[Effects of Different Forms of Nitrogen Addition on Soil Physical and Chemical Properties and Microbial Community Structure of Perennial Alpine Cultivated Grassland].

This study aimed to investigate the impact of different nitrogen forms on soil physicochemical properties and microbial community structure in perennial alpine cultivated grasslands, in order to provide scientific basis for developing nitrogen addition strategies for perennial alpine cultivated grasslands. In June 2022, a 4-year-old Qinghai grassland mixed with Poa pratensis Qinghai and Festuca sinensis Qinghai was established at the Bakatai Farm in Gonghe County, Hainan Tibetan Autonomous Prefecture, Qinghai Province. The study was conducted without fertilization as a control (CK), and three different forms of nitrogen treatments were set up, namely, U:urea (amide nitrogen), A:ammonium sulfate (ammonium nitrogen), and N:calcium nitrate (nitrate nitrogen); the nitrogen application rate for each treatment was 67.5 kg·(hm2·a)-1, and the composition and diversity of soil nutrients and microbial communities under different treatments were analyzed. The results showed that the input of exogenous ammonium nitrogen significantly increased NH4+-N content, AP content, and EC; amide nitrogen input significantly increased SOC content and TN content; and nitrate nitrogen input significantly increased NO3--N content, AN content, and TC content. Exogenous nitrogen input changed the structure of soil bacterial and fungal communities, as well as the relative abundance of dominant phyla and genera, but it did not significantly affect the alpha diversity of bacterial and fungal communities. Principal coordinate analysis (PCoA) showed that different forms of nitrogen addition had a significant impact on the Beta diversity of bacterial communities, whereas the impact on fungal communities was not significant. Redundancy analysis (RDA) indicated that nitrogen addition mainly changed the composition and structure of microbial communities through soil ammonium nitrogen. Overall, ammonium nitrogen fertilizer should be given priority in the soil remediation process of perennial cultivated grasslands in the Qinghai Tibet Plateau.

Structural position vectors and symmetries in complex networks.

Symmetries, due to their fundamental importance to dynamical processes on networks, have attracted a great deal of current research. Finding all symmetric nodes in large complex networks typically relies on automorphism groups from algebraic-group theory, which are solvable in quasipolynomial time. We articulate a conceptually appealing and computationally extremely efficient approach to finding and characterizing all symmetric nodes by introducing a structural position vector (SPV) for each node in networks. We establish the mathematical result that symmetric nodes must have the same SPV value and demonstrate, using six representative complex networks from the real world, that all symmetric nodes in these networks can be found in linear time. Furthermore, the SPVs not only characterize the similarity of nodes but also quantify the nodal influences in propagation dynamics. A caveat is that the proved mathematical result relating the SPV values to nodal symmetries is not sufficient; i.e., nodes having the same SPV values may not be symmetric, which arises in regular networks or networks with a dominant regular component. We point out with an analysis that this caveat is, in fact, shared by the known existing approaches to finding symmetric nodes in the literature. We further argue, with the aid of a mathematical analysis, that our SPV method is generally effective for finding the symmetric nodes in real-world networks that typically do not have a dominant regular component. Our SPV-based framework, therefore, provides a physically intuitive and computationally efficient way to uncover, understand, and exploit symmetric structures in complex networks arising from real-world applications.

Metamorphoses and explosively remote synchronization in dynamical networks.

We uncover a phenomenon in coupled nonlinear networks with a symmetry: as a bifurcation parameter changes through a critical value, synchronization among a subset of nodes can deteriorate abruptly, and, simultaneously, perfect synchronization emerges suddenly among a different subset of nodes that are not directly connected. This is a synchronization metamorphosis leading to an explosive transition to remote synchronization. The finding demonstrates that an explosive onset of synchrony and remote synchronization, two phenomena that have been studied separately, can arise in the same system due to symmetry, providing another proof that the interplay between nonlinear dynamics and symmetry can lead to a surprising phenomenon in physical systems.

State-by-State prediction of likely COVID-19 scenarios in the United States and assessment of the role of testing and control measures

Due to the heterogeneity among the States in the US, predicting COVID-19 trends and quantitatively assessing the effects of government testing capability and control measures need to be done via a State-by-State approach. We develop a comprehensive model for COVID-19 incorporating time delays and population movements. With key parameter values determined by empirical data, the model enables the most likely epidemic scenarios to be predicted for each State, which are indicative of whether testing services and control measures are vigorous enough to contain the disease. We find that government control measures play a more important role than testing in suppressing the epidemic. The vast disparities in the epidemic trends among the States imply the need for long-term placement of control measures to fully contain COVID-19.

Triclocarban exposure affects mouse oocyte in vitro maturation through inducing mitochondrial dysfunction and oxidative stress.

Triclocarban (TCC), a broad-spectrum lipophilic antibacterial agent, is the main ingredient of personal and health care products. Nonetheless, its ubiquitous presence in the environment has been established to negatively affect the reproduction in humans and animals. In this work, we studied the possible toxic effects of TCC on mouse oocytes maturation in vitro. Our findings revealed that TCC-treated immature mouse oocytes had a significantly reduced rate of polar body extrusion (PBE) compared to that of control. Further study demonstrated that the cell cycle progression and cytoskeletal dynamics were disrupted after TCC exposure, which resulted in the continuous activation of spindle assembly checkpoint (SAC). Moreover, TCC-treated oocytes had mitochondrial damage, reduced ATP content, and decreased mitochondrial membrane potential (MMP). Furthermore, TCC exposure induced oxidative stress and subsequently triggered early apoptosis in mouse oocytes. Besides, the levels of histone methylation were also affected, as indicated by increased H3K27me2 and H3K27me3 levels. In summary, our results revealed that TCC exposure disrupted mouse oocytes maturation through affecting cell cycle progression, cytoskeletal dynamics, oxidative stress, early apoptosis, mitochondria function, and histone modifications in vitro.

Diethylstilbestrol exposure disrupts mouse oocyte meiotic maturation in vitro through affecting spindle assembly and chromosome alignment.

An adverse tendency induced by the environmental estrogens in female reproductive health is one serious problem worldwide. Diethylstilbestrol (DES), as a synthetic estrogen, is still used as an animal growth stimulant in terrestrial livestock and aquaculture illegally. It has been reported to negatively affect ovarian function and oogenesis. Nevertheless, the mechanism and toxicity of DES on oocyte meiotic maturation are largely unknown. Herein, we found that DES (40 µM) intervened in mouse oocyte maturation and first polar body extrusion (PBE) was decreased in vitro. Cell cycle analysis showed meiotic process was disturbed with oocytes arrested at metaphase I (MI) stage after DES exposure. Further study showed that DES exposure disrupted the spindle assembly and chromosome alignment, which then continuously provoke the spindle assemble checkpoint (SAC). We also observed that the acetylation levels of α-tubulin were dramatically increased in DES-treated oocytes. In addition, the dynamics of actin were also affected. Moreover, the distribution patterns of estrogen receptor α (ERα) were altered in DES-treated oocyte, as indicated by the significant signals accumulation in the spindle area. However, ERα inhibitor failed to rescue the defects of oocyte maturation caused by DES. Of note, the same phenomenon was observed in estrogen-treated oocytes. Collectively, we showed that DES exposure lead to the oocyte meiotic failure via impairing the spindle assembly and chromosome alignment. Our research is helpful to understand how environmental estrogen affects female germ cells and contribute to design the potential therapies to preserve fertility especially for occupational exposure.

Doxorubicin Exposure Affects Oocyte Meiotic Maturation through DNA Damage-Induced Meiotic Arrest.

Developments in chemotherapeutics have enhanced the survival rate of cancer patients, however, adverse effects of chemotherapeutics on ovarian functions causes the fertility loss in young female cancer patients. Doxorubicin (DOX), as an anthracycline antitumor antibiotic, is extensively used to cure various malignancies. Recent studies have suggested that DOX can cause ovarian damage and affect the oocyte maturation, nevertheless the mechanism by which DOX on oocytes meiosis is poorly understood. In this study, we explored the mechanism for DOX-induced oocytes meiotic failure in vitro at human relevant exposure levels and time periods. Results described that DOX (100 nM) can interrupt the mouse oocytes meiotic maturation directly with reduced first polar body extrusion. Cell cycle analysis showed that most oocytes were arrested at metaphase I (MI) stage. However, DOX treatment had no effect on spindle structure but chromosomal misalignment. We observed that kinetochore-microtubule structure was affected and the spindle assemble checkpoint was provoked after DOX treatment. Moreover, severe DNA damage was found in DOX-treated oocytes indicated by the positive γ-H2A.X foci signal, which then may trigger oocytes early apoptosis. Besides, metaphase II oocytes with disorganized spindle morphologies and misaligned chromosomes were observed after DOX treatment. In conclusion, DOX have the potential to disrupt oocyte meiotic maturation through DNA damage induced meiotic arrest mediated by spindle assemble checkpoint activation. These findings can contribute to design the new therapies to alleviate DNA damage to preserve fertility for young female cancer patients with chemotherapeutics.

Luteolin-induced protection of H2O2-induced apoptosis in PC12 cells and the associated pathway.

Increasing evidence has indicated that the generation of reactive oxygen species (ROS) contributes to H2O2­induced nerve injury. This may result in oxidative stress that leads to cell damage or death. Dietary or pharmaceutical augmentation of the endogenous antioxidant defense capacity is a potential means by which to prevent ROS­induced damage. The aim of the current study was to investigate the effect of luteolin on H2O2­induced cell apoptosis in cultured rat pheochromocytoma cells (PC12 cells) and to investigate the role of the phosphatidylinositol­3­kinase (PI3K)/protein kinase B (Akt) pathway on H2O2­induced apoptosis. The results demonstrated that luteolin was able to inhibit the reduction in cell viability induced by H2O2. In addition, luteolin reduced ROS generation and lactate dehydrogenase release in H2O2­treated PC12 cells. The levels of superoxide dismutase and glutathione peroxidase activity were increased following treatment with luteolin, however malondialdehyde levels were observed to be reduced. Additionally, luteolin increased the Bcl­2/Bax ratio and enhanced Akt phosphorylation. However, these alterations were attenuated by pretreatment with an inhibitor of the PI3K/Akt pathway. In conclusion, luteolin inhibited H2O2­induced apoptosis via reducing ROS levels and activating the PI3K/Akt pathway.

Artificial cervical disc replacement: range of motion of replacement segment and degeneration of adjacent segments / 中国组织工程研究

BACKGROUND:In recent years,artificial cervical disc replacement surgery as a new method for the treatment of cervical disease has gradualy been accepted and understood,but relevant complications have gradualy attracted attention.OBJECTIVE:To investigate the clinical outcomes of artificial cervical disc replacement in the treatment of cervical disease and the range of motion of the replacement segment.METHODS: A total of 25 patients with artificial cervical disc replacement in the treatment of cervical spondylosis,who were treated in the Department of Orthopedics,Air Force General Hospital of Chinese PLA from August 2006 to April 2012,were enroled in this study,including 15 males and 10 females,aged 31-76 years,averagely 51.04 years.There were 6 cases of double segments and 19 cases of single segment.They were folowed up for 24 to 93 months.Clinical results were assessed using the Japanese Orthopaedic Association score,cervical dysfunction index and pain visual analog scale scores.Imaging was used to observe range of motion,cervical curvature,heterotopic ossification,and degeneration of adjacent segments.RESULTS AND CONCLUSION:Neurological function in al patients was improved to different degrees.One case suffered from mild heterotopic ossification,but no clinical symptoms were found.No significant difference in range of motion of surgical segment,and range of motion of upper and lower adjacent segments was detected between pre-replacement and final folow-up results (P＞0.05).No significant difference in range of motion of C2-C7 was found between pre-replacement and final folow-up results (P＞0.05).Japanese Orthopaedic Association score,cervical dysfunction index and pain visual analog scale scores were significantly improved during final folow-up compared with pre-replacement (P＜0.05).These results indicated that artificial cervical disc replacement in the treatment of cervical disease can achieve better clinical efficacy,can keep the range of motion of replacement segment and avoid the accelerated degeneration of adjacent segments.

Case-control study on minimally invasive percutaneous locking compression plate internal fixation for the treatment of type II and III pilon fractures / 中国骨伤

<p><b>OBJECTIVE</b>To explore the clinical efficacy of delayed open reduction and internal fixation with minimally invasive percutaneous locking compression plate for the treatment of type II and III Pilon fractures.</p><p><b>METHODS</b>From January 2007 to September 2009, 32 patients with type II and III Pilon fractures were treated with open reduction and anatomic plate fixation (AP group) and minimally invasive percutaneous locking compression plate osteosynthesis (LCP group). There were 11 males and 6 females in AP group, with an average age of (37.4 +/- 13.3) years (ranged, 19 to 55 years). And there were 10 males and 5 females in LCP group, with an average age of (34.6 +/- 11.3) years(ranged, 21 to 56 years). The operating time, fracture healing time, aligned angulation and ankle function were compared between the two groups.</p><p><b>RESULTS</b>All the patients were followed up, and the during ranged from 12 to 25 months, with a mean of (15.0 +/- 1.7) months. The average operation time was (76.5 +/- 8.3) min for AP group and (58.3 +/- 3.4) min for LCP group; the average time of fracture healing was (20.5 +/- 0.4) weeks for AP group and (15.7 +/- 0.2) weeks for LCP group; the total angulation between anterior posterior film and lateral film was averaged (6.6 +/- 0.5) degrees for AP group and (3.6 +/- 0.2) degrees for LCP group. As to above index, the results of LCP group were better than those of AP group (P < 0.05). According to Kofoed criteria for ankle joint, the results of LCP group were better than those of AP group in ankle joint pain, wakling and ankle joint function (P < 0.05).</p><p><b>CONCLUSION</b>The method of minimally invasive percutaneous locking compression plate internal fixation is effective in the treatment of Pilon fracture with less invasion, faster bone union, more stabilized fixation, quicker recovery of ankle function and fewer complications, which is more advantaged for type II and III Pilon fractures.</p>

Fixation of Elderly Fracture of Proximal Humerus with Locking Compression Plate by Mini-incision Approach from Lateral Shoulder / 中国康复理论与实践

@#ObjectiveTo investigate the clinical efficacy of the fixation of elderly fracture of proximal humerus with locking compression plate(LCP) by mini-incision approach from lateral shoulder.Methods31 elderly patients suffered from elderly fracture of proximal humerus were treated with locking compression plate(LCP) by mini-incision approach from lateral shoulder, male 13 cases, female 18 cases; aged from 56 to 72, average 62-8 years old; fractures according to Neer classification: type Ⅱ(8 cases), type Ⅲ (19 cases), type Ⅳ (4 cases). Cause of injuries: traffic accident (9 cases), falling (20 cases), other injuries(2 cases).ResultsThe patients were followed up 6 to 36 months, an average of about 24 months. Fracture healing time was 2-2 ～ 6-4 months, on average 3-7 months; No wound infection occurred. Post-operative functional score (Neer score) revealed: excellent(18 cases), good (11 cases), fair (2 cases), the ratio of excellent(18 cases), good (11 cases) was 93-5%. ConclusionFixation of elderly fracture of proximal humerus with locking compression plate(LCP) by minimally invasive approach from lateral shoulder is a safe, reliable and minimally invasive procedure with good reduction and stable fixation. Early post-operative functional exercise may be permitted for preventing shoulder joint adhesion.

The treatment for complications of polyacrylamide hydrogel injection for augmentation mammaplasty by dual-plane breast augmentation / 中华整形外科杂志

<p><b>OBJECTIVE</b>To search for the perfect therapy for the complications of breast augmentation by injecting polyacrylamide hydrogel.</p><p><b>METHODS</b>15 patients whose complications were severe after hydrogel injection were included in this study. Open suction and irrigation of cavity were performed in all patients and all received immediately dual-plane augmentation mammaplasty with silicon gel prostheses.</p><p><b>RESULTS</b>12 patient were followed up for 3 months to 1 year (mean 6.8 months) and no malposition or deformation occurred. 10 patients (20 breasts) had satisfactory results. The edges of the implant shell could be felt in 2 patients (3 breasts). 1 patient (1 breast) with breast firmness ranked Baker II .</p><p><b>CONCLUSIONS</b>The dual-plane breast augmentation is a valuable technique to treat the complications of polyacrylamide hydrogel injection.</p>

Hospital Infection:Analysis of 706 Patients / 中华医院感染学杂志

OBJECTIVE To understand the related factors,the situation and dynamics of hospital infection in order to effectively prevent and control it.METHODS From 12306 cases of inpatients who had investigated retrospectively,706 cases were with nosocomial infection monitored from Jan to Dec 2006.RESULTS The hospital infection rate was 5.74% in 2006.The hematological disease and,cancer patients and the elderly,were the high-risk population.The main infection site was the respiratory tract.Fungi accounted for 21.35%,the top was the Candida albicans.CONCLUSIONS To strengthen the training of medical staff,to monitor the key departments of hematology and cancer and respiratory diseases and to attend the disease surveillance and rationally use of antibiotics are the effective measures to reduce hospital-acquired infections.

Effects of morphine and endomorphins on the polysynaptic reflex in the isolated rat spinal cord.

At the spinal level, mu-opioids exert their actions on nociceptive primary afferent neurons both pre- and postsynaptically. In the present study, we used an in vitro isolated neonatal rat (11-15 days old) spinal cord preparation to examine the effects of morphine and the endogenous mu-opioid ligands endomorphin-1 (EM-1) and endomorphin-2 (EM-2) on the polysynaptic reflex (PSR) of dorsal root-ventral root (DR-VR) reflex. The actions of mu-opioids on spinal nociception were investigated by quantification of the firing frequency and the mean amplitude of the PSR evoked by stimuli with 20 x threshold intensity. EM-1 decreased the mean amplitude of PSR, whereas EM-2 and morphine decreased the firing frequency. The pattern of the effects elicited by morphine was the same as that for EM-2, except at high concentration. Naloxonazine, a selective mu(1) opioid receptor antagonist, had no significant effect on PSR by itself, but blocked the inhibition of PSR firing frequency or amplitude induced by EM-1, -2 and morphine. This may suggest that EM-1, EM-2 and morphine modulate spinal nociception differently and act mainly at the mu(1)-opioid receptors. Although they all act via mu(1)-opioid receptors, their different effects on the PSR may suggest the existence of different subtypes of the mu(1)-opioid receptor. The present data is also consistent with a further hypothesis, namely, that morphine and EM-2 activate a subtype of mu(1)-opioid receptor presynaptically, while EM-1 acts mainly through another subtype postsynaptically. However, since other reports indicate that EM-2, but not EM-1, could stimulate the release of enkephalins or dynorphin, presynaptic delta and kappa receptors may be also involved indirectly in the different regulation by mu-opioids at the spinal level.

Osteoinductivity of recombinent human bone morphogenetic protein-2 gene mediated with cationic liposome transfer in skeletal muscle stem cells of rabbits in vitro / 中国康复理论与实践

@#ObjectiveTo evaluate the osteoinductivity of cationic liposome mediated recombined human bone morphogenetic protein-2 gene (rhBMP-2) transfer in skeletal muscle stem cells (SMSCs) of rabbits. MethodsSMSCs were transfered by pAGFP rhBMP-2 liposome complex. Gene transferred SMSCs were evaluated with immunohistochemistry.ResultsThe transfection rate of SMSCs transferred by cationic liposome mediated pAGFP-rhBMP-2 was 14.18%. Positive stain of rhBMP-2, alkaline phosphatase(ALP),collegenⅠhad been found in the transferred SMSCs.ConclusionQuantity of SMSCs is enough to be target cells of gene therapy. Cationic liposome can mediated bone morphogenetic protein-2 gene transfected SMSCs in vitro. Compared with AdrhBMP-2,the transfection rate of liposome mediated bone morphogenetic protein-2 gene transfected SMSCs is lower.

Study of repair of bone defect using rabbit skeletal muscle stem cells transduced by AdrhBMP-2 gene / 中国康复理论与实践

@#ObjectiveTo observe the effect of rabbit skeletal muscle stem cells (RSMSCs) modified by adenovirus mediated bone morphogenetic protein-2 (BMP-2) gene ex vivo in combination with demineralized bone matrix (DBM) on repair of longer bone defect in rabbit.MethodsModel of radial bone defects (20 mm) of rabbits was established. 50 rabbits were divided into 5 groups, group A (AdrhBMP-2 trusduced RSMSCs/DBM group), group B (adGFP trusduced RSMSCs/DBM group), group C (not trusduced RSMSCs/DBM group), group D (DBM group), and group E (untreated group). Roentgenographic, histologic, biomechanical, bone density of all animals were examined at the end of 4th and 6th week after surgery.ResultsAt 4th week, radial bone defects healed in group A. The healing rates from group A to group E were 100%, 50%, 33%, 0%, and 0% respectively at 6th week.ConclusionRSMSCs modified by AdrhBMP-2 ex vivo in combination with DBM can repair radial longer segemental defect in rabbit. It's possible to be used in the clinical treatment of longer segemental bone defect.

Role of exogenous epidermal growth factor in nerve regeneration after terminolateral neurorrhaphy / 中国组织工程研究

BACKGROUND: It is proved that nerve regeneration induced by terminolateral neurorrhaphy(TLN) is not as active as that induced by end-to-end suture. Exogenous epidermal growth factor(EGF) increases the opportunity of neuron survival in vitro and promotes nerve regeneration. Whether it can increase nerve regeneration after terminolateral neurorrhaphy deserves further study.OBJECTIVE: To evaluate the effect of exogenous EGF in promoting nerve regeneration after terminolateral neurorrhaphy.DESIGN: A randomized controlled trial.SETTING: Orthopedic Institute of Chinese PLA General Hospital.PARTICIPANTS: The trial was conducted in the Orthopedic Institute of Chinese PLA General Hospital from September 2001 to February 2002. A total of 32 male Wistar rats, weighting 200- 250 g, were randomized to control group and EGF group with 16 rats in each group.METHODS: The right peroneal nerve was transected and an epineural window of 1 mm was created on the neighboring tibial nerve. The distal end of the transected peroneal nerve was sutured to the windowed tibial nerve by means of end-to-side attachment. Each rat in EGF group received injection of 0. 1 mL/d EGF diluted with normal saline at 2 g/L for two weeks while each in control group received injection of normal saline (0. 1 mL/d) at the distal site of the transected peroneal nerve for two weeks. Histological, morphological and electrophysiological examinations were performed 4 and 8 weeks after operation.MAIN OUTCOME MEASURES: The regeneration rate of myelinated nerve, motor nerve conduction velocity and ultrastructural changes of the two groups.rate of myelinated nerve fibers: 4 and 8 weeks after operation, it was better in EGF group[ (52.42 ± 1.45)% and(61.41 ± 1.54)% ] than that in control nerve conduction velocity: 4 and 8 weeks after operation it was obviously greater in EGF group[ (30. 33 ±0. 88)m/s and(34. 36 ± 1.09)m/s] than that in conObservation of ultrastructure: The number of myelinated nerve fibers, and the thickness and maturation degree of myelin sheath were significantly better than those in control group.CONCLUSION: Exogenous EGF can promote nerve regeneration, increase nerve conduction velocity after terminolateral neurorrhaphy.

Promotion of nerve regeneration in peripheral nerve by exogenous epidermal growth factor after terminola-teral neurorrhaphy:an experimental study / 中华显微外科杂志

Objective To evaluate the effect of exogenous epidermal growth factor (EGF) on promoting nerve regeneration after terminolateral neurorrhaphy (TLN). Methods Thirty-two adult Wistar rats were randomly divided into 2 groups. In the EGF group,the left peroneal nerve was transected,then an 1mm epineural window was created on the neighbouring tibial nerve. The distal end of peroneal nerve was sutured to the windowed tibial nerve by means of end-to-side attachment. in the control group,nerve TLN was performed as In the EGF group. Injection of EGF/normal saline (20?g/10?l) and normal saline (10?l) was done at the distal site of peroneal nerve transected in the EGF group and control group for two weeks respectively. Histological,morphological and electrophysiological examinations were performed in 4 and 8 weeks after the operation. Results The cross area of the regenerated myelinated nerve fibres,axon numbers,motor nerve conduction velocity were significantly better in the EGF group than in the control group ( P