Leisure experience and mobile phone addiction: Evidence from Chinese adolescents.

Background: During the Covid-19 pandemic, online learning became the mainstream because of many restrictions on interpersonal relationships. Children spent more and more time using mobile phones, which also aroused public concern.In past research on the prevention of problematic mobile phone use, it was easy to neglect meaningful part of leisure. Hence, based on Davis's cognitive-behavioral model, this study was designed to verify how leisure experience influences mobile phone addiction through maladaptive cognition, which received little attention before. Methods: By convenient sampling method, it involved a sample of 1007 middle school students recruited from Northern China. We used adolescent leisure experience questionnaire, maladaptive cognition scale and mobile phone addiction scale to measure adolescents' leisure experience, maladaptive cognition and mobile phone addiction respectively. Results: The findings revealed that leisure experience was negatively correlated with maladaptive cognition (r = -0.21, p < 0.01) and mobile phone addiction (r = -0.20, p < 0.01) respectively. Maladaptive cognition was positively correlated with mobile phone addiction (r = 0.51, p < 0.01). Given gender, age and family economic conditions, the negative predictive effect of leisure experience on mobile phone addiction was significant (ß = -0.18，p < 0.001). Besides, the process by which leisure experience predicted mobile phone addiction through maladaptive cognition was significant, indirect effect = -0.10, SE = 0.02, 95 % CI = [-0.13, -0.07]. Conclusions: Adolescents' great leisure experience has a positive impact on mobile phone addiction, which can be achieved by reducing maladaptive cognition. Therefore，it is significant to improve their leisure experience and guide them to perceive their irrational beliefs in leisure and rethink offline leisure and real life from more positive views.

Microwave-assisted aqueous two-phase extraction of polysaccharides from Hippophae rhamnoide L.: Modeling, characterization and hypoglycemic activity.

Natural polysaccharides are concerned for their high biological activity and low toxicity. Two kinds of polysaccharides were extracted from Hippophae rhamnoide L. by microwave-assisted aqueous two-phase system. Under the optimal conditions predicted by RSM model (K2HPO4/ethanol (18.93 %/28.29 %), liquid to material ratio 77 mL/g, power 625 W and temperature 61 °C), the yield of total polysaccharides reached 35.91 ± 0.76 %. Moreover, the polysaccharides extraction was well fitted to the Weibull model. After purification by Sepharose-6B, the polysaccharides from top phase (PHTP, purity of 81.44 ± 1.25 %) and bottom phase (PHBP, purity of 88.85 ± 1.40 %) were obtained. GC, FT-IR, methylation and NMR analyses confirmed the backbone of PHTP was composed of a repeated unit →4)-ß-D-Glcp-(1 â†’ 2)-α-L-Rhap-(1 â†’ 4)-ß-D-Galp-(1 â†’ 4)-α-D-GalAp-(1 â†’ 3)-α-L-Araf-(1 â†’ 3)-α-D-Manp-(1→, while the repeated unit in PHBP was →3)-α-L-Araf-(1 â†’ 2)-α-L-Rhap-(1 â†’ 4)-ß-D-Glcp-(1 â†’ 3)-α-D-Manp-(1 â†’ 4)-ß-D-Galp-(1 â†’ 4)-α-D-GalAp-(1→. Compared with PHTP (6.46 × 106 g/mol), PHBP with relatively low molecular weight (8.2 × 105 g/mol) exhibited the smaller particle size, better water-solubility, thermal and rheological property, stronger anti-glycosylation and α-amylase inhibitory effects. Moreover, PHTP and PHBP displayed a reversible inhibition on α-amylase in a competitive manner. This study provides a high-efficient and eco-friendly method for polysaccharides extraction, and lays a foundation for sea buckthorn polysaccharides as potential therapeutic agents in preventing and ameliorating diabetes.

Effect of Dapagliflozin on Indicators of Myocardial Fibrosis and Levels of Inflammatory Factors in Heart Failure Patients.

Objective: To explore the effect of dapagliflozin on the myocardial fibrosis and the levels of inflammatory factors in heart failure patients. Methods: 60 patients with T2DM who were diagnosed as acute left heart failure or acute exacerbation of chronic left heart failure in the Department of Cardiology of our hospital from November 1, 2020, to December 31, 2021, during hospitalization were the study subjects. According to the treatment regimen, they were divided into the experimental group (EG) which received dapagliflozin and conventional drugs and the control group (CG) which received conventional drugs, with 30 cases in each group to compare and analyze the clinical indicators such as myocardial fibrosis and inflammatory factors. Results: The levels of TNF-α, IL-1ß, IL-6, and hs-CRP in the two groups were decreased gradually after treatment, and the levels of TNF-α, IL-1ß, IL-6, and hs-CRP in the EG were visibly lower compared with those in the CG at week 4 of treatment (P < 0.05). The cardiac function evaluation of patients showed that the levels of LVEF and LVEDD in both groups were gradually improved after treatment, with a significant difference from the fourth week. In other words, compared with the CG, the LVEF level in the EG was obviously higher (P < 0.05), the LVEDD level was distinctly lower (P < 0.05), and the levels of ST2, BNP, and MCP-1 in the EG were clearly lower at week 4 of treatment (P < 0.05) with a statistical significance in difference. Conclusion: Dapagliflozin has a definite curative effect in heart failure patients with type 2 diabetes mellitus, which can effectively reduce the inflammatory response of patients and inhibit the myocardial fibrosis, and has a potential value in improving cardiac function and promoting prognosis.

Relationship Between Preoperative Hypoalbuminemia and Postoperative Pneumonia Following Geriatric Hip Fracture Surgery: A Propensity-Score Matched and Conditional Logistic Regression Analysis.

Background: Pneumonia is a devastating complication following geriatric hip fracture surgery, and preoperative hypoalbuminemia may be a potentially modifiable factor leading to improved outcome. This study aimed to quantify the relationship between preoperative hypoalbuminemia and postoperative pneumonia. Methods: We retrospectively reviewed the medical records of elderly patients (≥60 years) who underwent surgeries for hip fracture in a tertiary referral center between 2016 and 2020. According to the preoperative serum albumin level, they were divided into two groups: <35 g/ L and ≥35 g/ L. To reduce potential confounding, propensity score matching (PSM) in a 1:1 ratio was performed, with the caliper value set as 0.002; and further conditional logistic regression analysis was used to control the other potential confounders to determine the association strength. Results: Among 3,147 eligible patients included, PSM yielded 1,318 matched patients, with 659 in each respective group, suggesting significantly improved balance in most variables (standardized mean deviation improvement range, 20.7% to 99.1%), except for basophil count. The conditional logistic regression analysis, adjusted for PS and other intra- or post-operative variables, showed 6.18-fold (relative ratio, 6.18; 95% CI, 3.15-11.98; P<0.001) increased risk of postoperative pneumonia associated with preoperative hypoalbuminemia. Conclusion: Preoperative hypoalbuminemia was identified to be independently and highly associated with development of postoperative pneumonia in elderly patients undergoing hip fracture surgeries. However, whether the patients who had such condition may benefit from preoperative targeted nutritional support needs to be clarified by more prospective studies.

Incidence and risk factors for postoperative pneumonia following surgically treated hip fracture in geriatric patients: a retrospective cohort study.

OBJECTIVE: Large sample investigations for risk factors for pneumonia in elderly patients after hip fracture surgeries are lacking. The purpose of this study is to determine the incidence and risk factors for postoperative pneumonia in geriatric patients following hip fracture operations. METHODS: A retrospective study of incidence and risk factors in a tertiary referral center between 2016 and 2020 was conducted. Geriatric patients who developed postoperative pneumonia after surgeries of hip fracture during hospitalization stay were defined as cases and those without as controls. Multivariate logistic regression model was used to evaluate risk factors for postoperative pneumonia. RESULTS: This study included 3147 patients, and 182 developed postoperative pneumonia, denoting the rate of 5.8%. In the multivariate analyses, age (OR 1.04; 95% CI 1.02-1.06), sex (males) (OR 2.27; 95% CI 1.64-3.13), respiratory disease (OR 3.74; 95% CI 2.32-6.04), heart disease (OR 1.68; 95% CI 1.14-2.47), cerebrovascular disease (OR 1.58; 95% CI 1.11-2.27), liver disease (OR 2.61; 95% CI 1.33-5.15), preoperative stay (OR 1.08; 95% CI 1.05-1.11) and general anesthesia (OR 1.61; 95% CI 1.15-2.27) were identified as independent risk factors for postoperative pneumonia. CONCLUSIONS: This study identified several risk factors for pneumonia in geriatric patients after hip fracture operations, providing a viable preventive strategy for optimizing clinical conditions for reduction of postoperative pneumonia.

Modic changes of the cervical spine: T1 slope and its impact on axial neck pain.

BACKGROUND: The purpose of the research was to evaluate cervical sagittal parameters on magnetic resonance imaging (MRI) in patients with Modic changes and its impact on axial neck pain. METHODS: This study consisted of 266 consecutive asymptomatic or symptomatic patients with Modic changes, whose average age was 50.9±12.6 years from January 2015 to December 2016. Cervical sagittal parameters included sagittal alignment of the cervical spine (SACS), T1 slope, thoracic inlet angle (TIA), and neck tilt (NT). The Modic changes group was compared with an asymptomatic control group of 338 age- and gender-matched adults. RESULTS: In the Modic changes group, T1 slope was significantly higher (25.8°±6.3°) compared with that in the control group (22.5°±6.8°) (P=0.000). However, there was no significant difference of the NT, TIA, and SACS between the two groups. Patients in the Modic changes group were more likely to have experienced historical axial neck pain compared with the control group (P=0.000). With regard to the disc degeneration, it indicated that the disc in the Modic changes group had more severe disc degeneration (P=0.032). CONCLUSION: T1 slope in the Modic changes group was significantly higher compared to that of the control group. The findings suggested that a higher T1 slope with broken compensation of cervical sagittal mechanism may be associated with the development of Modic changes in the cervical spine.

Effect of OPG gene mutation on protein expression and biological activity in osteoporosis.

The effect of an osteoprotegerin (OPG) gene mutation was investigated on its protein expression and biological activity in osteoporosis. The pcDNA3.0-OPG plasmid or wild-type plasmid were transfected into HEK293 cells. Osteoclast tartrate-resistant acid phosphatase (TRAP) staining and counting were then performed, and the expression of genes related to osteoclast differentiation and activation were measured by RT-PCR. The wild-type or mutant-type OPG at concentrations of 0, 10, 20, 50 and 100 ng/ml were added respectively to RAW264.7 cells and incubated for 24 h. The viability of cells treated with the wild-type and mutant-type OPG at a concentration of 100 ng/ml was still over 99%, which indicated that the wild-type and mutant-type OPG at this concentration had no cytotoxic effect on RAW264.7 cells. The number of TRAP-positive cells decreased with increasing concentration of wild-type or mutant-type OPG. At the concentrations of 20, 50 and 100 ng/ml, the inhibitory effect of wild-type OPG was significantly higher than that of mutant-type OPG (p<0.05). Both mutant-type and wild-type OPG inhibited the bone resorption activity of osteoclasts, and the inhibitory effect of wild-type OPG was significantly higher than that of mutant-type OPG at the concentrations of 20, 50 and 100 ng/ml (p<0.05). The levels of TRAP and RANK mRNA in the wild-type OPG treatment group were significantly lower than those in the control group, while the levels of TRAP and RANK mRNA in the mutant-type OPG treatment group were significantly lower than those in the wild-type group (p<0.05). The genetic mutation did not affect the protein expression levels of OPG, but inhibited the normal activity of OPG.

Microscopic composition maps of poly(styrene-co-2-hydroxyethyl methacrylate) colloidal crystals and interconnected colloidal arrays.

Colloidal crystalline films were prepared from poly(styrene-co-2-hydroxyethyl methacrylate) (PS-HEMA) latex particles by evaporative deposition. The hexagonally ordered surfaces of the colloidal crystals (CCs) were transformed with styrene vapor at room temperature to interconnected colloidal arrays (ICAs) that have a honeycomb-like ridge of polymer surrounding hexagonally ordered dimples in the surface. When the styrene vapor temperatures were increased systematically to 45 degrees C, the regularity of ICA structure decreased and finally disappeared. Images from transmission electron microscopy (TEM) and from atomic force microscopy (AFM) show that the surfaces of the PS-HEMA particles and the ICAs have raspberry textures. Monolayer CCs and ICAs fabricated on TEM grids were analyzed by energy dispersive spectroscopy (EDS) to determine the elemental compositions of the different regions of the textured surfaces. Carbon, oxygen, and sulfur were distributed all over the surface of the CC. While carbon was distributed over the entire surface of the ICA, oxygen, sulfur, sodium, and potassium were concentrated mainly on the ridges of the honeycomb and not in the dimples of the ICA. The results are discussed in terms of a mechanism of transformation of the CC to the ICA in which styrene monomer swells the polystyrene-rich regions of the particles, and the swollen polystyrene rises to the surface. The polyHEMA-rich regions of the particles maintain the hexagonal periodicity, and liquid styrene evaporates to leave a more polystyrene-rich textured surface.

Motion of single wandering diblock-macromolecules directed by a PTFE nano-fence: real time SFM observations.

Using SFM we have observed a peculiar twisting motion of diblock macromolecules pre-collapsed in ethanol vapour during their subsequent spreading in water vapour. The intrinsic asymmetry of the diblock macromolecules has been considered to be the reason for such twisting. Further, friction-deposited PTFE nano-stripes have been employed as nano-trails with the purpose of inducing lateral directed motion of the asymmetric diblock macromolecules under cyclic impact from the changing vapour surroundings. Indeed, some of the macromolecules have demonstrated a certain tendency to orient along the PTFE stripes, and some of the oriented ones have moved occasionally in a directed manner along the trail. However, it has been difficult to reliably record such directed motion at the single molecule level due to some mobility of the PTFE nano-trails themselves in the changing vapour environment. In vapours, the PTFE stripes have demonstrated a distinct tendency towards conjunction. This tendency has manifested itself in efficient expelling of groups of the mobile brush-like molecules from the areas between two PTFE stripes joining in a zip-fastener manner. This different kind of vapour-induced cooperative macromolecular motion has been reliably observed as being directed. The PTFE nano-frame experiences some deformation when constraining the spreading macromolecules. We have estimated the possible force causing such deformation of the PTFE fence. The force has been found to be a few pN as calculated by a partial contribution from every single molecule of the constrained group.

Versatile coordination chemistry towards multifunctional carbon nanotube nanohybrids.

Dispersible single-walled carbon nanotubes grafted with poly(4-vinylpyridine), SWNT-PVP, were tested in coordination assays with zinc tetraphenylporphyrin (ZnP). Kinetic and spectroscopic evidence corroborates the successful formation of a SWNT-PVPZnP nanohybrid. Within this SWNT-PVPZnP nanohybrid, static electron-transfer quenching (2.0+/-0.1) x 10(9) s(-1) converts the photoexcited-ZnP chromophore into a radical-ion-pair state with a microsecond lifetime, namely one-electron oxidized-ZnP and reduced-SWNT.

Donor-acceptor nanoensembles of soluble carbon nanotubes.

Donor-acceptor nanoensembles, prepared via electrostatic interactions of single wall carbon nanotubes and porphyrin salts, give rise to photoinduced intra-complex charge separation that lasts tens of microseconds.

Polymer brushes on single-walled carbon nanotubes by atom transfer radical polymerization of n-butyl methacrylate.

Polymer brushes with single-walled carbon nanotubes (SWNT) as backbones were synthesized by grafting n-butyl methacrylate (nBMA) from the ends and sidewalls of SWNT via atom transfer radical polymerization (ATRP). Carboxylic acid groups on SWNT were formed by nitric acid oxidation. The ATRP initiators were covalently attached to the SWNT by esterification of 2-hydroxyethyl 2'-bromopropionate with carboxylic acid groups. Methyl 2-bromopropionate (MBP) was added as free initiator during the brush preparation to control growth of the brushes and to monitor the polymerization kinetics. Size-exclusion chromatography (SEC) results show that the molecular weight of free poly(n-butyl methacrylate) (PnBMA) increased linearly with nBMA monomer conversion. PnBMA cleaved from the SWNT after high conversion had the same molecular weight as PnBMA produced in solution. Thermogravimetric analyses (TGA) show that the amount of PnBMA grown from the SWNT increased linearly with the molecular weight of the free PnBMA. The most highly PnBMA-functionalized SWNT dissolve in 1,2-dichlorobenzene, chloroform, and tetrahydrofuran, and solubility increases with the amount of PnBMA bound to SWNT. Near-infrared and Raman spectra indicate that the side walls of the SWNT were lightly functionalized by the nitric acid treatment and that the degree of functionalization of the SWNT did not change significantly during the formation of initiator or during the polymerization. Atomic force microscopy (AFM) images show contour lengths of the SWNT brushes on a mica surface from 200 nm to 2.0 microm and an average height of the backbone of 2-3 nm, indicating that the bundles of original SWNT were broken into individual tubes by functionalization and polymerization.

Monitoring the transformation of colloidal crystals by styrene vapor using atomic force microscopy.

The stages of transformation of a colloidal crystalline film of latex spheres to a new periodic structure were imaged by atomic force microscopy. Colloidal crystalline films were prepared with 320 nm diameter poly(styrene-co-2-hydroxyethyl methacrylate) (PSt/HEMA) spheres. The hexagonally ordered surfaces of the colloidal crystalline films were transformed with styrene vapor at room temperature to a new morphology having holes in the surface and the same periodicity as the original films. The surfaces of colloidal crystals and the transformed films have a raspberry-like texture superposed on the 320 nm hexagonal periodicity. Both height images and phase images reveal that the latex spheres shrink and the transformation proceeds by an order-disorder-order sequence. The final structure is an interconnected colloidal array with smaller polystyrene particles dispersed in a continuous PSt/HEMA matrix.

Multiarm molecular brushes: effect of the number of arms on the molecular weight polydispersity and surface ordering.

Individual molecules of multiarm starlike molecular brushes were visualized by atomic force microscopy. In the studied series of brushes, the number of arms varied from one for a linear chain to four, while the length of the side chains was kept approximately constant. Molecular visualization provided a unique opportunity for independent size characterization of the brush arms separately from that of the entire molecule. In agreement with the Schulz-Flory theory for chain coupling, the polydispersity of the total length was significantly lower than that of the arm length. The variation in polydispersity had an effect on molecular ordering. Lateral compression of the starlike brushes caused a transition from an extended dendritic-like conformation to a compact disklike conformation. In contrast to one-, two-, and three-arm brushes, the four-arm molecules with a lower polydispersity index of 1.04 demonstrated local hexagonal order.