glucose tolerance (NGT) are few. The aim of this study was to explore the relationships among triglyceride (TG), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), oxidative stress indicators, insulin resistance, and beta cell function in populations with different glucose and lipid metabolism states. METHODS: A total of 517 individuals were recruited from a rural community in Beijing, China. Glucose metabolism status was defined according to the results of a 75-g oral glucose tolerance test (OGTT). Dyslipidemia was defined as abnormal TG, HDL-c, or LDL-c levels. The population was divided into four groups: individuals with normal glucose and lipid levels (group A, n = 62); those with dyslipidemia alone (group B, n = 82); those with dysglycemia alone (group C, n = 121); and those with dysglycemia and dyslipidemia (group D, n = 247). Oxidative stress indicators, including superoxide dismutase (SOD), glutathione reductase (GR) and 8-hydroxydeoxyguanosine (8-OHdG), were measured. Homeostasis model assessment of insulin resistance (HOMA-IR) and glucose disposition index (DI30, DI120) were calculated to assess insulin resistance and islet beta cell function, respectively. Stratified multiple linear regression analysis was used to explore relationships between TG, HDL-c, LDL-c, oxidative stress indicators, and insulin resistance (natural log transformation of HOMA-IR, LnHOMA-IR) and beta cell function (natural log transformation of DI30, Ln DI30). RESULTS: Compared with the control group, populations with dyslipidemia and/or dysglycemia showed significantly increased insulin resistance. Dyslipidemia aggravated insulin resistance and beta cell dysfunction in individuals with dysglycemia. Stratified regression analysis showed that TG positively correlated with LnHOMA-IR in individuals with normal glucose levels (beta = 0.321, 0.327, P = 0.011, 0.003 in groups A and B, respectively) and negatively correlated with LnDI30 in participants with dyslipidemia (beta = - 0.225, - 0.122, P = 0.035, 0.048 in groups B and D, respectively). Reduced serum SOD levels in individuals with dysglycemia plus dyslipidemia were observed, and a negative association between TG and SOD levels was found (r = - 0.461, P < 0.001). CONCLUSION: TG correlated with both insulin resistance and beta cell function in individuals with dyslipidemia alone. SOD negatively correlated with TG, indicating a close relationship between oxidative stress and glucose-lipid metabolism. Due to the adverse effect of hypertriglyceridemia on insulin sensitivity and islet beta cell function, more attention should be paid to the detection and management of hypertriglyceridemia.

Dietary Magnesium Intake and Leukocyte Telomere Attrition in Adults: The Regulatory Role of Serum Tumor Necrosis Factor α.

OBJECTIVES: In this study, we assessed the effects of dietary magnesium on leukocyte telomere length (LTL). DESIGNS: The current cross-sectional analysis was based on data collected within a type 2 diabetes project. Settings. Dietary magnesium intake is associated with peripheral blood leukocyte telomere length (LTL). However, few epidemiological studies have evaluated the effects of magnesium on LTL in the clinical setting. Participants. This cross-sectional analysis included 467 participants (34.8% men). Measurements. Serum blood lipid profile, HbA1c, oxidative stress, and proinflammatory mediator levels were measured. Detailed dietary data were obtained using a 24 h food recall. LTL was assessed using a real-time PCR assay. Regression models and simple regulatory models were used for data analysis. RESULTS: There was an inverse relationship between dietary magnesium and LTL (P < 0.001), with a between-extreme-quarter difference of -0.55. Conversely, there was a positive relationship between dietary magnesium and serum tumor necrosis factor (TNF) α, with an interquarter difference of 3.79 pmol/mL (P for trend = 0.006). Multivariate regression analysis revealed that the odds ratios (ORs) for shorter LTL and higher serum TNFα increased with magnesium intake, and the ORs of the differences between extreme quartiles were 2.60 (95% confidence interval (CI): 1.31-5.36; P = 0.003) and 1.98 (95% CI: 1.09-3.59; P = 0.008). There was a direct negative effect of dietary magnesium intake on LTL (B = -0.002; P = 0.001), which appeared to be indirectly influenced by TNFα (-0.002 to -0.0005). CONCLUSIONS: Dietary magnesium intake may be a critical component of the cellular aging process, and its effect could be partly mediated by TNFα.

Corrigendum to "Dietary Magnesium Intake and Leukocyte Telomere Attrition in Adults: The Regulatory Role of Serum Tumor Necrosis Factor α".

[This corrects the article DOI: 10.1155/2020/7610436.].

Hydrocephalus due to aqueductal stenosis presenting with acute bilateral ptosis: case report.

Hydrocephalus may cause Parinaud's syndrome which consists of vertical gaze palsy, convergence palsy, lid retraction and pupil light-near dissociation. We are aware of only two prior reports of hydrocephalus presenting with bilateral ptosis. Both were cured by ventriculoperitoneal shunts. We report a 28-month-old girl who presented acute bilateral ptosis but full eye movements both sides. Neuroimages revealed chronic hydrocephalus and aqueductal stenosis. The bilateral ptosis resolved quickly after endoscopic third ventriculostomy (ETV).

Ring resonator based polarization diversity WDM receiver.

A ring resonator based 4 channel wavelength division multiplexing (WDM) receiver with polarization diversity is demonstrated at 10 Gb/s per channel. By forming a waveguide loop between the two output ports of a polarization splitter-rotator (PSR), the input signals in the quasi-transverse-electric (quasi-TE) and the quasi-transverse-magnetic (quasi-TM) polarizations can be demultiplexed by the same set of ring resonator filters, thus reducing the number of required channel control circuits by half compared to methods which process the two polarizations individually. Large signal measurement results indicate that the design can tolerate a signal delay of up to 30% of the unit interval (UI) between the two polarizations, which implies that compensating for manufacturing variability with optical delay lines on chip is not necessary for a robust operation. The inter-channel crosstalk is found negligible down to 0.4nm (50 GHz) spacing, at which point the adjacent channel isolation is 17 dB, proving the design's compatibility for dense WDM application.

Sub-wavelength grating-assisted polarization splitter-rotators for silicon-on-insulator platforms.

We propose and demonstrate broadband, entirely mode-evolution-based, polarization splitter-rotators (PSR) using sub-wavelength grating (SWG) assisted adiabatic waveguides for two SOI platforms. Our PSRs are more compact than previously demonstrated entirely mode-evolution-based designs. The devices were fabricated using two fabrication processes and, in both cases, the measured spectra show close matches to the simulation results. One of the processes uses standard optical lithography and, hence, this is the first time that an SWG-based PSR has been experimentally implemented using such a process. Finally, measurements for arbitrary input polarizations on an active, automated polarization receiver, that uses one of our PSRs, are also presented.

Compact, silicon-on-insulator, series-cascaded, contradirectional-coupling-based filters with >50 dB adjacent channel isolation.

In this work, we present optical add/drop multiplexer (OADM) filters for coarse wavelength-division-multiplexing (CWDM) systems with high sidelobe suppressions that result in high adjacent channel isolations (Ai). The filters are realized by using a compact, series-cascaded configuration of apodized, contradirectional-coupling-based filters. We experimentally demonstrate a device with a measured Ai of 53 dB (these devices hold the promise of achieving even higher Ais). While having large Ais, our devices have the wide bandwidths and low insertion losses required for CWDM applications. In addition, our demonstrated OADM has a nearly constant group delay, which results in low dispersion in the passband.

Laparoscopic common bile duct exploration with primary closure is safe for management of choledocholithiasis in elderly patients.

BACKGROUND: Laparoscopic common bile duct exploration (LCBDE) is one of the minimally invasive options for choledocholithiasis. Primary closure of the common bile duct (CBD) upon completion of laparoscopic choledochotomy is safe in selected patients. The present study aimed to evaluate the feasibility and safety of primary closure of CBD after LCBDE in patients aged 70 years or older. METHODS: A total of 116 patients (51 males and 65 females) who suffered from choledocholithiasis and underwent primary closure of the CBD (without T-tube drainage) after LCBDE from January 2003 to December 2017 were recruited. They were classified into two groups according to age: group A (≥70 years, n = 56), and group B (<70 years, n = 60). The preoperative characteristics, intraoperative details, and postoperative outcomes of the two groups were evaluated. RESULTS: The mean operative time was 172.02 min for group A and 169.92 min for group B (P = 0.853). The mean hospital stay was 7.40 days for group A and 5.38 days for group B (P < 0.001). Bile leakage occurred in two patients in group A and one in group B (3.57% vs 1.67%, P = 0.952). There were no significant differences in the rates of postoperative complications and mortality between the two groups. At median follow-up time of 60 months, stone recurrence was detected in one patient in group A and two in group B (1.79% vs 3.33%, P = 1.000). Stenosis of CBD was not observed in group A and slight stenosis in one patient in group B (0 vs 1.67%, P = 1.000). CONCLUSION: Primary closure of the CBD upon completion of laparoscopic choledochotomy is safe and feasible in elderly patients ≥70 years old.

Shunt surgery for early-onset severe hydrocephalus in methylmalonic acidemia: report on two cases and review of the literature.

OBJECT: Methylmalonic acidemia (MMA) with early-onset severe hydrocephalus is rare. In this paper, we described two cases of MMA with hydrocephalus and review the literature to elucidate the clinical features of the disease, treatment options, and follow-up results. METHODS: The PubMed and Embase databases were searched for clinical reports on MMA with severe hydrocephalus, and two unreported cases were presented to illustrate the clinical spectrum. RESULTS: Six cases of MMA with severe hydrocephalus were observed in the previous literature. Our two patients with severe hydrocephalus but not bulging fontanelle received a ventriculo-peritoneal shunt, and intracranial hypertension was confirmed in both cases during the operation. These patients' clinical symptoms significantly improved after the operation. CONCLUSIONS: Intracranial hypertension can exist in early-onset severe hydrocephalus in MMA, even if the bulging anterior fontanelle is not apparent. These patients could benefit from a ventriculo-peritoneal shunt.

Dinoflagellate Proton-Pump Rhodopsin Genes in Long Island Sound: Diversity and Spatiotemporal Distribution.

Microbial proton-pump rhodopsin (PPR)-based phototrophy, a light-harvesting mechanism different from chlorophyll-based photosystems, may contribute significantly to solar energy entry into the marine ecosystem. PPR transforms solar energy into cellular energy that is used for various metabolic processes in the cells or flagellar movement. Although rhodopsins or their encoding genes have been documented in a wide phylogenetic range of cultured dinoflagellates, information is limited about how widespread and how spatiotemporally dynamical dinoflagellate PPR (DiPPR) are in natural marine ecosystems. In this study, we investigated DiPPR in Long Island Sound (LIS), a temperate estuary of the Atlantic Ocean between Connecticut and Long Island, New York, USA. We isolated six novel full-length dinoflagellate proton-pump rhodopsin cDNAs, expanding the DiPPR database that is crucial to PPR research. Based on these new sequences and existing sequences of DiPPR, we designed primers and conducted quantitative PCR and sequencing to determine the abundance and diversity of DiPPR genes spatially and temporally throughout a year in the water samples collected from LIS. DiPPR genes were found year-round and throughout LIS but with higher abundances in the eutrophic Western Sound and in April and July. The gene diversity data suggest that there are at least five distinct rhodopsin-harboring groups of dinoflagellates throughout the year. The abundance of DiPPR genes, measured as copy number per mL of seawater, appeared not to be influenced by water temperature or nitrogen nutrient concentration but exhibited weak negative correlations with orthophosphate concentration and salinity and a positive correlation with the abundance of DiPPR-harboring dinoflagellates. This first quantitative profiling of PPR in natural plankton reveals the prevalence and dynamics of this plastid-independent photoenergy harvesting mechanism in a temperate estuary and provides efficient DiPPR primers potentially useful for future research. Furthermore, this study shed light on the potential role of DiPPR in phosphor nutrition and dinoflagellate population, which warrants further studies.

Novel Plastid Genome Characteristics in Fugacium kawagutii and the Trend of Accelerated Evolution of Plastid Proteins in Dinoflagellates.

Typical (peridinin-containing) dinoflagellates possess plastid genomes composed of small plasmids named "minicircles". Despite the ecological importance of dinoflagellate photosynthesis in corals and marine ecosystems, the structural characteristics, replication dynamics, and evolutionary forcing of dinoflagellate plastid genomes remain poorly understood. Here, we sequenced the plastid genome of the symbiodiniacean species Fugacium kawagutii and conducted comparative analyses. We identified psbT-coding minicircles, features previously not found in Symbiodiniaceae. The copy number of F. kawagutii minicircles showed a strong diel dynamics, changing between 3.89 and 34.3 copies/cell and peaking in mid-light period. We found that F. kawagutii minicircles are the shortest among all dinoflagellates examined to date. Besides, the core regions of the minicircles are highly conserved within genus in Symbiodiniaceae. Furthermore, the codon usage bias of the plastid genomes in Heterocapsaceae, Amphidiniaceae, and Prorocentraceae species are greatly influenced by selection pressure, and in Pyrocystaceae, Symbiodiniaceae, Peridiniaceae, and Ceratiaceae species are influenced by both natural selection pressure and mutation pressure, indicating a family-level distinction in codon usage evolution in dinoflagellates. Phylogenetic analysis using 12 plastid-encoded proteins and five nucleus-encoded plastid proteins revealed accelerated evolution trend of both plastid- and nucleus-encoded plastid proteins in peridinin- and fucoxanthin-dinoflagellate plastids compared to plastid proteins of nondinoflagellate algae. These findings shed new light on the structure and evolution of plastid genomes in dinoflagellates, which will facilitate further studies on the evolutionary forcing and function of the diverse dinoflagellate plastids. The accelerated evolution documented here suggests plastid-encoded sequences are potentially useful for resolving closely related dinoflagellates.

Gender Differences in Relation to Body Composition, Insulin Resistance, and Islet Beta Cell Function in Newly Diagnosed Diabetic or Pre-Diabetic Patients.

Objective: To assess the correlation between body components with insulin resistance (IR) and islet beta cell function in patients with newly diagnosed type 2 diabetes mellitus (T2DM) or pre-diabetes mellitus (pre-DM) and to explore whether this correlation differs in males and females. Methods: 111 newly diagnosed diabetic or pre-diabetic patients were recruited in this cross-sectional study. 75g oral glucose tolerance test was used to determine the diagnosis of DM or pre-DM. Homeostasis model assessment of insulin resistance (HOMA-IR) and glucose disposition index (DI30) was calculated to assess IR and islet beta cell function, respectively. Whole-body and regional lean mass (LM) and fat mass (FM) were obtained by dual-energy X-ray absorptiometry (DEXA). Partial correlation and multiple linear regression analyses were used to determine the associations between body composition, IR, and islet beta cell function. Results: More body fat and appendicular fat was observed in female patients than in male, though with similar BMI. Legs fat % was negatively correlated with HOMA-IR, whereas legs lean % was positively associated with HOMA-IR in females (r = -0.673, p = 0.017; r =0.664, p = 0.018, respectively). The regression analysis showed that legs LM was positively correlated with HOMA-IR in females. However, in male patients, android FM was positively correlated with HOMA-IR (r = 0.462, p = 0.007), and trunk LM was negatively associated with DI30 (r = -0.458, p = 0.007). Nevertheless, no significant correlation was observed between body composition and islet beta cell function in female patients. Conclusion: Android FM was positively correlated with IR only in male patients but not in females. Besides, relative legs fat and LM were independently associated with IR in female patients but not in males. Further studies are needed to explore the underlying mechanism.

Association of Bedtime with Early-Onset Diabetes and Islet Beta Cell Function in Patients with Newly Diagnosed Type 2 Diabetes Mellitus.

Objective: To investigate the association of bedtime with the risk of early-onset diabetes mellitus (DM) and islet beta cell function. Methods: 138 participants with treat-naïve DM were included in this study. All participants underwent a 75g oral glucose tolerance test. Sleep habit was obtained through a standardized questionnaire. Bedtime was categorized as < 22:00, 22:00-24:00, and ≥ 24:00 in this study. Multivariate logistic regression and multiple linear regression were used to estimate the association between bedtime and risk of early-onset DM and islet beta cell function, respectively. Results: Patients with early-onset DM had a later bedtime than those with late-onset DM. Individuals with bedtime ≥ 24:00 had a higher prevalence of early-onset DM than those with bedtime at 22:00-24:00 and < 22:00 (51.2% vs 29.3% vs 14.3%, respectively, p = 0.028). The multivariate logistic regression showed that per hour later in bedtime was associated with a 52% increased risk of early-onset DM (p = 0.023). Patients with bedtime after 24:00 had a 146% increased risk of early-onset DM compared to those went to bed between 22:00 to 24:00 (OR = 2.46, 95% CI 1.05 to 5.77, p = 0.039). The multiple linear regression showed that bedtime was independently negatively correlated with late-phase insulin secretion (assessed by disposition index, DI120). Conclusion: Later bedtime was associated with worse late-phase insulin secretion and may be a risk factor for early-onset DM. Proper bedtime to lower risk of early-onset DM deserves further investigation.

In Situ Molecular Ecological Analyses Illuminate Distinct Factors Regulating Formation and Demise of a Harmful Dinoflagellate Bloom.

The development and demise of a harmful algal bloom (HAB) are generally regulated by multiple processes; identifying specific critical drivers for a specific bloom is important yet challenging. Here, we conducted a whole-assemblage molecular ecological study on a dinoflagellate bloom to address the hypothesis that energy and nutrient acquisition, defense against grazing and microbial attacks, and sexual reproduction are critical to the rise and demise of the bloom. Microscopic and molecular analyses identified the bloom-causing species as Karenia longicanalis and showed that the ciliate Strombidinopsis sp. was dominant in a nonbloom plankton community, whereas the diatom Chaetoceros sp. dominated the after-bloom community, along with remarkable shifts in the community structure for both eukaryotes and prokaryotes. Metatranscriptomic analysis indicated that heightened energy and nutrient acquisition in K. longicanalis significantly contributed to bloom development. In contrast, active grazing by the ciliate Strombidinopsis sp. and attacks by algicidal bacteria (Rhodobacteracea, Cryomorphaceae, and Rhodobacteracea) and viruses prevented (at nonbloom stage) or collapsed the bloom (in after-bloom stage). Additionally, nutrition competition by the Chaetoceros diatoms plausibly contributed to bloom demise. The findings suggest the importance of energy and nutrients in promoting this K. longicanalis bloom and the failure of antimicrobial defense and competition of diatoms as the major bloom suppressor and terminator. This study provides novel insights into bloom-regulating mechanisms and the first transcriptomic data set of K. longicanalis, which will be a valuable resource and essential foundation for further elucidation of bloom regulators of this and related species of Kareniaceae in the future. IMPORTANCE HABs have increasingly occurred and impacted human health, aquatic ecosystems, and coastal economies. Despite great efforts, the factors that drive the development and termination of a bloom are poorly understood, largely due to inadequate in situ data about the physiology and metabolism of the causal species and the community. Using an integrative molecular ecological approach, we determined that heightened energy and nutrient acquisition promoted the bloom, while resource allocation in defense and failure to defend against grazing and microbial attacks likely prevented or terminated the bloom. Our findings reveal the differential roles of multiple abiotic and biotic environmental factors in driving the formation or demise of a toxic dinoflagellate bloom, suggesting the importance of a balanced biodiverse ecosystem in preventing a dinoflagellate bloom. The study also demonstrates the power of whole-assemblage metatranscriptomics coupled to DNA barcoding in illuminating plankton ecological processes and the underlying species and functional diversities.

A comparative study reveals the relative importance of prokaryotic and eukaryotic proton pump rhodopsins in a subtropical marginal sea.

Proton-pump rhodopsin (PPR) in marine microbes can convert solar energy to bioavailable chemical energy. Whereas bacterial PPR has been extensively studied, counterparts in microeukaryotes are less explored, and the relative importance of the two groups is poorly understood. Here, we sequenced whole-assemblage metatranscriptomes and investigated the diversity and expression dynamics of PPR in microbial eukaryotes and prokaryotes at a continental shelf and a slope site in the northern South China Sea. Data showed the whole PPRs transcript pool was dominated by Proteorhodopsins and Xanthorhodopsins, followed by Bacteriorhodopsin-like proteins, dominantly contributed by prokaryotes both in the number and expression levels of PPR unigenes, although at the continental slope station, microeukaryotes and prokaryotes contributed similarly in transcript abundance. Furthermore, eukaryotic PPRs are mainly contributed by dinoflagellates and showed significant correlation with nutrient concentrations. Green light-absorbing PPRs were mainly distributed in >3 µm organisms (including microeukaryotes and their associated bacteria), especially at surface layer at the shelf station, whereas blue light-absorbing PPRs dominated the <3 µm (mainly bacterial) communities at both study sites, especially at deeper layers at the slope station. Our study portrays a comparative PPR genotype and expression landscape for prokaryotes and eukaryotes in a subtropical marginal sea, suggesting PPR's role in niche differentiation and adaptation among marine microbes.

Fatigue Fracture Analysis on 2524 Aluminum Alloy with the Influence of Creep-Aging Forming Processes.

The different creep-aging forming processes of 2524 aluminum alloy were taken as the research object, and the effects of creep-aging temperature and creep stress on the fatigue-crack propagation properties of the alloy were studied. The research results showed the following under the same sintering time of 9 h, at creep-aging temperatures of 100 °C, 130 °C, 160 °C, and 180 °C, respectively, with an increase in creep-aging temperature: the fatigue-crack propagation rate was promoted, the spacing of fatigue striations increased, and the sizes of dimples decreased while the number was enlarged; this proves that the fatigue property of the alloy was weakened. Compared with the specimens with creep deformation radii of 1000 mm and 1500 mm, the creep deformation stress was the smallest when the forming radius was 1800 mm, with a higher threshold value of fatigue-crack growth in the near-threshold region of fatigue-crack propagation (ΔK ≤ 8 MPa·m1/2). Under the same fatigue cycle, the specimens under the action of larger creep stress endured a longer fatigue stable-propagation time and a faster fracture speed. Comparing the effect of creep-aging temperature and creep stress, the creep-aging temperature plays a dominant role in the fatigue-crack propagation of creep-aged 2524 aluminum alloy.