Frequency selective surface filters with high-quality factors based on a Fano resonance.

In this work, we propose a design method of the narrow passband filter with a high Q-factor based on a Fano resonance. A single-layer metallic frequency selective surface (FSS) with a simple structure is first designed according to this idea, but the result is not satisfying since the filter transmittance will significantly decrease with the increase of the Q-factor due to the presence of an inherent ohmic damping. Further, to improve the design, a ceramic-based FSS filter based on the similar mechanism is proposed, and the requirements of the ultrahigh Q-factors can be met owing to the high permittivity and low loss tangent of microwave ceramics. The design strategy proposed in this paper may have a promising potential in modern wireless communication and related fields.

[Genetic analysis of a fetus with cryptophthalmos due to variants of FREM2 gene].

OBJECTIVE: To explore the genetic etiology of a fetus with cryptophthalmos detected by prenatal ultrasonography. METHODS: A fetus undergoing induced labor at 32nd gestational week due to absence of bilateral eye fissures detected by prenatal ultrasonography in January 2017 was selected as the study subject. Umbilical cord blood sample from the fetus and peripheral blood samples from its parents were collected for the extraction of genomic DNA. Pathogenic variants were screened through whole exome sequencing (WES) and verified by Sanger sequencing. Pathogenicity of candidate variants was verified by bioinformatic analysis and protein structure simulation. Based on the results of genetic testing, prenatal diagnosis was provided to the couple upon their subsequent pregnancy. RESULTS: The couple had four adverse pregnancies previously. The aborted fetus was the fifth, with fused bilateral upper and lower eyelids, poorly developed eyeballs, adhesion of the cornea with the upper eyelid, low-set ears, and abnormal plantar creases, and was diagnosed with cryptophthalmos. WES and Sanger sequencing revealed that the fetus has harbored compound heterozygous variants of the FREM2 gene, namely c.4537G>A (p.D1513N) and c.7292C>T (p.T2431M). Both variants were unreported associated with cryptophthalmos previously. Protein structure simulation showed that they may lead to loss of hydrogen bonds in the protein product. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were predicted to be likely pathogenic (PM1_Supporting+PM2_Supporting+PM5+PP3+PP4; PM2_Supporting+PM3+PP3+PP4). The mother was performed prenatal diagnosis in her sixth pregnancy based on the variants detected in this family, and delivered a daughter with normal phenotype. CONCLUSION: The FREM2: c.4537G>A and c.7292C>T compound heterozygous variants probably underlay the pathogenesis of cryptophthalmos in this fetus. Above finding has enriched the mutational spectrum of the FREM2 gene.

Investigation of perfect narrow-band absorber in silicon nano hole array.

In this paper, we proposed a triple layer structure consisting of the bottom silver layer, thin silicon oxide space layer, and ultrathin semiconductor silicon film with nano hole array achieving three absorption peaks with narrow band. The absorption spectrum can be easily controlled by adjusting the structural parameters including the radius and period of the nano hole array, and the maximal absorption can reach 99.0% and the narrowest full width of half maximum can reach about 6.5 nm in theory. We also clarified the physical mechanism of the proposed structure in details by finite-difference time-domain simulation, in which the three narrow band perfect adsorption peaks can be attributed to electric dipole resonance, magnetic dipole resonance and plasmonic resonance respectively. At the same time, we used a low-cost nanosphere lithography method to fabricate the proposed nano hole array in large area. In experiment, the absorption peak of the proposed triple layer structure can reach up to 98.3% and the narrowest full width of half maximum can reach up to about 10.1 nm. The highest quality factor Q can reach up to 98.4. This work can open a new avenue for high-quality factor narrow band perfect absorption using ultrathin semiconductor film and benefit for many fields such as infrared sensors, plasmonic filters, and hyperspectral imaging.

Design of the all-silicon long-wavelength infrared achromatic metalens based on deep silicon etching.

An all-silicon long-wavelength infrared (LWIR) achromatic metalens based on deep silicon etching is designed in this paper. With a fixed aperture size, the value range of the equivalent optical thickness of the non-dispersive meta-atoms constructing the achromatic metalens determines the minimum f-number. The fabrication characteristic with high aspect ratio of deep silicon etching amplifies the difference value of optical thickness between different meta-atoms by increasing the propagation distance of the propagation mode, which ensures a small f-number to obtain a better imaging resolution. A 280-µm-diameter silicon achromatic metalens with a f-number of 1 and the average focusing efficiency of 27.66% has been designed and simulated to validate the feasibility of this strategy. The simulation results show that the maximum focal length deviation percentage from the target value between the wavelength of 8.6 and 11.4 µm is 1.61%. This achromatic metalens design is expected to play a role in the field of LWIR integrated optical system.

Multi-layered all-dielectric grating visible color filter with a narrow band and high-quality factor.

In this paper, we proposed a double-layer all-dielectric grating. Under the premise of ensuring the strength of the resonance peak, the upper SiO2 grating layer suppresses the tendency of high-order dipole resonance excitation and improves the transmittance at the non-resonant position (T > 99%). The distribution of chromaticity coordinates on the CIE 1931 chromaticity diagram also proves that suppressing side peaks can effectively increase the saturation of structural colors, which is essential for a high precision imaging system. The cyclic displacement current excites the magnetic dipole resonance, which causes the magnetic field to be confined in the high refractive index material HfO2 grating layer. By adjusting the duty cycle of the grating structure, a reflection spectrum with low full width half maximum (FWHM) (∼2 nm) and high-quality factor Q (∼424.5 nm) can be obtained. And the spectral intensity is more sensitive to the polarization angle. This work is of great significance to the development of sensors, display imaging and other fields. At the same time, the material of the grating filter meets the requirements of high damage threshold of the high-power laser system, and its high-power laser application potential is inestimable.

Near-infrared narrow-band minus filter based on a Mie magnetic dipole resonance.

The traditional minus filter is composed of many layers of thin films, which makes it difficult and complicated to manufacture. It is sensitive to incident light angle and polarization. Here, we propose a near-infrared narrow-band minus filter with a full width at half maximum around 5 nm made of all-dielectric Si-SiO2 structures without any ohmic loss. The stop band transmittance of the proposed filter is close to 0, while its broad pass band transmittance is as high as 90% in the work wavelength range. Theoretical analysis shows that the transmission dip originated from magnetic dipole resonance: Its position can be tuned from 1.3 µm to 1.8 µm by changing the thickness of Si structure, and the proposed structure is insensitive to changes in incident light angle and polarization angle. We further studied its potential applications as a refractive index sensor. The sensitivity of dip1 and dip2 are as high as 953.53 nm/RIU and 691.09 nm/RIU, while their figure of merit is almost unchanged: 59.59 and 115.18, respectively.

Management of hemophagocytic lymphohistiocytosis in pregnancy: Case series study and literature review.

AIM: The diagnosis and treatment of hemophagocytic lymphohistiocytosis (HLH) in pregnancy is challenging due to its rarity. We aim to analyze and summarize the clinical characteristics of HLH in pregnancy, and to discuss effective diagnostic and treatment options. METHODS: Thirteen patients with HLH during pregnancy who were diagnosed and treated at the Peking Union Medical College Hospital of the Chinese Academy of Medical Sciences from January 2000 to December 2019 were studied retrospectively. We collected data on treatment regimens and on maternal and pregnancy outcomes. RESULTS: All patients had a singleton pregnancy, with a median age of 28 years (range, 22-33 years) and a median gestational age of 23 weeks (7-36 weeks). Twelve patients received corticosteroids, and four patients (with/without intravenous immunoglobulin) showed a curative effect. Two patients who were treated with dexamethasone and etoposide after termination of pregnancy achieved complete remission. Two patients attained remission after termination of pregnancy. Four pregnant women died, and the mortality rate was 30.8% (4/13). Fetal or neonatal death up to 1 week after delivery occurred in eight (61.5%) pregnancies. CONCLUSIONS: Early diagnosis and treatment are important for maternal survival, and corticosteroids are the first choice for most patients with HLH during pregnancy. For patients who do not respond to corticosteroids, etoposide and termination of pregnancy may be life-saving.

Cross-cultural adaptation, reliability, and validity of a Chinese version of the pelvic girdle questionnaire.

BACKGROUND: The Pelvic Girdle Questionnaire (PGQ) is the only specific instrument designed to evaluate pain and activity limitations in pregnant or postpartum women with pelvic girdle pain (PGP). This study aimed to translate and culturally adapt the PGQ for Chinese patients and to verify the validation of the psychometric items of the PGQ in the Chinese population. METHODS: First, the translation and cultural adaptation process of the PGQ was conducted on the basis of international guidelines. Eighteen women suffering from PGP (11 pregnant women and 7 postpartum women) were enrolled in the pilot tests. Second, a total of 130 pregnant and postpartum women with PGP were enrolled to evaluate the validation of the psychometric items of the Chinese version. RESULTS: The calculated Cronbach's alphas demonstrated a high level of internal consistency for the Chinese version of the PGQ, ranging from 0.77 to 0.93. The convergent validity showed a high positive correlation between the PGQ total score and the Oswestry Disability Index (0.84) and Numeric Rating Scale (0.73) for pain intensity. Furthermore, a good discriminatory ability was found for the Chinese version of the PGQ for distinguishing women who needed treatment from those not (area under the curve [AUC] = 0.843, p < 0.001), but not for discriminating the pregnant and postpartum states (AUC = 0.488, p = 0.824). The results of test-retest showed good reproducibility for the total PGQ (ICC = 0.93), the PGQ activity subscale (ICC = 0.92), and the PGQ symptom subscale (ICC = 0.77). CONCLUSION: Our study presents the translation, validation and psychometric features of the Chinese version of the PGQ, showing good construct validity and discriminative power for assessing the consequences of PGP among pregnant or postpartum Chinese women.

Obstetric outcomes for twins from different conception methods - A multicenter cross-sectional study from China.

INTRODUCTION: The effects of assisted reproductive technology on the outcomes of twin pregnancies are controversial. Therefore, the purpose of this study was to compare the maternal and perinatal outcomes of twin pregnancies conceived spontaneously and those conceived by assisted reproductive technology. MATERIAL AND METHODS: This was a cross-sectional study performed at Peking Union Medical College Hospital (PUMCH). Data on twin pregnancies (conceived spontaneously and by in vitro fertilization [IVF]/intracytoplasmic sperm injection [ICSI]) were obtained from the National Birth Registry of China for the period between 1 October 2016, and 30 September 2017. The primary obstetric outcomes were compared between twin pregnancies conceived by different methods. Logistic regression analysis with 95% confidence intervals (95% CI) was used for the multivariate analysis. RESULTS: A total of 3270 twin pregnancies (2003 and 1209 conceived spontaneously and by IVF/ICSI, respectively) were identified. The proportion of twin pregnancies among all pregnancies was 3.4% (3332/97 278). Multiple regression analysis indicated that the incidences of gestational diabetes mellitus (adjusted odds ratio [AOR] = 1.42, 95% CI 1.10-1.83, p = 0.007), preterm premature rupture of membranes (AOR = 1.65, 95% CI 1.21-2.25, p = 0.002), placenta accreta spectrum (AOR = 2.12, 95% CI 1.42-3.17, p < 0.001) and postpartum hemorrhage (AOR = 1.38, 95% CI 1.02-1.86, p = 0.037) were significantly higher in the IVF/ICSI group than in the natural pregnancy group. Multivariate analysis also revealed that conception mode was not an independent risk factor for neonate outcomes. CONCLUSIONS: In twin pregnancies, IVF/ICSI is independently associated with multiple maternal complications, including gestational diabetes mellitus, preterm premature rupture of membranes and placenta accreta spectrum compared with spontaneous conception, although potential residual confounders due to indications for assisted reproductive technology exist.

Association of a unicornuate uterus with adverse obstetric outcomes: A retrospective cohort study.

OBJECTIVE: To estimate the association of unicornuate uterus (UU) with adverse obstetric outcomes. METHODS: Using data from 26 737 singleton childbirths from a tertiary hospital from 1999 to 2019, we identified 44 births from women with a UU. A total of 367 births from women with a normal uterus were randomly selected as controls. The outcome measures were preterm birth (PTB), breech presentation, and cesarean delivery. The subdivisions of PTB and indications for cesarean delivery were described. RESULTS: The presence of UU was associated with an increased risk of PTB (adjusted risk ratio [aRR], 2.3; 95% confidence interval [CI], 1.1-4.9), breech presentation (aRR, 6.2; 95% CI, 2.9-13.2), and cesarean delivery (aRR, 2.1; 95% CI, 1.8-2.7). For women with a UU, most PTBs (7/9) were moderate to late PTBs, and approximately half of the PTBs (4/9) were iatrogenic due to preeclampsia (PE). Breech presentation, PE, and prior surgery for rudimentary horn resection were UU-related indications for cesarean delivery. CONCLUSIONS: Women with a UU have a higher risk of PTB, breech presentation, and cesarean delivery. Understanding of the subdivisions of PTBs and indications for cesarean delivery might help clinicians when counseling women with pregnancy complicated by a UU.

[Characteristics and Management of High-risk Maternal Patients in General Tertiary Hospital].

Objective To analyze the characteristics of high-risk maternal patients and evaluate the multidisciplinary medical care system we established correspondingly. Method We collected and analyzed the medical records of high-risk maternal patients who received medical care from January 1,2017 to December 31,2020 in Peking Union Medical College Hospital. Results Ninety-eight high-risk maternal patients were included in this study,and 84.7%(83/98)of them were combined with different severe systemic diseases.Under the multidisciplinary medical care system,91 patients showed improved conditions and were discharged,and the other 7 cases had poor prognosis. Conclusions General tertiary hospitals in Beijing are receiving maternal patients with more high-risk complications.Considering the high risk and diverse diseases of maternal patients admitted to our hospital,we established a medical care system composed of a multidisciplinary panel of experts for high-risk maternal patients to improve the medical care and prognosis of the patients with high efficiency.

Linewidth reduction effect of a cavity-coupled dual-passband plasmonic filter.

We propose a novel cavity-coupled MIM nano-hole array structure that exhibits a tunable dual passband in the near-infrared regime. When compared with the traditional single metal film, the designed structure provides a coupling effect between Gspp and SPP to significantly reduce the linewidths of the two transmission peaks. We also reveal the physical origin of the positive and negative influence of the cavity effect on the transmission of high-frequency and low-frequency peaks. This work supplies a new modulation theory for plasmonic devices based on the EOT phenomenon and has a wide application prospect in the fields of infrared sensor, plasmonic filter, and hyperspectral imaging.

Genotypic and phenotypic characterization of Chinese patients with osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a rare hereditary skeletal dysplasia, characterized by recurrent fractures and bone deformity. This study presents a clinical characterization and mutation analysis of 668 patients, aiming to establish the mutation spectrum and to elucidate genotype-phenotype correlations in Chinese OI patients. We identified 274 sequence variants (230 in type I collagen encoding genes and 44 in noncollagen genes), including 102 novel variants, in 340 probands with a detection rate of 90%. Compared with 47 loss-of-function variants detected in COL1A1, neither nonsense nor frameshift variants were found in COL1A2 (p < 0.0001). The major cause of autosomal recessive OI was biallelic variants in WNT1 (56%, 20/36). It is noteworthy that three genomic rearrangements, including one gross deletion and one gross duplication in COL1A1 as well as one gross deletion in FKBP10, were detected in this study. Of ten individuals with glycine substitutions that lie towards the N-terminal end of the triple-helical region of the α1(I) chain, none exhibited hearing loss, suggesting a potential genotype-phenotype correlation. The findings in this study expanded the mutation spectrum and identified novel correlations between genotype and phenotype in Chinese OI patients.

Cavity-driven hybrid plasmonic ultra-narrow bandpass filter.

We propose a novel compound grating structure that exhibits a tunable ultra-narrowband transmission in the near infrared regime. The thin microstructure can realize a steep wave form through a Fano-like resonance by coupling different propagation-type SPP modes and with a narrow line width formed by the energy band gap. Additionally, the out-of-band suppression is remarkably enhanced. It effectively solves the constraint relationship between high transmittance, narrow line width, and weak side peak of the plasmonic filter, and the structure is suitable for integration with detectors in the near infrared regime.

Novel mutations in TPM2 and PIEZO2 are responsible for distal arthrogryposis (DA) 2B and mild DA in two Chinese families.

BACKGROUND: Distal arthrogryposis (DA) is a group of clinically and genetically heterogeneous disorders that involve multiple congenital limb contractures and comprise at least 10 clinical subtypes. Here, we describe our findings in two Chinese families: Family 1 with DA2B (MIM 601680) and Family 2 with mild DA. METHODS: To map the disease locus, two-point linkage analysis was performed with microsatellite markers closed to TPM2, TNNI2/TNNT3 and TNNC2. In Family 1, a positive LOD (logarithm of odds) score was only obtained at the microsatellite marker close to TPM2 and mutation screening was performed using direct sequencing of TPM2 in the proband. In Family 2, for the LOD score that did not favor linkage to any markers, whole-exome sequencing (WES) was performed on the proband. PCR-restriction fragment length polymorphism (RFLP) and bioinformatics analysis were then applied to identify the pathogenic mutations in two families. In order to correlate genotype with phenotype in DA, retrospective analyses of phenotypic features according to the TPM2 and PIEZO2 mutation spectrums were carried out. RESULTS: A heterozygous missense mutation c.308A > G (p.Q103R) in TPM2 in Family 1, and a novel variation c.8153G > A (p.R2718Q) in PIEZO2 in Family 2 were identified. Each of the two novel variants was co-segregated with the DA manifestations in the corresponding family. Bioinformatics analysis from several tools supported the pathogenicity of the mutations. Furthermore, our study suggests that there is no relation between the types or locations of TPM2 mutations and the clinical characteristics, and that different inheritance modes and mutation types concerning PIEZO2 cause distinct clinical manifestations. CONCLUSIONS: We report two novel mutations within TPM2 and PIEZO2 responsible for DA2B and mild DA in two Chinese families, respectively. Our study expands the spectrum of causal mutations in the TPM2 and PIEZO2 genes.

Achieving a tunable metasurface based on a structurally reconfigurable array using SMA.

We introduce a structurally reconfigurable metasurface which is made of shape memory alloys (SMA). It could change the morphology of the unit cells repeatedly as we expect in response to a thermal stimulus and realize a tuning range from 13.3GHz to 17.2GHz for both polarizations simultaneously. Equivalent circuit models describe the operational principle and design methodology, the physical mechanism is interpreted with the variation of surface current distribution on the structure. The experimental results coincide with the numerical simulations, making the all-metal metasurface an attractive choice for manipulating the electromagnetic wave in a wide range of spectrums with the merits of higher controllability for dynamic behavior and greater freedom for design and manufacturing.

[Rapid detection of hot spot mutations of FGFR3 gene with PCR-high resolution melting assay].

OBJECTIVE: To identify the causative mutations in five individuals affected with dyschondroplasia and develop an efficient procedure for detecting hot spot mutations of the FGFR3 gene. METHODS: Genomic DNA was extracted from peripheral blood samples with a standard phenol/chloroform method. PCR-Sanger sequencing was used to analyze the causative mutations in the five probands. PCR-high resolution melting (HRM) was developed to detect the identified mutations. RESULTS: A c.1138G>A mutation in exon 8 was found in 4 probands, while a c.1620C>G mutation was found in exon 11 of proband 5 whom had a mild phenotype. All patients were successfully distinguished from healthy controls with the PCR-HRM method. The results of HRM analysis were highly consistent with that of Sanger sequencing. CONCLUSION: The Gly380Arg and Asn540Lys are hot spot mutations of the FGFR3 gene among patients with ACH/HCH. PCR-HRM analysis is more efficient for detecting hot spot mutations of the FGFR3 gene.

Silicon-based multilayer gratings with a designable narrowband absorption in the short-wave infrared.

We demonstrate an Al/Si multilayer-grating microstructure covered on Si substrate. This microstructure presents a designable narrowband absorption in short-wave infrared (SWIR) waveband (2.0 µm-2.3 µm). We investigate its absorption mechanism by both modeling and simulations, and explain the results well with metal-insulator-metal and Fabry-Perot cavity theory. Furthermore, we present the absorption of fabricated multilayer-grating microstructure through experiment, and discuss the influence of structure's lateral angle on its absorption in detail. This work provides the possibility to design Si-based devices with designable working bands in SWIR spectrum.

Novel aluminum plasmonic absorber enhanced by extraordinary optical transmission.

We report a theoretical and experimental study on a novel type of aluminum super absorber which exhibits a near perfect absorption based on the surface plasmon resonance in the visible and near-infrared spectrum. The absorber consists of Ag/SiO2/Al triple layers in which the top Al layer is patterned by a periodic nano hole array. The absorption spectrum can be easily controlled by adjusting the structure parameters including the radius of the nano hole and the maximal absorption can reach 99.0% in theory. We completely analyze the SPP and LSP modes supported by the metal-dielectric-metal structure and their contribution to the ultrahigh absorption. On this basis, we find a novel method to enhance the absorption via the simultaneous excitation of SPP at different interfaces theoretically and experimentally. Moreover, for the first time we clarify the EOT caused by the nano hole array can enhance the absorption by experiment, which is not reported in previous works. This kind of absorber can be fabricated by low-cost colloidal sphere lithography and the use of stable Al overcomes the disadvantages brought by the noble metal, which make it a more appropriate candidate for photovoltaics, spectroscopy, photodetectors, sensing, and surface enhanced Raman scattering.

[Identification of a novel mutation of DSPP gene in a Chinese family affected with dentinogenesis imperfecta shields type II].

OBJECTIVE: To identify the causative mutation in a Chinese family affected with dentinogenesis imperfecta shields type II (DGI-II). METHODS: With informed consent obtained from all participants, peripheral blood or chorionic villi samples were collected from the family members. Genomic DNA was extracted using a standard SDS-proteinase K-phenol/chloroform method. The whole coding region and exon/intron boundaries of the DSPP gene were amplified with polymerase chain reaction (PCR) and subjected to Sanger sequencing. To confirm the pathogenicity of the identified mutation, an Alu I recognition sequence was introduced into the mutant allele using mismatch primers by semi-nested PCR. Restriction fragment length polymorphism (RFLP) analysis was then carried out for all family members and 60 unrelated healthy controls. Meanwhile, mini-DSPP constructs were conducted to confirm the effect of the mutation in vitro. RESULTS: A splicing site mutation, c.52-1G>A, which was located upstream of exon 3, was found in all three patients and the fetus of the proband. Restriction analysis confirmed that all unaffected individuals and the 60 healthy controls did not carry the same mutation. The expression of minigene showed that the exon 3 of the DSPP gene was skipped during the transcription. CONCLUSION: A novel pathogenic splicing-mutation c.52-1G>A has been detected in a Chinese family affected with DGI-II, which enabled prenatal diagnosis for the fetus of the proband.