Ultraclean Suspended Graphene by Radiolysis of Adsorbed Water.

Access to intrinsic properties of a 2D material is challenging due to the absence of a bulk that would dominate over surface contamination, and this lack of bulk also precludes effective conventional cleaning methods that are almost always sacrificial. Suspended graphene and carbon contaminants represent the most salient challenge. This work has achieved ultraclean graphene, attested by electron energy loss (EEL) spectra unprecedentedly exhibiting fine-structure features expected from bonding and band structure. In the cleaning process in a transmission electron microscope, radicals generated by radiolysis of intentionally adsorbed water remove organic contaminants, which would otherwise be feedstock of the notorious electron irradiation induced carbon deposition. This method can be readily adapted to other experimental settings and other materials to enable previously inhibited undertakings that rely on the intrinsic properties or ultimate thinness of 2D materials. Importantly, the method is surprisingly simple and robust, easily implementable with common lab equipment.

Evaluating Modified Ultrasound-Guided Serratus Anterior Plane Block for Enhanced Postoperative Recovery in Thoracoscopic Lobectomy Patients.

BACKGROUND Thoracoscopic lobectomy is accompanied by intense trauma and pain due to impaired chest wall integrity. We aimed to introduce a modified ultrasound-guided serratus anterior plane block (MUG-SAPB) for postoperative analgesia in patients who underwent thoracoscopic lobectomy, and to determine whether it could effectively alleviate postoperative pain and improve recovery quality. MATERIAL AND METHODS Overall, 78 patients randomly received either combined MUG-SAPB (0.25% ropivacaine, 10 mg dexamethasone, 40 mL) with patient-controlled intravenous analgesia (PCIA) or received PCIA alone. The primary outcomes were visual analog scale (VAS) scores at rest and during movement at 4, 8, 12, 20, 24, 48, and 72 h postoperatively. The secondary outcomes included use of opioids during surgery, numbers of rescue analgesics (butorphanol), frequency of patient-controlled analgesia (PCA), comfort score within 24 h postoperatively, and postoperative complications within 72 h. RESULTS Compared to the PCIA group, in the MUG-SAPB group, resting VAS scores at 4-24 h (P<0.05) and movement VAS scores at 4-12 h postoperatively (P<0.05) were lower; intraoperative use of sufentanil and frequency of PCA were less, and less rescue analgesia was used (P=0.02, P=0.04 and P=0.03, respectively). Patients in the MUG-SAPB group had faster first mobilization (P=0.04). The MUG-SAPB group had higher comfort scores than the PCIA group (P=0.03). None of the MUG-SAPB patients had any SAPB-related complications. CONCLUSIONS MUG-SAPB effectively relieved postoperative pain, reduced opioid consumption, and accelerated early ambulation in comparison with PCIA alone in patients who underwent thoracoscopic lobectomy.

Correlation between body composition and serum lipid and uric acid in Maonan Guangxi population / 解剖学报

Objective To investigate the relationship between body composition and serum lipids and uric acid among adults in Maonan, and to analyze the effect of body composition changes on blood lipid and uric acid. Methods Totally 584 Maonan adult volunteers in Maonan village of Maonan Autonomous County in Guangxi, the age from 20 to 80 were recruited. The height was measured by the personal height tester; the body composition was measured by the ANITAMC-180 instrument; and the blood lipids and blood uric acid were measured by the Hitachi 7600 instrument. The obtained data were statistically analyzed by SPSS 20. 0. Results The age,height, weight, free fat mass, muscle mass, presumptive bone mass, body water, proptein,extracellular water, intracellular water, and waist-to-hip ratio were greater in Maonan men than in women (P<0. 05). However, whereas male fat content, body fat rate, and subcutaneous fat content were smaller than those of female (P < 0. 01). The total prevalence of hyperuricemia and hyperlipidemia in Maonan nationality was 13. 9% and 28. 4%, respectively. The prevalence of hyperuricemia and hyperlipidemia in males was higher than in females. In males, the body mass, body mass index, free fat mass, fat mass, muscle mass, presumptive bone mass, protein, extracellular water, body fat rate, visceral fat content, subcutaneous fat content and waist-hip ratio of the hyperlipidemia group were higher than the normal group (P<0. 05); and in females, the age, body mass index, fat mass, body fat rate, visceral fat content and waist-hip ratio of the hyperlipidemia group were higher than the normal group. In male, The body mass, free fat mass, presumptive bone mass, body water, extracellular water of the hyperuricemia group were higher than the normal group (P<0. 05); In females, the age, body mass, body mass index, fat mass, extracellular water, body fat ratio, muscle mass, visceral fat content, subcutaneous fat content, and waist-hip ratio of the hyperuricemia group were higher than the normal group. Conclusion The detection rate of hyperlipidemia and hyperuricemia in males of Guangxi Maonan nationality is all higher than that in females. The body composition is significant differences between the normal adults and the patients with hyperlipidemia and hyperuricemia of Maonan nationality in Guangxi.

Effect of repeated intranasal insulin on postoperative delirium in elderly patients undergoing general anesthesia / 中华麻醉学杂志

Objective:To evaluate the effect of repeated intranasal insulin on postoperative delirium (POD) in elderly patients undergoing general anesthesia.Methods:Seventy elderly patients, aged ≥65 yr, with body mass index ≤28 kg/m 2, of American Society of Anesthesiologists physical statusⅠ-Ⅲ, undergoing elective radical gastrectomy for gastric cancer under general anesthesia, were divided into 2 groups ( n=35 each) according to the random number table method: control group (group C) and insulin group (group I). In group C, normal saline 0.5 ml was administered intranasally twice a day from 2 days before surgery until the day of surgery.In group I, insulin 20 U (0.5 ml) was administered intranasally twice a day from 2 days before surgery until the day of surgery.The regional tissue oxygen saturation (rSO 2) was measured after entering the operating room (T 0), at intubation (T 1), at 1, 2 and 3 h after the start of operation (T 2-4), at the end of surgery (T 5) and at extubation (T 6). The insulin allergic reactions, nasal irritation and hypoglycemic reactions were recorded after intranasal administration of insulin or normal saline within 2 days before operation.The blood glucose concentrations were measured at T 0, T 3 and T 5.The occurrence of POD within 3 days after operation was recorded. Results:Compared with group C, the incidence of POD was significantly decreased within 3 days after operation, and the rSO 2 was increased at T 1-6 in group I ( P<0.05). The rSO 2 was significantly higher at T 1-6 than at T 0 in two groups ( P<0.05). There were no significant changes in blood glucose concentrations at T 0, T 3 and T 5 between the two groups ( P>0.05). No insulin allergic reactions, nasal irritation and hypoglycemic reactions occurred in two groups ( P>0.05). Conclusion:Repeated intranasal administration of insulin can increase the rSO 2 during operation and decrease the occurrence of POD in elderly patients undergoing radical gastrectomy for gastric cancer.

Synthesis of Honeycomb-Structured Beryllium Oxide via Graphene Liquid Cells.

Using high-resolution transmission electron microscopy and electron energy-loss spectroscopy, we show that beryllium oxide crystallizes in the planar hexagonal structure in a graphene liquid cell by a wet-chemistry approach. These liquid cells can feature van-der-Waals pressures up to 1 GPa, producing a miniaturized high-pressure container for the crystallization in solution. The thickness of as-received crystals is beyond the thermodynamic ultra-thin limit above which the wurtzite phase is energetically more favorable according to the theoretical prediction. The crystallization of the planar phase is ascribed to the near-free-standing condition afforded by the graphene surface. Our calculations show that the energy barrier of the phase transition is responsible for the observed thickness beyond the previously predicted limit. These findings open a new door for exploring aqueous-solution approaches of more metal-oxide semiconductors with exotic phase structures and properties in graphene-encapsulated confined cells.

Engineering Edge States of Graphene Nanoribbons for Narrow-Band Photoluminescence.

Solid-state narrow-band light emitters are on-demand for quantum optoelectronics. Current approaches based on defect engineering in low-dimensional materials usually introduce a broad range of emission centers. Here, we report narrow-band light emission from covalent heterostructures fused to the edges of graphene nanoribbons (GNRs) by controllable on-surface reactions from molecular precursors. Two types of heterojunction (HJ) states are realized by sequentially synthesizing GNRs and graphene nanodots (GNDs) and then coupling them together. HJs between armchair GNDs and armchair edges of the GNR are coherent and give rise to narrow-band photoluminescence. In contrast, HJs between the armchair GNDs and the zigzag ends of GNRs are defective and give rise to nonradiative states near the Fermi level. At low temperatures, sharp photoluminescence emissions with peak energy range from 2.03 to 2.08 eV and line widths of 2-5 meV are observed. The radiative HJ states are uniform, and the optical transition energy is controlled by the band gaps of GNRs and GNDs. As these HJs can be synthesized in a large quantity with atomic precision, this finding highlights a route to programmable and deterministic creation of quantum light emitters.

Peculiar bond characters of fivefold coordinated octet compound crystals.

The present work exemplifies complementary perspectives offered by the band and bond pictures of solids, with an emphasis on the chemical intuition pertaining to the latter, especially in the presence of interfaces. The modern computational method of constructing a unique set of maximally localized Wannier functions from delocalized band states imparts new interpretations to the familiar concept of chemical bonds in the context of crystalline solids. By bridging the band and bond pictures using advanced computational tools, we reveal for the first time the unusual bond characters of a long-predicted fivefold coordinated structure of binary octet compounds A N B8-N consisting of AA' stacked planar AB honeycombs. While the isolated monolayer retains the familiar p z -π bonding in a honeycomb framework as in graphene and hexagonal boron nitride, the bulk foregoes in-plane π bonding and embraces out-of-plane ⋯A-B-A-B⋯ chain bonding via overlapping p z orbitals. Not only does the chemical intuition gained by invoking the bond picture clarify the chemical nature of the fivefold coordination, but it also facilely explains a salient discrepancy in theoretical predictions in otherwise sound ample experimental evidence in the form of epitaxial thin films, paving the way towards rational synthesis of such thin films for optoelectronic applications. On the other hand, we show that the conduction band minimum, important in determining the electrical and optical properties, is a distinctly extended state that can only be properly described within the band picture.

Multifunctional metaoptics based on bilayer metasurfaces.

Optical metasurfaces have become versatile platforms for manipulating the phase, amplitude, and polarization of light. A platform for achieving independent control over each of these properties, however, remains elusive due to the limited engineering space available when using a single-layer metasurface. For instance, multiwavelength metasurfaces suffer from performance limitations due to space filling constraints, while control over phase and amplitude can be achieved, but only for a single polarization. Here, we explore bilayer dielectric metasurfaces to expand the design space for metaoptics. The ability to independently control the geometry and function of each layer enables the development of multifunctional metaoptics in which two or more optical properties are independently designed. As a proof of concept, we demonstrate multiwavelength holograms, multiwavelength waveplates, and polarization-insensitive 3D holograms based on phase and amplitude masks. The proposed architecture opens a new avenue for designing complex flat optics with a wide variety of functionalities.

Direct imaging of the nitrogen-rich edge in monolayer hexagonal boron nitride and its band structure tuning.

Identification of edge atoms and tracking the edge structure evolution of two-dimensional (2D) crystals at the scale of individual atoms is critical for understanding the edge-dominated properties and behavioral responses to external field stimuli. Here, direct imaging of the edge configuration of monolayer hexagonal boron nitride (h-BN) is demonstrated at the atomic scale, by using aberration-corrected transmission electron microscopy. Tracking of the edge atoms revealed that a nitrogen-terminated zigzag arrangement dominates along the edge, naturally leading to nitrogen rich (N-rich) characteristics in this area, while the stoichiometric interior of the h-BN monolayer is maintained. Both top-down fabrication and bottom-up growth were proposed to obtain novel h-BN flakes with an N-rich ratio larger than 1% when the size is reduced to the threshold of 25 nm. Furthermore, density functional theory calculations revealed that a new bandgap of ∼3 eV is created by the N-rich characteristics, and h-BN transforms into an n-type semiconductor by self-doping. The results call for the development of ultra-small h-BN islands to be used in intriguing 2D electronic devices with a photoresponse function to visible light.

Multilayer Noninteracting Dielectric Metasurfaces for Multiwavelength Metaoptics.

Metasurfaces provide a versatile platform for manipulating the wavefront of light using planar nanostructured surfaces. Transmissive metasurfaces, with full 2π phase control, are a particularly attractive platform for replacing conventional optical elements due to their small footprint and broad functionality. However, the operational bandwidth of metasurfaces has been a critical limitation and is directly connected to either their resonant response or the diffractive dispersion of their lattice. While multiwavelength and continuous band operation have been demonstrated, the elements suffer from either low efficiency, reduced imaging quality, or limited element size. Here, we propose a platform that provides for multiwavelength operation by employing tightly spaced multilayer dielectric metasurfaces. As a proof of concept, we demonstrate a multiwavelength metalens doublet (NA = 0.42) with focusing efficiencies of 38% and 52% at wavelengths of 1180 and 1680 nm, respectively. We further show how this approach can be extended to three-wavelength metalenses as well as a spectral splitter. This approach could find applications in fluorescent microscopy, digital imaging, and color routing.

Green's function for a sharpened and metal-coated dielectric probe.

In apertureless scanning-probe optical microscopy and in the case of more traditional scanned optical probes coated with a metal that is thin near the probe tip (in lieu of an aperture), samples are probed via interaction between the probe and surface. In the nanometer-scale region between the tip and the sample, the field can be approximated by quasi-electrostatic analytics. Hence, the coated probe can be modeled as in the present case as a hyperboloid of revolution without the need for hyperboloidal wave functions in the near zone. The solutions to Laplace's equation and in general Green's function with the application of the boundary conditions, therefore, yield an appropriate approximation and allow a completely analytical solution for the resonance effects upon the probe tip to be obtained. The large field enhancements due to the sharpness of the tip and to surface plasmon fields may thus be analytically examined.

Role of hippocampal PI3K∕Akt signaling pathway in exogenous orexin A-induced improvement of isoflurane anesthesia-caused decline in memory function of mice / 中华麻醉学杂志

Objective To evaluate the role of hippocampal phosphatidylinositol 3-kinase∕serine-threonine kinase (PI3K∕Akt) signaling pathway in exogenous orexin A-induced improvement of isoflurane anesthesia-caused decline in memory function of mice. Methods A total of 100 pathogen-free healthy adult male C57BL∕6 mice, aged 8-12 weeks, weighing 20-25 g, in which the lateral ventricle was catheter-ized, were divided into 5 groups (n = 20 each) using a random number table: control group (group C), isoflurane group (group I), orexin A group (group OA), orexin A plus dimethyl sulfoxide group (group OA+D) and orexin A plus PI3K inhibitor LY294002 group (group OA+LY). Normal saline was administra-ted in group C and group I. Orexin A 1. 5 mmol∕L was given in group OA. Orexin A 1. 5 mmol∕L (dissolved in dimethyl sulfoxide) was given in group OA+D. Orexin A 1. 5 mmol∕L and LY29400210 mmol∕L were given in group OA+LY. Group C only inhaled pure oxygen for 2 h (oxygen flow rate 2 L∕min), all the rest groups inhaled 1. 4％ isoflurane for 2 h, and the corresponding drug 2 μl was injected into the lateral cere-bral ventricle according to the concentration mentioned above at 15 min before the end of anesthesia. Twelve mice were randomly selected from each group and trained for contextual fear conditioning test, and then fear memory retrieval was conducted at 24 h after training. The rest 8 mice in each group were sacrificed at 2 h after the end of anesthesia and their brains were removed for determination of the expression of PI3K, Akt and phosphor-Akt (p-Akt) protein by Western blot. Results Compared with group C, the freezing time was significantly shortened, the expression of PI3K, Akt and p-Akt was down-regulated, and p-Akt∕Akt ratio was decreased in group I (P<0. 05). Compared with group I, the freezing time was significantly pro-longed, the expression of PI3K, Akt and p-Akt was up-regulated, and p-Akt∕Akt ratio was increased in group OA (P<0. 05). There was no significant difference in each parameter mentioned above between group OA and group OA+D (P>0. 05). Compared with group OA+D, the freezing time was significantly short-ened, the expression of PI3K, Akt and p-Akt was down-regulated, and p-Akt∕Akt ratio was decreased in group OA+LY (P<0. 05). Conclusion Hippocampal PI3K∕Akt signaling pathway is involved in exoge-nous orexin A-induced improvement of isoflurane anesthesia-caused decline in memory function of mice.

Effects of Alcohol Dependence or Withdrawal on Median Effective Dose of Propofol in Rats / 中国药房

OBJECTIVE:To determine the median effective dose (ED50) of propofol with single intravenous injection in alcohol dependence or withdrawal model rats,and to observe the anaesthetic effect of 2-fold ED50 propofol. METHODS:Fifty SD rats were divided into drinking group(n＝23)and control group(n＝27)based on whether the consumption of alcohol was greater than 3.0 g/(kg·d). Drinking group continued to drink freely and intermittently to establish alcohol dependence model. Control group was only given drinking water for ethanol elution 16 rats were randomly selected from each group to determine ED50 of propofol with single intravenous injection by sequential method,and initial dose was 6.02 mg/kg. After eluting for a week,alcohol dependence rats stopped drinking for 24 hours and had alcohol withdrawal symptoms to establish alcohol withdrawal model. ED50 of propofol in alcohol withdrawal group and control group were determined with same method. After eluting for a week,anaesthetic effect [disappearance time and reappearance time of forepaw righting reflex(FRR),time of activity complete recovery] of 2-fold ED50 propofol with single intravenous injection were observed in alcohol dependence group,alcohol withdrawal group and control group,and corresponding time point and the frequency of respiration before administration were also observed. Changes of liver function indexes(serum albumin,alanine transaminase,total bilirubin,γ glutamyl transaminopeptidase)and liver histomorphology were observed 48 h after medication,10 in each group. RESULTS:ED50 of propofol in alcohol dependence model rats was 9.563 mg/kg,which was higher than 5.623 mg/kg of control group. ED50 of propofol in alcohol withdrawal model rats was 4.086 mg/kg,which was lower than 5.297 mg/kg of control group. Compared with control group,reappearance time of FRR was prolonged significantly in alcohol dependence group and alcohol withdrawal group (P＜0.05). There was no statistical significance in disappearance time of FRR or activity complete recovery time (P＞0.05). The frequency of respiration during FRR disappearance was lower than before propofol injection,FRR reappearance and activity complete recovery (P＜0.01). After intravenous injection of 2-fold ED50 propofol,reappearance time of FRR in alcohol dependence group and alcohol withdrawal group were longer than control group(P＜0.05)；the alcohol dependence group was longer than the alcohol withdrawal group(P＜0.05).The time of activity complete recovery in alcohol dependence group was longer than control group and alcohol withdrawal group (P＜0.05). The frequency of respiration in 3 groups during FRR disappearance were all lower than before propofol injection,FRR reappearance and activity complete recovery(P＜0.01). There was no significant difference in the change of liver function indexes or liver histomorphology. CONCLUSIONS:ED50 of propofol is increased in alcohol dependence rats,while ED50 of propofol is decreased in alcohol withdrawal rats. 2-fold ED50 of propofol has no significant toxicity to liver function.

Influences of sufentanil and midazolam coprocessing on myocardial injury in rats during myocardial is-chemia-reperfusion / 临床麻醉学杂志

Objective To explore the influences of sufentanil and different dose midazolam coprocessing on myocardial injury in rats during myocardial ischemia-reperfusion (IR ). Methods Forty two healthy male SD rats were selected and randomly divided into 7 groups including,group A:rats were treated with sham operation;groups B0-B5:rat IR model was con-structed;group B0:rats were untreated with sufentanil or midazolam;group B1:rats were per-trea-ted with 3 μg/kg sufentanil;group B2:rats were post-treated with 0.1 mg/kg midazolam;group B3:rats were post-treated with 0.3 mg/kg midazolam;group B4:rats were per-treated with 1.5 μg/kg sufentanil and post-treated with 0.05 mg/kg midazolam;group B5:rats were per-treated with 1.5μg/kg sufentanil and post-treated with 0.15 mg/kg midazolam.Sufentanil was injected through cervi-cal vein before ischemia.Midazolam was injected through cervical vein after ischemia.After reperfu-sion,arterial blood was collected for detecting the activity of CK-MB,LDH or SOD,and the concen-tration of MDA,TNF-α,or IL-6.Rat hearts were picked off to measure the severity of myocardial in-farction (IS/AAR).The expressions of Bax,cleaved-caspase-3 and Bcl-2 in myocardial tissues were detected by Western blots.Results CK-MB activity,LDH activity,MDA concentration,TNF-αlev-el,IL-6 level,Bax and cleaved-caspase 3 expression levels in groups B0-B5 were obviously higher than those in group A (P <0.05),in groups B1-B5 were obviously lower than those in group B0 (P<0.05),in groups B3 and B4 were obviously lower than those in group B2 (P <0.05),in group B5 were obviously lower than those in groups B1-B4 (P < 0.05 );values of IS and IS/AAR (%)in groups B1-B5 were obviously lower than those in group B0 (P <0.05),in groups B3 and B4 were ob-viously lower than those in group B2 (P < 0.05 ),in group B5 were obviously lower than those in groups B1-B4 (P <0.05 );SOD activity and Bcl-2 expression level in groups B0-B5 were obviously lower than those in group A (P <0.05),in groups B1-B5 were obviously higher than those in group B0 (P <0.05),in groups B3 and B4 were obviously higher than those in group B2 (P <0.05 ),in group B5 were obviously higher than those in groups B1-B4 (P <0.05).CK-MB declined when com-pared with group B0;LDH declined;SOD rose;MDA declined;TNF-αdeclined;IL-6 declined;IS/AAR declined;Bcl-2 expression rose to 2.25 fold;Bax expression dropped to 54.89%;cleaved-caspase-3 expression dropped to 49.67%.Conclusion Sufentanil pretreatment combined with mid-azolam aftertreatment can significantly alleviate rat myocardial IR injury,which plays more effective cardioprotective effects than being used alone.

Unraveling the Fundamental Mechanisms of Solvent-Additive-Induced Optimization of Power Conversion Efficiencies in Organic Photovoltaic Devices.

The realization of controllable morphologies of bulk heterojunctions (BHJ) in organic photovoltaics (OPVs) is one of the key factors enabling high-efficiency devices. We provide new insights into the fundamental mechanisms essential for the optimization of power conversion efficiencies (PCEs) with additive processing to PBDTTT-CF:PC71BM system. We have studied the underlying mechanisms by monitoring the 3D nanostructural modifications in BHJs and correlated the modifications with the optical analysis and theoretical modeling of charge transport. Our results demonstrate profound effects of diiodooctane (DIO) on morphology and charge transport in the active layers. For small amounts of DIO (<3 vol %), DIO promotes the formation of a well-mixed donor-acceptor compact film and augments charge transfer and PCE. In contrast, for large amounts of DIO (>3 vol %), DIO facilitates a loosely packed mixed morphology with large clusters of PC71BM, leading to deterioration in PCE. Theoretical modeling of charge transport reveals that DIO increases the mobility of electrons and holes (the charge carriers) by affecting the energetic disorder and electric field dependence of the mobility. Our findings show the implications of phase separation and carrier transport pathways to achieve optimal device performances.

Tunneling spectra of graphene on copper unraveled.

Scanning tunneling spectroscopy is often employed to study two-dimensional (2D) materials on conductive growth substrates, in order to gain information on the electronic structures of the 2D material-substrate systems, which can lead to insight into 2D material-substrate interactions, growth mechanisms, etc. The interpretation of the spectra can be complicated, however. Specifically for graphene grown on copper, there have been conflicting reports of tunneling spectra. A clear understanding of the mechanisms behind the variability is desired. In this work, we have revealed that the root cause of the variability in tunneling spectra is the variation in graphene-substrate coupling under various experimental conditions, providing a salutary perspective on the important role of 2D material-substrate interactions. The conclusions are drawn from measured data and theoretical calculations for monolayer, AB-stacked bilayer, and twisted bilayer graphene coexisting on the same substrates in areas with and without intercalated oxygen, demonstrating a high degree of consistency. The Van Hove singularities of the twisted graphene unambiguously indicate the Dirac energy between them, lending strong evidence to our assignment of the spectral features. In addition, we have discovered an O-Cu superstructure that has never been observed before.

Peculiarity of Two Thermodynamically-Stable Morphologies and Their Impact on the Efficiency of Small Molecule Bulk Heterojunction Solar Cells.

Structural characteristics of the active layers in organic photovoltaic (OPV) devices play a critical role in charge generation, separation and transport. Here we report on morphology and structural control of p-DTS(FBTTh2)2:PC71BM films by means of thermal annealing and 1,8-diiodooctane (DIO) solvent additive processing, and correlate it to the device performance. By combining surface imaging with nanoscale depth-sensitive neutron reflectometry (NR) and X-ray diffraction, three-dimensional morphologies of the films are reconstituted with information extending length scales from nanometers to microns. DIO promotes the formation of a well-mixed donor-acceptor vertical phase morphology with a large population of small p-DTS(FBTTh2)2 nanocrystals arranged in an elongated domain network of the film, thereby enhancing the device performance. In contrast, films without DIO exhibit three-sublayer vertical phase morphology with phase separation in agglomerated domains. Our findings are supported by thermodynamic description based on the Flory-Huggins theory with quantitative evaluation of pairwise interaction parameters that explain the morphological changes resulting from thermal and solvent treatments. Our study reveals that vertical phase morphology of small-molecule based OPVs is significantly different from polymer-based systems. The significant enhancement of morphology and information obtained from theoretical modeling may aid in developing an optimized morphology to enhance device performance for OPVs.

Correlating high power conversion efficiency of PTB7:PC71BM inverted organic solar cells with nanoscale structures.

Advances in material design and device engineering led to inverted organic solar cells (i-OSCs) with superior power conversion efficiencies (PCEs) compared to their "conventional" counterparts, in addition to the well-known better ambient stability. Here, we report an in-depth morphology study of the i-OSC active and cathode modifying layers, employing a model system with a well-established bulk-heterojunction, PTB7:PC71BM as the active layer and poly-[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) as the cathode surface modifying layer. We have also identified the role of a processing additive, 1,8-diiodooctane (DIO), used in the spin-casting of the active layer to increase PCE. Using various characterization techniques, we demonstrate that the high PCEs of i-OSCs are due to the diffusion of electron-accepting PC71BM into the PFN layer, resulting in improved electron transport. The diffusion occurs when residual solvent molecules in the spun-cast film act as a plasticizer. Addition of DIO to the casting solution results in more PC71BM diffusion and therefore more efficient electron transport. This work provides important insight and guidance to further enhancement of i-OSC performance by materials and interface engineering.

Long-term clinical efficacy of mild hypothermia therapy in neonates with hypoxic-ischemic encephalopathy: a Meta analysis / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To systematically evaluate the long-term clinical efficacy and safety of mild hypothermia therapy in neonates with hypoxic-ischemic encephalopathy (HIE).</p><p><b>METHODS</b>All randomized controlled trials (RCTs) of mild hypothermia therapy for neonatal HIE from inception to March 2014 were retrieved from databases including Cochrane Library, PubMed, Embase, CBMdisc, and Wanfang Data. Meta analysis was performed using RevMan 5.1 Software.</p><p><b>RESULTS</b>Eight RCTs met the search criteria. The results of Meta analysis showed that, compared with the control group, systemic hypothermia significantly reduced the mortality rate and the incidence of growth delay (RR=0.73, 95% CI: 0.61-0.89; RR=0.70, 95%CI: 0.54-0.93); selective head or systemic hypothermia therapy significantly reduced the incidence of cerebral palsy (RR=0.65, 95%CI: 0.46-0.94; RR=0.67, 95%CI: 0.52-0.86) up to 12-24 months of age. One study reported that hypothermia reduced the mortality rate and the rate of a composite end point of death or severe disability compared with the control group at 6 to 7 years of age. The incidence of adverse events including sinus bradyarrhythmia, thrombocytopenia and hypoglycemia was significantly higher in the hypothermia group than in the control group, whereas the incidence of cardiac arrhythmia, hypotension, thrombosis or bleeding, hypokalemia, sepsis, and liver dysfunction showed no significant differences between the two groups.</p><p><b>CONCLUSIONS</b>Mild hypothermia therapy demonstrates a significant efficacy in children with HIE up to 12-24 months of age, but there is still a need for further research on childhood outcomes after mild hypothermia for neonatal HIE. This therapy has few adverse effects and a high clinical tolerability.</p>

Spatially resolved one-dimensional boundary states in graphene-hexagonal boron nitride planar heterostructures.

Two-dimensional interfaces between crystalline materials have been shown to generate unusual interfacial electronic states in complex oxides. Recently, a one-dimensional interface has been realized in hexagonal boron nitride and graphene planar heterostructures, where a polar-on-nonpolar one-dimensional boundary is expected to possess peculiar electronic states associated with edge states of graphene and the polarity of boron nitride. Here we present a combined scanning tunnelling microscopy and first-principles theory study of the graphene-boron nitride boundary to provide a first glimpse into the spatial and energetic distributions of the one-dimensional boundary states down to atomic resolution. The revealed boundary states are about 0.6 eV below or above the Fermi level depending on the termination of the boron nitride at the boundary, and are extended along but localized at the boundary. These results suggest that unconventional physical effects similar to those observed at two-dimensional interfaces can also exist in lower dimensions.