Cable-Like Core-Shell Mesoporous SnO2 Nanofibers by Single-Nozzle Electrospinning Phase Separation for Formaldehyde Sensing

In this study, we have developed a simple and efficient single-nozzle electrospinning strategy involving the phase separation of polystyrene and poly(vinylpyrrolidone) to construct cable-like core-shell mesoporous SnO₂ nanofibers. Compared with traditional multi-axial electrospinning approaches to the synthesis of core-shell nanofibers, the single-nozzle electrospinning process requires no complex multi-axial electrospinning setups or post-treatments, just drying and annealing after electrospinning. The obtained SnO₂ nanofibers show promise as a sensing material for formaldehyde at low concentrations, the detection limit being about 1 ppm. Furthermore, the nanofibers exhibited good cycling stability and selectivity, with response and recovery times toward 10 ppm formaldehyde being approximately 18 and 196 s, respectively, at an operating temperature of 195 °C.

Direct Growth of Continuous and Uniform MoS2 Film on SiO2/Si Substrate Catalyzed by Sodium Sulfate

Because of its unique electronic band structure, molybdenum disulfide (MoS₂) has been regarded as a star semiconducting material. However, direct growth of continuous and high-quality MoS₂ films on SiO₂/Si substrates is still very challenging. Here, we report a facile chemical vapor deposition (CVD) method based on synergistic modulation of precursor and Na₂SO₄ catalysis, realizing the centimeter scale growth of a continuous MoS₂ film on SiO₂/Si substrates. The as-grown MoS₂ film had an excellent spatial homogeneity and crystal quality, with an edge length of the composite domain as large as 632 μm. Both experimental and theoretical results proved that Na tended to bond with SiO₂ substrates rather than to interfere with as-grown MoS₂. Thus, they showed decent and uniform electrical performance, with electron mobilities as high as 5.9 cm² V^-1 s^-1_. We believe our method will pave a new way for MoS₂ toward real application in modern electronics.

In-vivo evaluation of a reinforced ovine biologic: a comparative study to available hernia mesh repair materials

Purpose

Two innovative reinforced biologic materials were studied in a non-human primate hernia repair model. The test articles, which combine layers of ovine decellularized extracellular matrix with minimal amounts of synthetic polymer, were evaluated for their biologic performance as measured by inflammatory response, healing kinetics, integration, and remodeling into functional host tissue. For comparison, seven clinically used biologic and synthetic meshes were also studied.

Methods

Animals were implanted with test articles in surgically created full-thickness midline abdominal wall defects, and evaluated macroscopically and histologically at 4, 12, and 24 weeks.

Results

Macroscopically, biologics resorbed and remodeled into naturally appearing tissue; the reinforced biologics appeared similar, but remodeled earlier and were less prone to stretch. Synthetics developed a layer of reactive tissue above and separate from the contracted mesh structure. At early time points, the collagen networks of biologics and reinforced biologics were infiltrated by host cells primarily as a peripheral layer on the biologics. As early as 12 weeks, the collagen networks associated with the reinforced biologics remodeled into organized host collagen. By 24 weeks, both reinforced biologics and biologics had low levels of inflammation. In contrast, a foreign body response persisted at 24 weeks with the synthetics, which had developed less organized collagen, separate in space from the actual mesh.

Conclusions

The current study shows a favorable response to reinforced biologics, which were associated with an initial inflammatory response, resolving by later time points, followed by active remodeling, and the formation of new morphologically functional collagen.

Electronic supplementary material

The online version of this article (10.1007/s10029-019-02119-z) contains supplementary material, which is available to authorized users.

A 9-year experience study of single-port micro-laparoscopic repair of pediatric inguinal hernia using a simple needle

Purpose

As laparoscopic techniques and equipments improve, laparoscopic inguinal hernia repair has been gaining popularity. The objective of the study was to summarize 9 years of experience using a single-port micro-laparoscopic approach to repair pediatric inguinal hernias with a simple hernia needle.

Methods

1880 children with inguinal hernias were enrolled using micro-laparoscopic surgery between June 2009 and 2018. All patients underwent high ligation surgery using a single-port micro-laparoscopic technique. The clinical data were retrospectively analyzed.

Results

All micro-laparoscopic surgeries were successfully performed in the 1880 patients, who ranged in age from 2 months to 14 years (3.66 ± 2.96 years) including 1622 males and 258 females. Among them, 1299 cases were unilateral hernias and 581 cases were bilateral hernias. The average operating time was 12.5 ± 3.5 min for a unilateral hernia and 20.5 ± 4.5 min for bilateral hernias. All patients were discharged 1–2 days after surgery, and the average length of their hospital stay was 2–4 days. Complications of knot reaction and pneumoscrotum occurred in 5 cases (0.27%) and 54 cases (2.87%), respectively, but these cases were properly managed, with no major impact on the operational outcomes. All patients were followed up for 3–65 months; there were 13 recurrent cases (0.69%).

Conclusions

Single-port micro-laparoscopic herniorrhaphy in children using a simple hernia needle is a reliable and minimally invasive procedure.

Shape-Engineered Synthesis of Atomically Thin 1T-SnS2 Catalyzed by Potassium Halides

Shape engineering plays a crucial role in the application of two-dimensional (2D) layered metal dichalcogenide (LMD) crystalline materials in terms of physical and chemical property modulation. However, controllable growth of 1T phase tin disulfide (SnS₂) with multifarious morphologies has rarely been reported and remains challenging. Herein, we report a direct synthesis of large-size, uniform, and atomically thin 1T-SnS₂ with multiple morphologies by adding potassium halides via a facile chemical vapor deposition process. A variety of morphologies, i.e., from hexagon, triangle, windmill, and dendritic to coralloid, corresponding to fractal dimensions from 1.01 to 1.81 are accurately controlled by growth conditions. Moreover, the Sn concentration controls the morphology change of SnS₂. The edge length of the SnS₂ dendritic flake can grow larger than 500 μm in 5 min. Potassium halides can significantly reduce the surface migration barrier of the SnS₂ cluster and enhance the SnS₂ adhesion force with substrate to facilitate efficient high in-plane growth of monolayer SnS₂ compared to sodium halides by density functional theory calculations. More branched SnS₂ with higher fractal dimension provides more active sites for enhancing hydrogen evolution reactions. Importantly, we prove that potassium halides are preferable for 1T-phase LMDs structures, while sodium halides are more suitable for 2H-phase materials. The growth mechanism proposed here provides a general approach for controllable-phase synthesis of 2D LMD crystals and related heterostructures. Shape engineering of 2D materials also provides a strategy to tune LMD properties for demanding applications.

Acute benzo[a]pyrene treatment causes different antioxidant response and DNA damage in liver, lung, brain, stomach and kidney

Acute effects of oxidative damage induced by benzo[a]pyrene (B[a]P) on various organs are still not clear. In this study, we investigated oxidative stress and DNA damage in liver, lung, stomach, brain and kidney of ICR male mice induced by acute B[a]P treatment. B[a]P treatment led to a significant decrease at the different doses in body weight. For the variations of superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), glutathione (GSH) and GSH/GSSG, significant increases were observed at 24 h, then decreased till 72 h after B[a]P injection. The increase percent indicated in a dose- dependent decrease manner. However, glutathione peroxidase (GPx), GSSG and MDA were significantly increased in a time- and dose-dependent increase manner. DNA damage showed the significant and top levels at 24 h, and increased in proportion to the doses of B[a]P treatment. The total induction could be indicated by the variation of MDA at 24 h after B[a]P injection and showed the following order of predominance: lung > liver > kidney = stomach > brain. This was further certificated by histopathological changes in the examined organs. Additionally, the levels of serum glutamic-oxaloacetic transaminase (GOT), glutamic-pyruvic transaminase (GPT), and blood urea nitrogen (UN), creatinine were also significantly increased at 24 h after B[a]P injection. These findings suggested the disturbance of antioxidant responses and aggravation of DNA damages, and the different responses on various organs induced by acute B[a]P treatment in organism.