Muscle prestimulation tunes velocity preflex in simulated perturbed hopping.

Muscle fibres possess unique visco-elastic properties, which generate a stabilising zero-delay response to unexpected perturbations. This instantaneous response-termed "preflex"-mitigates neuro-transmission delays, which are hazardous during fast locomotion due to the short stance duration. While the elastic contribution to preflexes has been studied extensively, the function of fibre viscosity due to the force-velocity relation remains unknown. In this study, we present a novel approach to isolate and quantify the preflex force produced by the force-velocity relation in musculo-skeletal computer simulations. We used our approach to analyse the muscle response to ground-level perturbations in simulated vertical hopping. Our analysis focused on the preflex-phase-the first 30 ms after impact-where neuronal delays render a controlled response impossible. We found that muscle force at impact and dissipated energy increase with perturbation height, helping reject the perturbations. However, the muscle fibres reject only 15% of step-down perturbation energy with constant stimulation. An open-loop rising stimulation, observed in locomotion experiments, amplified the regulatory effects of the muscle fibre's force-velocity relation, resulting in 68% perturbation energy rejection. We conclude that open-loop neuronal tuning of muscle activity around impact allows for adequate feed-forward tuning of muscle fibre viscous capacity, facilitating energy adjustment to unexpected ground-level perturbations.

Slack-based tunable damping leads to a trade-off between robustness and efficiency in legged locomotion.

Animals run robustly in diverse terrain. This locomotion robustness is puzzling because axon conduction velocity is limited to a few tens of meters per second. If reflex loops deliver sensory information with significant delays, one would expect a destabilizing effect on sensorimotor control. Hence, an alternative explanation describes a hierarchical structure of low-level adaptive mechanics and high-level sensorimotor control to help mitigate the effects of transmission delays. Motivated by the concept of an adaptive mechanism triggering an immediate response, we developed a tunable physical damper system. Our mechanism combines a tendon with adjustable slackness connected to a physical damper. The slack damper allows adjustment of damping force, onset timing, effective stroke, and energy dissipation. We characterize the slack damper mechanism mounted to a legged robot controlled in open-loop mode. The robot hops vertically and planarly over varying terrains and perturbations. During forward hopping, slack-based damping improves faster perturbation recovery (up to 170%) at higher energetic cost (27%). The tunable slack mechanism auto-engages the damper during perturbations, leading to a perturbation-trigger damping, improving robustness at a minimum energetic cost. With the results from the slack damper mechanism, we propose a new functional interpretation of animals' redundant muscle tendons as tunable dampers.

Chemodynamic therapy agents Cu(II) complexes of quinoline derivatives induced ER stress and mitochondria-mediated apoptosis in SK-OV-3 cells.

Three Cu(II) complexes of quinoline derivatives as cancer chemodynamic therapy agents were synthesized and characterized. These complexes were heavily taken up by cells and reacted with cellular glutathione (GSH) to reduce Cu2+ to Fenton-like Cu+, which catalyzed endogenous H2O2 to produce the highly toxic hydroxyl radicals (•OH) to kill cancer cells. Cu1 and Cu2 initiated CAT activity declines, mitochondrial membrane potential and ATP concentration decrease, mitochondrial Ca2+ overload and ER stress response, leading to cell cycle arrest in sub-G1 and cancer cell caspase-dependent apoptosis. On account of the high GSH and H2O2 specific properties of the tumor microenvironment, Cu1 and Cu2 exhibited higher in vitro anticancer activity and lower toxicity to normal cells. Cu1 and Cu2 efficiently inhibited tumor growth in the SK-OV-3 xenograft mouse model without obvious systemic toxicity.

[Effect of anatomical parameters of maxillary sinus on the outcomes of transcrestal sinus lift].

OBJECTIVE: To investigate the effect of three anatomical parameters (maxillary sinus width, maxillary sinus angle, and residual bone height) on the outcomes of transcrestal sinus lift with simultaneous implant placement. METHODS: A total of 60 maxillary sinuses in 42 patients were included in this study. All patients were treated with transcrestal sinus lift procedure associated with simultaneous implant placement using a composite graft material of autogenous bone and Bio-Oss. For each patient, beam computed tomography (CBCT) scans were performed preoperatively, immediately after surgery, and 6 months after surgery. The parameters were measured on the preoperative and postoperative CBCT images. The correlation of three anatomical parameters with graft resorption was analyzed using Pearson's correlation test. RESULTS: The average residual bone height was (4.46±1.55) mm. The average width of maxillary sinus was (13.86±2.71) mm. The average sinus angle was 78.09°±10.27°. A significant positive correlation was observed between maxillary sinus width and graft resorption (P<0.01). A positive association was also found between sinus angle and graft resorption (P<0.01). CONCLUSIONS: The findings show that graft bone resorption in elevated sinus has a positive correlation with the sinus width and sinus angle.

Effective Viscous Damping Enables Morphological Computation in Legged Locomotion.

Muscle models and animal observations suggest that physical damping is beneficial for stabilization. Still, only a few implementations of physical damping exist in compliant robotic legged locomotion. It remains unclear how physical damping can be exploited for locomotion tasks, while its advantages as sensor-free, adaptive force- and negative work-producing actuators are promising. In a simplified numerical leg model, we studied the energy dissipation from viscous and Coulomb damping during vertical drops with ground-level perturbations. A parallel spring- damper is engaged between touch-down and mid-stance, and its damper auto-decouples from mid-stance to takeoff. Our simulations indicate that an adjustable and viscous damper is desired. In hardware we explored effective viscous damping and adjustability, and quantified the dissipated energy. We tested two mechanical, leg-mounted damping mechanisms: a commercial hydraulic damper, and a custom-made pneumatic damper. The pneumatic damper exploits a rolling diaphragm with an adjustable orifice, minimizing Coulomb damping effects while permitting adjustable resistance. Experimental results show that the leg-mounted, hydraulic damper exhibits the most effective viscous damping. Adjusting the orifice setting did not result in substantial changes of dissipated energy per drop, unlike adjusting the damping parameters in the numerical model. Consequently, we also emphasize the importance of characterizing physical dampers during real legged impacts to evaluate their effectiveness for compliant legged locomotion.

Hybrid control combined with a voluntary biosignal to control a prosthetic hand.

In this research, the combination of fuzzy/PD and EMG signals, as direct command control, is proposed. Although fuzzy/PD strategy was used to control force position of the artificial hand, the combination of that with EMG signaling to voluntary direct command control is a novel method. In this paper, the EMG signal and its role in effective communication between a DC motor with a voltage trigger and neurofeedback are initially explained. Moreover, by introducing a filtration method, EMG pulses are obtained as stepping pulses with a signal-specific height of a voltage between 0 and 6 V, according to EMG domain voltage, with a time interval adapted from the EMG stimulus pulses. Two data points from each channel of EMG were extracted. The domain of the voltage of the EMG signal is impacted on the output of the fuzzy logic unit, and also the time amount between each stimulus of the EMG signal is the input of the PD controller. By this method, a user can influence grip position and grasping force of his/her prosthesis.

TK1 overexpression is associated with the poor outcomes of lung cancer patients: a systematic review and meta-analysis.

AIM: The study aimed to unveil the effect of TK1 expression on the clinicopathological significance and prognosis in patients with lung cancer. Results & methodology: Studies for meta-analysis were selected according to a thorough literature search in databases (PubMed, EMBASE and Chinese databases). Ten studies containing 1393 lung cancer patients were investigated in our analysis. The TK1 overexpression was associated with poorer overall survival(OS) in lung cancer patients (hazard ratio = 1.881; 95% CI:1.318-2.684, Z = 3.48; p = 0.001). Furthermore, The TK1 expression is associated with the clinicopathological features of lung cancer patients (tumor type, age, lymph node metastasis, distant metastasis and tumor, node, metastasis [TNM] stages).  Discussion & conclusion: The TK1 expression might have a supportive implication in assessing biological behavior and prognosis of lung cancer patients.

Marginal bone loss around non-submerged implants is associated with salivary microbiome during bone healing.

Marginal bone loss during bone healing exists around non-submerged dental implants. The aim of this study was to identify the relationship between different degrees of marginal bone loss during bone healing and the salivary microbiome. One hundred patients were recruited, and marginal bone loss around their implants was measured using cone beam computed tomography during a 3-month healing period. The patients were divided into three groups according to the severity of marginal bone loss. Saliva samples were collected from all subjected and were analysed using 16S MiSeq sequencing. Although the overall structure of the microbial community was not dramatically altered, the relative abundance of several taxonomic groups noticeably changed. The abundance of species in the phyla Spirochaeta and Synergistetes increased significantly as the bone loss became more severe. Species within the genus Treponema also exhibited increased abundance, whereas Veillonella, Haemophilus and Leptotrichia exhibited reduced abundances, in groups with more bone loss. Porphyromonasgingivalis, Treponemadenticola and Streptococcus intermedius were significantly more abundant in the moderate group and/or severe group. The severity of marginal bone loss around the non-submerged implant was associated with dissimilar taxonomic compositions. An increased severity of marginal bone loss was related to increased proportions of periodontal pathogenic species. These data suggest a potential role of microbes in the progression of marginal bone loss during bone healing.

[Characteristics of hydroxyapatite/PMMA nanocomposites for provisional restoration and its biocompatibility with human gingival fibroblasts].

OBJECTIVE: To formulate hydroxyapatite (HA)/polymethyl methacrylate (PMMA) composites with improved cytocompatibility for provisional restoration. METHODS: Nanocomposites with 20 wt%, 30 wt%, 40 wt%, and 50 wt% HA/PMMA (H/P) were developed and examined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). Human gingival fibroblasts were cultured on those HA/PMMA discs and investigated by fluorescent staining on 24 h and MTT assay at 1 d, 3 d, 5 d and 7 d. RESULTS: Chemical integration of HA/PMMA interface was confirmed by XPS. Typical fusiform cells with adhesion spots were detected on 40 wt% and 50 wt% H/P discs. MTT results showed insignificant differences in cell growth between 40 wt% H/P and pure titanium (Ti, P > 0.05), while the other H/P discs showed significantly lower cell growth than pure Ti (P < 0.05). CONCLUSION: 40 wt% H/P might be a promising candidate for provisional dental implant restoration and for esthetic gingival contour.

Investigation of the mechanical properties of a low-shrinkage liquid crystalline matrix combined with nano-hydroxyapatite.

The objective of this study was to investigate the mechanical properties of a low-shrinkage acrylate liquid crystalline resin matrix (ALCRM), (4-3-(acryloyloxy)-2-hydroxypropoxy) phenyl 4-(3-(acryloyloxy)-2-hydroxypropoxy) benzoate, combined with nano-hydroxyapatite (na-HA). The ALCRM monomer and diluent monomer triethylene glycol dimethacrylate (TEGDMA) were mixed at a mass ratio of 7:3 to prepare the resin matrix. The volume shrinkage of the ALCRM/TEGDMA and the traditional resin matrix Bis-GMA (2, 2-bis [4-(3-methacryloxy-2-hydroxypropoxy) phenyl] propane)/TEGDMA were measured. Then 20%, 30%, and 40% na-HA were added to ALCRM/TEGDMA and Bis-GMA/TEGDMA, respectively. Compressive strength (CS) and Vickers hardness (VHN) were tested to identify mechanical properties of the composites. The volume shrinkage of the ALCRM/TEGDMA was 3.60% ± 0.36%, which was lower than that of the traditional resin matrix. Moreover, with the same amount of na-HA filler, the mechanical properties of the ALCRM-based composites were superior to those of Bis-GMA-based composites. ALCRM-based composites exhibited the highest CS and VHN values when the filler content was 30%. These results indicate that the low-shrinkage liquid crystalline resin matrix has strong mechanical properties after incorporating the na-HA. The experimental ALCRM-based composites have promising potential for the development of novel low-shrinkage dental resins with strong mechanical properties.

[Evaluation of clinical therapeutic efficiency of immediate loaded implant].

OBJECTIVE: Clinical cases of immediate loaded implants were retrospectively analyzed, in the aim of evaluating the clinical value of immediate loading. METHODS: From July 2005 to October 2009, 99 immediate loaded implants were implanted in 29 patients. The overall data including radiography, clinical examination were collected during the follow-up periods ranged from 4 to 46 months. The implants were evaluated with the survival rate, bone resorption, soft tissue esthetics (including gingiva papilla index and pink esthetic score). RESULTS: Survival rate for immediate loaded implant was 97.0%. The average bone resorption were 0.22 mm at 4-6 months after surgery, bone increase of 0.15 mm were found at 6-12 month, and bone increase up to 0.16 mm at 12-46 months. The gingival papilla index was 2.68, while pink esthetic score was 12.58. CONCLUSION: Immediate loaded implant is an effective repairing method for patients missing teeth and the esthetics effect is ideal.

Neurosyphilis Mimicking Temporal Arteritis

No abstract available.

Temporary Spontaneous Remission in Primary CNS Lymphoma

Spontaneous remission in untreated primary central nervous system lymphoma is rare. A 66-year-old man was admitted with dizziness and gait disturbance. Initial fluid-attenuated inversion-recovery images revealed hyperintensities in the upper brainstem, left temporal lobe, and right occipital lobe. The patient's symptoms and lesions disappeared spontaneously after 1 month. However, he was readmitted after 4 months with right hemiparesis. Magnetic resonance imaging revealed a homogenous enhanced lesion in the left basal ganglia with a vasogenic pattern. This disease warranted biopsy, which revealed large B-cell lymphoma.

The Usefulness of Serum S-100B Protein and Neuron-Specific Enolase as a Screening Test for Making the Differential Diagnosis of Patients with Non-Traumatic Altered Mentality

PURPOSE: There are so many causes of an altered mental status, including acute stroke and nonorganic causes. Making the differential diagnosis and the diagnostic approach for cases with an altered mental status represent a challenge to all emergency physicians. The serum S-100B protein concentration and the neuron-specific enolase (NSE) concentration have been used to evaluate brain damaged patients. We evaluated the usefulness of the serum S-100B protein concentration and the NSE concentration as screening tests for the patients with an altered mentality METHODS: Seventy-eight patients with an altered mentality were included in this prospective study. The patients were divided in two groups. One was the acute stroke group and the other was the non-organic cause group. We analyzed the serum S-100B protein and NSE concentrations of the two groups. We also assessed the correlation of the serum S-100B protein and NSE concentrations with the clinical and laboratory data of the two groups RESULTS: The serum concentration of S-100B was higher in the acute stroke group (median: 0.376, interquartile range: 0.18-1.05) than that in the nonorganic group (0.123, 0.087-0.307, p=0.000). The NSE level was also higher in the acute stroke group (median: 19.12, interquartile range: 14.42-27.19) than that in the non-organic group (13.71, 10.48-19.29, p=0.002). To differentiate the acute stroke group from the non-organic group, the sensitivity and specificity was 81.1% and 61.0%, respectively, at a cutoff value for the serum S-100B protein concentration of 0.14 microgram/L, and these were 81.1% and 51.2%, respectively, at a cutoff value for the serum NSE concentration of 13.71 microgram/L CONCLUSION: Our study suggests that the serum S-100B protein and NSE concentrations may be useful as screening markers for differentiating acute stroke from non-organic causes. However, further studies are needed to evaluate the relationship between the two proteins and the various diseases that have possibility to alter patients' mental status before these two proteins can be used clinically as screening tests.

[Management and outcome of 47 patients with acute myocardial infarction complicating cardiogenic shock].

OBJECTIVE: To evaluate the clinical outcomes of patients with acute myocardial infarction (AMI) complicating cardiogenic shock underwent various treatments. METHODS: From January, 2002 to May, 2007, 47 AMI patients with cardiogenic shock were treated in our department by optimal medication (dopamine, epinephrine, norepinephrine, etc.), intra-aortic balloon pump (IABP), mechanical ventilation when indicated, percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG). Outcome and factors related to mortality for these patients were analyzed in this retrospective study. RESULTS: Besides optimal medication and IABP in all patients, 31 patients underwent PCI (66.0%), 6 patients received emergency CABG (12.8%). The overall in-hospital mortality rate was 36.2% (17/47), 6 patients (14.9%) died before coronary revascularization and 11 patients (21.3%) died after revascularization. Nine patients died of pump failure and 8 patients died of renal and (or) respiratory failure. Regression analysis showed that acute renal failure (r = 0.734, P = 0.000), acute respiratory failure (r = 0.606, P = 0.000) and diabetes (r = 0.372, P = 0.012) were positively related to in-hospital mortality. CONCLUSION: Despite improvements in treatment options for AMI patients complicating cardiogenic shock, in-hospital mortality remained high, especially for patients complicating further with acute renal failure and acute respiratory failure.

[Effect of silver-hydroxyapatite/titania nanocomposites on proliferation, vitality and ultrastructure of osteoblasts].

OBJECTIVE: Osteoblasts behaviors were investigated when cultured in the presence of silver-hydroxyapatite/titania nanoparticles (nAg-HA/TiO2) in vitro. METHODS: Rat calvaria osteoblasts were cultured in the presence of 10 mirog/mL-500 mirog/mL nHA or nAg-HA/TiO2 for 2 h, 6 h, 8 h, 24 h, 72 h and 120 h. Cell proliferation, vitality and ultrastructure were tested using cell counting chamber, MTT assay, and transmission electron microscope (TEM). RESULTS: Both cell proliferation and vitality were restricted by addition of nanoparticles, while the respiration rates as an index for unit cell viability were enhanced. nAg-HA/TiO2 at low concentration showed superiority. No remarkable ultrastructural changes were observed in the osteoblasts exposed to nanoparticles. The differences in cell proliferation and cell vitality between nAg-HA/TiO2 group and nHA group at the same concentration were insignificant. CONCLUSION: nAg-HA/TiO2 restricted cells proliferation, but triggered unit cell viability. Cytocompatibility of nAg-HA/TiO2 is almost the same as that of nHA's.

[Characterization and antibacterial effect of Ag-nHA-nTiO2/polyamide 66 nanocomposite membrane on oral bacteria].

OBJECTIVE: Undried silver-hydroxyapatite-titania (Ag-nHA-nTiO2) nanoparticles slurry was used to make membrane with polyamide 66 (PA66) by co-polymerization method. The purpose of this study is to test the physical and chemical characteristics and antibacterial ability. METHODS: The morphology, chemical components and structures of the membrane were characterized by atomic absorption spectrometer (AAS), X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDX). Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Porphyromonas gingivalis (P. gingivalis), Fusobacterium nucleatum (F. nucleatum) and Streptococcus mutans (S. mutans) were utilized to test the antibacterial effect. RESULTS: XRD results demonstrated that the membrane have characteristic diffraction peaks of pure hydroxyapatite (HA). A homogeneous distribution of the Ca, P, Ti and Ag element in the membrane was confirmed by EDX. Both surface and section showed porous structure which was confirmed by SEM and the average hole size was 20-30 microm. The bacteria assay reflected to the antibacterial effect, 50.10% of S. aureus and 56.31% of E. coli were killed. However, 91.84% of P. gingivalis, 90.64% of F. nucleatum and 90.49% of S. mutans were killed and pictures of SEM showed obviously fewer cells on the surface. CONCLUSION: The nanocomposite membrane could be one of the bioactive materials with antibacterial properties for oral guided bone regeneration technique.

[Study on the microstructure of acellular dermal matrix and its biocompatibility with MG63 osteoblast-like cells].

OBJECTIVE: To study the microstructue of acellular dermal matrix (ADM) and the attachment and proliferation of MG63 osteoblast-like cells on the membrane. METHODS: ADM was experimental group and expanded polytetrafluoroethylene (e-PTFE) membrane was control group. Light microscope and scanning electronic microscope (SEM) were used to observe the microstructure of the two kinds of membrane. MG63 osteoblast-like cells were cultured on the two kinds of membrane and the blank group. The cell viability was checked by cell viability analyzer (CVA) and alkaline phosphatase (ALP) activity was detected by ELISA. SEM was used to observe the adhesion and proliferation of the MG63 osteoblast-like cells on the two kinds of membrane. RESULTS: The ADM was composed of the tissular side and basal lamina side. The tissue side showed scale-shaped structure and the basal lamina side demonstrated many digitations and some pores of folliculus pili. The e-PTFE showed many tiny lined cracks in elliptic structure. The viability of the MG63 osteoblast-like cells on the two kinds of membranes and ALP measurement showed that there was no significant difference between each of the two membrane groups and the blank. The adhesion and proliferation of osteoblast-like cells on the two kinks of membranes were both well. CONCLUSION: ADM has no negative effects on the growth of osteoblast-like cells. ADM is biocompatibile and its microstructure is appropriate for guided bone regeneration materials.

Protective effects of pretreatment with Radix Paeoniae Rubra on acute lung injury induced by intestinal ischemia/reperfusion in rats.

OBJECTIVE: To investigate the effect of pretreatment with Radix Paeoniae Rubra (RPR) on acute lung injury induced by intestinal ischemia/reperfusion in rats and its protective mechanism. METHODS: Thirty-two Wistar rats were randomly divided into four groups: Sham-operation group, ischemia/reperfusion group (I/R group), RPR-pretreatment group and hemin group. The model of intestinal ischemia/reperfusion was established by clamping the superior mesenteric artery for 1 hour followed by 2-hour reperfusion. The effect of RPR on the expression of heme oxygenase-1 (HO-1) in lung tissues was detected by immunohistochemistry and morphometry computer image analysis. Arterial blood gas analysis, lung permeability index, malondialdehyde (MDA) and superoxide dismutase (SOD) contents in lungs were measured. The histological changes of lung tissue were observed under light microscope. RESULTS: The expression of HO-1 in RPR-pretreatment group and hemin group was obviously higher than that in sham-operation group and I/R group (P < 0.01). The level of MDA and lung permeability index in RPR-pretreatment and hemin group were significantly lower than those in I/R group (P < 0.01 or P < 0.05), while the activity of SOD in RPR-pretreatment and hemin group was obviously higher than that in I/R group (P < 0.01). Under light microscope, the pathologic changes induced by I/R were significantly attenuated by RPR. CONCLUSION: Intestinal ischemia/reperfusion may result in acute lung injury and pretreatment with RPR injection can attenuate the injury. The protective effect of RPR on the acute lung injury is related to its property of inducing HO-1 expression and inhibiting lipid peroxidation.

Electrophysiological Changes in Lambert-Eaton Myasthenic Syndrome With Intravenous Immunoglobulin Therapy

No abstract available.