The Emotional Content of Children's Writing: A Data-Driven Approach.

Emotion is closely associated with language, but we know very little about how children express emotion in their own writing. We used a large-scale, cross-sectional, and data-driven approach to investigate emotional expression via writing in children of different ages, and whether it varies for boys and girls. We first used a lexicon-based bag-of-words approach to identify emotional content in a large corpus of stories (N>100,000) written by 7- to 13-year-old children. Generalized Additive Models were then used to model changes in sentiment across age and gender. Two other machine learning approaches (BERT and TextBlob) validated and extended these analyses, converging on the finding that positive sentiments in children's writing decrease with age. These findings echo reports from previous studies showing a decrease in mood and an increased use of negative emotion words with age. We also found that stories by girls contained more positive sentiments than stories by boys. Our study shows the utility of large-scale data-driven approaches to reveal the content and nature of children's writing. Future experimental work should build on these observations to understand the likely complex relationships between written language and emotion, and how these change over development.

Antibiotic resistance characteristics and risk factors analysis of Helicobacter pylori strains isolated from patients in Liaoning Province, an area in North China.

Background: The prevalence of Helicobacter pylori (H. pylori) keeps rising while the eradication rate continues to decline due to the increasing antibiotic resistance. Regional variations of antimicrobial resistance to H. pylori have been recommended by guidelines in recent years. This study aims to investigate the antibiotic resistance rate of H. pylori and its association with infected subjects' characteristics in Liaoning Province, an area in north China. Methods: Gastric tissues from 178 H. pylori positive participants without previous antibiotic use within four weeks were collected for H. pylori culture. Antibiotic susceptibility to furazolidone (AOZ), tetracycline (TC), levofloxacin (LFX), metronidazole (MET), clarithromycin (CLA), and amoxicillin (AMX) were examined with the agar dilution method. Associations between H. pylori resistance and patient characteristics were further analysed. Results: No resistance was observed in AOZ or TC. For LFX, MET, CLA, and AMX, the overall resistance rates were 41.10%, 79.14%, 71.78%, and 22.09% respectively. There were significant differences between resistance to CLA and MALToma (P = 0.021), and between resistance to MET and age (P < 0.001). Conclusions: The primary resistant rates of LEX, MET, CLA, and AMX were relatively high in Liaoning. Treatment effectiveness improvement could be achieved by prior antimicrobial susceptibility tests before antibiotic prescription.

Rheological Characteristics of Starch-Based Biodegradable Blends.

Thermoplastic starch was blended with commercially available biodegradable polyesters of poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA) for its improved performance and processability. The morphology and elemental composition of these biodegradable polymer blends were observed by scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively, while their thermal properties were analyzed using thermogravimetric analysis and differential thermal calorimetry. For rheological analysis, the steady shear and dynamic oscillation tests of three samples at various temperatures were investigated using a rotational rheometer. All three samples exhibited significant shear thinning at all measured temperatures, and their shear viscosity behavior was plotted using the Carreau model. The frequency sweep tests showed that the thermoplastic starch sample exhibited a solid state at all temperatures tested, whereas both starch/PBAT and starch/PBAT/PLA blend samples exhibited viscoelastic liquid behavior after the melting temperature such that their loss modulus at low frequencies was greater than the storage modulus, and inversion occurred at high frequencies (storage modulus > loss modulus).

A Metal Coordination-Based Supramolecular Elastomer with Shape Memory-Assisted Self-Healing Effect.

Rubber materials are widely used in aerospace, automotive, smart devices and artificial skin. It is significant to address the aging susceptibility of conventional vulcanized rubber and to impart it rapid self-healing performance for destructive crack damage. Herein, a novel supramolecular rubber elastomer is prepared by introducing metal coordination between carboxyl-terminated polybutadiene and polystyrene-vinylpyridine copolymer. Based on the metal coordination interaction, the elastomer exhibits shape memory and self-healing properties. Moreover, a rapid closure-repair process of destructive cracks is achieved by presetting temporary shapes. This shape memory-assisted self-repair model is shown to be an effective means for rapid repair of severe cracks. An approach to enhance the mechanical and self-healing properties of elastomer was demonstrated by adding appropriate amounts of oxidized carbon nano-onions (O-CNO) into the system. The tensile strength of the elastomer with an O-CNOs content of 0.5 wt% was restored to 83 ± 10% of the original sample after being repaired at 85 °C for 6 h. This study confirms that metal coordination interaction is an effective method for designing shape memory self-healing rubber elastomer. The shape memory-assisted self-healing effect provides a reference for the rapid self-repairing of severe cracks.

Evaluation of remodeling and regeneration of electrospun PCL/fibrin vascular grafts in vivo.

The success of artificial vascular graft in the host to obtain functional tissue regeneration and remodeling is a great challenge in the field of small diameter tissue engineering blood vessels. In our previous work, poly(ε-caprolactone) (PCL)/fibrin vascular grafts were fabricated by electrospinning. It was proved that the PCL/fibrin vascular graft was a suitable small diameter tissue engineering vascular scaffold with good biomechanical properties and cell compatibility. Here we mainly examined the performance of PCL/fibrin vascular graft in vivo. The graft showed randomly arranged nanofiber structure, excellent mechanical strength, higher compliance and degradation properties. At 9 months after implantation in the rat abdominal aorta, the graft induced the regeneration of neoarteries, and promoted ECM deposition and rapid endothelialization. More importantly, the PCL/fibrin vascular graft showed more microvessels density and fewer calcification areas at 3 months, which was beneficial to improve cell infiltration and proliferation. Moreover, the ratio of M2/M1macrophage in PCL/fibrin graft had a higher expression level and the secretion amount of pro-inflammatory cytokines started to increase, and then decreased to similar to the native artery. Thus, the electrospun PCL/fibrin tubular vascular graft had great potential to become a new type of artificial blood vessel scaffold that can be implanted in vivo for long term.

Preparation of PU/Fibrin Vascular Scaffold with Good Biomechanical Properties and Evaluation of Its Performance in vitro and in vivo.

PURPOSE: The development of tissue-engineered blood vessels provides a new source of donors for coronary artery bypass grafting and peripheral blood vessel transplantation. Fibrin fiber has good biocompatibility and is an ideal tissue engineering vascular scaffold, but its mechanical property needs improvement. METHODS: We mixed polyurethane (PU) and fibrin to prepare the PU/fibrin vascular scaffolds by using electrospinning technology in order to enhance the mechanical properties of fibrin scaffold. We investigated the morphological, mechanical strength, hydrophilicity, degradation, blood and cell compatibility of PU/fibrin (0:100), PU/fibrin (5:95), PU/fibrin (15:85) and PU/fibrin (25:75) vascular scaffolds. Based on the results in vitro, PU/fibrin (15:85) was selected for transplantation in vivo to repair vascular defects, and the extracellular matrix formation, vascular remodeling, and immune response were evaluated. RESULTS: The results indicated that the fiber diameter of the PU/fibrin (15:85) scaffold was about 712nm. With the increase of PU content, the mechanical strength of the composite scaffolds increased, however, the degradation rate decreased gradually. The PU/fibrin scaffold showed good hydrophilicity and hemocompatibility. PU/fibrin (15:85) vascular scaffold could promote the adhesion and proliferation of mesenchymal stromal cells (MSCs). Quantitative RT-PCR experimental results showed that the expression of collagen, survivin and vimentin genes in PU/fibrin (15:85) was higher than that in PU/fibrin (25:75). The results in vivo indicated the mechanical properties and compliance of PU/fibrin grafts could meet clinical requirements and the proportion of thrombosis or occlusion was significantly lower. The graft showed strong vasomotor response, and the smooth muscle cells, endothelial cells, and ECM deposition of the neoartery were comparable to that of native artery after 3 months. At 3 months, the amount of macrophages in PU/fibrin grafts was significantly lower, and the secretion of pro-inflammatory and anti-inflammatory cytokines decreased. CONCLUSION: PU/fibrin (15:85) vascular scaffolds had great potential to be used as small-diameter tissue engineering blood vessels.

Improved mechanical properties by modifying fibrin scaffold with PCL and its biocompatibility evaluation.

Previous studies have proved that fibrin is an excellent scaffold material for tissue engineered blood vessel. However, the mechanical properties of fibrin are not enough. One way to solve the problem is to combine polymer materials with fibrin to enhance its biomechanical properties. In this study, a novel polycaprolactone (PCL)/fibrin composite scaffold was prepared by electrospinning technology. The morphological, physicochemical analysis, blood compatibility, biomechanical properties, biocompatibility and biodegradability of this vascular scaffold were evaluated. The results showed that electrospun PCL/fibrin scaffold possessed smaller aperture and larger fiber diameter than that of fibrin scaffold. The swelling ratio of the vascular PCL/fibrin scaffold at (0:100), (10:90), (20:80) and (30:70) was 112 ± 5.3, 103 ± 6.9, 94 ± 5.9 and 89 ± 3.4%, respectively. Mechanical properties of fibrin scaffolds were enhanced significantly by the addition of PCL. Furthermore, the time of plasma re-calcification, activated partial thromboplastin time and thromboplastin time in four different proportions of PCL/fibrin scaffolds were similar to that of the control group. Degradation experiments in vitro demonstrated that the degradation rate of PCL/fibrin scaffold was closely related to the content of PCL. MTT assays and immunofluorescence staining indicated that the stem cells cocultured with the PCL/fibrin scaffold had good proliferation behavior. Live/dead assay confirmed that the number of MSCs in the PCL/fibrin (10:90) group was significantly increased as compared to other groups. The tests in vivo results showed PCL/fibrin scaffold could promote cell infiltration and tissue regeneration and its degradation in vivo was faster than that of PCL scaffold. In summary, PCL/fibrin (20:80) scaffold exhibited balanced mechanical properties and degradability, as well as good cell compatibility properties; therefore, it was a promising tissue engineering material for vascular graft.

Lipoxin A4 protects against spinal cord injury via regulating Akt/nuclear factor (erythroid-derived 2)-like 2/heme oxygenase-1 signaling.

Spinal cord injury (SCI) is a devastating physical trauma worldwide. The mechanisms of SCI are still not clear and the effective treatment is limited. Lipoxin A4 (LXA4) possesses anti-inflammatory and neuroprotective effects. The present study was designed to further evaluate the molecular mechanisms of LXA4-induced protective effects in a rat model of SCI. We found that LXA4 increased Basso, Beattie and Bresnahan (BBB) scores, increased mechanical paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) to a radiant heat, reduced the lesion volume, decreased Bax mRNA expression and increased Bcl-2 expression after SCI. The phosphorylation of Akt and protein expression of Nrf2 and HO-1 were reduced after SCI. LXA4 treatment significantly inhibited the reduction of Akt phosphorylation and Nrf2 and HO-1 protein expression. Injection of LY294002 notably inhibited the phosphorylation of Akt, and the expression of total Akt and Nrf2 and HO-1 after SCI in LXA4-treated rats. LY294002 prohibited LXA4-induced effects after SCI. shNrf2 injection markedly decreased both Nrf2 and HO-1 expression in LXA4-treated rats after SCI. ZnPP notably decreased HO-1 expression but did not markedly affect Nrf2 expression. shNrf2 and ZnPP prohibited LXA4-induced increase of BBB scores, and PWT and PWL, decrease of lesion volume of spinal cord, reduction of Bax expression and increase of Bcl-2 expression. The results indicate that LXA4 protects against SCI through Akt/Nrf2/HO-1 signaling. The data provide novel insights into the mechanisms of LXA4-mediated neuprotective effects against SCI and suggest that LXA4 may be a potential therapeutic agent for SCI and its associated complications.

Effects of exogenous neurotrophin-3 on myocyte apoptosis and Ca(2+)-ATP enzyme levels following nerve injury in rats.

This study aims to determine the influence of neurotrophin-3 (NT-3) plasmids on neuronal apoptosis and Ca(2+)-ATP enzyme levels in injured muscles. We also investigated the mechanism underlying the role of NT-3 in delaying muscle atrophy following a peripheral nerve injury. Sixty adult Wistar rats were used to generate the peripheral nerve injury models. The rats were randomly assigned to the saline and NT-3 groups. Related indicators, such as caspase-3 protein expression, skeletal muscle cell apoptosis, and Ca(2+)-ATP enzyme expression were quantified. The expression levels of caspase-3 and the histone-muscle cell apoptosis rate in the NT-3 group decreased at different post-operative times following peripheral nerve injury, whereas NT-3 expression and the sarcoplasmic reticulum Ca(2+)-ATP enzyme levels increased. Statistically significant differences were observed in the NT-3 group as compared to the saline group (P < 0.05). NT-3 mitigated muscle atrophy following peripheral nerve damage by inhibiting caspase-3 gene expression and increasing Ca(2+)-ATP enzymatic activity, ultimately reducing muscle apoptosis.

Transplantation of neurotrophin-3-transfected bone marrow mesenchymal stem cells for the repair of spinal cord injury.

Bone marrow mesenchymal stem cell transplantation has been shown to be therapeutic in the repair of spinal cord injury. However, the low survival rate of transplanted bone marrow mesenchymal stem cells in vivo remains a problem. Neurotrophin-3 promotes motor neuron survival and it is hypothesized that its transfection can enhance the therapeutic effect. We show that in vitro transfection of neurotrophin-3 gene increases the number of bone marrow mesenchymal stem cells in the region of spinal cord injury. These results indicate that neurotrophin-3 can promote the survival of bone marrow mesenchymal stem cells transplanted into the region of spinal cord injury and potentially enhance the therapeutic effect in the repair of spinal cord injury.

[Impact of PTTG1 downregulation on cell proliferation, cell cycle and cell invasion of osteosarcoma and related molecular mechanisms].

OBJECTIVE: To downregulate the expression of pituitary tumor transforming gene 1 (PTTG1) in osteosarcoma (OS) cells by siRNA technology and to investigate related biological impact on cell proliferation, cell cycle and cell invasion of OS. METHODS: Three OS cell lines and osteoblast hFOB1.19 cell line were used in this study. Control siRNA and PTTG1 siRNA were employed to transfect OS U2OS cells, and PTTG1 protein level was detected by Western blot after the transfection. Effects of PTTG1 siRNA on cell proliferation, cell cycle and cell invasion were investigated by CCK-8, flow cytometry and Boyden chamber, respectively. Finally, activity of Akt and its downstream target gene expression were analyzed by Western blot in U2OS cells upon various treatments. RESULTS: Expression of PTTG1 protein in 3 OS cells (MG-63, SaOS-2 and U2OS) was significantly higher than that in osteoblast hFOB1.19, among which U2OS cells displayed the highest level. PTTG1 siRNA markedly downregulated the expression of PTTG1 protein in U2OS cells, leading to obvious inhibition of cell proliferation, altered cell cycle distribution and reduced ability of invasion of U2OS cells. Moreover, downregulation of PTTG1 reduced the expression of p-Akt (S473 and T308), MMP-2 and MMP-9 proteins, along with enhanced expression of p21 and E-cadherin proteins. CONCLUSIONS: PTTG1 may be tightly linked to the development of OS and therefore may serve as a novel target for precision therapy of OS.

The association of XPG and MMS19L polymorphisms response to chemotherapy in osteosarcoma.

OBJECTIVE: To assess the role of XPG, XPC, CCNH and MMS19L polymorphisms response to chemotherapy in osteosarcoma, and the clinical outcome of osteosarcoma. METHODS: One hundred and sixty eight osteosarcoma patients who were histologically confirmed were enrolled in our study between January 2007 and March 2009. Genotyping of XPG, XPC, CCNH and MMS19L was performed in a 384-well plate format on the MassARRAY® platform. RESULTS: Individuals with rs2296147 TT genotype showed a better response as compared with CC genotype, with the OR (95% CI) of 3.89(1.49-10.95). Those carrying rs29001322 TT genotype presented better response to chemotherapy, and the OR (95% CI) was as high as 12.25(2.63-121.84). Patients carrying TT genotype of XPG rs2296147 and MMS19L rs29001322 showed a significantly longer overall survival than CC genotype, they had 0.37 and 0.31-fold risk of death when compared with wide-type of this gene. CONCLUSIONS: XPG rs2296147 and MMS19L rs29001322 are correlated with response to chemotherapy and prognosis of osteosarcoma. Our findings would provide important evidence for prognostic and therapeutic implications in osteosarcoma.

Nanoparticles carrying neurotrophin-3-modified Schwann cells promote repair of sciatic nerve defects.

Schwann cells and neurotrophin-3 play an important role in neural regeneration, but the secretion of neurotrophin-3 from Schwann cells is limited, and exogenous neurotrophin-3 is inactived easily in vivo. In this study, we have transfected neurotrophin-3 into Schwann cells cultured in vitro using nanoparticle liposomes. Results showed that neurotrophin-3 was successfully transfected into Schwann cells, where it was expressed effectively and steadily. A composite of Schwann cells transfected with neurotrophin-3 and poly(lactic-co-glycolic acid) biodegradable conduits was transplanted into rats to repair 10-mm sciatic nerve defects. Transplantation of the composite scaffold could restore the myoelectricity and wave amplitude of the sciatic nerve by electrophysiological examination, promote nerve axonal and myelin regeneration, and delay apoptosis of spinal motor neurons. Experimental findings indicate that neurotrophin-3 transfected Schwann cells combined with bridge grafting can promote neural regeneration and functional recovery after nerve injury.

[Effects of neurotrophic factor 3 gene modified SC on sciatic nerve regeneration in rats].

OBJECTIVE: To investgate the effects of neurotrophic factor 3 (NT-3) genes modified SC on facilitating nerve regeneration and protecting neuronal survival after the sciatic nerve transection in rats. METHODS: The double sciatic nerves were harvested from 3-day-old Wistar rats and the SCs were separated, cultured and purified with double enzyme digestion and adherent culture. The third generation purified SCs were used. The NT-3 cDNA gene was transfected into cultured SCs by using cationic liposome. The NT-3 expression were identified by ELISA after 1, 2, 4 and 8 weeks. The plasmids expressing NT-3 genes were transfected into SCs with lipofectamine. The purity of SCs were detecting before and after modified with NT-3. The nerve-grafting complexes were constructed by SCs (3 x 10(7)/mL) modified NT-3, third generation SCs (3 x 10(7)/mL), NT-3 gene, respectively. And the nerve-grafting complexes were combined with ECM gel and PLGA conduit. Forty-eight adult SD rats were made the models of the right sciatic nerve defect (10 mm). According to the nerve-grafting complexes which were repaired the sciatic nerve defects, the models were divided into 4 groups randomly (n=12): group A (ECM gel and PLGA conduits), group B (SC, ECM gel and PLGA conduits), group C (NT-3 gene, ECM gel and PLGA conduits) and group D (NT-3 modified SC, ECM gel and PLGA conduits). At 2, 4, 6, 8 and 12 weeks after operation, the nerve gross were observed. Electrophysiological examination, histological observation and transmission electron microscope observation were performed at 12 weeks after operation. RESULTS: The concentrations of NT-3 protein were 0.39 +/- 0.25, 0.76 +/- 0.22, 1.06 +/- 0.38 and 1.61 +/- 0.35 at 1, 2, 4 and 8 weeks after operation; showing statistically significant differences (P < 0.05). The purity of SCs was 94.7% +/- 2.1% and 95.6% +/- 2.5% before and after modified with NT-3, respectively; showing a statistically significant difference (P < 0.05). The feet of injury rats began inflammation and ulcer, which healed at 12 weeks in group D, followed by groups C and B, but which was serious in group A gradually. The observations of gross, sections under microscope and transmission electron microscope at 12 weeks showed the regeneration of defect nerve was best in group D, followed by groups C and B, and group A was worst. There were statistically significant differences (P < 0.05) in latent period, amplitude, motor nerve conduction velocity, the number and thickness of axon, the diameter of nerve fiber, the percentage of the nerve tissue area between group A and groups B, C, D, between groups B, C and group D at 12 weeks. At 12 weeks after operation, the transmission electron microscope showed observation the maturation of medullary sheath was best in group D, followed by groups C and B, and group A was worst. CONCLUSION: The nerve-grafting complex of NT-3 genes modified SCs could repair injured nerve. The competence is superior to SCs and neurotrophic factors.

[Study of animal model of hypertensive disorder complicating pregnancy in pregnant rats stimulated by homocysteine and monosodium glutamate].

OBJECTIVE: To determine whether homocysteine (Hcy) and monosodium glutamate (MSG) could lead to animal model of hypertensive disorder complicating pregnancy and its mechanism. METHODS: Female adult Wistar rats were randomly divided into 4 groups: pregnant control group (PN), pregnant Hcy group (PH), pregnant glutamic acid group (PG) and pregnant Hcy and glutamic acid group (PHG). The rats of each group were injected with Hcy 200 mg/kg or physiological saline every day intraperitoneally and with MSG or 0.9% saline every other day via Hcy injection from the 10th day to the 20th day of pregnancy. The blood pressure, urine protein, function of liver and kidney, weight of placenta, length and weight of fetus were all measured. The histological change of the pallium and the change of behavior of pregnant rats were also observed. RESULTS: (1) The blood pressure in PH [(107 +/- 8) mm Hg, 1 mm Hg = 0.133 kPa], and PHG group [(109 +/- 10) mm Hg] after the treatment increased significantly compared with those in other groups from the 12 th day after pregnancy (P < 0.01). (2) The level of urine protein [(1.42 +/- 0.53) g/L, (1.53 +/- 0.24) g/L] in PH and PHG groups after the treatment was significantly higher than the other groups (P < 0.01). (3) Obvious changes of the function of liver and kidney [alanine aminotransferase (ALT) (57 +/- 15) U/L, (69 +/- 24) U/L, aspartate aminotransferase (AST) (265 +/- 61) U/L, (293 +/- 118) U/L, blood urea nitrogen (BUN) (9.5 +/- 0.8) mmol/L, (9.5 +/- 1.6) mmol/L, creatinine (Cr) (54 +/- 10) micromol/L, (54 +/- 10) micromol/L], were found in PHG group and PH group (P < 0.01). (4) The weight of placenta [(0.49 +/- 0.28) g, (0.45 +/- 0.03) g], length and weight of fetus [(3.6 +/- 1.5) cm, (3.5 +/- 1.5) cm] in PH group and PHG group were significantly lower than that in PN group and PG group (P < 0.01). Obvious histological changes in pallium and kidney were found in PH group and PHG group. Changes of behavior were found in PHG group. CONCLUSION: Hcy and MSG could induce the symptoms of hypertensive disorder complicating pregnancy in pregnant rats, especially pre-eclampsia, possibly through injuring vascular endothelial cell and nerve cell of the cerebral cortex.

[Effect of interleukin-6 on gene expression of certain cytokines during wound healing process of mouse skin].

To examine the effect of the interlukin-6 (IL-6) in wound healing process, gene expression profiles of cytokines including interlukin-1alpha (IL-1alpha), interlukin-1beta (IL-1beta), keratinocyte chemoattractant (KC), macrophage inflammatory protein-1alpha (MIP-1alpha), and macrophage inflammatory protein-2 (MIP-2) during the skin wound healing on the IL-6(+/+) and IL-6(-/-) mice were detected using immunochemical staining and RT-PCR methods at different phases after wound. The results showed that these cytokines were expressed at early phage after wound, and a expressing peak were found on the third day after wound, and decreased on the sixth day after wound. Meanwhile, on the third and sixth day after wound, all the levels of the five cytokines expressed of the IL6(-/-) mice were significantly lower than those of the IL-6(+/+) mice, but on the first day after wound, only the levels of MIP-1alpha and KC of the IL-6(-/-) mice were lower. The process of skin wound healing was later in IL-6(-/-) mice than that in IL-6(+/+) mice, but it was complete in IL-6(-/-) mice. These results showed that IL-6 induce expression of the other five cytokines detected, and advance the repair of the wound on skin of mice, but in the mice of IL-6 deletion, the wound healing process was not disturbed significantly.