[Risk factors and short-term prognosis of early pulmonary hypertension in preterm infants]

Objectives: To investigate the risk factors and short-term prognosis of early pulmonary hypertension (PH) in preterm infants. Methods: A retrospective case-control study was performed in preterm infants (gestational age <32 weeks) in the neonatal intensive care unit (NICU) of the Children's Hospital, Zhejiang University School of Medicine from January 2012 to December 2019. Eighty preterm infants with a diagnosis of PH between 3 and 14 days (early PH group) were matched in gestational age and sex with the controls (1∶2) of the same period in NICU. Perinatal clinical records, complications, echocardiography and early outcomes were collected. Characteristics and outcomes were compared between the two groups with t-test, nonparametric test or Chi-square test. Multivariate Logistic regression was used to analyze the predictive factors of early PH. Results: The gestational age of the early PH group and the control group were both (27.9±1.4) weeks, and 52 (65.0%) and 104 (65.0%) were males in each group, respectively. Univariate analysis showed that birth weights were lower in the early PH group than those in the control group (1 030 (850, 1 200) vs. 1 110 (1 000, 1 278) g, Z=-3.27, P=0.001). The early PH group had higher rates of pregnancy-induced hypertension, prolonged rupture of membranes (PROM) >1 week, born by caesarean, small for gestational age (SGA), 1 and 5 min Apgar score ≤7 scores, neonatal respiratory distress syndrome (RDS) and hemodynamic significant patent ductus arteriosus (hsPDA) (12.5% (10/80) vs. 3.8% (6/160), 11.2% (9/80) vs. 3.8% (6/160), 48.8% (39/80) vs. 28.8% (46/160), 10.0% (8/80) vs. 1.9% (3/160), 70.8% (51/72) vs. 51.7% (74/143), 50.0% (36/72) vs. 20.3% (29/143), 88.8% (71/80) vs. 59.4% (95/160), 85.0% (68/80) vs. 22.5% (36/160), χ²=6.56, 5.12, 3.31, 8.05, 7.17, 20.05, 21.58, 84.84, all P<0.05). Multivariate Logistic regression analysis showed that the independent predictive factors of early PH were PROM >1 week, SGA, 5 min Apgar score ≤7 scores, nenonatal RDS and hsPDA (OR=10.40, 18.61, 4.47, 4.13, 20.10, 95%CI 1.93-56.12, 2.82-122.76, 1.91-10.46, 1.50-11.39, 8.28-48.80, all P<0.05),respectively. Infants with early PH had higher incidence of bronchopulmonary dysplasia (BPD), BPD associated PH, severe intraventricular hemorrhage (IVH), extrauterine growth retardation (EUGR), laser treatment for retinopathy of prematurity (ROP) and mortality than the controls (all P<0.05). The duration of invasive mechanical ventilation was also longer in the early PH group than that in the control group (P<0.05). Conclusions: Risk of early PH will be increased in preterm infants with PROM >1 week, SGA, 5 min Apgar score ≤7 scores, and comorbidities of nenonatal RDS and hsPDA. Early PH is associated with increased mortality, BPD, BPD associated PH, severe IVH, EUGR and laser treatment for ROP.

[A comparison of the clinical diagnosis and outcome in preterm infants with bronchopulmonary dysplasia under two different diagnostic criteria]

Objective: To compare the clinical diagnosis and outcomes of preterm infants with bronchopulmonary dysplasia (BPD) under two different diagnostic criteria. Methods: A retrospective study was performed in 157 preterm infants who were admitted to Neonatal Intensive Care Unit of the Children's Hospital, Zhejiang University School of Medicine from January 2015 to December 2018. Enrolled infants, with gestational age <32 weeks and survived >14 days, met the 2001 National Institute of Child Health and Human Development(NICHD) definition of moderate and severe BPD or died between 14 days of postnatal age and 36 weeks owing to persistent parenchymal lung disease and respiratory failure. The severities of BPD were revaluated according to the 2018 revised definition of BPD proposed by NICHD. Characteristics and outcomes of these infants were compared with the two different diagnostic criteria with t-test, nonparametric test or Chi-square test. Results: In the 157 enrolled infants (100 males), severities of BPD were classified as moderate in 62, severe in 84 and unclassifiable in 11 according to the 2001 NICHD criteria, while grade Ⅰ in 51, Ⅱ in 29, Ⅲ in 66 and ⅢA in 11 infants respectively according to the 2018 NICHD criteria. Duration of oxygen therapy, positive pressure ventilation and endotracheal intubation in grade Ⅱinfants of 2018 criteria were much longer than that in moderate infants of 2001 criteria (80 (65, 95) vs. 65 (59, 77) d, 52 (38, 58) vs.30 (19, 48) d, 10 (2, 17) vs.4 (0, 12) d, Z=-2.995, -3.750, -2.073, all P<0.05). Mortality of moderate and severe infants in 2001 criteria was 10.3% (15/146), while mortality of BPD in 2018 criteria was 16.6% (26/157). Mortality of grade Ⅲ and ⅢA BPD in 2018 criteria was much higher than mortality of severe BPD in 2001 criteria (33.8% (26/77) vs. 17.9%(15/84), χ(2)=5.357, P<0.05). Conclusion: Definition and classification of BPD based on 2001 NICHD criteria may cause missed or unclassified cases, resulting in the underestimation of the morbidity and mortality of infants with severe BPD.

[Treatment of postprandial discomfort syndrome in the elderly: a multi-centered prospective randomized controlled clinical study]

Objective: To evaluate the efficacy and safety of Oryz-Aspergillus enzyme and pancreatin tablets (Combizym(®)) in the treatment of postprandial distress syndrome (PDS) in the elderly, compared with gastrointestinal motility drugs. Methods: A prospective randomized controlled trial was designed and registered in the China Clinical Trials Registry (ChiCTR-IPR-16008185). The elderly patients with PDS were randomly divided into three groups, including Mosapride group with Mosapride citrate tablets 5 mg 3 times per day for 2 weeks; Combizym(®) group with Combizym tablets 244 mg 3 times per day for 2 weeks; combined treatment group with both drugs and same doses for 2 weeks. The modified Nepean dyspepsia index (NDSI) score, discomfort intensity score and PDS score were calculated on patients before treatment, at the end of first and second week of treatment, as well as 4 weeks after treatment finished, respectively. Adverse effects were evaluated. Results: A total of 323 patients from 16 tertiary hospitals in China were enrolled in this study. Among them, 105 patients were in Mosapride group, 109 in Combizym(®) group and 109 in combined treatment group. There were 148 males (45.8%) and 175 females (54.2%) with median age 71.4±9.0 years (60-100 years). Baseline characteristics of three groups were comparable. After treatment, the NDSI scores in three groups all decreased significantly (P<0.001), while they were similar between groups (P>0.05). The discomfort intensity score and PDS score in three groups showed a significant reduction after treatment (P<0.001), especially in the combined treatment group. Compared with Mosapride group, the scores in Combizym(®) group decreased significantly after one or two weeks [discomfort intensity score: after one week, 4.0(2.5, 8.0) vs. 6.0(3.0, 10.0); after two weeks, 3.0(0.0, 5.0) vs. 4.0(2.0, 6.0); all P<0.05. PDS score: after one week, 6.0(3.0, 9.0) vs. 7.0(3.5, 10.5); after two weeks, 3.0(0.0, 5.0) vs. 4.0(2.0, 7.0); all P<0.05]. The efficacy rate in all patients after first week of treatment was over 15.0%. The efficacy rates after two weeks were 55.2%, 68.8% and 73.4% in Mosapride group, Combizym(®) group and combined treatment group, respectively. After two week treatment, the efficacy rates in Combizym(®) group (P=0.041) and combined group (P=0.006) were higher than that of Mosapride group. The recurrence rate of Mosapride group was 9.5%, which was significantly higher than that of Combizym(®) group (1.8%, P<0.05) and combined treatment group (1.8%, P<0.05). There were no serious adverse effects in the three groups. Conclusions: The efficacy of Oryz-Aspergillus enzyme and pancreatin tablets is comparable with that of Mosapride in elderly PDS patients, with fewer adverse effects and low recurrence rate. Combination regimen indicates better efficacy than that of Oryz-Aspergillus enzyme and pancreatin tablets or Mosapride alone.

[Efficacy of probiotics on the treatment of non-alcoholic fatty liver disease]

Objective: To study the clinical effect of probiotics in the treatment of non-alcoholic fatty liver disease (NAFLD). Methods: A total of 200 patients with NAFLD were randomly divided into 4 groups: control group (routine treatment group) and combined treatment group A, B and C. Each group had equal patients. The control group received orally polyene phosphatidylcholine capsules; whereas combined group A, B and C were given orally the live "combined Bifidobacterium Lactobacillus and Enterococcus powder" , "two live combined Bacillus subtilis and Enterococcus" , and the both probiotics respectively. The duration of treatment was 1 month. Laboratory parameters were evaluated before treatment and thirtieth day after treatment, including cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol(LDL-C), alanine aminotransferase(ALT), aspartate aminotransferase (AST), fasting blood glucose (FPG), serum high molecular weight adiponectin (HMW-APN) and serum TNFα. Meanwhile the faece sample was collected for routine test and bacterial culture. Liver ultrasound scan was done in all patients. Results: In terms of blood lipids and blood glucose, each group improved after treatment with significant differences (P<0.05) except for HDL-C. As for liver function, serum ALT and AST decreased after treatment in each group; especially in combined group C which were lower than those of control group [(33.7±7.6) U/L vs. (45.0±8.5) U/L; (22.0±1.6) U/L vs. (29.4±3.7) U/L; P<0.05]. TNFα levels decreased after treatment in each group, in addition the values in combined group C was significantly lower than that of control group[(0.51±0.27) µg/L vs. (0.82±0.28) µg/L, P<0.05]. Serum HMW-APN increased after treatment in each group, and the HMW-APN in combined C group was significantly higher than that of control group[(9.28±3.72) µg/L vs. (7.87±3.96)µg/L, P<0.05]. (5) After treatment, all groups showed improvement of fatty liver by ultrasound, but the difference between groups was not statistically significant. (6) Compared with before treatment, fecal flora in combined groups was all reduced (P<0.01), but it was comparable before and after treatment in control group. Conclusions: Probiotics improve intestinal microecological system in NAFLD patients via inhibiting TNFα and enhancing adiponectin, possibly resulting in regulating blood glucose, lipid metabolism, and protecting liver injury from NAFLD.

[Use of noninvasive high-frequency oscillatory ventilation in very low birth weight infants]

Objective: To evaluate the effectiveness and safety of the use of noninvasive high-frequency oscillation ventilation (nHFOV) in very low birth weight infants. Method: A total of 36 cases received nHFOV between January 2016 and October 2016 in Children's Hospital, Zhejiang University School of Medicine, including 24 males and 12 females, with the gestational age of (27.5±2.5) weeks and birth weight of(980±318)g. The data of the ventilator settings, side effects, and changes of the respiratory function before and after nHFOV were collected and analyzed retrospectively. Nonparametric tests or t tests or χ(2) tests were used. Result: Thirty-two (89%) out of the 36 cases successfully avoided intubation or re-intubation after using of nHFOV. nHFOV was used as the rescue treatment after failure of other noninvasive ventilation in 17 cases, and as the prophylactical treatment preventing re-intubation after extubation in the remaining 19 cases. There were significant decreases in the incidences of apnea and desaturation(SpO(2)<0.85), the level of PaCO(2, )and the FiO(2) 24 h after the initiation of the nHFOV as the rescue therapy((1.2±1.1)vs.(6.3±2.1)episodes , (1.1±1.2) vs.(4.3±1.5) episodes, (43±8) vs.(56±10) mmHg, 0.30±0.07 vs. 0.39±0.11, respectively; 1 mmHg=0.133 kPa, t=7.562, 8.913, 4.179, 3.437 respectively, all P<0.01). No significant changes were found in FiO(2) and PaCO(2) levels 24 h after initiation of nHFOV as the prophylactical therapy after extubation (0.42±0.12 vs.0.40±0.10, (49±8)vs.(48±7)mmHg, t=0.872 and 0.501 respectively, both P>0.05), except for the significant decreases in the mean airway pressure ((7.9±2.6)vs.(9.6±1.6)cmH(2)O, 1 cmH(2)0=0.098 kPa, t=2.198, P=0.041). There were 4 cases suffered from nasal septum injury, while no other nHFOV related complications were noted. Conclusion: nHFOV can be applied in preterm infants as a rescue treatment after the failure of other noninvasive ventilation, or prophylactically used in patients who have high risk of re-intubation.

Breaking the speed limits of phase-change memory

Phase-change random-access memory (PCRAM) is one of the leading candidates for next-generation data-storage devices, but the trade-off between crystallization (writing) speed and amorphous-phase stability (data retention) presents a key challenge. We control the crystallization kinetics of a phase-change material by applying a constant low voltage via prestructural ordering (incubation) effects. A crystallization speed of 500 picoseconds was achieved, as well as high-speed reversible switching using 500-picosecond pulses. Ab initio molecular dynamics simulations reveal the phase-change kinetics in PCRAM devices and the structural origin of the incubation-assisted increase in crystallization speed. This paves the way for achieving a broadly applicable memory device, capable of nonvolatile operations beyond gigahertz data-transfer rates.

Crystalline amorphous semiconductor superlattice

A new class of superlattice, crystalline amorphous superlattice (CASL), by alternatively depositing two semiconductor materials, is proposed. CASL displays three states depending on the component materials' phase: both polycrystalline phases, both amorphous phases, and one polycrystalline phase while another amorphous phase. Using materials capable of reversible phase transition, CASL can demonstrate reversibility among three states. GeTe/Sb(2)Te(3) CASL has been synthesized and proved by x-ray reflectometry and TEM results. The reversible transition among three states induced by electrical and laser pulse was observed. The changes in the optical absorption edge, electrical resistivity, thermal conductivity, and crystallization temperature as a function of layer thickness are interpreted as quantum or nanoeffects. The unique properties of CASL enable the design of materials with specific properties.

Nanophase change for data storage applications

Phase change materials are widely used for date storage. The most widespread and important applications are rewritable optical disc and Phase Change Random Access Memory (PCRAM), which utilizes the light and electric induced phase change respectively. For decades, miniaturization has been the major driving force to increase the density. Now the working unit area of the current data storage media is in the order of nano-scale. On the nano-scale, extreme dimensional and nano-structural constraints and the large proportion of interfaces will cause the deviation of the phase change behavior from that of bulk. Hence an in-depth understanding of nanophase change and the related issues has become more and more important. Nanophase change can be defined as: phase change at the scale within nano range of 100 nm, which is size-dependent, interface-dominated and surrounding materials related. Nanophase change can be classified into two groups, thin film related and structure related. Film thickness and clapping materials are key factors for thin film type, while structure shape, size and surrounding materials are critical parameters for structure type. In this paper, the recent development of nanophase change is reviewed, including crystallization of small element at nano size, thickness dependence of crystallization, effect of clapping layer on the phase change of phase change thin film and so on. The applications of nanophase change technology on data storage is introduced, including optical recording such as super lattice like optical disc, initialization free disc, near field, super-RENS, dual layer, multi level, probe storage, and PCRAM including, superlattice-like structure, side edge structure, and line type structure. Future key research issues of nanophase change are also discussed.

Optimization of venous return tubing diameter for cardiopulmonary bypass

OBJECTIVE

To determine the optimal venous tubing diameter for adult cardiopulmonary bypass (CPB) to improve gravity drainage and to reduce priming volume.

METHODS

(A) Maximum bovine blood flow rates by gravity drainage were assessed in vitro for four different tubing diameters (1/2, 3/8, 5/16,1/4 inch) with three different lengths and various pre- and afterloads. Based on the results of (A) and multiple regression analyses, we developed equations to predict tubing sizes as a function of target flows. (C) The equations obtained in (B) were validated by ex vivo bovine experiments. (D) The clinically required maximal flows were determined retrospectively by reviewing 119 perfusion records at Zurich University. (E) Based on our model (B), the clinical patient and hardware requirements, the optimal venous tubing diameter was calculated. (F) The optimized venous tubing was evaluated in a prospective clinical trial involving 312 patients in Hangzhou.

RESULTS

For a mean body surface area of 1.83+/-0.2 m(2), the maximal perfusion flow rate (D) achieved with 1/2-inch (=1.27 cm(2)) venous tubing was 4.62+/-0.57 l/min (range: 2.50-6.24 l/min). Our validated model (B,C) predicted 1.0 cm(2) as optimal cross-sectional area for the venous line. New tubing packs developed accordingly were used routinely thereafter. The maximal flow rate was 4.93+/-0.58 l/min (range: 3.9-7.0) in patients with a mean body surface area of 1.62+/-0.21 m(2).

CONCLUSION

The new venous tubing with 1.0-cm(2) cross-sectional area improves the drainage in the vast majority of adult patients undergoing CPB and reduces the priming volume (-27 ml/m). Reduced hemodilution can prevent homologous transfusions if a predefined transfusion trigger level is not reached.

Molecular theory of HexB-SmA-isotropic transitions in ultrathin liquid crystal films

A microscopic theory is developed to treat the ultrathin film of liquid crystals of molecules that have no cylindrical symmetry. The Hamiltonian is derived from the basic electrostatic interaction among electrons by considering the dipole-dipole and dipole-quadrupole interactions between nonchiral molecules. It exhibits the in-plane sixfold symmetry. From a unified model with the same interaction constants we are able to explain simultaneously the layer-thinning SmA-I transition, the anomalous multiplex heat capacity, the strong singularity in the HexB-SmA transition, and the coexistence of different phases. The theoretical calculations agree quantitatively with recent experimental results for the free-standing 54COOBC films.

Extended IWKB method for determination of the refractive=index profile in optical waveguides

A simple method is outlined for the calculation of the refractive-index profiles of both multimode and monomode planar optical waveguides. The method is an extension of the well-established IWKB method. The parameters required are the dispersion relation of the surface index changes and the effective indices at different wavelengths. As an example, the refractive-index profile of a monomode z-cut KTiOPO(4) planar waveguide fabricated by Rb(+):K(+) exchange is computed. Close agreement is obtained, indicating the practicality of this method. The method is also applicable to optical waveguides in other materials, such as LiNbO(3), LiTaO(3), and glass.