OsciDrop: A Versatile Deterministic Droplet Generator.

This paper describes OsciDrop, a versatile chip-free droplet generator used to produce size-tunable droplets on demand. Droplet generation is fundamental to miniaturized analysis. We designed OsciDrop to segment the fluid flowing out of the orifice of a disposable pipette tip into droplets by oscillating its distal end underneath an immiscible continuous phase. We described the theoretical model and investigated the effect of flow rate, oscillating amplitude, frequency, and waveform on droplet generation. Our study revealed a previously underexplored Weber number-dominated regime that leverages inertial force instead of viscous force to generate droplets. The same pipette tip allowed robust and deterministic generation of monodisperse droplets with programmable sizes ranging from 200 pL to 2 µL by asymmetrical oscillation. We validated this platform with two droplet-based nucleic acid amplification tests: a digital loop-mediated isothermal amplification assay for absolute quantification of African swine fever virus and a multi-volume digital polymerase chain reaction assay for the high dynamic range measurement of human genomic DNA. The OsciDrop method opens a facile avenue to miniaturization, integration, and automation, exhibiting full accessibility for digital molecular diagnostics.

Tunable and Contamination-Free Injection with Microfluidics by Stepinjection.

Droplet microfluidics with picoinjection provides significant advantages to multistep reactions and screenings. The T-junction design for picoinjection is convenient in adding picoliter reagents into passing droplets to initiate reactions. However, conventional picoinjectors face difficulties in eliminating cross-contamination between droplets, preventing them from widespread use in sensitive biological and molecular assays. Here, we introduce stepinjection, which uses a T-junction with a stepped channel design to elevate the diffusional buffer zone into the main channel and consequently increases the pressure difference between droplets and the inlet of the injection channel. To demonstrate the stepinjector's ability to perform contamination-sensitive enzymatic assays, we inject casein fluorescein isothiocyanate (FITC-casein) into a mixture of savinase and savinase-free (labeled with a red fluorescent dye) droplets. We observe no cross-contamination using stepinjection but find a severe cross-talk using an optimal picoinjection design. We envision that the simple, tunable, and reliable stepinjector can be easily integrated in various droplet processing devices, and facilitate various biomedical and biochemical applications including multiplex digital PCR, single-cell sequencing, and enzymatic screening.

All-In-One OsciDrop Digital PCR System for Automated and Highly Multiplexed Molecular Diagnostics.

Digital PCR (dPCR) holds immense potential for precisely detecting nucleic acid markers essential for personalized medicine. However, its broader application is hindered by high consumable costs, complex procedures, and restricted multiplexing capabilities. To address these challenges, an all-in-one dPCR system is introduced that eliminates the need for microfabricated chips, offering fully automated operations and enhanced multiplexing capabilities. Using this innovative oscillation-induced droplet generation technique, OsciDrop, this system supports a comprehensive dPCR workflow, including precise liquid handling, pipette-based droplet printing, in situ thermocycling, multicolor fluorescence imaging, and machine learning-driven analysis. The system's reliability is demonstrated by quantifying reference materials and evaluating HER2 copy number variation in breast cancer. Its multiplexing capability is showcased with a quadruplex dPCR assay that detects key EGFR mutations, including 19Del, L858R, and T790M in lung cancer. Moreover, the digital stepwise melting analysis (dSMA) technique is introduced, enabling high-multiplex profiling of seven major EGFR variants spanning 35 subtypes. This innovative dPCR system presents a cost-effective and versatile alternative, overcoming existing limitations and paving the way for transformative advances in precision diagnostics.

Dual Dirac Nodal Line in Nearly Freestanding Electronic Structure of ß-Sn Monolayer.

Two-dimensional topological insulators (2D TIs) have distinct electronic properties that make them attractive for various applications, especially in spintronics. The conductive edge states in 2D TIs are protected from disorder and perturbations and are spin-polarized, which restrict current flow to a single spin orientation. In contrast, topological nodal line semimetals (TNLSM) are distinct from TIs because of the presence of a 1D ring of degeneracy formed from two bands that cross each other along a line in the Brillouin zone. These nodal lines are protected by topology and can be destroyed only by breaking certain symmetry conditions, making them highly resilient to disorder and defects. However, 2D TNLSMs do not possess protected boundary modes, which makes their investigation challenging. There have been several theoretical predictions of 2D TNLSMs, however, experimental realizations are rare. ß-Sn, a metallic allotrope of tin with a superconducting temperature of 3.72 K, may be a candidate for a topological superconductor that can host Majorana Fermions for quantum computing. In this work, single layers of α-Sn and ß-Sn on a Cu(111) substrate are successfully prepared and studied using scanning tunneling microscopy, angle-resolved photoemission spectroscopy, and density functional theory calculations. The lattice and electronic structure undergo a topological transition from 2D topological insulator α-Sn to 2D TNLSM ß-Sn, with two types of nodal lines coexisting in monolayer ß-Sn. Such a realization of two types of nodal lines in one 2D material has not been reported to date. Moreover, we also observed an unexpected phenomenon of freestanding-like electronic structures of ß-Sn/Cu(111), highlighting the potential of ultrathin ß-Sn films as a platform for exploring the electronic properties of 2D TNLSM and topological superconductors, such as few-layer superconducting ß-Sn in lateral contact with topological nodal line single-layer ß-Sn.

Two-gap topological superconductor LaB2 with high Tc = 30 K.

Since two gap superconductivity was discovered in MgB2, research on multigap superconductors has attracted increasing attention because of its intriguing fundamental physics. In MgB2, the Mg atom donates two electrons to the borophene layer, resulting in a stronger gap from the σ band and a weaker gap from the π bond. First-principles calculations demonstrate that the two gap anisotropic superconductivity strongly enhances the transition temperature of MgB2 in comparison with that given by the isotropic model. In this work, we report a three-band (B-σ, B-π, and La-d) two-gap superconductor LaB2 with very high Tc = 30 K by solving the fully anisotropic Migdal-Eliashberg equation. Because of the σ and π-d hybridization on the Fermi surface, the electron-phonon coupling constant λ = 1.5 is significantly larger than the λ = 0.7 of MgB2. Our work paves a new route to enhance the electron-phonon coupling strength of multigap superconductors with d orbitals. On the other hand, our analysis reveals that LaB2 belongs to the weak topological semimetal category, leading to a possible topological superconductor with the highest Tc to date. Moreover, upon applying pressure and/or doping, the topology is tunable between weak and strong with Tc varying from 15 to 30 K, opening up a flexible platform for manipulating topological superconductors.

Hoffa's fracture in an adolescent treated with an innovative surgical procedure: A case report.

BACKGROUND: Hoffa fracture is rare, especially in adolescents, and has a high rate of complications such as avascular necrosis and osteoarthritis; moreover, there are no definitive guidelines for its treatment. This report could provide a new potential treatment for Hoffa fracture. CASE SUMMARY: A 16-year-old girl presented to the orthopedic emergency department of No. 2 People's Hospital of Yibin City with persistent pain following a right knee injury sustained during a sprint race. Her knee was swollen and tender, and the range of motion was restricted by the pain. X-ray and computed tomography revealed a Hoffa fracture in the right knee. After consultation, surgical treatment was performed, and the fracture was fixed with three 3.5-mm cannulated cancellous screws; osteochondral plugs that were harvested from the screw insertion site were re-implanted to cover the screw head. The patient's fracture and osteochondral plug healed 6 mo postoperatively, and she presented a knee range of motion of 0-135 without pain, and was walking without support with a normal gait. CONCLUSION: Here, we describe an innovative surgical procedure for Hoffa fracture that could provide a new possibility for the treatment of similar fractures, and further improve their management.

Recent Progress in Wearable Biosensors: From Healthcare Monitoring to Sports Analytics.

Recent advances in lab-on-a-chip technology establish solid foundations for wearable biosensors. These newly emerging wearable biosensors are capable of non-invasive, continuous monitoring by miniaturization of electronics and integration with microfluidics. The advent of flexible electronics, biochemical sensors, soft microfluidics, and pain-free microneedles have created new generations of wearable biosensors that explore brand-new avenues to interface with the human epidermis for monitoring physiological status. However, these devices are relatively underexplored for sports monitoring and analytics, which may be largely facilitated by the recent emergence of wearable biosensors characterized by real-time, non-invasive, and non-irritating sensing capacities. Here, we present a systematic review of wearable biosensing technologies with a focus on materials and fabrication strategies, sampling modalities, sensing modalities, as well as key analytes and wearable biosensing platforms for healthcare and sports monitoring with an emphasis on sweat and interstitial fluid biosensing. This review concludes with a summary of unresolved challenges and opportunities for future researchers interested in these technologies. With an in-depth understanding of the state-of-the-art wearable biosensing technologies, wearable biosensors for sports analytics would have a significant impact on the rapidly growing field-microfluidics for biosensing.

The Role of Cardiokines in Heart Diseases: Beneficial or Detrimental?

Cardiovascular disease remains the leading cause of morbidity and mortality, imposing a major disease burden worldwide. Therefore, there is an urgent need to identify new therapeutic targets. Recently, the concept that the heart acts as a secretory organ has attracted increasing attention. Proteins secreted by the heart are called cardiokines, and they play a critical physiological role in maintaining heart homeostasis or responding to myocardial damage and thereby influence the development of heart diseases. Given the critical role of cardiokines in heart disease, they might represent a promising therapeutic target. This review will focus on several cardiokines and discuss their roles in the pathogenesis of heart diseases and as potential therapeutics.

Three-Dimensionally Printed Silk-Sericin-Based Hydrogel Scaffold: A Promising Visualized Dressing Material for Real-Time Monitoring of Wounds.

A wound dressing which can be convenient for real-time monitoring of wounds is particularly attractive and user-friendly. In this study, a nature-originated silk-sericin-based (SS-based) transparent hydrogel scaffold was prepared and evaluated for the visualization of wound care. The scaffold was fabricated from a hybrid interpenetrating-network (IPN) hydrogel composed of SS and methacrylic-anhydride-modified gelatin (GelMA) by 3D printing. The scaffold transformed into a highly transparent hydrogel upon swelling in PBS, and thus, anything underneath could be easily read. The scaffold had a high degree of swelling and presented a regularly macroporous structure with pores around 400 µm × 400 µm, which can help maintain the moist and apinoid environment for wound healing. Meanwhile, the scaffolds were conducive to adhesion and proliferation of L929 cells. A coculture of HaCaT and HSF cells on the scaffold showed centralized proliferation of the two cells in distributed layers, respectively, denoting a promising comfortable environment for re-epithelialization. Moreover, in vivo studies demonstrated that the scaffold showed no excessive inflammatory reaction. In short, this work presented an SS-based transparent hydrogel scaffold with steerable physical properties and excellent biocompatibility through 3D printing, pioneering promising applications in the visualization of wound care and drug delivery.

A novel role of fragile X mental retardation protein in pre-mRNA alternative splicing through RNA-binding protein 14.

Fragile X mental retardation protein (FMRP), an important RNA-binding protein responsible for fragile X syndrome, is involved in posttranscriptional control of gene expression that links with brain development and synaptic functions. Here, we reveal a novel role of FMRP in pre-mRNA alternative splicing, a general event of posttranscriptional regulation. Using co-immunoprecipitation and immunofluorescence assays, we identified that FMRP interacts with an alternative-splicing-associated protein RNA-binding protein 14 (RBM14) in a RNA-dependent fashion, and the two proteins partially colocalize in the nuclei of hippocampal neurons. We show that the relative skipping/inclusion ratio of the micro-exon L in the Protrudin gene and exon 10 in the Tau gene decreased in the hippocampus of Fmr1 knockout (KO) mice. Knockdown of either FMRP or RBM14 alters the relative skipping/inclusion ratio of Protrudin and Tau in cultured Neuro-2a cells, similar to that in the Fmr1 KO mice. Furthermore, overexpression of FMRP leads to an opposite pattern of the splicing, which can be offset by RBM14 knockdown. RNA immunoprecipitation assays indicate that FMRP promotes RBM14's binding to the mRNA targets. In addition, overexpression of the long form of Protrudin or the short form of Tau promotes protrusion growth of the retinoic acid-treated, neuronal-differentiated Neuro-2a cells. Together, these data suggest a novel function of FMRP in the regulation of pre-mRNA alternative splicing through RBM14 that may be associated with normal brain function and FMRP-related neurological disorders.

Involvement of FMRP in Primary MicroRNA Processing via Enhancing Drosha Translation.

Fragile X mental retardation protein (FMRP), associated with fragile X syndrome, is known as an RNA-binding protein to regulate gene expression at post-transcriptional level in the brain. FMRP is also involved in microRNA (miRNA) biogenesis during the process of precursor miRNA (pre-miRNA) into mature miRNA. However, there is no description of the effect of FMRP on primary miRNA (pri-miRNA) processing. Here, we uncover a novel role of FMRP in pri-miRNA processing via controlling Drosha translation. We show that the expression of DROSHA protein, instead of its messenger RNA (mRNA) transcripts, is downregulated in both the hippocampus of Fmr1-knockout mice and the FMRP-knockdown Neuro-2a cells. Overexpression or knockdown FMRP does not alter Drosha mRNA stability. Immunoprecipitation and polysome analyses demonstrate that FMRP binds to the Drosha mRNA and enhances its translation. Additionally, we show that loss of FMRP in Fmr1-deficient mice results in the accumulation of three in six analyzed pri-miRNAs and the reduction of the corresponding pre-miRNAs and mature miRNAs. Thus, our data suggest that FMRP is involved in pri-miRNA processing via enhancing DROSHA expression that may play an important role in fragile X syndrome.

[Association between HLA-DRB1, DQB1 genes and pemphigus vulgaris in Chinese Hans].

OBJECTIVE: To investigate the predisposing role of HLA-DRB1, DQB1 genes in pemphigus vulgaris (PV). METHODS: Polymerase chain reaction-specific sequence primers method was used to type HLA-DRB1, DQB1 subregion in the patients with PV of Han nationality from Jiangsu and Anhui provinces and matched control subjects. RESULTS: DR4, DRB1*14(*1401,*1404,*1405) gene frequencies in PV patients were significantly higher than those in controls (Pc<0.05 and Pc<0.01 respectively). DQB1*0302, DQB1*0503 gene frequencies were significantly higher in PV patients (Pc<0.05). Further typing of DR4 positive subjects revealed that the gene frequencies of DRB1*0406, *0403 were significantly increased in PV patients as compared with controls (Pc<0.05). The haplotype frequencies of HLA-DRB1*04, DQB1*0302 and HLA-DRB1*14, DQB1*0503 in PV patients were significantly higher than those in controls (P<0.05). CONCLUSION: The results suggest that the combination of HLA-DRB1*4, DQB1*0302 and HLA-DRB1*14, DQB1*0503 forms putative susceptible haplotypes for PV patients in Chinese Hans.

[Epidemiological and bacteriological characteristics of Neisseria gonorrhoeae isolates in China].

OBJECTIVE: To investigate the antimicrobial susceptibility,auxotype, and plasmid profile of Neisseria gonorrhoeae isolates in China and to provide evidence for the development of treatment guideline and policy for control. METHODS: Agar dilution was used to detect antimicrobial susceptibility. The auxotype was determined by GC genetic medium. The plasmid was extracted by alkaline cleavage and electrophoresed. RESULTS: A total of 4,976 gonococcal isolates were tested in the last 8 years. The resistant rate for penicillin was 71.60% with PPNG being 15.54%. Tetracycline-resistant (TRNG) isolates accounted for 93.02% with 10.48% high level tetracycline-resistant. The resistant rate for ciprofloxacin was also relatively high (31.78%). The resistant rates for spectinomycin and ceftriaxone were 0.36% and 0.46%. The predominant auxotypes of gonococcal isolates were proto and pro(-) during 1995 - 1996 in Nanjing, accounted for 46.4% and 47.53%, 48.4% and 50.22%, respectively. There were 8 strains harboring 4.2, 5.4, 39.5 kb plasmids and 2 harboring 4.2, 4.9, 5.4, 39.5 kb plasmids in 10 PPNG strains; 2 harboring no plasmid, 28 harboring 4.2, 4.9, 5.4, 39.5 kb plasmids in 30 non-PPNG strains. The 5.4 kb plasmid of PPNG could be digested with restriction endonuclease BamHI while the 5.4 kb plasmid of non-PPNG could not. CONCLUSION: The gonococcal isolates were highly resistant to penicillin, tetracycline, and ciprofloxacin, while were still sensitive to spectinomycin and ceftriaxone. No significant auxotyping change was found in terms of predominant gonococcal strains in the last two years in Nanjing while 5.4 kb plasmid might be the most prevalent resistant plasmid in Nanjing.