Event History Analysis of Factors Affecting Survival of Older Adults in Taiwan.

(1) Background: Due to rapidly increasing average age of Taiwan's population, it is very important to analyze the factors affecting the survival of older adults. (2) Methods: In this study, the 1989 Taiwan Longitudinal Study on Aging, which lasted 22 years and consisted of seven surveys, was used. Furthermore, Cox and Aalen's time-dependent frailty models were used to analyze factors that affect the survival of older adults. (3) Results: Based on past literature, we selected 15 important factors that were closely associated with the survival of older adults and constructed six models based on these factors. The study results showed that, in addition to background characteristics, physical and mental conditions, activities of daily living (ADL), physical performance, and self-rated health had a huge association with the survival of older adults. (4) Conclusions: We selected ten variables (age, gender, population, education level, ADL status, physical performance, self-rated health, smoking, chewing betel nut, and the presence of a spouse), and their combinations were used to generate reduced models, which could be considered as important markers that affect and predict the survival of older adults.

Factors Related to Diabetes Mellitus in the Middle-Aged and Over in Taiwan.

Study Objective: to investigate the factors related to diabetes mellitus in the middle-aged and over in Taiwan. Method: data from seven surveys (in 1989-2011) from the "Taiwan Longitudinal Study on Aging" (TLSA), among cohort B (above the age 60 in 1989), cohort A (aged 50-66 in 1996), and cohort C (aged 50-66 in 2003), were analyzed by the interval-censored Cox model. Results: in the early aging stage (aged 60-64), diabetes mellitus prevalence among the same age appeared the lowest in cohort B, followed by cohort A; cohort C reveals the highest than the young generation. Moreover, suffering from hypertension and kidney diseases are closely related to diabetes mellitus, with the diabetes mellitus suffering hazard ratio of 2.53 (95%: 2.35, 2.73) and 1.26 (95%: 1.11, 1.44) times, respectively. For people with fair and poor self-rated health, the risk of suffering from diabetes mellitus is 1.16 (95%: 1.07, 1.27) and 1.50 (95%: 1.35, 1.67) times compared to people with good self-rated health, respectively. Conclusions: in this study, it is considered that an advanced interval censoring model analysis could more accurately grasp the characteristics of factors in people who are middle-aged and over suffering from diabetes mellitus in Taiwan.

Femtosecond and nanosecond dual-laser optical emission spectroscopy of gas mixtures.

A method employing an integrated femtosecond (fs) and nanosecond (ns) dual-laser system was developed to generate plasma with desired radical species from gas mixtures via a fs laser pulse and then to excite selected radical species to higher electronic states using a wavelength-tunable ns laser pulse. An optical spectrometer was used to measure the emission spectra and identify the transition from the excited electronic state to the ground state. The proposed technique has been demonstrated for an N2-CO2 mixture with various time delays between the two fs and ns pulses. The results have indicated that the population of selected radical species at the excited electronic state can be increased using the subsequent ns laser pulse, which also enhances the intensity of emission spectra allowing better identifications of the radical species. This technique holds a promise of detection and identification of signature plasma species, particularly for trace elements and long-distance standoff detections.

Effects of continuous passive motion on reversing the adapted spinal circuit in humans with chronic spinal cord injury.

OBJECTIVE: To investigate the possibility of restoring the adapted spinal circuit after spinal cord injury (SCI) by means of long-term continuous passive motion (CPM) of the ankle joint. DESIGN: Randomized controlled trial with repeated measures. SETTING: Research laboratory in a general hospital. PARTICIPANTS: Individuals with motor complete SCI (N=14) were recruited from a community. INTERVENTION: CPM of the ankle joint for 1 hour a day, 5 days a week for 4 weeks. MAIN OUTCOME MEASURES: Modified Ashworth Scale (MAS) scores for evaluation of spasticity and postactivation depression (PAD) were documented prior to and after intervention. RESULTS: MAS scores improved after 4 weeks of CPM intervention, indicating a reduction in spasticity of the ankle joint. PAD was restored after 4 weeks of training. CONCLUSIONS: Passive motion of the ankle joint alone was sufficient in reversing the adapted spinal circuit, and therefore indicates that spasticity after SCI could possibly be managed by CPM intervention. The results of this study support the use of the passive mode of robot-assisted therapy for humans with complete SCI who cannot exercise actively.

Femtosecond and nanosecond laser fabricated substrate for surface-enhanced Raman scattering.

We report a simple and repeatable method for fabricating a large-area substrate for surface-enhanced Raman scattering. The substrate was processed by three steps: (i) femtosecond (fs) laser micromachining and roughening, (ii) thin-film coating, and (iii) nanosecond laser heating and melting. Numerous gold nanoparticles of various sizes were created on the surface of the silicon substrate. The 3D micro-/nanostructures generated by the fs laser provide greater surface areas with more nanoparticles leading to 2 orders of magnitude higher of the enhancement factor than in the case of a flat substrate. Using an He-Ne laser with a 632.8 nm excitation wavelength, the surface-enhanced Raman scattering enhancement factor for Rhodamine 6G was measured up to 2×10(7).

Decreased central fatigue in multiple sclerosis patients after 8 weeks of surface functional electrical stimulation.

Effective treatments for multiple sclerosis (MS)-associated central fatigue have not been established. Surface functional electrical stimulation (FES), which can challenge the peripheral neuromuscular system without overloading the central nervous system, is a relatively safe therapeutic strategy. We investigated the effect of 8 weeks of surface FES training on the levels of general, central, and peripheral fatigue in MS patients. Seven of nine individuals with MS (average age: 42.86 +/- 13.47 years) completed 8 weeks of quadriceps muscle surface FES training. Maximal voluntary contraction, voluntary activation level, twitch force, General Fatigue Index (FI), Central Fatigue Index (CFI), Peripheral Fatigue Index, and Modified Fatigue Impact Scale (MFIS) scores were determined before and after training. The results showed that FI (p = 0.01), CFI (p = 0.02), and MFIS (p = 0.02) scores improved significantly after training. Improvements in central fatigue contributed significantly to improvements in general fatigue (p < 0.01). The results of the current study showed that central fatigue was a primary limitation in patients with MS during voluntary exercise and that 8 weeks of surface FES training for individuals with MS led to significantly reduced fatigue, particularly central fatigue.

Surface-enhanced Raman scattering microchip fabricated by femtosecond laser.

We report a surface-enhanced Raman scattering (SERS) microchip that is capable of measuring SERS signals of liquid samples with high sensitivity. The microdevice is an integration of a silicon-based SERS substrate, a multimode optical fiber (MMF), and a microchannel embedded in the photosensitive glass fabricated by the femtosecond laser followed by thermal treatment, wet etching, and annealing. The performance of the SERS microchip is evaluated by measuring rhodamine 6G using a 632.8 nm He-Ne laser at 4.3 mW excitation power, which reveals that the detection limit is lower than 10(-10) M at a 1 s short accumulation time.

Investigations of femtosecond-nanosecond dual-beam laser ablation of dielectrics.

We have conducted experimental investigations for the micromachining of dielectrics (fused silica) using an integrated femtosecond (fs) and nanosecond (ns) dual-beam laser system at different time delays between the fs and ns pulses. We found that the maximum ablation enhancement occurs when the fs pulse is shot near the peak of the ns pulse envelope. Enhancements up to 13.4 times in ablation depth and 50.7 times in the amount of material removal were obtained, as compared to fs laser ablation alone. The fs pulse increases the free electron density and changes the optical properties of fused silica to have metallic characteristics, which increases the absorption of the ns laser energy. This study provides an opportunity for efficient micromachining of dielectrics.

Laser-treated substrate with nanoparticles for surface-enhanced Raman scattering.

A rapid and simple approach to fabricate a large area of nanostructured substrate for surface-enhanced Raman scattering (SERS) is reported. Gold nanoparticles ranging from 10 to 40 nm in diameter uniformly distributed on a silicon substrate were obtained by annealing the gold film precoated on the silicon substrate with UV nanosecond (ns) laser pulses. The gold nanoparticles were formed by surface tension of the melted gold layer heated by ns laser pulses. The enhancement factor of the SERS substrate for Rhodamine 6G at 632.8 nm excitation was measured to be higher than 10(5). The proposed technique provides the opportunity to equip a functional microchip with SERS capability of high sensitivity and chemical stability.

The non-linear relationship between muscle voluntary activation level and voluntary force measured by the interpolated twitch technique.

Interpolated twitch technique (ITT) is a non-invasive method for assessing the completeness of muscle activation in clinical settings. Voluntary activation level (VA), measured by ITT and estimated by a conventional linear model, was reported to have a non-linear relationship with true voluntary contraction force at higher activation levels. The relationship needs to be further clarified for the correct use by clinicians and researchers. This study was to established a modified voluntary activation (modified VA) and define a valid range by fitting a non-linear logistic growth model. Eight healthy male adults participated in this study. Each subject performed three sets of voluntary isometric ankle plantar flexions at 20, 40, 60, 80 and 100% maximal voluntary contraction (MVC) with real-time feedback on a computer screen. A supramaximal electrical stimulation was applied on tibia nerve at rest and during contractions. The estimated VA was calculated for each contraction. The relationship between the estimated VA and the actual voluntary contraction force was fitted by a logistic growth model. The result showed that according to the upper and lower limit points of the logistic curve, the valid range was between the 95.16% and 10.55% MVC. The modified VA estimated by this logistic growth model demonstrated less error than the conventional model. This study provided a transfer function for the voluntary activation level and defined the valid range which would provide useful information in clinical applications.

One-step fabrication of nanostructures by femtosecond laser for surface-enhanced Raman scattering.

This paper reports an efficient fabrication of nanostructures on silicon substrates for surface-enhanced Raman scattering (SERS). Silicon wafer substrates in the aqueous solution of silver nitrate were machined by the femtosecond laser direct writing to achieve simultaneously in one-step the generation of grating-like nanostructures on the surface of the substrate and the formation of silver nanoparticles on the surface of the nanostructures via the laser-induced photoreduction effect. Parametric studies were conducted for the different concentrations of aqueous silver nitrate solutions and scanning speeds. The enhancement factor of the SERS is found to be higher than 10(9). The patterning technique provides an opportunity to incorporate the SERS capability in a functional microchip.

Fabry-Perot interferometer embedded in a glass chip fabricated by femtosecond laser.

We report a simple Fabry-Perot interferometer (FPI) embedded in a glass chip, which is capable of precisely measuring the refractive indices of liquid samples. The microdevice is the integration of a single-mode optical fiber and a microchannel in the photosensitive glass fabricated by femtosecond laser followed by thermal treatment, wet etching, and annealing. The function of the FPI is demonstrated by measuring the refractive indices of water and methanol. The interference visibility is more than 4.0 dB, which is sufficient for most sensing applications. This refractive index sensor with rigid structure could be further integrated to become a more complex 3D lab-on-a-chip for reliable biomedical applications.

The phase-response effect of size-dependent optical enhancement in a single nanoparticle.

We demonstrate detailed simulations and experiments of near-field phase-response in a single silver nanoparticle. The plasmon-photon interaction is directly observed in the vicinity of silver nanoparticles through a near-field scanning optical microscope (NSOM). Our results manifest the correlation of phase-response and size-dependent optical enhancement. Detailed interference behaviors between optical excitation and plasmon mediated re-radiation are revealed on a single particle basis. This observation facilitates nano-applications in controlling the spatial distribution of surface plasmon (SP) modes by means of nanostructures.

Using Electromyography to Detect the Weightings of the Local Muscle Factors to the Increase of Perceived Exertion During Stepping Exercise.

Rate of perceived exertion (RPE) is a clinically convenient indicator for monitoring exercise intensity in cardiopulmonary rehabilitation. It might not be sensitive enough for clinicians to determine the patients' physiological status because its association with the cardiovascular system and local muscle factors is unknown. This study used the electromyographic sensor to detect the local muscle fatigue and stabilization of patella, and analyzed the relationship between various local muscle and cardiovascular factors and the increase of RPE during stepping exercise, a common exercise program provided in cardiopulmonary rehabilitation. Ten healthy adults (4 males and 6 females) participated in this study. Each subject used their right bare foot to step up onto a 23-cm-high step at a constant speed until the RPE score reached 20. The RPE, heart rate (HR), and surface EMG of the rectus femoris (RF), vastus medialis, and vastus lateralis were recorded at 1-minute intervals during the stepping exercise. The generalized estimating equations (GEE) analysis indicated that the increase in RPE significantly correlated with the increase in HR, and decrease in median frequency (MF) of the EMG power spectrum of the RF. Experimental results suggest that the increase in RPE during stepping exercise was influenced by the cardiovascular status, localized muscle fatigue in the lower extremities. The weighting of the local muscle factors was more than half of the weighting of the cardiovascular factor.

Adaptive-optics system with liquid-crystal phase-shift interferometer.

We develop an adaptive-optics system based on a Mach-Zehnder radial shearing interferometer with liquid-crystal-device (LCD) phase-shift interferometry (PSI). Using accurate phase calibration and transient nematic driving of the LCD, the developed three-step PSI procedure can be achieved in a time of 5 ms. The proposed Mach-Zehnder radial shearing PSI method reconstructs the phase information using a digital signal processor (DSP). The DSP then computes appropriate control signals to drive a deformable mirror in such a way as to eliminate the wavefront distortion. The current adaptive-optics system is capable of suppressing low-frequency thermal disturbances with a signal-to-noise ratio improvement of more than 20 dB and a steady-state phase error of less than 0.02pi root mean square when the control loop is operated at a frequency of 30 Hz.

Predictive model of muscle fatigue after spinal cord injury in humans.

The fatigability of paralyzed muscle limits its ability to deliver physiological loads to paralyzed extremities during repetitive electrical stimulation. The purposes of this study were to determine the reliability of measuring paralyzed muscle fatigue and to develop a model to predict the temporal changes in muscle fatigue that occur after spinal cord injury (SCI). Thirty-four subjects underwent soleus fatigue testing with a modified Burke electrical stimulation fatigue protocol. The between-day reliability of this protocol was high (intraclass correlation, 0.96). We fit the fatigue index (FI) data to a quadratic-linear segmental polynomial model. FI declined rapidly (0.3854 per year) for the first 1.7 years, and more slowly (0.01 per year) thereafter. The rapid decline of FI immediately after SCI implies that a "window of opportunity" exists for the clinician if the goal is to prevent these changes. Understanding the timing of change in muscle endurance properties (and, therefore, load-generating capacity) after SCI may assist clinicians when developing therapeutic interventions to maintain musculoskeletal integrity.