Equibiaxial strain regulates the electronic structure and mechanical, piezoelectric, and thermal transport properties of the 2H-phase monolayers CrX2 (X = S, Se, Te).

A superior piezoelectric coefficient and diminutive lattice thermal conductivity are advantageous for the application of a two-dimensional semiconductor in piezoelectric and thermoelectric devices, whereas an imperfect piezoelectric coefficient and large lattice thermal conductivity limit the practical application of the material. In this study, we investigate how the equibiaxial strain regulates the electronic structure, and mechanical, piezoelectric, and thermal transport properties. Tensile strain can deduce the bandgap of the monolayer CrX2 (X = S, Se, Te), whereas compressive strain has an opposite effect. Additionally, the transition from a semiconductor to a metal state and the transition between direct and indirect band gaps will occur at appropriate strain values, so the electronic structure can be effectively regulated. The reason is the different sensitivities of the energy corresponding to K and Γ on the valence band to the strain due to the changes in different orbital overlaps. The tensile strain can effectively improve the flexibility of monolayers CrX2, which provides a possibility for the application of flexible electronic devices. Furthermore, the tensile strain can improve the piezoelectric strain coefficient of monolayers CrX2. Using Slacks formulation, we calculate the lattice thermal conductivity, and the tensile biaxial strain can reduce the lattice thermal conductivity. Our research provides a strategy to enhance the piezoelectric and flexible electronic applications and decrease the lattice thermal conductivity, which can benefit the thermoelectric applications.

Factors associated with heterochronic gastric cancer development post-endoscopic mucosal dissection in early gastric cancer patients.

BACKGROUND: Endoscopic mucosal resection is an innovative method for treating early gastric cancer and has been widely used in clinical practice. AIM: To analyze the factors associated with the development of heterochronic gastric cancer in patients with early gastric cancer who had undergone endoscopic mucosal dissection (EMD). METHODS: A cohort of patients with early gastric cancer treated using EMD was retrospectively analyzed, and patients who developed heterochronic gastric cancer after the surgery were compared with those who did not. The effects of patient age, sex, tumor size, pathological type, and surgical technique on the development of heterochronic gastric cancer were assessed using statistical analysis. RESULTS: Of the 300 patients with early gastric cancer, 150 patients developed heterochronic gastric cancer after EMD. Statistical analysis revealed that patient age (P value = XX), sex (P value = XX), tumor size (P value = XX), pathological type (P value = XX), and surgical technique (P value = XX) were significantly associated with the occurrence of heterochronic gastric cancer. CONCLUSION: Age, sex, tumor size, pathological type, and surgical technique are key factors influencing the occurrence of heterochronic gastric cancer after EMD in patients with early gastric cancer. To address these factors, postoperative follow-up and management should be strengthened to improve the prognosis and survival rate of patients.

Hexagonal warping effect in the Janus group-VIA binary monolayers with large Rashba spin splitting and piezoelectricity.

In this paper, the electronic band structure, Rashba effect, hexagonal warping, and piezoelectricity of Janus group-VIA binary monolayers STe2, SeTe2, and Se2Te are investigated based on density functional theory (DFT). Due to the inversion asymmetry and spin-orbit coupling (SOC), the STe2, SeTe2 and Se2Te monolayers exhibit large intrinsic Rashba spin splitting (RSS) at the Γ point with the Rashba parameters 0.19 eV Å, 0.39 eV Å, and 0.34 eV Å, respectively. Interestingly, based on the k·p model via symmetry analysis, the hexagonal warping effect and a nonzero spin projection component Sz arise at a larger constant energy surface due to nonlinear k3 terms. Then, the warping strength λ was obtained by fitting the calculated energy band data. Additionally, in-plane biaxial strain can significantly modulate the band structure and RSS. Furthermore, all these systems exhibit large in-plane and out-of-plane piezoelectricity due to inversion and mirror asymmetry. The calculated piezoelectric coefficients d11 and d31 are about 15-40 pm V-1 and 0.2-0.4 pm V-1, respectively, which are superior to those of most reported Janus monolayers. Because of the large RSS and piezoelectricity, the studied materials have great potential for spintronic and piezoelectric applications.

Chronic high­salt intake induces cardiomyocyte autophagic vacuolization during left ventricular maladaptive remodeling in spontaneously hypertensive rats.

The role of autophagy in high-salt (HS) intake associated hypertensive left ventricular (LV) remodeling remains unclear. The present study investigated the LV autophagic change and its association with the hypertensive LV remodeling induced by chronic HS intake in spontaneously hypertensive rats (SHR). Wistar Kyoto (WKY) rats and SHR were fed low-salt (LS; 0.5% NaCl) and HS (8.0% NaCl) diets and were subjected to invasive LV hemodynamic analysis after 8, 12 and 16 weeks of dietary intervention. Reverse transcription-quantitative PCR and western blot analysis were performed to investigate the expression of autophagy-associated key components. The LV morphologic staining was performed at the end of the study. The rat H9c2 ventricular myoblast cell-associated experiments were performed to explore the mechanism of HS induced autophagic change. A global autophagy-associated key component, as well as increased cardiomyocyte autophagic vacuolization, was observed after 12 weeks of HS intake. During this period, the heart from HS-diet-fed SHR exhibited a transition from compensated LV hypertrophy to decompensation, as shown by progressive impairment of LV function and interstitial fibrosis. Myocardial extracellular [Na+] and the expression of tonicity-responsive enhancer binding protein (TonEBP) was significantly increased in HS-fed rats, indicating myocardial interstitial hypertonicity by chronic HS intake. The global autophagic change and overt deterioration of LV function were not observed in LS-fed SHR and HS-fed WKY rats. The study of rat H9c2 cardiomyocytes demonstrated a cytosolic [Na+] elevation-mediated, reactive oxygen species-dependent the autophagic change occurred when exposed to an increased extracellular [Na+]. The present findings demonstrated that a myocardial autophagic change participates in the maladaptive LV remodeling induced by chronic HS intake in SHR, which provides a possible target for future intervention studies on HS-induced hypertensive LV remodeling.

Pseudolaric Acid B Attenuates High Salt Intake-Induced Hypertensive Left Ventricular Remodeling by Modulating Monocyte/Macrophage Phenotypes.

BACKGROUND Studies in ApoE knockout mice have shown that pseudolaric acid B (PB) can act as an immunomodulatory drug and attenuate atherosclerosis progression by modulating monocyte/macrophage phenotypes. Our previous study demonstrated that high salt intake could shift the phenotype of monocytes/macrophages to an inflammatory phenotype, and that this shift was related to hypertension and hypertensive left ventricular (LV) remodeling. However, no comprehensive assessment of the effects of PB on hypertensive LV remodeling has been conducted. MATERIAL AND METHODS In this study, RAW264.7 macrophages cultured with different concentrations of NaCl were used to investigate the modulating effects of PB on macrophage phenotype. Furthermore, N-nitro-L-arginine methyl ester hypertensive mice were used to investigate the modulating effects of PB on monocyte phenotype. LV remodeling was investigated by echocardiography. LV morphologic staining (for cardiomyocyte hypertrophy and collagen deposition) was performed at the time of sacrifice. RESULTS The results showed that PB significantly improved the viability of RAW264.7 cells, suppressed their phagocytic and migration abilities, and inhibited their phenotypic shift to M1 macrophages. In addition, the blood pressure of PB-treated mice was significantly decreased relative to that of control mice. Furthermore, after PB treatment, the percentage of Ly6Chi monocytes was significantly decreased while that of Ly6Clo monocytes was apparently increased. Moreover, PB preserved LV function and alleviated myocardial fibrosis and cardiomyocyte hypertrophy as measured at the end of the experimental period. The transfer of monocytes from PB-treated mice to hypertensive mice achieved the same effects. CONCLUSIONS Together, these findings indicate that PB exerts its protective effects on hypertensive LV remodeling by modulating monocyte/macrophage phenotypes and warrants further investigation.

Biaxial Tensile Strain-Induced Enhancement of Thermoelectric Efficiency of α-Phase Se2Te and SeTe2 Monolayers.

Thermoelectric (TE) materials can convert waste heat into electrical energy, which has attracted great interest in recent years. In this paper, the effect of biaxial-tensile strain on the electronic properties, lattice thermal conductivity, and thermoelectric performance of α-phase Se2Te and SeTe2 monolayers are calculated based on density-functional theory and the semiclassical Boltzmann theory. The calculated results show that the tensile strain reduces the bandgap because the bond length between atoms enlarges. Moreover, the tensile strain strengthens the scatting rate while it weakens the group velocity and softens the phonon model, leading to lower lattice thermal conductivity kl. Simultaneously, combined with the weakened kl, the tensile strain can also effectively modulate the electronic transport coefficients, such as the electronic conductivity, Seebeck coefficient, and electronic thermal conductivity, to greatly enhance the ZT value. In particular, the maximum n-type doping ZT under 1% and 3% strain increases up to six and five times higher than the corresponding ZT without strain for the Se2Te and SeTe2 monolayers, respectively. Our calculations indicated that the tensile strain can effectively enhance the thermoelectric efficiency of Se2Te and SeTe2 monolayers and they have great potential as TE materials.

Effects of allisartan isoproxil on blood pressure and target organ injury in patients with mild to moderate essential hypertension.

Evidence has shown that angiotensin II type 1 receptor antagonists have lower blood pressure and have target organ protective effects, but this is not the case for the drug allisartan isoproxil. The aim of this study was to evaluate the effects of allisartan isoproxil on blood pressure and target organ injury in patients with mild to moderate essential hypertension.In total, 80 essential hypertensive participants were randomly divided into an allisartan group and a nifedipine group (n = 40 per group), and their blood pressure was measured once per month for 6 months. A 2-dimensional echocardiogram was performed at baseline and at the end of the study. The serum levels of renal injury indexes, endothelial function markers, inflammatory factors, blood biochemical assays and urinary measurements were determined at baseline and at 6 months.At the end of the study, both systolic and diastolic blood pressure were significantly decreased in the allisartan group compared with baseline and showed the same antihypertensive effect as the nifedipine group. Meanwhile, the left ventricular remodeling, 24-hours levels of urinary microalbumin, endothelial dysfunction, and arterial stiffness were all significantly improved compared with that of the baseline and the nifedipine group (all P < .05).The present study showed that allisartan isoproxil had favorable blood pressure lowering and heart, renal, and endothelial protective effects in patients with mild to moderate essential hypertension.

Discordance Between VASP Phosphorylation and Platelet Aggregation in Defining High On-Clopidogrel Platelet Reactivity After ST-Segment Elevation Myocardial Infarction.

To investigate potential clinical characteristics associated with discordance between platelet vasodilator-stimulated phosphoprotein phosphorylation (VASP-P) flow cytometry (FCM) assay and light transmission aggregometry (LTA) in defining high on-clopidogrel platelet reactivity (HPR) after ST-segment elevation myocardial infarction (STEMI). In this study, platelet responsiveness was measured by the above 2 methods simultaneously on day 1 and on day 6 of STEMI onset in 90 consecutive patients who underwent primary percutaneous coronary intervention. The FCM-derived platelet reactivity index and LTA-derived platelet aggregation rate were both significantly reduced after dual antiplatelet therapy on day 6. Multiple variable-adjusted logistic regression analysis revealed that smoking (odds ratio [OR]: 4.507, 95% confidence interval [CI]: 1.123-18.09, P = .034) and onset-to-admission time (per 1 hour increase, OR: 1.196, 95% CI: 1.023-1.398, P = .025) both were independent predictors for the discordance between the 2 methods. Additionally, improved correlation and concordance was observed in nonsmokers compared with smokers. Our data show that smoking and prolonged onset-to-admission time are associated with discordance between platelet VASP-P and LTA in defining HPR after STEMI, which should be considered when planning personalized antiplatelet therapy.

Establishment of an ideal time window model in hypothermic-targeted temperature management after traumatic brain injury in rats.

Although hypothermic-targeted temperature management (HTTM) holds great potential for the treatment of traumatic brain injury (TBI), translation of the efficacy of hypothermia from animal models to TBI patientshas no entire consistency. This study aimed to find an ideal time window model in experimental rats which was more in accordance with clinical practice through the delayed HTTM intervention. Sprague-Dawley rats were subjected to unilateral cortical contusion injury and received therapeutic hypothermia at 15mins, 2 h, 4 h respectively after TBI. The neurological function was evaluated with the modified neurological severity score and Morris water maze test. The brain edema and morphological changes were measured with the water content and H&E staining. Brain sections were immunostained with antibodies against DCX (a neuroblast marker) and GFAP (an astrocyte marker). The apoptosis levels in the ipsilateral hippocampi and cortex were examined with antibodies against the apoptotic proteins Bcl-2, Bax, and cleaved caspase-3 by the immunofluorescence and western blotting. The results indicated that each hypothermia therapy group could improve neurobehavioral and cognitive function, alleviate brain edema and reduce inflammation. Furthermore, we observed that therapeutic hypothermia increased DCX expression, decreased GFAP expression, upregulated Bcl-2 expression and downregulated Bax and cleaved Caspase-3 expression. The above results suggested that HTTM at 2h or even at 4h post-injury revealed beneficial brain protection similarly, despite the best effect at 15min post-injury. These findings may provide relatively ideal time window models, further making the following experimental results more credible and persuasive.

The influence of different anticoagulants and time-delayed sample processing and measurements on human monocyte subset and monocyte-platelet aggregate analyses.

BACKGROUND: Measuring human monocyte subsets (CD14++CD16-, CD14++CD16+, and CD14 + CD16++) and subset-specific monocyte-platelet aggregates (MPA) is vulnerable to analytical bias due to unavailability of a standardized methodology. We aimed to address this issue by focusing on the impacts of time-delayed sample processing and measurement between two commonly used anticoagulants. METHODS: Ethylenediaminetetraacetic acid (EDTA)- and sodium citrate (SC)-anticoagulated blood samples from 12 healthy donors were subject to either delayed (2-h delay, kept at 4°C) or immediate processing (without fixation) before four-color flow cytometry (FCM) analysis. RESULTS: In SC-anticoagulated samples, a 2-h delay in sample processing contributed to a significant decrease in CD14++CD16- monocyte percent and a reciprocal increase in CD14++CD16+ monocytes, as well as increases in all three subset-specific MPA. Similar slight, but non-significant changes were observed in EDTA-treated samples. In samples processed immediately and stored at 4°C, delayed measurement at 0, 1, 3, and 5 h after processing led to a time-dependent decrease in CD14++CD16- monocyte percent and a reciprocal increase in CD14++CD16+ subset in SC-treated, but not in EDTA-treated, samples. Moreover, a time-dependent increase in all three subset-specific MPA was observed in SC-treated samples, which, to a lesser extent, was only observed in CD14++CD16+ MPA in EDTA-treated samples after storage at 4°C for 3-5 h after processing. CONCLUSIONS: We recommend EDTA for anticoagulation. Additionally, sample should be stored at 4°C and processing and measuring should be performed within 2 h after harvest and 3 h after processing, respectively. © 2016 International Clinical Cytometry Society.

Complete mitochondrial genome of Pseudolaubuca engraulis (Pisces: Cyprinidae, Cultrinae).

The complete mitogenome of Pseudolaubuca engraulis was determined using long-distance polymerase chain reaction and sequenced by primer walking method. It is 16,612 bp in length and contains 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA (tRNA) genes and 1 A + T-rich control region. The gene arrangement and characterization of P. engraulis are similar to most vertebrates. The overall base composition of the heavy strand is 27.1% A, 27.5% C, 25.9% T and 19.5% G, with a slight A + T bias. The shortest tRNA-Ser2 lacks the dihydrouridine arm and is replaced with a simple loop. The termination-associated sequence and the conserved sequence blocks (1-3) are found in the control region.

Parallel evolution of IDH2 gene in cetaceans, primates and bats.

Cetaceans and primates both have large brains that require large amounts of aerobic energy metabolism. In bats, the cost of flight makes locomotion energetically demanding. These mammalian groups may represent three independent evolutionary origins of an energy-demanding lifestyle in mammals. IDH2 encodes an enzyme in the tricarboxylic acid cycle in the mitochondrion, which plays a key role in aerobic energy metabolism. In this study, we cloned and sequenced this gene in two cetaceans, and 19 bat species, and compared the data with available primate sequences to test its evolution. We found significant signals of parallel evolution in this gene among these three groups. Parallel evolution of this gene may reflect their parallel evolution towards a higher demand for energy.

Left ventricular systolic dyssynchrony in patients with isolated symptomatic myocardial bridge.

OBJECTIVES: The impact of myocardial bridge (MB) on left ventricular (LV) systolic synchrony is insufficiently understood. DESIGN: Thirty-five subjects with isolated mid-left, anterior, descending artery (LAD) MB, preserved LV ejection fraction (LVEF > 50%), and otherwise, normal coronary angiogram were identified from 3607 patients who underwent diagnostic coronary angiography and were evaluated by tissue Doppler imaging and real-time three-dimensional echocardiography (RT3DE). Control subjects consisted of 26 age and sex-matched coronary angiographically "normal" subjects. RESULTS: MB patients were characterized by reduced, early, diastolic strain rate in LAD-supplied apical segments (lateral and anterior), with prevalence of LV systolic dyssynchrony of 25.7% (9/35). MB patients were further classified by the medians of MB stenosis and length. For MB stenosis < 52.5%, Class I: length < 17 mm (n = 7), Class II: length ≥ 17 mm (n = 10); for stenosis ≥ 52.5%, Class III: length < 17 mm (n = 10), Class IV: length ≥ 17 mm (n = 8). Binary Logistic regression model revealed that higher MB lesion classification (odds ratio: 4.944, 95%CI 1.174-20.82, P < 0.05) and hypertension (odds ratio: 15.32, 95%CI: 1.252-187.6, P < 0.05) are statistically associated with LV systolic dyssynchrony, which was independent of LV mass. CONCLUSIONS: MB in the mid LAD is associated with myocardial dyssynchrony. Hypertensive individuals and those with more severe bridging (determined by length and stenosis) tend to have an increased incidence of dyssynchrony.

[Effects of three antigens extracted from Vibrio vulnificus on the immunological protection of Nibea albiflora].

Nibea albiflora was immunized by intraperitoneal injection with either Lipopolysaccharide (LPS) or outer membrane protein (OMP) extracted from Vibrio vulnificus or formalin killed Vibrio vulnificus (FKC). The influence of the three antigens on the immunological function of Nibea albiflora was determined at different time points following the injection by testing the agglutinating antibody titers of the serum, lysozyme activity of the serum, phagocytic activity of the blood and the relative survival percentage. The results showed that the three antigens have higher immunogenicity and antigenicity than the control group(injection with sterile saline). The agglutinating antibody titers of the immune challenged groups increased quickly, and were highest on the day 28. The lysozyme activity and phagocytic activity were raised significantly (P<0.01), reaching their top value on day 21, and then the index gradually reduced. The immunological indexes of three immune groups were higher than the control group (P<0.05). The agglutinating antibody titers of the LPS group or the OMP group were lower than the control group, but the relative survival percentage was adverse when challenged with a Vibrio vulnificus infection. The order of relative survival percentage was group LPS>OMP>FKC>Control.

[Eco-physiological responses of high-latitude transplanted Aegiceras corniculatum seedlings to NaCl stress].

A sand culture pot experiment was conducted to study the eco-physiological responses of high-latitude transplanted mangrove Aegiceras corniculatum seedlings to varying concentration of NaCl (0, 100, 200, 300, and 400 mmol x L(-1)). Under the stress of 100 mmol NaCl x L(-1), the seedling growth was slightly promoted; whereas at 300 mmol NaCl x L(-1), the plant height, stem basal diameter, fresh and dry mass, and root/shoot ratio were decreased significantly. High salt stress inhibited the leaf superoxide dismutase (SOD) and peroxidase (POD) activities, increased the leaf malondialdehyde (MDA) content, and decreased the leaf chlorophyll and carotenoids contents as well as the total soluble sugar and free amino acid contents in different organs. Under the stress of different concentration NaCl, the Na+ contents in leaf, stem, and root increased rapidly while the K+ contents had a relatively decrease, resulting in a rapid decrease of K+/Na+ ratio and an imbalance between K+ and Na+ in A. corniculatum vegetative organs. When the NaCl concentration in the medium was higher than 300 mmol x L(-1), the C and N metabolism of A. corniculatum vegetative organs was maladjusted, which inhibited the normal growth of the seedlings, resulting in a significant decrease in the plant height and fresh and dry mass.

[Critical tidal level for Kandelia candel forestation in strong tidal range area].

Taking Ximen island of Yueqing bay, the biggest tidal range area among the coasts of China, as study site, an investigation was made on the survival rate, growth characteristics, and attached barnacles of 1- and 3-year-old Kandelia candel seedlings at the elevations 1.96, 1.66, 1.35, and 1.03 m above the zero tidal level of Yellow Sea. Significant differences were observed in the survival rate and growth situation of the seedlings among the elevations. There were two barnacle species, Balanus albicostatus and Balanus amphitrite amphitrite, and B. albicostatus was the major species which attached K. candel most seriously at elevation 1.35 m. The critical tidal level for K. candel in the site was 1.66 m above the zero tidal level, i.e., at least 1.29 m higher than the local mean sea level, and the flooding time per tide cycle being less than 3.65 h. Barnacle, strong tide, and extreme weather event were the main reasons for the higher critical tidal level.

[Benefits of placing intra-aortic vacant guide wire on interventional treatment of aorto-ostial lesions].

OBJECTIVE: To evaluate the potential benefits of placing intra-aortic vacant guide wire on interventional treatment of aorto-ostial lesions. METHODS: A total of 86 consecutive patients underwent percutaneous coronary interventions (PCI) for aorto-ostial lesions were randomly divided into conventional treatment group (group A) and intra-aortic vacant guide wire group (group B). Standard PCI techniques were applied in group A and an intra-aortic vacant guide wire was placed outside the guiding catheter before the guiding catheter into the target coronary artery in group B on basis of standard PCI techniques. The number of guiding catheter, guide wire, X-ray exposure time, total PCI time, the incidence of pressure drop and malignant arrhythmia, contrast agent dose and the number of failure cases were compared between the two groups. RESULTS: The number of used guide wire was similar between the groups (2.0 ± 1.1 vs. 2.2 ± 0.4, P > 0.05) and the number of guiding catheter used was significantly more in group A than in group B (2.3 ± 1.1 vs. 1.3 ± 0.5, P < 0.01). The X-ray exposure time (18.8 min ± 6.9 min vs. 14.2 min ± 5.7 min, P < 0.01) was significantly less in groups B and the total PCI time (31.2 min ± 8.1 min vs. 20.1 min ± 4.5 min, P < 0.01) and the amount of contrast agent (193.5 ml ± 25.4 ml vs. 130.6 ml ± 32.8 ml, P < 0.01) and the frequency of pressure drop (19 cases vs. 2 cases, P < 0.01) were all significantly higher in group A than in group B. Incidence of malignant ventricular arrhythmia (8 vs. 0) and procedure failure (6 vs. 0) was also higher in group A compared to group B. CONCLUSION: The method of using Intra-aortic vacant guide wire is associated with reduced risk and improved success rate of PCI for aorto-ostial lesions.

[Polymorphisms of mitochondrial Cyt b gene and D-loop region in sweetfish (Plecoglossus altivelis Temminck et Schlegel) from Zhejiang and Fujian Provinces].

We reported here the molecular analysis of mitochondrial genomes in sweetfish (Plecoglossus altivelis). Thirty-one specimens were recruited from Ruian, Zhejiang Province, Ningde, Fujian Province, and Dongzhang reservoir, Fujian Province. DNA segments spanning cytochrome b gene and D-loop region derived from these specimens were PCR-amplified and subsequently characterized by direct DNA sequence analysis. The resultant sequence data were compared with the consensus sequence and further analyzed for proportion of each nucleotide. The average A, T, C, and G con-tents in Cyt b gene were 19.72%, 29.71%, 32.25%, and 18.32%, respectively, while the contents of A+T and G+C were 49.43% and 50.57%. In the D-loop region, the average A, T, C and G contents were 29.99%, 29.29%, 23.80%, and 16.92% and the contents of A+T and G+C were 59.28% and 40.72%, respectively. There was only one variant in the Cyt b gene belong to two haplotypes and the nucleotide diversity (pi) was merely 0.00028. In the D-loop region, there were only 5 polymorphic sites belonging to 5 haplotypes and its nucleotide diversity (pi) was only 0.00199. These results showed that the genetic diversity of P. altivelis from these regions was very low.

[Clinical study on respiratory mechanics of synchronized intermittent mandatory ventilation in premature infants with respiratory failure].

OBJECTIVE: To evaluate the clinical significance of synchronized intermittent mandatory ventilation (SIMV) in prematures infants necessitating assistant ventilation. METHODS: Forty-two premature infants were studied in whom SIMV was used in 24 and intermittent mandatory ventilation (IMV) was used in 18. The parameters of fractional concentration of inspired oxygen (FiO(2)), peak inspiratory pressure (PIP), expiratory tidal volume (V(Texp)), oxygen index (OI), compliance of the respiratory system (Crs) and airway resistance (Raw) were compared. The frequency of administration of sedatives and incidence rate of complications were also compared between two groups. RESULTS: In SIMV group, PIP, V(Texp), Raw and Crs were significant better after 2 hours ventilation (all P<0.05). There were significant difference in FiO(2) after 12 hours and OI at 24 hours in two groups. They were better in SIMV group. Sedatives were less used in SIMV group than IMV group (P<0.05). CONCLUSION: In premature infants, SIMV could reduce FiO(2), PIP, OI, Raw and improve V(Texp), Crs more rapidly when assistant ventilation is necessary. The sedatives are used less in patients on SIMV.

[Effects of Evan Blue on perfused dimension display and rabbit left ventricular action potential].

OBJECTIVE: Simultaneous recording of transmembrane action potential at endocardium, midcardium and epicardium and transmural ECG in arterially perfused left ventricular preparation is a new method for researching into the mechanism about ventricular arrhythmia, and in this connection, how to distinguish the perfused area plays a key role in keeping preparations under normal condition. This study is aimed to evaluate the effects of Evan Blue on the displaying of the perfused area and on the characters of transmembrane action potential of the arterially perfused left ventricular preparations. METHODS: Rabbit left ventricular wedge preparations were perfused with Tyrode solution continuously via left circumflex, and the action potential of endocardium, midmyocardium, epicardium or transmural electrocardiogram were recorded simultaneously. The action poatential duration (APD), transmural dispersion of repolarization (TDR) or QT intervals were compared and the color variation of the preparations were studied before and 30 min after perfusion with Evan Blue. RESULTS: Under the basic stimulatory cycle length of 1000, 2000, 4000 ms, there was no significant difference of APD in the same transmural layer or TDR before and after Evan Blue perfusion (P<0.01), but APD or TDR stimulated at basic cycle length of 1000-4000 ms were all higher than those recorded at 500 ms (P<0.01); APDs of endocardium were much longer than those of epicardium or midmyocardium (P<0.01); there was no significant difference in APD, TDR and QT intervals before and after Evan Blue perfusion (P>0.05). No premature ventricular contractions and ventricular tachycardia happened during the experiments. CONCLUSION: Evan Blue can be used as a marker to identify the perfused area.