Investigation of a Side-polished Fiber MZI and Its Sensing Performance

A novel all-fiber Mach–Zehnder interferometer (MZI), which consists of lateral core fusion splicing of a short section of side-polished single mode fiber (SMF) between two SMFs was proposed and demonstrated. A simple fiber side-polished platform was built to control the side polished depth through a microscope. The sensitivity of the fiber MZI structure to the surrounding refractive index (RI) can be greatly improved with the increase of the side-polished depth, but has no effect on the temperature sensitivity. The sensor with a polished depth of 44.2 μm measured RI sensitivity up to -118.0 nm/RIU (RI unit) in the RI range from 1.333 to 1.387, which agrees well with simulation results by using the beam propagation method (BPM). In addition, the fiber MZI structure also can achieve simultaneous measurement of both RI and temperature. These results show its potential for use in-line fiber type sensing application

Bulleyaconitine A reduces fracture-induced pain and promotes fracture healing in mice

A fracture is a severe trauma that causes dramatic pain. Appropriate fracture pain management not only improves the patient’s subjective perception, but also increases compliance with rehabilitation training. However, current analgesics for fracture pain are unsatisfactory because of their negative effects on fracture healing or addiction problems. Bulleyaconitine A (BLA), a non-addictive analgesic medicine, is used for the treatment of chronic pain of musculoskeletal disorders in clinical practice, whereas the effects of BLA on fracture pain is undefined. To evaluate the analgesic effects of BLA on fracture, we generated tibial fracture mice here. It is found that oral administration of BLA to mice alleviates fracture-induced mechanical and thermal hyperalgesia. Interestingly, BLA significantly increases locomotor activity levels and reduces anxiety-like behaviors in fractured mice, as determined by open-field test. Notably, BLA treatment promotes bone mineralization and therefore fracture healing in mice, which may be attributed to the increase in mechanical stimulation caused by exercise. Our study suggests that BLA can be used as a promising analgesic agent for the treatment of fracture pain

Novel Microfiber Sensor and Its Biosensing Application for Detection of hCG Based on a Singlemode-Tapered Hollow Core-Singlemode Fiber Structure

A novel microfiber sensor is proposed and demonstrated based on a singlemode-tapered hollow core -singlemode (STHS) fiber structure. Experimentally a STHS with taper waist diameter of 26.5 μm has been fabricated and RI sensitivity of 816, 1601.86, and 4775.5 nm/RIU has been achieved with RI ranges from 1.3335 to 1.3395 , from 1.369 to 1.378, and from 1.409 to 1.4175 respectively, which agrees very well with simulated RI sensitivity of 885, 1517, and 4540 nm/RIU at RI ranges from 1.3335 to 1.337, from 1.37 to 1.374, and from 1.41 to 1.414 . The taper waist diameter has impact on both temperature and strain sensitivity of the sensor structure: (1) the smaller the waist diameter, the higher the temperature sensitivity, and experimentally 26.82 pm/°C has been achieved with a taper waist diameter of 21.4 μm; (2) as waist diameter decrease, strain sensitivity increase and 7.62 pm/με has been achieved with a taper diameter of 20.3 μm. The developed sensor was then functionalized for human chorionic gonadotropin (hCG) detection as an example for biosensing application. Experimentally for hCG concentration of 5 mIU/ml, the sensor has 0.5 nm wavelength shift, equivalent to limit of detection (LOD) of 0.6 mIU/ml by defining 3 times of the wavelength variation (0.06 nm) as measurement limit. The biosensor demonstrated relatively good reproducibility and specificity, which has potential for real medical diagnostics and other applications

Antiarrhythmic and proarrhythmic effects of subcutaneous nerve stimulation in ambulatory dogs

Background High output subcutaneous nerve stimulation (ScNS) remodels the stellate ganglia and suppresses cardiac arrhythmia. Objective To test the hypothesis that long duration low output ScNS causes cardiac nerve sprouting, increases plasma norepinephrine concentration and the durations of paroxysmal atrial tachycardia (PAT) in ambulatory dogs. Methods We prospectively randomized 22 dogs (11 males and 11 females) into 5 different output groups for 2 months of ScNS: 0 mA (sham) (N=6), 0.25 mA (N=4), 1.5 mA (N=4), 2.5 mA (N=4) and 3.5 mA (N=4). Results As compared with baseline, the changes of the durations of PAT episodes per 48 hours were significantly different among different groups (sham, -5.0±9.5 s; 0.25 mA 95.5±71.0 s; 1.5 mA, -99.3±39.6 s; 2.5 mA, -155.3±87.8 s and 3.5 mA, -76.3±44.8 s, p<0.001). The 3.5 mA group had greater reduction of sinus heart rate than the sham group (-29.8±15.0 bpm vs -14.5±3.0 bpm, p=0.038). Immunohistochemical studies showed that the 0.25 mA group had a significantly increased while 2.5 mA and 3.5 mA stimulation had a significantly reduced growth-associated protein 43 nerve densities in both atria and ventricles. The plasma Norepinephrine concentrations in 0.25 mA group was 5063.0±4366.0 pg/ml, which was significantly higher than other groups of dogs (739.3±946.3, p=0.009). There were no significant differences in the effects of simulation between males and females. Conclusions In ambulatory dogs, low output ScNS causes cardiac nerve sprouting, increases plasma norepinephrine concentration and the duration of PAT episodes while high output ScNS is antiarrhythmic

Triterpenoids and Sterols from the Leaves and Twigs of Melia azedarach

Two new triterpenoids (1 and 2) and a new sterol (3), together with six known constituents (4–9), were isolated from the leaves and twigs of Melia azedarach. Their chemical structures were elucidated on the basis of spectroscopic analysis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s13659-014-0019-1) contains supplementary material, which is available to authorized users

Wearable optical fiber sensor based on a bend singlemode-multimode-singlemode fiber structure for respiration monitoring

Respiration rate (RR) is an important information related to human physiological health. A wearable optical fiber sensor for respiration monitoring based on a bend singlemode-multimodesinglemode (SMS) fiber structure, which is highly sensitive to bend, is firstly proposed and experimentally demonstrated. The sensor fastened by an elastic belt on the abdomen of a person will acquire the respiration signal when the person breaths, which will introduce front and back movement of the abdomen, and thus bend of SMS fiber structure. Short-time Fourier transform (STFT) method is employed for signal processing to extract characteristic information of both the time and frequency domain of the measured waveform, which provides accurate RR measurement. Six different SMS fiber sensors have been tested by six individuals and the experimental results demonstrated that the RR signals can be effectively monitored among different individuals, where an average Pearson Correlation Coefficient of 0.88 of the respiration signal has been achieved, which agrees very well with that of commercial belt respiration sensor. The proposed technique can provide a new wearable and portable solution for monitoring of respiratory with advantage of easy fabrication and robust to environment

Skin sympathetic nerve activity and the temporal clustering of cardiac arrhythmias

BACKGROUND: Simultaneous noninvasively recorded skin sympathetic nerve activity (SKNA) and electrocardiogram (neuECG) can be used to estimate cardiac sympathetic tone. We tested the hypothesis that large and prolonged SKNA bursts are associated with temporal clustering arrhythmias. METHODS: We recorded neuECG in 10 patients (69 ± 10 years old) with atrial fibrillation (AF) episodes and in 6 patients (50 ± 13 years old) with ventricular tachycardia (VT) or fibrillation (VF) episodes. Clustering was defined by an arrhythmic episode followed within 1 minute by spontaneous recurrences of the same arrhythmia. The neuECG signals were bandpass filtered between 500-1000 Hz to display SKNA. RESULTS: There were 22 AF clusters, including 231 AF episodes from 6 patients, and 9 VT/VF clusters, including 99 VT/VF episodes from 3 patients. A total duration of SKNA bursts associated with AF was longer than that during sinus rhythm (78.9 min/hour [interquartile range (IQR) 17.5-201.3] vs. 16.3 min/hour [IQR 14.5-18.5], P = 0.022). The burst amplitude associated with AF in clustering patients was significantly higher than that in nonclustering patients (1.54 μV [IQR 1.35-1.89], n = 114, vs. 1.20 μV [IQR 1.05-1.42], n = 21, P < 0.001). The SKNA bursts associated with VT/VF clusters lasted 9.3 ± 3.1 minutes, with peaks that averaged 1.13 ± 0.38 μV as compared with 0.79 ± 0.11 μV at baseline (P = 0.041). CONCLUSION: Large and sustained sympathetic nerve activities are associated with the temporal clustering of AF and VT/VF. FUNDING: This study was supported in part by NIH grants R42DA043391 (THE), R56 HL71140, TR002208-01, R01 HL139829 (PSC), a Charles Fisch Cardiovascular Research Award endowed by Suzanne B. Knoebel of the Krannert Institute of Cardiology (TK and THE), a Medtronic-Zipes Endowment, and the Indiana University Health-Indiana University School of Medicine Strategic Research Initiative (PSC)

Stability analysis of inclined coal seam roadway along goaf considering non-uniform filling of gob gangue

After the mining of inclined coal seam, the roof falling gangue of goaf moves downward to fill the goaf due to gravity, which makes the strata behavior law of gob-side entry retaining in inclined coal seam different from that in horizontal coal seam. In order to study the influence of non - uniform filling of gangue on surrounding rock stability of gob - side entry retaining in inclined coal seam, taking No.3131 machine roadway of Longmenxia South Coal Mine in Sichuan as engineering background. The filling zone length of caving rock in goaf was quantified, and the compaction parameters of rock in quantified goaf were obtained by double yield model inversion. On this basis, a numerical calculation model was established to study the evolution characteristics of surrounding rock stress field and the distribution pattern of plastic zone in the whole service cycle of gob-side entry retaining in inclined coal seam, as well as the stress state and support performance of roadside filling body under bearing state. The results showed that the inclined lengths of filling compaction zone, complete filling zone and partial filling zone in goaf of 3131 working face were 57.20 m, 72.18 m and 10.62 m, respectively. For the gob-side entry retaining of inclined coal seam considering the zoning compaction characteristics of goaf, the abutment pressure in front of working face and the residual abutment pressure in goaf increase with the increase of depth. Compared with the first mining, the peak value and influence range of the abutment pressure in front of the working face under the second mining were significantly increased, and the concentration degree of the lateral abutment pressure was also significantly improved. The rock in the caving zone of goaf had a certain supporting effect on the roof strata of roadway, and the lateral abutment pressure had obvious stress concentration. Affected by repeated mining, the failure range of the plastic zone of the two sides extended along the layer, the plastic zone of roadway roof and goaf roof was connected, and the roof near the high sidewall and the surrounding rock of the two sidewalls were seriously broken and the stability was poor. The bearing stress of gob side of roadside backfill used in the mine was significantly greater than that of roadway side, and the horizontal stress was greater than the vertical stress. The roadside filling body can meet the strength requirements, but the anti-tilting performance was weak. On this basis, the control effect of roadway surrounding rock stability under existing support conditions was analyzed, and the reinforcement support scheme of 3131 machine roadway surrounding rock was put forward

Skin sympathetic nerve activity precedes the onset and termination of paroxysmal atrial tachycardia and fibrillation

Background Skin sympathetic nerve activity (SKNA) is useful for estimating sympathetic tone in humans. Objective The purpose of this study was to test the hypotheses that (1) increased SKNA is associated with the onset and termination of paroxysmal atrial tachycardia (AT) and atrial fibrillation (AF) and (2) sinoatrial node response to SKNA is reduced in patients with more frequent AT or AF episodes. Methods SKNA and electrocardiogram were recorded in 11 patients (4 men and 7 women; average age 66 ± 10 years), including 3 patients with AT (11 ± 18 episodes per patient) and 8 patients with AF (24 ± 26 episodes per patient). Results The average SKNA (aSKNA) 10 seconds before AT onset was 1.07 ± 0.10 μV and 10 seconds after termination was 1.27 ± 0.10 μV; both were significantly (P = .032 and P < .0001) higher than that during sinus rhythm (0.97 ± 0.09 μV). The aSKNA 10 seconds before AF onset was 1.34 ± 0.07 μV and 10 seconds after termination was 1.31 ± 0.07 μV; both were significantly (P < .0001) higher than that during sinus rhythm (1.04 ± 0.07 μV). The aSKNA before onset (P < .0001) and after termination (P = .0011) was higher in AF than in AT. The sinus rate correlated (P < .0001) with aSKNA in each patient (average r = 0.74; 95% confidence interval 0.65–0.84). The r value in each patient negatively correlated with the number of AT and AF episodes (r = −0.6493; 95% confidence interval −0.8990 to −0.08073; P = .0306). Conclusion Increased SKNA was observed both at the onset and termination of AT and AF. Patients with more frequent AT and AF episodes had a weak correlation between sinus rate and aSKNA, suggesting sinoatrial node remodeling by tachycardia

The Small Conductance Calcium Activated Potassium Current Modulates the Ventricular Escape Rhythm in Normal Rabbit Hearts

Background The apamin-sensitive small-conductance calcium-activated K (SK) current (IKAS) modulates automaticity of the sinus node; IKAS blockade by apamin causes sinus bradycardia. Objective To test the hypothesis that IKAS modulates ventricular automaticity. Methods We tested the effects of apamin (100 nM) on ventricular escape rhythms in Langendorff perfused rabbit ventricles with atrioventricular (AV) block (Protocol 1) and on recorded transmembrane action potential (TMP) of pseudotendons of superfused right ventricular (RV) endocardial preparations (Protocol 2). Results All preparations exhibited spontaneous ventricular escape rhythms. In Protocol 1, apamin decreased the atrial rate from 186.2±18.0 bpm to 163.8±18.7 bpm (N=6, p=0.006) but accelerated the ventricular escape rate from 51.5±10.7 to 98.2±25.4 bpm (p=0.031). Three preparations exhibited bursts of nonsustained ventricular tachycardia (NSVT) and pauses, resulting in repeated burst-termination pattern. In Protocol 2, apamin increased the ventricular escape rate from 70.2±13.1 to 110.1±2.2 bpm (p=0.035). Spontaneous phase 4 depolarization was recorded from the pseudotendons in 6 of 10 preparations at baseline and in 3 in the presence of apamin. There were no changes of phase 4 slope (18.37±3.55 vs. 18.93±3.26 mV/s, p=0.231, N=3), but the threshold of phase 0 activation (mV) reduced from -67.97±1.53 to -75.26±0.28 (p=0.034). Addition of JTV-519, a ryanodine receptor 2 (RyR2) stabilizer, in 5 preparations reduced escape rate back to baseline. Conclusions Contrary to its bradycardic effect in the sinus node, IKAS blockade by apamin accelerates ventricular automaticity and causes repeated NSVT in normal ventricles. RyR2 blockade reversed the apamin effects on ventricular automaticity