Integration of Highly Luminescent Lead Halide Perovskite Nanocrystals on Transparent Lead Halide Nanowire Waveguides through Morphological Transformation and Spontaneous Growth in Water.

The integration of highly luminescent CsPbBr3 quantum dots on nanowire waveguides has enormous potential applications in nanophotonics, optical sensing, and quantum communications. On the other hand, CsPb2 Br5 nanowires have also attracted a lot of attention due to their unique water stability and controversial luminescent property. Here, the growth of CsPbBr3 nanocrystals on CsPb2 Br5 nanowires is reported first by simply immersing CsPbBr3 powder into pure water, CsPbBr3- γ Xγ (X = Cl, I) nanocrystals on CsPb2 Br5 -γ Xγ nanowires are then synthesized for tunable light sources. Systematic structure and morphology studies, including in situ monitoring, reveal that CsPbBr3 powder is first converted to CsPb2 Br5 microplatelets in water, followed by morphological transformation from CsPb2 Br5 microplatelets to nanowires, which is a kinetic dissolution-recrystallization process controlled by electrolytic dissociation and supersaturation of CsPb2 Br5 . CsPbBr3 nanocrystals are spontaneously formed on CsPb2 Br5 nanowires when nanowires are collected from the aqueous solution. Raman spectroscopy, combined photoluminescence, and SEM imaging confirm that the bright emission originates from CsPbBr3 -γ Xγ nanocrystals while CsPb2 Br5 -γ Xγ nanowires are transparent waveguides. The intimate integration of nanoscale light sources with a nanowire waveguide is demonstrated through the observation of the wave guiding of light from nanocrystals and Fabry-Perot interference modes of the nanowire cavity.

The impact of dexmedetomidine added to ropivicaine for transversus abdominis plane block on stress response in laparoscopic surgery: a randomized controlled trial.

BACKGROUND: Intravenous dexmedetomidine is known to attenuate stress response in patients undergoing laparoscopic surgery. We investigated whether the addition of the highly selective alpha-2 adrenergic agonist dexmedetomidine into ropivacaine for ultrasound-guided transversus abdominis plane block could inhibit stress response during laparoscopic surgery, and determined the optimal dose of dexmedetomidine in it. METHODS: One hundred and twenty-five patients undergoing laparoscopic gynecological surgery were included in this prospective and randomized double-blind study. Patients received general anesthesia with or without a total of 60 ml of 0.2% ropivacaine in combination with low (0.25 µg/kg), medium (0.50 µg/kg) or high dose (1.0 µg/kg) of dexmedetomidine for the four-quadrant transversus abdominis plane block (n = 25). The primary outcomes were stress marker levels during the operation. RESULTS: One hundred and twenty patients completed the study protocol. Dexmedetomidine added to ropivacaine for transversus abdominis plane block significantly reduced serum levels of cortisol, norepinephrine, epinephrine, interleukin-6, blood glucose, mean arterial pressure and heart rate in a dose-dependent manner (P < 0.05), accompanied with decreased anesthetic and opioid consumption during the operation (P < 0.05), but the high dose of dexmedetomidine induced higher incidences of bradycardia than low or medium dose of dexmedetomidine (P < 0.05). CONCLUSION: The addition of dexmedetomidine at the dose of 0.5 µg/kg into ropivacaine for ultrasound-guided transversus abdominis plane block is the optimal dose to inhibit stress response with limited impact on blood pressure and heart rate in patients undergoing laparoscopy gynecological surgery. TRIAL REGISTRATION: This study was registered at www.chictr.org.cn on November 6th, 2016 (ChiCTR-IOR-16009753).

A Single Eu-Doped In2O3 Nanobelt Device for Selective H2S Detection.

Eu-doped In2O3 nanobelts (Eu-In2O3 NBs) and pure In2O3 nanobelts (In2O3 NBs) are synthesized by the carbon thermal reduction method. Single nanobelt sensors are fabricated via an ion beam deposition system with a mesh-grid mask. The gas-sensing response properties of the Eu-In2O3 NB device and its undoped counterpart are investigated with several kinds of gases (including H2S, CO, NO2, HCHO, and C2H5OH) at different concentrations and different temperatures. It is found that the response of the Eu-In2O3 NB device to 100 ppm of H2S is the best among these gases and the sensitivity reaches 5.74, which is five times that of pure In2O3 NB at 260 °C. We also found that the former has an excellent sensitive response and great selectivity to H2S compared to the latter. Besides, there is a linear relationship between the response and H2S concentration when its concentration changes from 5 to 100 ppm and from 100 to 1000 ppm. The response/recovery time is quite short and remains stable with an increase of H2S concentration. These results mean that the doping of Eu can improve the gas-sensing performance of In2O3 NB effectually.

Synthesis and Gas Sensing Properties of Single La-Doped SnO2 Nanobelts.

Single crystal SnO2 nanobelts (SnO2 NBs) and La-SnO2 nanobelts (La-SnO2 NBs) were synthesized by thermal evaporation. Both a single SnO2 NB sensor and a single La-SnO2 NB sensor were developed and their sensing properties were investigated. It is found that the single La-SnO2 NB sensor had a high sensitivity of 8.76 to ethanediol at a concentration of 100 ppm at 230 °C, which is the highest sensitivity of a single SnO2 NB to ethanediol among three kinds of volatile organic (VOC) liquids studied, including ethanediol, ethanol, and acetone. The La-SnO2 NBs sensor also exhibits a high sensitivity, good selectivity and long-term stability with prompt response time to ethanediol. The mechanism behind the enhanced sensing performance of La-doped SnO2 nanobelts is discussed.

Intravenous pretreatment with emulsified isoflurane preconditioning protects kidneys against ischemia/reperfusion injury in rats.

BACKGROUND: Emulsified isoflurane (EIso) is a novel intravenous general anesthetic, which can provide rapid anesthetic induction and recovery. EIso preconditioning could attenuate heart, lung and liver ischemia/reperfusion (I/R) injury. We tested the hypothesis that intravenous pretreatment with EIso would protect kidneys against I/R injury by inhibiting systemic inflammatory responses and improving renal antioxidative ability. METHODS: RATS WERE RANDOMLY DIVIDED INTO THESE SIX GROUPS: sham, I/R, intralipid, 1, 2 or 4 ml/kg EIso. Rats were subjected to 45 min left renal pedicle occlusion followed by 3 h reperfusion after right nephrectomy. Rat were treated with intravenous 8% EIso with 1, 2 or 4 ml/kg, or 30% intralipid with 2 ml/kg for 30 min before ischemia, respectively. After reperfusion, renal functional parameters, serum mediator concentrations and markers of oxidative stress in kidney tissues were determined, and renal histopathological analysis were performed. RESULTS: Serum creatinine, blood urea nitrogen, cystatin c, tumor necrosis factor-α, interleukin-6, and interleukin-10 concentrations were significantly increased after renal I/R as compared to the sham group. So was renal tissue MDA content and histological scores, but renal tissue SOD activity was decreased. Additionally, severe morphological damages were observed in these study groups. In contrast, 2 or 4 ml/kg EIso reduced serum creatinine, blood urea nitrogen, cystatin c, tumor necrosis factor-α, and interleukin-6 levels, decreased renal tissue MDA content and histological scores, increased serum interleukin-10 level and tissue SOD activity as compared to the I/R, intralipid and 1 ml/kg EIso groups. Renal morphological damages were alleviated after pretreatment of 2 or 4 ml/kg EIso. CONCLUSIONS: Intravenous EIso produces preconditioning against renal I/R injury in rats, which might be mediated by attenuating inflammation and increasing antioxidation ability.

[Baseline correction of Raman spectrum based on piecewise linear fitting].

The baseline drifts of Raman spectra occur in many types of instrumental measurements. It is an important part and a routine step to correct the baseline drift for the data preprocessing. In the present work, the limitations of the baseline correction method based on polynomial fitting were highlighted and a modified polynomial fitting method, i. e. piecewise linear fitting method, was proposed. Combined with the computer, this method could eliminate the baseline automatically. A series of Raman spectra of single polystyrene bead, red blood cell or yeast cell acquired by laser tweezers Raman spectroscopy were preprocessed by this method and its efficiency was verified. The results demonstrated that piecewise linear fitting can correct the baseline shifts effectively and provides more accurate information for further data analysis. It is a feasible method for correction of Raman spectrum.

Heterometal doping on nickel selenide corrugations for solar-assisted electrocatalytic hydrogen evolution.

Since nickel exhibits good binding energy and is inexpensive, it is widely applied as a hydrogen evolution reaction (HER) electrocatalyst. Among all Ni-based materials, nickel selenide (NiSe) shows a unique electronic structure as a semiconductor with good electrocatalytic activity. Herein, we prepare Co-doped NiSe (Ni1-xCoxSe) with a structure of uniform corrugations by one-step chemical vapor deposition. For comparison, Fe-doped NiSe (Ni1-xFexSe) and NiSe are also prepared using the same method. In alkaline electrolyte, Ni1-xCoxSe shows great HER performance in terms of low overpotential (93 mV@10 mA cm-2 and 140 mV@50 mA cm-2) and long-term stability. Moreover, with the assistance of solar energy, the overpotential needed for Ni1-xCoxSe is reduced, making Ni1-xCoxSe better than most reported NiSe-based HER catalysts. On the other hand, the current density of Ni1-xCoxSe is 13 mA cm-2@93 mV and 63 mA cm-2@140 mV with illumination, which is 30% and 26% higher than that without solar illumination assistance, respectively. Therefore, we believe that inducing sunlight to electrocatalytic hydrogen evolution in water splitting could be a supplementary footprint toward the utilization of solar energy.

Resonant Degenerate Four-Wave Mixing at the Defect Energy Levels of 2D Organic-Inorganic Hybrid Perovskite Crystals.

Two-dimensional organic-inorganic lead halide perovskites are generating great interest due to their optoelectronic characteristics such as high solar energy conversion efficiency and a tunable direct band gap in the visible regime. However, the presence of defect states within the two-dimensional crystal structure can affect these properties, resulting in changes to their band gap emission as well as the emergence of nonlinear optical phenomena. Here, we have investigated the effects of the presence of defect states on the nonlinear optical phenomena of the 2D hybrid perovskite (BA)2(MA)2Pb3Br10. When two pulses, one narrowband pump pulse centered at 800 nm and one supercontinuum pulse with bandwidth from 800-1100 nm, are incident on a perovskite flake, degenerate four-wave mixing (FWM) occurs, with peaks corresponding to the energy levels of the defect states present within the crystal. The longer carrier lifetime of the defect state, in comparison to that of virtual transitions that take place in nonresonant FWM processes, allows for a larger population of electrons to be excited by the second pump photon, resulting in increased FWM signal at the defect energy levels. The quenching of the two-photon luminescence as flake thickness increases is also observed and attributed to the increased presence of defects within the flake at larger thicknesses. This technique shows the potential of detecting defect energy levels in crystals using FWM for a variety of optoelectronic applications.

Modified Translabyrinthine Approach for Massive Petrous Bone Cholesteatoma Removal and Cochlear Preservation Using Latent Spaces Anterior to the Cochlea.

OBJECTIVE: Microsurgery is the reference standard treatment of petrous bone cholesteatoma (PBC). In most cases, radical removal of an extensive PBC can only be achieved at the cost of sacrificing the cochlea. Such treatment will result in the impossibility of future cochlear implantation for hearing rehabilitation purposes. To address this issue, a modification of the traditional translabyrinthine (TL) approach with endoscopic assistance has been developed for radical removal of extensive PBC with preservation of the cochlea. METHODS: From June 2017 to December 2017, 3 patients with a massive PBC underwent surgical removal using the modified TL approach by the senior author in our department. We reviewed the patient characteristics and retrospectively studied the surgical outcomes and postoperative complications. In the present report, we have described our modified TL approach in detail. RESULTS: Complete resection of the PBC and successful cochlea preservation were achieved in all 3 patients. No recurrence had developed during the follow-up period. However, various degrees of cochlear ossification were observed in 2 patients postoperatively. CONCLUSIONS: This modified TL approach provides the possibility of fully exposing the whole petrous apex without removing the cochlea in selected cases. However, the development of long-term cochlear ossification requires further investigation to allow for successful cochlear implantation.

Direct Z-Scheme charge transfer in heterostructured MoO3/g-C3N4 photocatalysts and the generation of active radicals in photocatalytic dye degradations.

Photocatalytic degradation is an attractive strategy to purify waste water contaminated by macromolecular organics. Compared with the single-component photocatalysts, heterostructures of different semiconductors have been widely used to improve the photocatalytic performance. In this work, we fabricate a hetero-structured photocatalyst consisting of two-dimensional graphitic carbon nitride (g-C3N4) nanosheets and commercial MoO3 microparticles through a simple mixing and annealing process. The photocatalytic performance was evaluated in various dye degradation reactions, especially Rhodamine (RhB) degradation. The MoO3/g-C3N4 composite shown a significant improvement compared with individual MoO3 or g-C3N4 as well as their physical mixture. By applying electron spin resonance (ESR) spin-trap spectra, radical scavenge experiments and electrochemical analysis, we find that a direct Z-scheme charge transfer between MoO3 and g-C3N4 not only causes an accumulation of electrons in g-C3N4 and holes in MoO3, but also boosts the formation of superoxide radical and hydroxyl radical. The superoxide radical and hole dominate the photocatalytic degradation, while the hydroxyl radical plays a negligible role and its production can be suppressed by lowering the pH value.

Non-noble metal-nitride based electrocatalysts for high-performance alkaline seawater electrolysis.

Seawater is one of the most abundant natural resources on our planet. Electrolysis of seawater is not only a promising approach to produce clean hydrogen energy, but also of great significance to seawater desalination. The implementation of seawater electrolysis requires robust and efficient electrocatalysts that can sustain seawater splitting without chloride corrosion, especially for the anode. Here we report a three-dimensional core-shell metal-nitride catalyst consisting of NiFeN nanoparticles uniformly decorated on NiMoN nanorods supported on Ni foam, which serves as an eminently active and durable oxygen evolution reaction catalyst for alkaline seawater electrolysis. Combined with an efficient hydrogen evolution reaction catalyst of NiMoN nanorods, we have achieved the industrially required current densities of 500 and 1000 mA cm-2 at record low voltages of 1.608 and 1.709 V, respectively, for overall alkaline seawater splitting at 60 °C. This discovery significantly advances the development of seawater electrolysis for large-scale hydrogen production.

Extrinsic Green Photoluminescence from the Edges of 2D Cesium Lead Halides.

Since the first report of the green emission of 2D all-inorganic CsPb2 Br5 , its bandgap and photoluminescence (PL) origin have generated intense debate and remained controversial. After the discovery that PL centers occupy only specific morphological structures in CsPb2 Br5 , a two-step highly sensitive and noninvasive optical technique is employed to resolve the controversy. Same-spot Raman-PL as a static property-structure probe reveals that CsPbBr3 nanocrystals are contributing to the green emission of CsPb2 Br5 ; pressure-dependent Raman-PL with a diamond anvil cell as a dynamic probe further rules out point defects such as Br vacancies as an alternative mechanism. Optical absorption under hydrostatic pressure shows that the bandgap of CsPb2 Br5 is 0.3-0.4 eV higher than previously reported values and remains nearly constant with pressure up to 2 GPa in good agreement with full-fledged density functional theory (DFT) calculations. Using ion exchange of Br with Cl and I, it is further proved that CsPbBr3- x Xx (X = Cl or I) is responsible for the strong visible PL in CsPb2 Br5- x Xx . This experimental approach is applicable to all PL-active materials to distinguish intrinsic defects from extrinsic nanocrystals, and the findings pave the way for new design and development of highly efficient optoelectronic devices based on all-inorganic lead halides.

Promotion on Acetone Sensing of Single SnO2 Nanobelt by Eu Doping.

SnO2 nanobelts (NBs) have unique structural and functional properties which attract great attention in gas detecting. In this work, Eu doping is adopted to improve the gas sensitivity of pure SnO2, especially to enhance the response to one single gas. The Eu-doped SnO2 NBs, pure-SnO2 NBs, and their single NB devices are fabricated by simple techniques. The sensing properties of the two sensors have been experimentally investigated. It is found that the two sensors possess long-term stability with rapid response performance, and Eu doping improves the electronic performance and the gas-sensing response, particularly to acetone. In addition, the effects aroused by Eu have been theoretically calculated, which indicates that Eu doping enhances the sensing performance of SnO2. Consequently, Eu-doped SnO2 NBs show great potential applications in the detection of acetone.

Poly(3-hydroxybutyrate) anabolism in Cupriavidus necator cultivated at various carbon-to-nitrogen ratios: insights from single-cell Raman spectroscopy.

Cupriavidus necator accumulates large amounts of poly(3-hydroxybutyrate) (PHB), a biodegradable substitute for petroleum-based plastics, under certain nutrient conditions. Conventional solvent-extraction-based methods for PHB quantification only obtain average information from cell populations and, thus, mask the heterogeneity among individual cells. Laser tweezers Raman spectroscopy (LTRS) was used to monitor dynamic changes in the contents of PHB, nucleic acids, and proteins in

[Application of the displacement of the ventricular bands-epiglottis mucosal flap in the surgical management of glottis carcinoma].

OBJECTIVE: To investigate the plastic method of glottis carcinoma in surgery. METHOD: Retrospective analyzed 29 patients with T2, T3 glottis carcinoma who admitted in our department From 1996 to 2004. All of them were treated with the displacement of ventricular bands-epiglottis mucosal flap in the surgical management of glottis carcinoma. The tumour was primarily from vocal cords, and not exceeded 2 cm. RESULT: All cases were successfully renovated laryngeal cavity with the displacement of ventricular bands-epiglottis mucosal flap and followed up for 5 years after operation. Three years survival rate was 86.2%, 5 years survival rate was 78.9%, and tube drawing rate was 100%. CONCLUSION: With this method, surgery would be simplified and the patients would keep the voiced function and swallowing function.