Effects of public health interventions and zero COVID policy on paediatric diseases: A Southern China study.

Background: With the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in schools and communities, clinical evidence is needed to determine the impact of the pandemic and public health interventions under the zero coronavirus disease policy on the occurrence of common infectious diseases and non-infectious diseases among children. Methods: The current study was designed to analyse the occurrence of common infectious diseases before and after the pandemic outbreak in southern China. Data was obtained for 1 801 728 patients admitted into children's hospitals in Guangzhou between January 2017 and July 2022. Regression analysis was performed for data analysis. Results: The annual occurrence of common paediatric infectious diseases remarkably decreased after the pandemic compared to the baseline before the pandemic and the monthly occurrence. Cases per month of common paediatric infectious diseases were significantly lower in five periods during the local outbreak when enhanced public health measures were in place. Cases of acute non-infectious diseases such as bone fractures were not reduced. Non-pharmaceutical interventions decreased annual and monthly cases of paediatric respiratory and intestinal infections during the coronavirus disease 2019 (COVID-19) pandemic, especially when enhanced public health interventions were in place. Conclusions: Our findings provide clinical evidence that public health interventions under the dynamic zero COVID policy in the past three years had significant impacts on the occurrence of common respiratory and intestinal infectious diseases among children and adolescents but little impact on reducing non-infectious diseases such as leukaemia and bone fracture.

Mitochondrial Cardiomyopathy: Molecular Epidemiology, Diagnosis, Models, and Therapeutic Management.

Mitochondrial cardiomyopathy (MCM) is characterized by abnormal heart-muscle structure and function, caused by mutations in the nuclear genome or mitochondrial DNA. The heterogeneity of gene mutations and various clinical presentations in patients with cardiomyopathy make its diagnosis, molecular mechanism, and therapeutics great challenges. This review describes the molecular epidemiology of MCM and its clinical features, reviews the promising diagnostic tests applied for mitochondrial diseases and cardiomyopathies, and details the animal and cellular models used for modeling cardiomyopathy and to investigate disease pathogenesis in a controlled in vitro environment. It also discusses the emerging therapeutics tested in pre-clinical and clinical studies of cardiac regeneration.

Mesenchymal stem cell-derived extracellular vesicles for immunomodulation and regeneration: a next generation therapeutic tool?

Mesenchymal stem cells (MSCs) can be widely isolated from various tissues including bone marrow, umbilical cord, and adipose tissue, with the potential for self-renewal and multipotent differentiation. There is compelling evidence that the therapeutic effect of MSCs mainly depends on their paracrine action. Extracellular vesicles (EVs) are fundamental paracrine effectors of MSCs and play a crucial role in intercellular communication, existing in various body fluids and cell supernatants. Since MSC-derived EVs retain the function of protocells and have lower immunogenicity, they have a wide range of prospective therapeutic applications with advantages over cell therapy. We describe some characteristics of MSC-EVs, and discuss their role in immune regulation and regeneration, with emphasis on the molecular mechanism and application of MSC-EVs in the treatment of fibrosis and support tissue repair. We also highlight current challenges in the clinical application of MSC-EVs and potential ways to overcome the problem of quality heterogeneity.

Integration of an anti-resonant hollow-core fiber with a multimode Yb-doped fiber for high power near-diffraction-limited laser operation.

We proposed and demonstrated mode cleaning in a high-power fiber laser by integrating an anti-resonant hollow-core fiber (AR-HCF) into a multimode laser cavity of an ytterbium (Yb)-doped fiber (YDF). An in-house mode-matched AR-HCF was fusion-spliced to a commercial multimode LMA-YDF, ensuring efficient fundamental mode coupling. The AR-HCF inflicts a high propagation loss selectively on higher-order modes, facilitating fundamental mode operation. Thus, the AR-HCF works as an efficient spatial mode filter embedded in the multimode fiber laser cavity and reinforces preferential amplification of the fundamental mode. Beam quality factor enhancement was achieved from M2 = 2.09 to 1.39 at an output power of 57.7 W (pump-power limited). The beam quality can be further improved by refining the AR-HCF fabrication. The proposed technique has a great potential to be exploited in other multimode fiber laser cavities involving erbium- or thulium-doped fibers and obviates the need for complicated specialty active fiber designs. Compared with the commonly used fiber bending technique, our method can achieve an efficient higher-order mode suppression without inducing mode-field deterioration.

W-type normal dispersion thulium-doped fiber-based high-energy all-fiber femtosecond laser at 1.7 µm.

We propose a parabolic W-type thulium-doped fiber for the 1.7 µm high-energy femtosecond pulsed laser. Despite its attractive normal dispersion, the fiber offers high gain in 1.7 µm region thanks to its distributed short-pass filtering effect. With a proper dispersion management in an all-fiber chirped pulse amplification (CPA) scheme, we demonstrate so far the highest pulse energy of 128.0 nJ in a stable pulse of 174 fs in the 1.7-1.8 µm region, which marks above an order of magnitude improvement in pulse energy while exhibiting the shortest pulse duration among fiber-based CPA works at 1.7 µm. Hence, we provide a pathway to an energy scalable and efficient femtosecond laser at 1.7 µm via a compact and elegant all-fiber solution.

Large-mode-area multicore Yb-doped fiber for an efficient high power 976 nm laser.

We present an efficient 976 nm laser generation from an ytterbium (Yb)-doped step-index multicore fiber (MCF) with six cores placed in a ring shape. Each of the six cores has a large-mode-area (LMA) and a low numerical aperture (NA), which makes the MCF equipped with the features of a large core-to-cladding area ratio and differential bending loss for wavelength and mode selection. Hence, the Yb-doped MCF benefits 976 nm laser generation by simultaneously suppressing unwanted 1030 nm emission and higher-order modes (HOMs). A 976 nm laser is obtained in a short piece (88 cm) of the Yb MCF, with a good slope efficiency of 46% with respect to launched pump power and the maximum output power of 25 W (pump power limited). A mode area of 1432 µm2 at the 976 nm is expected for the fundamental in-phase mode.

CPW Fed Compact UWB 4-Element MIMO Antenna with High Isolation.

In the paper, an extremely compact multiple-input-multiple-output (MIMO) antenna is proposed for portable wireless ultrawideband (UWB) applications. The proposed prototype consists of four monopole antenna elements, which are placed perpendicularly to achieve polarization diversity. In addition, the mutual coupling between antenna elements is suppressed by designing the gap between the radiation element and the ground plane. Moreover, a matching stub has been connected to the feedline to ensure impedance matching in high frequency. Both simulated and measured results indicate that the proposed antenna has a bandwidth of 3-20 GHz, with a high isolation better than 17 dB. In addition, the designed MIMO antenna offers excellent radiation characteristics and stable gain over the whole working band. The envelope correlation coefficient (ECC) is less than 0.1, which shows that the antenna can meet the polarization diversity characteristics well.

Power stable 1.5-10.5 µm cascaded mid-infrared supercontinuum laser without thulium amplifier.

We demonstrate a simple and power stable 1.5-10.5 µm cascaded mid-infrared 3 MHz supercontinuum fiber laser. To increase simplicity and decrease cost, the design of the fiber cascade is optimized so that no thulium amplifier is needed. Despite the simple design with no thulium amplifier, we demonstrate a high average output power of 86.6 mW. Stability measurements for seven days with 8-9 h operation daily revealed fluctuations in the average power with a standard deviation of only 0.43% and a power spectral density stability of ±0.18dBm/nm for wavelengths <10µm. The high-repetition-rate, robust, and cheap all-fiber design makes this source ideal for applications in spectroscopy and imaging.

Influence of pulse duration and repetition rate on mid-infrared cascaded supercontinuum.

We experimentally investigate the influence of varying pulse parameters on the spectral broadening, power spectral density, and relative intensity noise of mid-infrared (mid-IR) in-amplifier cascaded supercontinuum generation (SCG) by varying the pulse duration (35 ps, 1 ns, 3 ns) and repetition rate (100, 500, 1000 kHz). The system is characterized at the output of the erbium-ytterbium-doped in-amplifier SCG stage, the thulium/germanium power redistribution stage, and the passive ZBLAN fiber stage. In doing so, we demonstrate that the output of the later stages depends critically on the in-amplifier stage, and relate this to the onset of modulation instability.

All-fiber short-wavelength tunable mode-locked fiber laser using normal dispersion thulium-doped fiber.

We report an all-fiber high pulse energy ultrafast laser and amplifier operating at the short wavelength side of the thulium (Tm) emission band. An in-house W-type normal dispersion Tm-doped fiber (NDTDF) exhibits a bending-induced distributed short-pass filtering effect that efficiently suppresses the otherwise dominant long wavelength emission. By changing the bending diameter of the fiber, we demonstrated a tunable mode-locked Tm-doped fiber laser with a very wide tunable range of 152 nm spanning from 1740 nm to 1892 nm. Pulses at a central wavelength of 1755 nm were able to be amplified in an all-fiber configuration using the W-type NDTDF, without the use of any artificial short-pass filter or pulse stretcher. The all-fiber amplifier delivers 2.76 ps pulses with an energy of ∼32.7 nJ without pulse break-up, due to the normal dispersion nature of the gain fiber, which marks so far, the highest energy amongst fiber lasers in the 1700 nm-1800 nm region.

Ultra-short wavelength operation of thulium-doped fiber amplifiers and lasers.

We fabricate and characterize a germanium/thulium (Ge/Tm) co-doped silica fiber in order to enhance the gain at the short wavelength edge of the thulium emission band (i.e. 1620-1660 nm). The Ge/Tm doped fiber shows an intrinsic blue-shifted absorption/emission cross-section compared to aluminum/thulium (Al/Tm) co-doped fiber, which greatly improves the short wavelength amplification and has enabled us to further extend the shortest wavelength of emission towards 1600 nm. Using this glass fiber composition, we have demonstrated both a silica-based thulium doped fiber amplifier (TDFA) in the 1628-1655 nm waveband and a tunable thulium-doped fiber laser (TDFL) capable of accessing the telecom U-band wavelength region. These results represent by far the shortest amplifier/laser wavelengths reported to-date from TDFAs/TDFLs.

Genome-wide analysis of bZIP-encoding genes in maize.

In plants, basic leucine zipper (bZIP) proteins regulate numerous biological processes such as seed maturation, flower and vascular development, stress signalling and pathogen defence. We have carried out a genome-wide identification and analysis of 125 bZIP genes that exist in the maize genome, encoding 170 distinct bZIP proteins. This family can be divided into 11 groups according to the phylogenetic relationship among the maize bZIP proteins and those in Arabidopsis and rice. Six kinds of intron patterns (a-f) within the basic and hinge regions are defined. The additional conserved motifs have been identified and present the group specificity. Detailed three-dimensional structure analysis has been done to display the sequence conservation and potential distribution of the bZIP domain. Further, we predict the DNA-binding pattern and the dimerization property on the basis of the characteristic features in the basic and hinge regions and the leucine zipper, respectively, which supports our classification greatly and helps to classify 26 distinct subfamilies. The chromosome distribution and the genetic analysis reveal that 58 ZmbZIP genes are located in the segmental duplicate regions in the maize genome, suggesting that the segment chromosomal duplications contribute greatly to the expansion of the maize bZIP family. Across the 60 different developmental stages of 11 organs, three apparent clusters formed represent three kinds of different expression patterns among the ZmbZIP gene family in maize development. A similar but slightly different expression pattern of bZIPs in two inbred lines displays that 22 detected ZmbZIP genes might be involved in drought stress. Thirteen pairs and 143 pairs of ZmbZIP genes show strongly negative and positive correlations in the four distinct fungal infections, respectively, based on the expression profile and Pearson's correlation coefficient analysis.