Chromosomal Fusions Facilitate Adaptation to Divergent Environments in Threespine Stickleback.

Chromosomal fusions are hypothesized to facilitate adaptation to divergent environments, both by bringing together previously unlinked adaptive alleles and by creating regions of low recombination that facilitate the linkage of adaptive alleles; but, there is little empirical evidence to support this hypothesis. Here, we address this knowledge gap by studying threespine stickleback (Gasterosteus aculeatus), in which ancestral marine fish have repeatedly adapted to freshwater across the northern hemisphere. By comparing the threespine and ninespine stickleback (Pungitius pungitius) genomes to a de novo assembly of the fourspine stickleback (Apeltes quadracus) and an outgroup species, we find two chromosomal fusion events involving the same chromosomes have occurred independently in the threespine and ninespine stickleback lineages. On the fused chromosomes in threespine stickleback, we find an enrichment of quantitative trait loci underlying traits that contribute to marine versus freshwater adaptation. By comparing whole-genome sequences of freshwater and marine threespine stickleback populations, we also find an enrichment of regions under divergent selection on these two fused chromosomes. There is elevated genetic diversity within regions under selection in the freshwater population, consistent with a simulation study showing that gene flow can increase diversity in genomic regions associated with local adaptation and our demographic models showing gene flow between the marine and freshwater populations. Integrating our results with previous studies, we propose that these fusions created regions of low recombination that enabled the formation of adaptative clusters, thereby facilitating freshwater adaptation in the face of recurrent gene flow between marine and freshwater threespine sticklebacks.

Broadband linearly polarized mode converter based on over-coupled long-period fiber grating.

We demonstrate the fabrication of over-coupled long-period fiber gratings (LPFGs) in the 1.55-µm and 2-µm wavebands enabling broadband linearly polarized LP11 mode conversion using a CO2 laser. The birefringence of the fiber is caused by on one side laser exposure and increases with the increase of refractive index modulation depth, which realizes the conversion of linearly polarized modes. The mode conversion bandwidth can be significantly increased by using the over-coupled LPFG. The 10-dB bandwidth of the LPFGs with |κ|L values of π/2, 3π/2, and 5π/2 are 33.04, 80.84, and 114.08 nm at 1.55 µm waveband, respectively. The maximum bandwidth of the over-coupled LPFG is 3.79 times higher than that of conventional LPFG. The operating wavelength of the mode converter can be extended to 2.0 µm wavebands and the maximum 10-dB bandwidth reaches 161.32 nm. The proposed broadband linearly polarized mode converters could have potential application in the fields of mode division multiplexing systems, fiber laser systems.

Ultrasensitive magnetic field sensor based on cladding-etched long-period grating.

We demonstrate a high-sensitivity fiber-optic magnetic field sensor, which consists of a cladding-etched long-period fiber grating (LPFG) near the dispersion turning point (DTP) integrated with a magnetic fluid (MF). By reducing the cladding diameter of the LPFG, the fundamental mode is coupled to the lowest order cladding mode (LP0,2) near the DTP, which has a much higher surrounding refractive index sensitivity. Thanks to the excellent magneto-optical characteristics of the MF, the proposed sensor can achieve a magnetic field intensity sensitivity of 44.69 nm/mT in the range of 3-7.4 mT. The minimum magnetic field intensity that can be detected is 0.45 µT due to the 0.02-nm wavelength resolution of the optical spectrum analyzer. The proposed etched DTP-LPFG-based sensor with ultrahigh magnetic field sensitivity could have potential applications in magnetic fields and electrical systems.

Bandwidth optimization of cascaded long-period gratings for broadband mode conversion over 1.0-2.2 µm waveband.

We investigated theoretically and experimentally the cascaded long-period fiber gratings (c-LPFGs) in a few-mode fiber (FMF) for the generation of LP11 core mode in a broad wavelength range. The dependence of the transmission spectra of the c-LPFGs on the spacing between the gratings, and grating periods are studied in detail. The c-LPFGs experimentally generate LP11 core mode in a 10-dB bandwidth of 193.6 nm in 1.55 µm waveband and 447.5 nm in 2 µm waveband, respectively. The first-order orbital angular momentum mode can be converted by the c-LPFGs with the same broadband wavelength range. The 10-dB bandwidth and corresponding wavelength range for mode conversion can be adjusted by changing the grating spacing and grating periods.

All-fiber bandwidth tunable ultra-broadband mode converters based on long-period fiber gratings and helical long-period gratings.

We demonstrated the fabrication of bandwidth tunable ultra-broadband mode converters based on CO2-laser inscribed long-period fiber gratings (LPFGs) and helical long-period gratings (HLPGs) in a two-mode fiber (TMF). The simulation and experimental results show that there is a dual-resonance coupling from LP01 to LP11 core mode at the dispersion turning point. The mode converters based on the TMF-LPFG and TMF-HLPG provide a 10-dB bandwidth of ∼300 nm and ∼297 nm, respectively, which covers O + E+S + C band. The 1st order orbital angular momentum (OAM) mode based on TMF-LPFG was generated by adjusting the polarization controllers (PCs), while the 1st order OAM mode can be generated directly by the TMF-HLPG. When the twist rate is varied from -36 rad/m ∼ 36 rad/m, the tunable range of the 10-dB bandwidth is ∼52 nm and ∼91 nm for the LPFG and HLPG mode converters, respectively. The ultra-broadband mode converter can be adopted as a bandwidth tunable mode converter, which can be applied in ultra-broadband mode-division-multiplexing transmission systems and optical fiber sensing systems based on few-mode fibers.

High-order mode conversion in a few-mode fiber via laser-inscribed long-period gratings at 1.55 µm and 2 µm wavebands.

We demonstrate high-order mode conversion in a few-mode fiber (FMF) via CO2 laser inscribed long-period fiber gratings (LPFGs) at both the 1.55 µm and 2 µm wavebands. At the 1.55 µm waveband, five high-order core modes (the LP11, LP21, LP02, LP31, and LP12 modes) can be coupled from the LP01 mode with high efficiency by the FMF-LPFGs. The orbital angular momentum beams with different topological charges (±1,±2,±3) are experimentally generated by adjusting the polarization controllers. At the 2 µm waveband, three high-order modes (the LP11, LP21, and LP02 mode) can be coupled by the FMF-LPFGs with different grating periods. The proposed LPFG-based mode converters could have a potential prospects in mode-division multiplexing and multiwindow broadband optical communication applications.

Ultra-broadband fiber mode converter based on apodized phase-shifted long-period gratings.

We have demonstrated an ultra-broadband fiber mode converter based on CO2-laser inscribed length apodized phase-shifted long-period gratings (LPGs) with a three-section linear length apodization profile, where a π-phase shift was introduced between two adjacent grating sections. The grating parameters were optimized theoretically to achieve the broadband mode conversion between the LP01 mode and LP11 mode. The demonstrated device provides mode conversion efficiency higher than 90% over an ultra- broad bandwidth of ∼182nm. The insertion loss of the LPGs is negligible. Orbital angular momentum modes with left- and right-handed circular polarization can be generated from the demonstrated ultra-broadband mode converter successfully.

Prevalence of cryptic species in morphologically uniform taxa - Fast speciation and evolutionary radiation in Asian frogs.

Diversity and distributions of cryptic species have long been a vexing issue. Identification of species boundaries is made difficult by the lack of obvious morphological differences. Here, we investigate the cryptic diversity and evolutionary history of an underappreciated group of Asian frog species (Megophrys) to explore the pattern and dynamic of amphibian cryptic species. We sequenced four mitochondrial genes and five nuclear genes and delineated species using multiple approaches, combining DNA and mating-call data. A Bayesian species tree was generated to estimate divergence times and to reconstruct ancestral ranges. Macroevolutionary analyses and hybridization tests were conducted to explore the evolutionary dynamics of this cryptic group. Our phylogenies support the current subgenera. We revealed 43 cryptic species, 158% higher than previously thought. The species-delimitation results were further confirmed by mating-call data and morphological divergence. We found that these Asian frogs entered China from the Sunda Shelf 48 Mya, followed by an ancient radiation event during middle Miocene. We confirmed the efficiency of the multispecies coalescent model for delimitation of species with low morphological diversity. Species diversity of Megophrys is severely underappreciated, and species distributions have been misestimated as a result.

CO2 laser-written long-period fiber grating with a high diffractive order cladding mode near the turning point.

We demonstrate the fabrication of a long-period fiber grating (LPFG) in a boron-doped single-mode fiber with a high-diffractive-order cladding mode (HDCM) near the turning point (TP). The simulations show that an LPFG with less than 0.2 duty cycles can couple light to the HDCM. An LPFG with a period of more than 400 µm can achieve strong mode coupling between the fundamental mode and the HDCM near the TP. The effect of the external refractive index on the transmission spectrum of a LPFG with different grating periods is investigated by simulations and experiments. With an increase in grating period, the spectral dip corresponding to the HDCM travels faster than the conventional dip, and overlapped dips appear in the transmission spectrum. High sensitivities of up to 13,497.7 nm/RIU and 0.77 nm/°C of, respectively, RI and temperature sensing can be achieved. Such LPFGs could be potentially used as optical filters and high-sensitivity sensors.

Narrow bandwidth passively mode locked picosecond Erbium doped fiber laser using a 45° tilted fiber grating device.

An all-fiber passively picosecond mode locked Erbium doped laser using a 45° tilted fiber grating (45° TFG) and a fiber Bragg grating (FBG) is reported in this work. Due to the strong polarization dependent loss (PDL) of 45° TFG and narrow 3-dB bandwidth of FBG, the Erbium doped fiber laser (EDFL) can generate picosecond mode locked pulse based on the nonlinear polarization rotation (NPR) effect. The laser features a repetition rate of 9.67 MHz, a pulse duration of 33 ps, a signal-to-noise ratio (SNR) of 70 dB, an average output power of 1.2 mW, and a single pulse energy of 124 pJ under the pump power of 102 mW. Besides, the central wavelength of the laser can be continuously adjusted from 1550.65 nm to 1551.44 nm. The technique of using a 45° TFG to generate picosecond pulses can be readily extended to other wavelength such as mid-infrared (mid-IR) where fiber polarizing components are either expensive or not available. To the best of our knowledge, the spectral width is the narrowest among all-fiber passively mode locked Erbium-doped laser based on NPR.

Description of two new species of the genus Megophrys (Amphibia: Anura: Megophryidae) from Heishiding Nature Reserve, Fengkai, Guangdong, China, based on molecular and morphological data.

Two new species, Megophrys acuta sp. nov. and Megophrys obesa sp. nov., are described based on a series of specimens collected from Heishiding Nature Reserve, Fengkai County, Guangdong Province, China. They can be distinguished from other known congeners occurred in southern and eastern China by morphological characters and molecular divergence in the mitochondrial 16S rRNA gene. M. acuta is characterized by small and slender body with adult females measuring 28.1-33.6 mm and adult males measuring 27.1-33.0 mm in snout-vent length; snout pointed, strongly protruding well beyond margin of lower jaw; canthus rostralis well developed and sharp; hindlimbs short, the heels not meeting, tibio-tarsal articulation reaching forward the pupil of eye. M. obesa is characterized by stout and slightly small body with adult females measuring 37.5-41.2 mm, adult male measuring 35.6 mm in snout-vent length; snout round in dorsal view; canthus rostralis developed; hindlimbs short, the heels not meeting, tibio-tarsal articulation reaching forward the posterior margin of eye. The discovery of these two new species further confirms that the diversity of this genus has been significantly underestimated. At present the genus Megophrys contains 56 species of which 35 species are distributed in China.

Treatment of Elderly Patients with Acute Symptomatic OVCF: A Study of Comparison of Conservative Treatment and Percutaneous Kyphoplasty.

Objective: The present study was designed for the contrastive analysis of conservative and percutaneous kyphoplasty (PKP) on pain severity and recovery of injured vertebrae in elderly patients with acute symptomatic osteoporotic vertebral compression fracture (OVCF). Methods: A total of 60 elderly patients with acute symptomatic OVCF were divided into two groups according to different treatment protocols, with 30 patients in each group. Patients in the Con group received conservative treatment, while patients in the PKP group received percutaneous kyphoplasty treatment. Clinical evaluation included the visual analogue scale (VAS), the Dallas pain questionnaire, the vertebral body leading edge height, the Cobb angle of injured vertebrae, the MOS item short-form health survey (SF-36), the Barthel index, and the mini-mental state examination (MMSE). Results: At 3 days, 3 months, and 6 months post-treatment, the score of VAS and the Cobb angle of injured vertebrae in patients of the PKP group were all significantly lower than those in the Con group (P < 0.05), while the height of vertebral body leading edge in patients of the PKP group was significantly longer than that in the Con group (P < 0.05). At 6 months post-treatment, the scores of the four dimensions of the Dallas pain questionnaire scale in the PKP group were all significantly lower than those in the Con group (P < 0.05), while the score of SF-36 (PCS), SF-36 (MCS), and Barthel index in patients of the PKP group were all significantly lower than those in the Con group (P < 0.05), and there was no significant difference in the scores of MMSE between these two groups (P > 0.05). Conclusion: Compared with conservative treatment, PKP treatment of elderly patients with acute symptomatic OVCF provides rapid pain relief, restoration of damaged vertebral body height, correction of Cobb's angle, and improved quality of life.

Clinical efficacy and learning curve of posterior percutaneous endoscopic cervical laminoforaminotomy for patients with cervical spondylotic radiculopathy.

In this study, we aimed to investigate the clinical efficacy and learning curve of posterior percutaneous endoscopic cervical laminoforaminotomy (PPECLF) in patients with cervical spondylotic radiculopathy (CSR). A total of 64 patients with CSR received PPECLF. Clinical outcome scores included the visual analog scale, Japanese Orthopedic Association score, neck disability index, and modified Macnab criteria. Radiological outcomes included the disc height, C2 to C7 Cobb angle, and range of motion. The learning curve was evaluated using cumulative sum analysis. Patients were divided into accumulation phase and mastery phase groups (A and B), and general data and surgical efficacy were compared between the 2 groups. Follow-up ranged from 12 to 24 months. Clinical outcome scores improved significantly at the final follow-up, and there were no differences in radiological outcomes. Surgical efficacy was excellent and good in 82.8% of patients. The operative time showed a decreasing trend with the accumulation of cases. Patients were divided and the 26th case was the cutoff point according to the learning curve. No significant differences were found in the clinical outcomes between the 2 groups. Decompression with PPECLF was safe and effective in the treatment of CSR. With the accumulation of cases, the operative time was gradually shortened, and the clinical efficacy was significant. The PPECLF procedure can be performed efficiently and safely to treat CSR.

Description of three new Boulenophrys species from eastern Guangdong, China, emphasizing the urgency of ecological conservation in this region (Anura, Megophryidae).

The hilly region in eastern Guangdong, China lacks comprehensive scientific investigations for decades, especially in terms of herpetofauna. In recent years, several highly threatened amphibians have been gradually discovered from this region. In this work, three new species of the genus Boulenophrys are described, which are endemic from only one or two known localities in eastern Guangdong. These discoveries enrich the diversity of Boulenophrys in eastern Guangdong. With the large number of threatened urodeles and anuran species occurring in this densely populated area, the unique herpetological diversity in eastern Guangdong is facing the impacts of habitat degradation and fragmentation, and conservation actions are urgently required.

Analysis on the Effect of Different Surgical Methods on the Treatment of Senile Osteoporotic Spinal Compression Fractures and the Influencing Factors of Complications.

Osteoporotic fractures are a common type of fractures in the elderly, among which spinal compression fractures are more common. After the occurrence of fractures, due to the compression and burst of the vertebral body, this will lead to local kyphosis deformity and even affect the balance of the sagittal spine. In the past, conservative treatments were used for osteoporotic spinal compression fractures. Although it can relieve pain symptoms, it can easily lead to complications such as aggravation of osteoporosis and deep vein thrombosis of the lower extremities. At present, percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) are the main clinical surgical treatments, both of which are minimally invasive surgery, short operation time, effective pain relief, and rapid postoperative recovery. Although both of them are effective, there is still controversy over the efficacy of both in the treatment of osteoporotic spinal compression fractures. The purpose of this study was to investigate the efficacy of PVP and PKP in the treatment of elderly osteoporotic spinal compression fractures and to analyze the related factors that affect the occurrence of postoperative complications. The results show that both PVP and PKP can effectively improve the pain and dysfunction of elderly patients with osteoporotic spinal compression fracture, restoration of vertebral height, and correct kyphosis, but PKP has better effect and higher safety and is worth promoting. Postoperative complications of patients are related to their age, bone mineral density, use of hormones, and antiosteoporosis treatment.

Four new species of Panophrys (Anura, Megophryidae) from eastern China, with discussion on the recognition of Panophrys as a distinct genus.

The diversity of Panophrys horned toads is considered highly underestimated with a large number of undescribed cryptic species. In this work, we describe four Panophrys species from eastern China which were proposed as cryptic species by molecular data in previous study, additionally provide new information on the biogeography of these four species. Panophrys daiyunensis sp. nov. from southern Fujian, Panophrys daoji sp. nov. from eastern Zhejiang, Panophrys sanmingensis sp. nov. from the hilly area among Fujian, Jiangxi and Guangdong, and Panophrys tongboensis sp. nov. from northeastern Jiangxi, can be distinguished from all recognized congeners by a combination of morphological characteristics. The descriptions of these four new species take the recognized species of Panophrys to 51, which is the largest genus within the Asian horned toads subfamily Megophryinae. Considered as an appropriate arrangement for the Asian horned toads currently and applied in this study to describe the new species, the generic recognition of Panophrys is also discussed.

Four new species of Asian horned toads (Anura, Megophryidae, Megophrys) from southern China.

Recent phylogenetic analysis encompassing multilocus nuclear-gene and matrilineal mtDNA genealogy has revealed a series of cryptic species of the subgenus Panophrys within genus Megophrys from southern and eastern China. This study demonstrates that the Panophrys specimens from the hilly areas among Guangdong, Guangxi and Hunan can be morphologically distinguished from all recognized congeners, thereby providing additional supports for the recognitions of four new species of Panophrys, namely Megophrys (Panophrys) mirabilis Lyu, Wang & Zhao, sp. nov. from northeastern Guangxi, Megophrys (Panophrys) shimentaina Lyu, Liu & Wang, sp. nov. from northern Guangdong, and Megophrys (Panophrys) xiangnanensis Lyu, Zeng & Wang, sp. nov. and Megophrys (Panophrys) yangmingensis Lyu, Zeng & Wang, sp. nov. from southern Hunan. The descriptions of these species take the number of Megophrys species to 101, 46 of which belong to the subgenus Panophrys.

Unilateral Laminectomy by Endoscopy in Central Lumbar Canal Spinal Stenosis: Technical Note and Early Outcomes.

STUDY DESIGN: Retrospective study. OBJECTIVE: To evaluate the outcomes and safety of endoscopic laminectomy for central lumbar canal spinal stenosis. SUMMARY OF BACKGROUND DATA: .: Spinal endoscopy is mostly used in the treatment of lumbar disc herniation, while endoscopic laminectomy for lumbar spinal stenosis is rarely reported. METHODS: From January 2016 to June 2017, 38 patients with central lumbar canal spinal stenosis were treated with endoscopic laminectomy. Clinical symptoms were evaluated at 1, 3, 6, and 12 months and the last follow-up after surgery. Functional outcomes were assessed by using the Japanese Orthopedic Association Scores (JOA) and Oswestry Disability Index (ODI). The decompression effect was assessed by using the dural sac cross-sectional area (DSCA). Lumbar stability was evaluated using lumbar range of motion (ROM), ventral intervertebral space height (VH), and dorsal intervertebral space height (DH). RESULTS: The mean age of the cases was 60.8 years, the mean operation time was 66.3 minutes, the blood loss was 38.8 mL, and the length of incision was 19.6 mm. The mean time in bed was 22.3 hours, and the mean hospital stay was 8.8 days. JOA scores were improved from 10.9 to 24.1 (P < 0.05), ODI scores were improved from 79.0 to 27.9 (P < 0.05), DSCA was improved from 55.7 to 109.5 mm (P < 0.05), ROM scores were improved from 5.6° to 5.7° (P < 0.05), and DH scores were reduced from 6.6 to 6.5 mm (P < 0.05). There was no significant difference in VH before and after operation (P > 0.05). There were no serious complications during the follow-ups. CONCLUSION: Endoscopic laminectomy had the advantage of a wider view, which was effective, safe, and less invasive for lumbar spinal stenosis. LEVEL OF EVIDENCE: 5.

Review of the genus Brachytarsophrys (Anura: Megophryidae), with revalidation of Brachytarsophrys platyparietus and description of a new species from China.

The genus-level recognition of monophyletic short-legged toads ( Brachytarsophrys) has been recently implicated in the taxonomic debate of Megophrys sensu lato. In the present study, Brachytarsophrys is reasonably regarded as a distinct genus based on significant morphological differentiations and recent molecular analyses. Furthermore, a comprehensive review of this genus is performed, with two species groups proposed based on morphological differences and phylogenetic relationships. Particularly, Brachytarsophrys platyparietus is removed as a synonym of Brachytarsophrys carinense and considered a valid species due to significant genetic divergence and distinct morphological differences. In addition, a new species, Brachytarsophrys orientalis sp. nov., is described based on a series of specimens collected from southeastern China. This work takes the member species of the genus Brachytarsophrys to seven, suggesting that the diversity of Brachytarsophrys is underestimated. In addition, the genus levels of other monophyletic groups within the subfamily Megophryinae are discussed.

Author Correction: Review of the genus Brachytarsophrys (Anura: Megophryidae), with revalidation of Brachytarsophrys platyparietus and description of a new species from China.

Following the publication of our paper (Li et al., 2020), it has come to our attention that, due to our oversight, the contributions of some colleagues were not reflected in the "ACKNOWLEDGEMENTS" section. Hereby, we wish to add the following to the "ACKNOWLEDGEMENTS" section as a correction.