Semiconductor Optical Amplifiers with Wide Gain Bandwidth and Enhanced Polarization Insensitivity Based on Tensile-Strained Quantum Wells.

The paper presents a wide-bandwidth, low-polarization semiconductor optical amplifier (SOA) based on strained quantum wells. By enhancing the material gain of quantum wells for TM modes, we have extended the gain bandwidth of the SOA while reducing its polarization sensitivity. Through a combination of tilted waveguide design and cavity surface optical thin film design, we have effectively reduced the cavity surface reflectance of the SOA, thus decreasing device transmission losses and noise figure. At a wavelength of 1550 nm and a drive current of 1.4 A, the output power can reach 188 mW, with a small signal gain of 36.4 dB and a 3 dB gain bandwidth of 128 nm. The linewidth broadening is only 1.032 times. The polarization-dependent gain of the SOA is below 1.4 dB, and the noise figure is below 5.5 dB. The device employs only I-line lithography technology, offering simple fabrication processes and low costs yet delivering outstanding and stable performance. The designed SOA achieves wide gain bandwidth, high gain, low polarization sensitivity, low linewidth broadening, and low noise, promising significant applications in the wide-bandwidth optical communication field across the S + C + L bands.

Research on the parameter design and calibration and control of EV in-vehicle active sound generation system.

In order to improve the interior sound quality of electric vehicles (EVs) under acceleration and uniform speed conditions, to balance the comfort and dynamics of the interior sound, and to improve the accuracy and performance of the active sound generation system (ASGS), this article carries out the research related to the parameter design, sound calibration, evaluation methodology, and control system of the EV ASGS. Propose an in-vehicle sound design method focusing on three dimensions, including engine order composition, spectral energy distribution, and sound amplitude enhancement in the typical speed range, and determine the in-vehicle sound design scheme and the total sound value target. Focus on the sound parameter design, calibration and evaluation methods of EV ASGS considering the frequency response characteristics of the loudspeaker, sound amplitude control accuracy, sound quality, and psychoacoustic parameters, clarify the active sound parameter settings of EVs, complete the analysis of sound extraction methods, complete the engine order sound fitting, and design the ASGS of the EV interior by combining the subjective and objective evaluations. Develop the control software and hardware of the ASGS, complete the construction and accuracy verification of the ASGS based on the in-vehicle sound system, and realize the sound calibration of the ASGS under the static conditions of the real vehicle and the verification of the target achievement. The real-vehicle test shows that the ASGS reduces the sharpness of 1.0 acum and 0.52 acum under acceleration and constant speed conditions, respectively, and improves the comfort and dynamics of in-vehicle sound. The objective and subjective evaluation results show that the parameter design, selection and accuracy of the sound calibration and evaluation methods of the ASGS in the EV determines the accuracy and effect of the ASGS.

Research on the characteristics of EV interior sound quality and its dynamic active control system design and development un-der accelerated driving conditions.

In order to improve the interior sound quality of Electric Vehicles (EV), solve the problem of low sense of power and comfort of the interior sound as well as the large electromagnetic excitation order noise of motor and the sharp interior sound, this article designs a dynamic active sound control system for EV under accelerated driving conditions. Firstly, by comparing and analyzing the sound spectrum characteristics of fuel vehicle (FV) and EV during acceleration, a short-time Fourier transform (STFT) is adopted to extract and synthesize the engine sound. Secondly, the influence of the engine order composition and the energy distribution in the frequency domain on the sound quality of the vehicle is analyzed, and an active control system for sound quality is proposed. And the software and hardware development of the active control sound system is completed. Finally, through real-vehicle testing and verification, the sense of comfort and power of the EV interior sound has been greatly improved during acceleration, and the total value of interior sound can meet the requirement. The sound pressure level and loudness of interior sound have been increased, and the sharpness of the sound inside the vehicle has been improved, with a maximum reduction of 1.0acum.

Low-Polarization, Broad-Spectrum Semiconductor Optical Amplifiers.

Polarization-insensitive semiconductor optical amplifiers (SOAs) in all-optical networks can improve the signal-light quality and transmission rate. Herein, to reduce the gain sensitivity to polarization, a multi-quantum-well SOA in the 1550 nm band is designed, simulated, and developed. The active region mainly comprises the quaternary compound InGaAlAs, as differences in the potential barriers and wells of the components cause lattice mismatch. Consequently, a strained quantum well is generated, providing the SOA with gain insensitivity to the polarization state of light. In simulations, the SOA with ridge widths of 4 µm, 5 µm, and 6 µm is investigated. A 3 dB gain bandwidth of >140 nm is achieved with a 4 µm ridge width, whereas a 6 µm ridge width provides more output power and gain. The saturated output power is 150 mW (21.76 dB gain) at an input power of 0 dBm but increases to 233 mW (13.67 dB gain) at an input power of 10 dBm. The polarization sensitivity is <3 dBm at -20 dBm. This design, which achieves low polarization sensitivity, a wide gain bandwidth, and high gain, will be applicable in a wide range of fields following further optimization.

Comparison of singleton and twin birth weight reference percentile curves by gestational age and sex in extremely preterm infants: a population-based study.

BACKGROUND: With the increasing survival rate of smaller newborns and twins, previous growth curves may not accurately assess the growth of extremely preterm infants (EPIs). Our study aimed to establish birth weight percentile curves for singletons and twins in EPIs from China and the USA and compare the differences between them. METHODS: In China, EPIs were from 31 provinces, from 2010 to 2021. The collected information was sex, gestational age, birth weight, singletons and twins. We used the generalised additive models for location scale and shape method to construct the birth weight percentile curves by gestational age and sex for EPIs. The National Vital Statistics System database from 2016 to 2021 was also analysed. We compared the differences between the 50th birth weight percentile curves of the two databases. RESULTS: We identified 8768 neonates in China (5536 singletons and 3232 twins) and 121 933 neonates in the USA (97 329 singletons and 24 604 twins). We established the 3rd, 10th, 25th, 50th, 75th, 90th and 97th birth weight reference curves for China and the USA. The results showed that males had higher birth weights than females. In China, for the same gestational age and sex, birth weights in singletons and twins were found to be similar, though singleton males born in China had slightly higher birth weights than male twins. In the USA, birth weights were also similar for females and males, with the same gestational age in singletons and twins. CONCLUSION: We established birth weight reference percentile curves by gestational age and sex for singletons and twins among EPIs in China and the USA.

Nanoplastics induce molecular toxicity in earthworm: Integrated multi-omics, morphological, and intestinal microorganism analyses.

The toxicity of nanoplastics (NPs) at relatively low concentrations to soil fauna at different organismal levels is poorly understood. We investigated the responses of earthworm (Eisenia fetida) to polystyrene NPs (90-110 nm) contaminated soil at a relatively low concentration (0.02 % w:w) based on multi-omics, morphological, and intestinal microorganism analyses. Results showed that NPs accumulated in earthworms' intestinal tissues. The NPs damaged earthworms' digestive and immune systems based on injuries of the intestinal epithelium and chloragogenous tissues (tissue level) and increased the number of changed genes in the digestive and immune systems (transcriptome level). The NPs reduced gut microorganisms' diversity (Shannon index) and species richness (Chao 1 index). Proteomic, transcriptome, and histopathological analyses showed that earthworms suffered from oxidative and inflammatory stresses. Moreover, NPs influenced the osmoregulatory metabolism of earthworms as NPs damaged intestinal epithelium (tissue level), increased aldosterone-regulated sodium reabsorption (transcriptome level), inositol phosphate metabolism (proteomic level) and 2-hexyl-5-ethyl-furan-3-sulfonic acid, and decreased betaine and myo-inositol concentrations (metabolic level). Transcriptional-metabolic and transcriptional-proteomic analyses revealed that NPs disrupted earthworm carbohydrate and arachidonic acid metabolisms. Our multi-level investigation indicates that NPs at a relatively low concentration induced toxicity to earthworms and suggests that NPs pollution has significant environmental toxicity risks for soil fauna.

Transient receptor potential melastatin 7 aggravates necrotizing enterocolitis by promoting an inflammatory response in children.

Background: As a rare disease in children, necrotizing enterocolitis (NEC) leads to high morbidity and mortality. However, its pathophysiology is largely unclear. Transient receptor potential melastatin 7 (TRPM7) is a membrane protein, which plays key roles in the inflammatory response. This study sought to examine the promoting effect of TRPM7 on NEC in children and explore the therapeutic effect of a TRPM7 inhibitor NS8593. Methods: First, we detected TRPM7 and NLR family pyrin domain containing 3 (NLRP3) expression and the state of inflammation in children with NEC through quantitative real-time polymerase chain reaction (RT-PCR), Western blot, and enzyme-linked immunosorbent assays. Next, Human intestinal epithelial cell lines were induced to NEC by lipopolysaccharides (LPSs). The level of cytokines and reactive oxygen species (ROS) were tested by RT-PCR and flow cytometry. The TRPM7 mediated calcium flux were determined by fluorescence. In addition, we used the TRPM7 inhibitor NS8593 to treat the in vivo rat model. The mRNA and protein expression were determined by real-time PCR and Elisa analysis, respectively. Results: TRPM7 and NLRP3 expression was more increased in the samples from children with NEC compared to the control samples. Additionally, the elevated secretion of interleukin-1ß, interleukin-6, and tumor necrosis factor alpha was also detected in the serum of children with NEC. These results showed that TRPM7 had a promoting effect on NEC development, possibly via the activation of NLRP3. To test our hypothesis, the TRPM7 inhibitor NS8593 was used to treat the LPS-stimulated IEC-6 cells. We found that the TRPM7 inhibitor NS8593 inhibited LPS-induced cytokine production and exhibited an anti-inflammatory effect by alleviating TRPM7-mediated NLRP3 inflammasome activation. Through in-vivo experiments, we found that TRPM7 was involved in the occurrence of NEC, and its inhibitor NS8593 played a certain therapeutic role in the rat model. Conclusions: Our study revealed TRPM7 inhibitors attenuated LPS-induced ROS and reduced the release of pro-inflammatory cytokines. It also exhibited protective effects on the NEC model.

Hemizygous deletion in the OTC gene results in ornithine transcarbamylase deficiency: A case report.

BACKGROUND: Ornithine transcarbamylase deficiency (OTCD) is a common ornithine cycle disorder, and OTC gene variation is the main pathogenic factor of this disease. This study explored and validated a variant in the OTC gene. CASE SUMMARY: The neonate exhibited high blood ammonia, lactic acid, and homocysteine levels on the fifth day after birth. A novel deletion variant in the OTC gene [NM_000531.5, c.970_979delTTCCCAGAGG, p.Phe324GlnfsTer16] was uncovered by exome sequencing. The variant caused a protein-coding frameshift and resulted in early translation termination at the 16th amino acid after the variant site. CONCLUSION: Our results provide a novel pathogenic variant in OTC and related clinical features for further OTCD screening and clinical consultation.

Necrotizing enterocolitis in low birth weight infants in China: Mortality risk factors expressed by birth weight categories.

BACKGROUND: We retrospectively investigated incidence, morbidity, and mortality of neonatal necrotizing enterocolitis in China, with special emphasis on determining the predictors of necrotizing enterocolitis associated mortality. METHODS: We identified neonates as having necrotizing enterocolitis if they met the accepted diagnostic criterion. Data pertaining to antenatal period, labor and birth, and the postnatal course of illness were collected. Multivariate analysis and logistic regression were used to analyze the risk factors. RESULTS: There were 1167 cases of necrotizing enterocolitis identified from the 95 participating NICUs in mainland China in 2011, with the incidence of 2.50% and 4.53% in LBW (birth weight <2500 g) and VLBW (birth weight <1500 g) infants, respectively. Stage 1, 2 and 3 diseases were noted in 51.1%, 30.3% and 18.6% of cases respectively. The mortality from stage 2 and 3 necrotizing enterocolitis in this cohort was 41.7%. In VLBW infants, the important risk factors for mortality were small for gestation age (OR: 5.02, 95% CI 1.73-14.6; P = 0.003) and stage 3 NEC (OR: 8.09, 95% CI 2.80-23.3, P < 0.001). In moderate LBW infants (birth weight 1500-2499 g), the risk factors identified for mortality were sepsis during hospitalization (OR: 2.59, 95% CI 1.57-4.28, P < 0.001) and stage 3 NEC (OR: 5.37, 95% CI 3.24-8.90; P < 0.001). CONCLUSIONS: Necrotizing enterocolitis remains an important cause of morbidity and mortality in prematurely born neonates in Chinese neonatal units. Awareness of the associated risk factors and appropriate interventions may improve the outcome of necrotizing enterocolitis in different birth weight subgroup.

Hyperbaric oxygenation promotes neural stem cell proliferation and protects the learning and memory ability in neonatal hypoxic-ischemic brain damage.

The aim of our study was to evaluate whether hyperbaric oxygenation (HBO) was an effective therapy for neonatal hypoxic ischemic brain damage (HIBD). Seven-day-old rat pups were divided into 3 groups: sham, hypoxia-ischemia (HI) control and HI-HBO group. HBO was administered for HI rats daily. The pathologic changes in brain tissues were observed by hematoxylin-eosin (H-E) staining. The immunohistochemical staining was applied to detect the Nestin and 5-bromo-2-deoxyuridine (BrdU) positive cells in hippocampal dentate gyrus region. The learning and memory function of rats was examined by Morris water maze. The HI rats showed obvious pathologic changes accompanied by levels decreasing and disorder arrangement of pyramidal cells, glial cells proliferation in postoperative, and nerve nuclei broken, while pathologic changes of rats in sham group was approximate to that in the HI + HBO group that was opposite to the HI group. Compared with the sham group, the Nestin and BrdU positive cells in HBO + HI group at different time points increased significantly (P < 0.01). Learning and memory function of rats in HI group was poor compared with the sham/HI + HBO group (P < 0.01), while that in HI + HBO group was approximate to that in sham group (P > 0.05). HBO treatment improved the learning and memory ability of the HI rats. HBO therapy may be effective for neonatal HIBD treatment.

[Neuroprotective effects of exogenous basic fibroblast growth factor on the hypoxic-ischemic brain damage of neonatal rats].

OBJECTIVE: To investigate the neuroprotective effect of basic fibroblast growth factor (bFGF) on neurological function after hypoxic-ischemic brain damage (HIBD) in neonatal rats. METHODS: Ninety-six HIBD models of neonatal Wistar rats were made by shearing right arteria carotis communis and then breathing 8% O(2)+92%N(2) for two hours. The models were divided into two groups randomly: the bFGF trial group and the normal saline control group. Each group had forty-eight rats. The other forty-eight neonatal Wistar rats were taken into the sham operation group. Forty rats were taken from each group and sacrificed on the 4 th, 7 th, 10 th, 17 th and 24 th days after the operation, respectively, The pathological changes in the brain were observed by optical microscope and the expressions of nestin and growth-associated protein-43 (GAP-43) in hippocampal CA1 region were examined with immunohistochemical staining and image quantitative analysis on the 4 th, 7 th, 10 th, 17 th and 24 th days after the operation. The spatial cognitive capability of other eight rats which were taken from each group respectively was evaluated by using the Morris water maze at the age of 30 days. RESULTS: (1) No brain damage was found in the sham operation group, the neurocytes were degenerative and necrotic in the control group of normal saline. The pathological manifestation of the brain damage in the bFGF trial group was milder than that of the normal saline control group. (2) Expression of nestin: The number of nestin-positive cells in hippocampal CA1 region of control group on the 4 th, 7 th, 10 th, 17 th and 24 th days after the operation was significantly increased compared with that of the sham operation group at all time points, and the numbers of nestin-positive cells in hippocampal CA1 region of the trial group were higher than those of the sham operation group and the control group (P < 0.01). (3) The expression of GAP-43 in hippocampal CA1 region of the neonatal rats reached peak on the 10th day after the operation in all the three groups. The integral optical density (IOD) of GAP-43 in hippocampal CA1 region of the control group was higher than that of the sham-operation group at all time points, and the IOD of GAP-43 in hippocampal CA1 region of the trial group was higher than those of the sham operation group and the control group at all time points (P < 0.01 for all). (4) The latency to escape platform in control group (51.75 +/- 11.27s) was longer than that in trial group (40.32 +/- 11.48s) and the sham operation group (36.58 +/- 10.83s) (P < 0.05); the frequency of passing through the platform in control group (2.34 +/- 2.42) was less than that in trial group (5.08 +/- 3.86) and the sham operation group (7.03 +/- 3.62) (P < 0.05). There was no significant difference between the trial group and the sham operation group (P > 0.05). CONCLUSIONS: (1) The expression of nestin and GAP-43 increased in hippocampal CA1 region of neonatal rats with HIBD, it may be involved in the activation of neural stem cells and the regeneration of neurocytes after HIBD. (2) The treatment with bFGF can improve the ability of learning and memory of neonatal rats with HIBD. (3) Exogenous bFGF could enhance the expression of nestin and GAP-43 in the brain of neonatal rats with HIBD, which may play an important role in restoration of neurons damaged due to hypoxia-ischemia.