Heat- and Pressure-driven Room-temperature Polymorphic Transition Accompanied with Switchable SHG Signal in a New Chiral Hexagonal Perovskite.

Endowing room-temperature polymorphs with both long-term stability and easy interconvertibility is a big challenge due to the complexity of intermolecular interactions. Herein, we present a chiral hexagonal perovskite (R-3-hydroxy-1-methylpiperidinium)[CdCl3 ] having two room-temperature crystalline forms featuring obviously distinct second-harmonic-generation (SHG) signals with a high switching contrast of ~18 times. The two room-temperature forms could be long-term stable yet easily interconvertible through an irreversible thermal-induced phase transition and a pressure-driven backward transition, by switching hydrogen bonds via collective reorientation of ordered homochiral cations. Based on the essential role of homochiral organic cations in inducing switchable hydrogen bond linkages, this present instance provides good evidence that relatively irregular organic cations could induce more obvious inorganic chain deformations, thus endowing polymorphs with significantly different SHG signals at room temperature.

An anomalous ferroelastic phase transition arising from an unusual cis-/anti-conformational reversal of polar organic cations.

Hybrid ferroelastics have attracted increasing attention for their potential application as mechanical switches. The sporadically documented anomalous ferroelastic phase transitions, i.e., ferroelasticity that appears at a high-temperature phase rather than a low-temperature phase, are of particular interest but are not well understood at the molecular level. By judiciously choosing a polar and flexible organic cation (Me2NH(CH2)2Br+) with cis-/anti- conformations as an A-site component, we obtained two new polar hybrid ferroelastics, A2[MBr6] (M = Te for 1 and Sn for 2). These materials undergo distinct thermal-induced ferroelastic phase transitions. The larger [TeBr6]2- anions anchor the adjacent organic cations well and essentially endow 1 with a conventional ferroelastic transition (P21 → Pm21n) arising from a common order-disorder transition of organic cations without conformational changes. Moreover, the smaller [SnBr6]2- anions can interact with the adjacent organic cations in energetically similar sets of intermolecular interactions, enabling 2 to undergo an anomalous ferroelastic phase transition (P212121 → P21) arising from an unusual cis-/anti-conformational reversal of organic cations. These two instances demonstrate the importance of the delicate balance of intermolecular interactions for inducing anomalous ferroelastic phase transitions. The findings here provide important insights for seeking new multifunctional ferroelastic materials.

Subtly tuning intermolecular hydrogen bonds in hybrid crystals to achieve ultrahigh-temperature molecular ferroelastic.

Molecular-based ferroic phase-transition materials have attracted increasing attention in the past decades due to their promising potential as sensors, switches, and memory. One of the long-term challenges in the development of molecular-based ferroic materials is determining how to promote the ferroic phase-transition temperature (T c). Herein, we present two new hexagonal molecular perovskites, (nortropinonium)[CdCl3] (1) and (nortropinium)[CdCl3] (2), to demonstrate a simple design principle for obtaining ultrahigh-T c ferroelastic phase transitions. They consist of same host inorganic chains but subtly different guest organic cations featuring a rigid carbonyl and a flexible hydroxyl group in 1 and 2, respectively. With stronger hydrogen bonds involving the carbonyl but a relatively lower decomposition temperature (T d, 480 K), 1 does not exhibit a crystalline phase transition before its decomposition. The hydroxyl group subtly changes the balance of intermolecular interactions in 2via reducing the attractive hydrogen bonds but increasing the repulsive interactions between adjacent organic cations, which finally endows 2 with an enhanced thermal stability (T d = 570 K) and three structural phase transitions, including two ferroelastic phase transitions at ultrahigh T c values of 463 K and 495 K, respectively. This finding provides important clues to judiciously tuning the intermolecular interactions in hybrid crystals for developing high-T c ferroic materials.

Impact of the number of examined lymph nodes on outcomes in patients with lymph node-negative gallbladder carcinoma.

AIM: To determine whether the number of examined lymph nodes (LNs) is correlated with the overall survival of gallbladder carcinoma (GBC) patients. METHODS: Patients were collected from the Surveillance Epidemiology and End Results database (2004-2013) and categorized by the number of LNs into six groups: 1 LN, 2 LNs, 3 LNs, 4 LNs, 5 LNs, and ≥ 6 LNs. Survival curves for overall survival were plotted with a Kaplan-Meier analysis. The log-rank test was used for univariate comparisons. RESULTS: In a cohort of 893 patients, the median number of examined LNs was two for the entire cohort. The survival for the 1 LN group was significantly poorer than those of the stage I and II disease groups and for the entire cohort. By dichotomizing the number of LNs from 1 to 6, we found that the minimum number of LNs that should be examined was four for stage I, four or five for stage II, and six for stage IIIA disease. Therefore, for the entire cohort, the number of examined LNs should be at least six, which is exactly consistent with the American Joint Committee on Cancer criteria. CONCLUSION: The examination of higher numbers of LNs is associated with improved survival after resection surgery for N0 GBC. The guidelines for GBC surgery, which recommend that six LNs be examined at least, are statistically valid and should be applied in clinical practice widely.

Stage III should be subclassified into Stage IIIA and IIIB in the American Joint Committee on Cancer (8th Edition) staging system for pancreatic cancer.

AIM: To ascertain the prognostic role of the T4 and N2 category in stage III pancreatic cancer according to the 8th edition of the American Joint Committee on Cancer (AJCC) classification. METHODS: Patients were collected from the Surveillance Epidemiology and End Results (SEER) database (2004-2013) and were divided into three groups: T(1-3)N2, T4N(0-1), and T4N2. Overall survival (OS) and disease-specific survival (DSS) of patients were evaluated by the Kaplan-Meier method. RESULTS: For the first time, we found a significant difference in OS and DSS between T(1-3)N2/T4N(0-1) and T4N2 but not between T(1-3)N2 and T4N(0-1). A higher grading correlated with a worse prognosis in the T(1-3)N2 and T4N2 groups. CONCLUSION: Patients with stage T4N2 had a worse prognosis than those with stage T(1-3)N2/T4N(0-1) in the 8th edition AJCC staging system for pancreatic cancer. We recommend that stage III should be subclassified into stage IIIA [T(1-3)N2/T4N(0-1)] and stage IIIB (T4N2).

[Biodiversity of subalpine meadow in Heyeping of Luya Mountain, China.] / èŠ¦èŠ½å±±è·å¶åªäºšé«˜å±±è‰ç”¸ç”Ÿç‰©å¤šæ ·æ€§.

In this study, investigation on plant community was conducted in Heyeping subalpine meadow of Luya Mountain in Shanxi Province of China. The importance values of 36 herbaceous species, α diversity index, phylogenetic diversity index, as well as their correlations were investigated. The results showed that the species diversity of the subalpine meadow was uniformly distributed. Species richness was higher in marginal areas, indicating an 'edge effect'. The phylogenetic structure of four plots was convergent and that of 12 plots was dispersive. The phylogenetic diversity index (PD) was positively correlated with the Petrick index, Simpson index and Shannon index, while there was no significant correlation of either the net relatedness index (NRI) or the nearest taxon index (NTI) to the α diversity indices.

[Temporal and spatial distribution of PM2.5 and PM10 pollution status and the correlation of particulate matters and meteorological factors during winter and spring in Beijing].

Fogs and hazes broke out many times in winter and spring of 2012-2013 in Beijing, inducing severe pollution of respirable particulate matters (PM10). As a fine particle component in PM10, PM2.5 would cause more severe air pollution if the proportion of PM2.5 to PM10 is high. Based on this, 30 monitoring stations recording the concentration of PM2.5 and PM1.0 all over Beijing were selected, and the contamination characteristics of particulate matters were analyzed, which further served to determine the characteristics of temporal and spatial pollution variations of PM2.5 and PM10. The distribution of PM2.5 and PM10 mass concentration in winter and spring in Beijing were derived by the Original Kriging interpolation method, and it was depicted from the figure that the concentration of particulate matters gradually increased from the northern mountain area to the southern part of Beijing; in the central urban area, the particulate concentration of the western region was generally higher than that of the eastern region, with certain differences between urban and rural area within some local areas. Monthly variation curve of PM2.5 and PM10 mass concentration showed single peak-valley pattern: the maximum was in January and the minimum was in April; daily variation indicated a good correlation between PM2.5 and PM10, both of which were significantly influenced by meteorological conditions; diurnal variation curve showed a double peak-valley type. Meteorological factors such as daily average temperature (degrees C), relative humidity (%), wind speed (wind scale), precipitation (mm) were chosen and their individual relationships with concentrations of PM10 and PM2.5 were investigated using Spearman rank correlation analyses. It was demonstrated that the concentrations of PM10 and PM2.5 were positively correlated with temperature and relative humidity, respectively, and strongly negatively correlated with wind speed; wind speed and relative humidity were two key factors affecting the distributions of PM2.5 and PM10 concentration.

[Influence of salbutamol inhalation during volume target pressure control ventilation on ventilation parameters in patients with respiratory failure].

OBJECTIVE: To compare the effects of volume target pressure control ventilation (VTPC) and volume control ventilation (VCV) on respiratory mechanics in patients with respiratory failure, and to investigate the effects of ventilated parameters after salbutamol inhalation. METHODS: Ten patients with mean age (68+/-5) years were intubated and mechanically ventilated for acute respiratory failure of diverse causes. After 30 minutes with VCV [tidal volume (VT) 8-10 ml/kg], measurements of respiratory mechanics were begun, and then the patients were ventilated with VTPC for 30 minutes. VCV and VTPC were repeated after salbutamol 600 microg inhalation. RESULTS: The static compliance (Cst) was (38.4+/-2.7) ml/cm H2O (1 cm H2O=0.098 kPa) and airway resistance (Raw) was (20.1+/-2.0) cm H2O x L(-1) x s(-1) in 10 patients. With the same tidal volume, peak inspiratory pressure (PIP) and mean inspiratory flow [VT/inflation time (Tinflate)]during VTPC were lower, but peak inspiratory flow (PIF) was significantly higher than that during VCV (all P<0.05). The same plateau pressure (Pplat) was observed during VCV as during VTPC, they were (22.1+/-0.9) cm H2O vs. (23.0+/-1.2) cm H2O. After salbutamol inhalation, PIP and Raw were significantly decreased in all patients (both P<0.05), but no changes were found in Cst and Pplat. PIF and peak expiratory flow (PEF) were increased much more during two modes than before inhalation (both P<0.05), but Tinflate was decreased (P<0.05). CONCLUSION: VTPC is a new mechanical ventilation mode in which closed-loop control theory is used. The airway pressure during VTPC is associated with Cst and not influenced by Raw.

Dietary supplementation of fermented soybean, natto, suppresses intimal thickening and modulates the lysis of mural thrombi after endothelial injury in rat femoral artery.

We have previously demonstrated that natto-extracts containing nattokinase (NK) inactivates plasminogen activator inhibitor type 1 and then potentiates fibrinolytic activity. In the present study, we investigated the effects of dietary supplementation with natto-extracts on neointima formation and on thrombolysis at the site of endothelial injury. Endothelial damage in the rat femoral artery was induced by intravenous injection of rose bengal followed by focal irradiation by transluminal green light. Dietary natto-extracts supplementation containing NK of 50 or 100 CU/body was started 3 weeks before endothelial injury and then continued for another 3 weeks. Intimal thickening in animals given supplementation was significantly (P<0.01) suppressed compared with controls and the intima/media ratio in animals with 50 and 100 CU/body NK and control group was 0.09 +/- 0.03, 0.09 +/- 0.06 and 0.16 +/- 0.12, respectively. Although femoral arteries were reopened both in control animals and those treated with NK within 8 hours after endothelial injury, mural thrombi were histologically observed at the site of endothelial injury. In the control group, the center of vessel lumen was reopened and mural thrombi were attached on the surface of vessel walls. In contrast, in NK-treated groups, thrombi near the vessel wall showed lysis and most of them detached from the surface of vessel walls. In conclusion, dietary natto-extracts supplementation suppressed intimal thickening produced by endothelial injury in rat femoral artery. These effects may partially be attributable to NK, which showed enhanced thrombolysis near the vessel wall.