The preparation and characterization of self-healing hydrogels based on polypeptides with a dual response to light and hydrogen peroxide.

Injectable self-healing hydrogels are being widely used in drug delivery, tissue engineering, and other fields. Because of their excellent biocompatibility and biodegradability, polypeptides are an ideal candidate for preparing injectable self-healing hydrogels. In this study, a polypeptide-based hydrogel with dual response to hydrogen peroxide and light was obtained by copolymerizing 4-arm PEG-amine, N-(p-nitrophenoxycarbonyl)-l-methionine, and N-(p-nitrophenoxycarbonyl)-γ-o-nitrobenzyl-l-glutamate. The hydrogel exhibits injectable self-healing behavior due to the hydrophobic interactions among peptide blocks, which also act as the reservoir of hydrophobic drug molecules. In the presence of hydrogen peroxide or under light irradiation, the thioether bond in methionine was oxidized to sulfoxide, whereas the o-nitro benzyl ester bond was broken to form glutamic acid. As a result, the corresponding hydrophobic blocks of polypeptide become hydrophilic, accelerating the release of drug molecules loaded in the polypeptide hydrophobic blocks. Using this technique, the controlled release of hydrophobic drug molecules was achieved. Our efforts could provide a new strategy for the preparation of self-healing hydrogels based on polypeptides with a dual response to hydrogen peroxide and light. In this view, the practical application of polypeptides in drug delivery, tissue engineering, and other fields, could be expanded and advanced.

Optical freeform reflective imaging system design method with manufacturing constraints.

With the development of space optics, optical freeform surfaces have gradually been utilized in reflective optical imaging systems in recent years. Freeform surfaces not only bring many benefits to the optical imaging system, but also present many challenges to their manufacture. Regardless of the machining method used, machining errors during the fabrication of freeform surfaces will exist, which limits the accuracy of freeform surface machining. In this paper, the deviation root mean square (RMS) of a freeform surface from the reference aspheric surface is proposed to evaluate the manufacturability of the freeform surface by using single-point diamond turning. Then the deviation RMS of freeform surfaces is added to the design process of the optical system as a manufacturing constraint. Subsequently, an off-axis three-mirror system and an off-axis two-mirror system with and without manufacturing constraints are designed, respectively. Then the imaging quality of these optical systems and the linear interpolation error RMS of freeform mirror are analyzed. It can be concluded that, on the basis of reaching the imaging quality requirements, the machining difficulty of a freeform mirror can be reduced when adding manufacturing constraints to the design process.

Flexible channel selection method based on optical combs for broadband signals receiving.

A flexible channel selection method based on optical combs is proposed for reconfigurable optical channels in this paper. Optical-frequency combs with a large frequency interval are used to modulate broadband radio frequency (RF) signals, and an on-chip reconfigurable optical filter [Proc. of SPIE, 11763, 1176370 (2021).10.1117/12.2587403] is used to perform periodic carrier separation of wideband and narrowband signals and channel selection. In addition, flexible channel selection is achieved by presetting the parameters of a fast-response programmable wavelength-selective optical switch and filter device. Channel selection only relies on the combs through the Vernier effect of the combs and the passbands for different periods and does not require the use an additional switch matrix. Finally, flexible switching between and selection of specific channels for 13 GHz and 19 GHz broadband RF signals are experimentally verified.

One-Step Crank-Nicolson Direct-Splitting Algorithm with Enhanced Absorption to Evaluate Low-Pressure Discharge for Satellite Sensors in Outer Space.

Low-pressure discharge causes air ionization resulting in performance degeneration or failure for the satellite sensors in outer space. Here, a one-step Crank-Nicolson Direct-Splitting (CNDS) algorithm is proposed to evaluate the electrical behavior of satellite sensors under the low-pressure discharge circumstance. To be more specific, the CNDS algorithm is proposed in the Lorentz medium, which can accurately analyze the ionized air and generated plasma. Higher order perfectly matched layer (PML) is modified in the Lorentz medium to efficiently terminate the unbounded lattice. It can be concluded that the proposed algorithm shows entire considerable performance in the low-pressure discharge evaluation. The proposed PML formulation behaviors enhanced absorbing performance compared with the existing algorithm. Through the experiments, it can be observed that the low-pressure discharge phenomenon causes performance variation, which shows a significant influence on the satellite sensors. Meanwhile, results show considerable agreement between the simulation and experiment results which indicates the effectiveness of the algorithm.

Narrow-Bandpass One-Step Leapfrog Hybrid Implicit-Explicit Algorithm with Convolutional Boundary Condition for Its Applications in Sensors.

A large number of sensors work in the narrow bandpass circumstance. Meanwhile, some of them hold fine details merely along one and two dimensions. In order to efficiently simulate these sensors and devices, the one-step leapfrog hybrid implicit-explicit (HIE) algorithm with the complex envelope (CE) method and absorbing boundary condition is proposed in the narrow bandpass circumstance. To be more precise, absorbing boundary condition is implemented by the higher order convolutional perfectly matched layer (CPML) formulation to further enhance the absorption during the entire simulation. Numerical examples and their experiments are carried out to further illustrate the effectiveness of the proposed algorithm. The results show considerable agreement with the experiment and theory resolution. The relationship between the time step and mesh size can break the Courant-Friedrichs-Levy condition which indicates the physical size/selection mesh size. Such a condition indicates that the proposed algorithm behaviors are considerably accurate due to the rational choice in discretized mesh. It also shows decrement in simulation duration and memory consumption compared with the other algorithms. In addition, absorption performance can be improved by employing the proposed higher order CPML algorithm during the whole simulation.

Generalized Radar Range Equation Applied to the Whole Field Region.

Most terahertz (THz) radar systems can only work in the near-field region, because the THz source power is limited and the size of the target scattered near field is up to tens of kilometers. Such conditions will result in the conventional radar range equation being unsuitable. Therefore, the near-field radar cross section (RCS) formula is given according to the numerical simulation on different targets. By modifying the parameters in the near field, including the gain of radar antennas and the RCS of targets, the generalized radar range equation is proposed. The THz radar working efficiency in the whole range and the simulation of the near-field RCS simulation model were employed to validate its effectiveness. Through comparison with the radar range equation, it can be concluded that the calculation results of the proposed equation are smaller in the near field, and the outcomes in the far field are identical. The proposed generalized radar range equation can be applied to the whole radiation area including the near field and the far field. Furthermore, more complicated real targets are calculated according to the generalized radar range equation and it can be extended from the submillimeter wave band to a much wider band range. Finally, the near-field radar theory is established, which shows its potential application to the radar cross section estimation in the extremely high frequency and fine design of THz radar systems.

UWB Low-Profile Boat-Radiator Antenna (BRA) with Dual C-Shape Co-Radiative Ground for Multi-Standard Communication Networks.

Multiple standard communication networks operate in the frequency band of 1.8-6 GHz, which makes lots of antennas available in the limited space. To solve the problem of interference and improve the performance of these antennas, an ultra-wideband (UWB) antenna is presented. It consists of a boat-radiator and a dual C-shape co-radiative ground (DCCRG). One half of the DCCRG plays a role of the ground of a co-planar waveguide fed to the proposed boat-radiator antenna (BRA), while the other half works as a multiple order L-resonant circuit to broaden the lower operating band. Uniform bidirectional radiation is presented with the size of 0.25 λ × 0.375 λ × 0.0063 λ over the frequency band of 1.7-6.3 GHz (115%). The proposed antenna achieves around twice the bandwidth (60%) of the same structured antenna without the structure acting as a multiple order L-resonant circuit. Moreover, the stable boresight gain of 3.6 dBi ± 1.25 dBi is realized over the operating band.

A Low-Profile End-Fire Conformal Surface Wave Antenna with Capacitive Feed Structure.

A high end-fire gain, low-profile surface wave antenna with capacitive feed structure is presented in this paper. The proposed dielectric-metal surface wave antenna is composed of a dielectric slab that is mounted on a metal carrier and a low-profile feed structure. The feed structure is composed of a monopole radiation pin that is loaded with a circular metal plate and a grounding pin. The profile height of the antenna is only one-tenth of the operating wavelength. With a good end-fire performance and low profile, the antenna is very suitable to be conformally mounted on the surface of flight vehicles. The proposed antenna was designed and manufactured at the center frequency of 6 GHz. Measured results demonstrated that the proposed antenna had a bandwidth of 7.33%, ranging from 5.89 to 6.33 GHz, and the antenna reached a high gain of 9.76 dBi with a length of 122.96 mm (2.45 λ) in the end-fire direction.

ARCS: Active Radar Cross Section for Multi-Radiator Problems in Complex EM Environments.

In order to analyze the scattering properties in multi-radiator problems, the active radar cross section (ARCS) concept is proposed under complex electromagnetic (EM) environments. The corresponding calculation methods and formulation are proposed by incorporating the monostatic radar cross section (RCS) concept with external disturbances. By introducing the phase characteristics into the ARCS concept, the coherent problems can be accurately solved. Through analyzing the external disturbance and the radar waves by employing the finite element method, the coherent and the incoherent characteristics of the external disturbance can be simulated in complex structures. Numerical examples and an experiment are carried out to further demonstrate the effectiveness of the proposed ARCS concept. The results demonstrate that the proposed ARCS concept obtains better universality compared with the existing incoherent multi-radiator formulation. Meanwhile, the ARCS can be identical with the solution which is obtained by the single radar wave. Compared with the existing incoherent methods for external disturbances calculations, the proposed ARCS concept is more rational. Through the experiment, the effectiveness of the calculation method and formulation is further demonstrated and validated.

Optical design and fabrication of an all-aluminum unobscured two-mirror freeform imaging telescope.

Freeform optics offers more degrees of freedom to optical design that can benefit from a compact package size and a large field of view for imaging systems. Motivated by the advances in modern optical fabrication and metrology, freeform optics has been found in many applications. In this paper, we will describe the challenging optical design, fabrication, metrology, and assembly of an all-aluminum unobscured two-mirror freeform imaging telescope. The telescope has a large field of view of 20∘×15∘. The freeform aluminum mirrors are manufactured by diamond turning based on a feedback modification strategy. The freeform mirrors are measured by a computer-generated hologram-based interferometric null test method. All-aluminum configuration has the advantages of being athermal and cost-effective.

Fast design method of smooth freeform lens with an arbitrary aperture for collimated beam shaping.

A method is presented for the fast design of a smooth freeform lens to tailor a collimated light beam with an arbitrary contour. This method begins by calculating an initial surface based on a simplified ray mapping. Then the surface is fitted by a system of Zernike polynomials, whose weights are treated as the optimization variables for further optimization. In the optimization, the objective function is analytically calculated using a partial differential-equation-based approach. To validate the effectiveness of the proposed method, a freeform lens is designed for a collimated Gaussian beam with a spline contour to form a uniform illumination distribution with another spline contour, which takes only 26 s. A freeform lens is also fabricated and experimented, and its practical performance approaches the design.

Reversible Histone H2B Monoubiquitination Fine-Tunes Abscisic Acid Signaling and Drought Response in Rice.

Histone H2B monoubiquitination (H2Bub1) plays important roles in several physiological and developmental processes, but its roles in the regulation of plant stress responses remain elusive. Here, we report that H2Bub1 is crucially involved in abscisic acid (ABA) signaling and drought response in rice. We found that rice HISTONE MONOUBIQUITINATION2 (OsHUB2), an E3 ligase for H2Bub1, interacted with OsbZIP46, a key transcription factor regulating ABA signaling and drought response in rice. Genetic analyses suggest that OsHUB2, upregulated by drought and ABA, positively modulates ABA sensitivity and drought resistance. The H2Bub1 levels were increased in the target genes of OsbZIP46 under the drought stress and ABA treatments, which were positively correlated with their increased expression levels. Interestingly, MODD, a reported suppressor of ABA signaling and drought resistance by mediating OsbZIP46 deactivation and degradation, could reduce the H2Bub1 levels in the target genes of OsbZIP46 by recruiting a putative deubiquitinase OsOTLD1. Suppression of OsOTLD1 in vivo resulted in increased H2Bub1 levels and expression of OsbZIP46 target genes. Collectively, these findings established an elaborate mechanism of histone monoubiquitination in the fine-turning of ABA signaling and drought response by balancing H2Bub1 deposition and removal.

The synergic effects of CTLA-4/Foxp3-related genotypes and chromosomal aberrations on the risk of recurrent spontaneous abortion among a Chinese Han population.

The current study was aimed to investigate the association of CLTA-4/Foxp3 polymorphisms and chromosomal abnormalities with recurrent spontaneous abortion (RSA) risk in a Chinese Han population. Altogether, 1284 RSA women and 1046 women with normal pregnancy were incorporated in this study. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was implemented to genotype the single-nucleotide polymorphisms (SNPs) located within CTLA4 and Foxp3. Moreover, the cytogenetic diagnosis was performed in line with the standards of G banding karyotype. As a consequence, rs231775 and rs3087243 of CTLA4, as well as rs2232365 and rs2232368 of Foxp3, all appeared to modify the risk of RSA. Besides, significant differences were found between the ratio of structural abnormality and that of numerical abnormality (P < 0.038), and chromosome abnormality was associated with higher miscarriage frequency (>3) than normal karyotypes. Of note, the synergic effects of the genotypes and chromosomal abnormality all tallied with the sub-multiplication model (ORchromosome × ORSNP > ORchromosome+SNP), while rs2232365 GG and chromosomal aberration impacted the RSA risk in a super-multiplicative way that ORchromosome × ORSNP < ORchromosome+SNP. In conclusion, susceptibility to RSA was subject to the synthetic regulation of chromosomal aberrations and genetic mutations within CLTA-4 and Foxp3, suggesting that the conduction of karyotype analysis and genetic detection for RSA patients could effectively guide effective RSA counseling and sound child rearing.

Design of a smooth freeform illumination system for a point light source based on polar-type optimal transport mapping.

A design method is proposed to generate smooth freeform illumination optics for a point light source based on the L2 optimal transport (LOT) mapping. In this method, the LOT mapping between an assumed circular planar source and a prescribed target is first obtained by solving a polar-type LOT problem. Then, the mapping calculated for the circular source is applied for a point light source. Finally, the freeform optical surface is generated by a geometric construction method to realize the ray mapping. As examples, a series of smooth-surface freeform lenses are designed for a point light source to form uniform and complex illumination patterns on rectangular targets. The ray-tracing results show that all the designs achieve excellent performance with the light utilization efficiency η over 0.87 (Fresnel loss considered) and the relative standard deviation (RSD) of the simulated illumination distribution less than 0.051 simultaneously.

Co-overexpression of the Constitutively Active Form of OsbZIP46 and ABA-Activated Protein Kinase SAPK6 Improves Drought and Temperature Stress Resistance in Rice.

Drought is one of the major abiotic stresses threatening rice (Oryza sativa) production worldwide. Drought resistance is controlled by multiple genes, and therefore, a multi-gene genetic engineering strategy is theoretically useful for improving drought resistance. However, the experimental evidence for such a strategy is still lacking. In this study, a few drought-responsive genes from rice were assembled by a multiple-round site-specific assembly system, and the constructs were introduced into the rice cultivar KY131 via Agrobacterium-mediated transformation. The transgenic lines of the multi-gene and corresponding single-gene constructs were pre-evaluated for drought resistance. We found that the co-overexpression of two genes, encoding a constitutively active form of a bZIP transcription factor (OsbZIP46CA1) and a protein kinase (SAPK6) involved in the abscisic acid signaling pathway, showed significantly enhanced drought resistance compared with the single-gene transgenic lines and the negative transgenic plants. Single-copy lines of this bi-gene combination (named XL22) and the corresponding single-gene lines were further evaluated for drought resistance in the field using agronomical traits. The results showed that XL22 exhibited greater yield, biomass, spikelet number, and grain number under moderate drought stress conditions. The seedling survival rate of XL22 and the single-gene overexpressors after drought stress treatment also supported the drought resistance results. Furthermore, expression profiling by RNA-Seq revealed that many genes involved in the stress response were specifically up-regulated in the drought-treated XL22 lines and some of the stress-related genes activated in CA1-OE and SAPK6-OE were distinct, which could partially explain the different performances of these lines with respect to drought resistance. In addition, the XL22 seedlings showed improved tolerance to heat and cold stresses. Our results demonstrate that the multi-gene assembly in an appropriate combination may be a promising approach in the genetic improvement of drought resistance.

Role of Metallothionein in Post-Burn Inflammation.

Metallothioneins (MTs) are a family of low molecular-weight and cysteine-rich metalloproteins that regulate metal metabolism and protect cells from oxygen free radicals. Recent studies suggested that MTs have some anti-inflammatory effects. However, the role of MTs in post-burn inflammation remains unclear. This study is designed to investigate the role of MTs in post-burn inflammation in a mouse burn model. MT-I/II null (-/-) and C57BL/6 wild-type (WT) mice were randomly divided into sham burn, burn, Zn treated, and Zn-MT-2 treated groups. The inflammatory cytokines levels were measured by enzyme-linked immunosorbent assay (ELISA). Myeloperoxidase (MPO) activity was determined by spectrophotometry. In in vitro study, exogenous MT-2 was added to macrophages that were stimulated with burn serum in the presence or absence of a p38 MAPK inhibitor SB203580. The IL-6 and TNF-α messenger RNA (mRNA) expression were detected by quantitative real-time polymerase chain reaction. The levels of p38 expression were determined by Western blot. Burn induced increased inflammatory cytokines such as interleukin (IL)-1ß, IL-6, tumor necrosis factors-α, and macrophage chemoattractant protein-1 production in burn wound and serum. The MPO activities in the lung and heart were also increased after burn. These effects were significantly more prominent in MT (-/-) mice than in WT mice. Furthermore, these effects were inhibited by administration of exogenous MT-2 to both WT and MT (-/-) mice. Exogenous MT-2 inhibited the p38 expression and abrogated the increase of IL-6 and TNF-α mRNA expression from macrophages that were stimulated with burn serum. The effect of MT-2 was not further strengthened in the presence of SB203580. MTs may have a protective role against post-burn inflammation and inflammatory organ damage, at least partly through inhibiting the p38 MAPK signaling.

Fetal echocardiography for congenital heart disease diagnosis: a meta-analysis, power analysis and missing data analysis.

BACKGROUND: Prenatal ultrasonography is the most widely available diagnostic test for fetal congenital heart disease (CHD), but the factors influencing its diagnostic accuracy remain uncertain despite extensive research. The aim of the present study was to evaluate the potential role of demographic, clinical and ultrasonographic characteristics on diagnostic yields for detecting CHD. METHODS: A systematic search of PubMed, ISI Web of Science, SinoMed, and the Cochrane Library was performed to identify studies assessing the accuracy of prenatal ultrasound in the detection of CHD. A random effects model was used to generate pooled sensitivity and specificity in addition to summary receiver operating characteristic (SROC) curves. RESULTS: Overall, prenatal ultrasound in the detection of CHD had a moderate sensitivity of 68.1% (95% CI 59.6-75.5) and a favorable specificity of 99.9% (99.7-99.9). Risk level and gestation age were independent predictors of diagnostic performance for detecting CHD (p = 0.004 vs. p = 0.002, respectively). The pooled sensitivities significantly increased to varying extents with the following echocardiographic views: 48.7% (34.8-67.2) for four-chamber view (4CV); 58.0% (40.3-73.9) for a combination of 4CV and outflow tract views (OTV); 73.5% (59.2-84.1) for combination of 4CV, OTV and three vessels and trachea view (3VTV); 77.1% (62.0-87.5) for extensive cardiac echocardiography examination (ECEE); and 89.6% (81.0-94.6) for spatiotemporal image correlation (STIC). CONCLUSIONS: Prenatal ultrasound is a powerful tool for the diagnosis of CHD; however, a single ultrasonographic regime is not definitive on its own and must be interpreted in the context of demographic and clinical characteristics.

Minimally invasive endoscopic staging for mediastinal lymphadenopathy in lung cancer: a systematic review protocol.

INTRODUCTION: Minimally invasive endoscopic biopsy techniques have been widely available as potential alternatives for mediastinal lesions staging in patients with known or suspected lung cancer. Previous efforts have been made to evaluate the diagnostic performance of specific endoscopic modality alone at the level of the mediastinum for staging lung cancer, however, few studies focus on the accuracy of comparisons between different endoscopic modalities, especially at the level of any individual lymph node station. The objective of our study is to determine the diagnostic yields of different endoscopic modalities for staging mediastinal lymphadenopathy in lung cancer, especially concerning the individual lymph node station. METHODS/DESIGN: A systematic electronic search of MEDLINE, EMBASE, SinoMed and ISI Web of Science were performed to identify studies evaluating endoscopic modalities accuracy with restriction of English and Chinese languages from inception to an update until May 2014. Data were extracted with the patient as the unit of analysis with regards to the abilities of different endoscopic modalities at the level of mediastinum and particular lymph node station. The methodological quality was assessed independently according to the Quality Assessment of Diagnostic Accuracy Study (QADAS) criteria. An exact binomial rendition of bivariate mixed-effects regression model was used to estimate the pooled sensitivity and specificity. Also, pre-post probability analysis, publication bias analysis and sensitivity analysis were performed for a synthesis of knowledge of this context. DISSEMINATION: The findings will advance our better available knowledge of optimal clinical decision-making when dealing with staging of mediastinal metastasis in lung cancer. TRIAL REGISTRATION NUMBER: PROSPERO-NIHR Prospective Register of Systematic Reviews (CRD42014009792).

[Evaluation of digital subtraction angiography rabbit VX2 hepatic carcinoma model with modified hepatic artery catheterization].

OBJECTIVE: To modify the success rate of establishing VX2 transplanted tumor model with different methods in rabbits, and access new typed modification and improved technique in catheterization. METHODS: In the study, 30 rabbits were randomly divided into 2 groups. In prophase, tumor cell suspension was implanted in group I, while tumor tissue particles were implanted into liver under direct vision, to establish VX2 transplanted tumor model. The rabbits were catheterized from femoral artery to selective hepatic artery under DSA, by using conventional modification with Seldinger technique in group I and by using new typed modification with improved technique in group II. The imaging and histological features of VX2 tumor were evaluated by combining pathology and DSA, then the success rate, operation time and postoperative complications were compared and evaluated. RESULTS: The success rates of the liver tumor model were 60.0% and 93.3%; the disposable success rates of catheterization were 66.7% and 92.8%; the operation time of catheterization were (35.6±5.8) min and (27.4±5.3) min; the incidence rates of adverse reaction were 22.5% and 18.0%; the differences between the two groups in the experimental rabbits were significant (P<0.05) statistically. CONCLUSION: The efficiency of tumor tissue particles implanted is better than that of tumor cell suspension implanted in establishing VX2 transplanted tumor model under direct vision. The cathetenzation quality and outcomes of new typed modification by improved technique, from femoral artery to selective hepatic artery, is superior to those of conventional modification with Seldinger technique.

Broadband converging plano-concave lens.

A plano-concave lens with source-tailored geometric profile and transformational gradient index is proposed for broadband illumination. Such a design, capable of focusing and collimating the electromagnetic fields, fulfils the functionality of a converging lens and can also achieve a steerable beam and multiple beams efficiently. Nonresonant synthesis with a perforated dielectric plate and dielectric rod arrays is demonstrated for the lensing realization, promising a wide operating frequency band in the practical implementation.