Broadband chaos generation utilizing a wavelength-tunable monolithically integrated chaotic semiconductor laser subject to optical feedback.

We demonstrate a broadband and wavelength-tunable chaotic laser by using a monolithically integrated wavelength-tunable chaotic semiconductor laser subject to optical feedback. The chip consists of a gain section, a distributed Bragg reflection grating section, a semiconductor optical amplifier section, and a phase section. By applying an optical feedback loop to the chaotic semiconductor laser chip, a nonlinear frequency mixing is stimulated in the laser cavity, and the chaos bandwidth is expanded to 33.6 GHz, which is 4.4 times larger than the bandwidth without optical feedback. Furthermore, the effect of feedback optical power on the bandwidth is investigated. The results show that the wide power spectrum of chaotic laser is available in a large wavelength range from 1556.44 nm to 1566.42 nm. This work explores a broadband and wavelength-tunable chaotic semiconductor laser for the wavelength division multiplexing to enlarge the capacity in chaotic secure optical communications.

Mechanical regulation of breast cancer migration and apoptosis via direct and indirect osteocyte signaling.

Bone metastases, the migration of cancers to bone, occur in 65-80% of patients with advanced breast cancer. Metastasized cancer cells interact with cells such as the bone-resorbing osteoclasts to alter bone remodeling. Exercise, often suggested as an intervention for cancer patients, regulates bone remodeling via osteocytes. Osteocytes also signal to endothelial cells, which may affect cancer cell extravasation. Therefore, we hypothesize that mechanically stimulated osteocytes can regulate processes in breast cancer bone metastasis. To test this, we exposed osteocytes to oscillatory fluid flow in vitro using parallel-plate flow chambers. We observed that conditioned medium from flow-stimulated osteocytes increased migration (by 45%) and reduced apoptosis (by 12%) of breast cancer cells. Conditioned medium from osteoclasts conditioned in flowed osteocytes' conditioned medium reduced migration (by 47%) and increased apoptosis (by 55%) of cancer cells. Cancer cell trans-endothelial migration was reduced by 34% toward flowed osteocytes' conditioned medium. This difference was abolished with ICAM-1 or IL-6 neutralizing antibodies. Conditioned medium from endothelial cells conditioned in flowed osteocytes' conditioned medium increased cancer cell apoptosis by 29%. To summarize, this study demonstrated mechanically stimulated osteocytes' potential to affect breast cancer cells not only through direct signaling, but also through osteoclasts and endothelial cells. The anti-metastatic potential of the indirect signalings is particularly exciting since osteocytes are further away from metastasizing cancer cells than osteoclasts and endothelial cells. Future studies into the effect of bone mechanical loading on metastases and its mechanism will assist in designing cancer intervention programs that lowers the risk for bone metastases.

24-hour aortic blood pressure variability showed a stronger association with carotid damage than 24-hour brachial blood pressure variability: The SAFAR study.

We aim to compare 24-hour aortic blood pressure variability (BPV) with brachial BPV in relation to carotid damage as estimated by carotid intima-media thickness (CIMT) and cross-sectional area (CCSA). Four hundred and forty five individuals received brachial and aortic 24-hour ambulatory BP monitoring with a validated device (Mobil-O-Graph). Systolic BPV was estimated by average real variability (ARV) and time-weighted standard deviation (wSD). In multiple logistic regression analysis, CIMT > 900 µm was significantly and independently associated with aortic ARV (OR = 1.38; 95% CI: 1.04-1.84), aortic wSD (OR = 1.65; 95% CI: 1.19-2.29) and brachial ARV (OR = 1.53; 95% CI: 1.07-2.18), but not with brachial wSD. CCSA > 90th percentile was significantly and independently associated with aortic ARV (OR = 1.50; 95% CI: 1.07-2.10) and wSD (OR = 1.70; 95% CI: 1.12-2.56), but not with brachial BPVs. In receiver operator characteristics curve analysis, aortic wSD identified CCSA > 90th percentile better than brachial wSD (AUC: 0.73 vs 0.68, P < .01). In conclusion, aortic 24-hour systolic BPV showed a slightly stronger association with carotid damage than brachial BPV.

Northern Shanghai Study: cardiovascular risk and its associated factors in the Chinese elderly-a study protocol of a prospective study design.

INTRODUCTION: Cardiovascular (CV) diseases are the leading cause of death and disability in the world. Increasing lifespans and ageing populations also contribute to an increasing CV burden. However, in China, there were few well-designed cohort studies focusing on the elderly population, let alone an established CV risk score. The objective of this study is to establish a CV risk score based on a community-dwelling Chinese elderly population, determining the profile of the associated CV risk factors and target organ damages (TODs), so as to guide the later intervention. METHODS AND ANALYSIS: The Northern Shanghai Study is an ongoing prospective community-based study. After enrolment, clinical examination, anthropometric measurement and a questionnaire will be administered to each participant at baseline and after every 2 years in the follow-up. Our tests and examinations include: blood/urine sample and biochemical measurements, office blood pressure recording, carotid ultrasonograph, echocardiograph, pulse wave velocity, pulse wave analysis, 4-limb blood pressure recording, body mass index, etc. Baseline measurement will also include the assessments on TODs and the conventional CV risk factors. In the follow-up, the incidence of CV events and mortality will be recorded. The Northern Shanghai Risk Score will be calculated, with considerations on CV risk factors and TODs. ETHICS AND DISSEMINATION: This study was approved by the Shanghai Tenth People's Hospital Institutional Review Board. All participants signed a written consent form. TRIAL REGISTRATION NUMBER: NCT02368938; Pre-results.

Comparison of central and peripheral hemodynamics in association with left ventricular diastolic dysfunction in the community-based elderly Chinese.

The aim of the study was to investigate the association of left ventricular diastolic dysfunction (LVDD) with central and peripheral hemodynamics. A total of 1599 community-based senior residents (aged ≥ 65 years) in northern Shanghai, China, were recruited as of August 2015. Echocardiography was performed for each participant using the MyLab30 Gold CV system. According to the recommendations from the American Society of Echocardiography, the ratio of E (peak early diastolic transmitral flow velocity) to E' (early diastolic lateral mitral annulus velocity) was assessed for the evaluation of LVDD. Central blood pressure (BP) components were measured using the SphygmoCor system. In community older population (72.7 ± 6.01 years), brachial systolic BP (mm Hg) was higher than central systolic BP (141.9 ± 19.5 vs. 130.3 ± 20.1 mm Hg). A total of 214 subjects (13.4%) showed LVDD, and female showed higher prevalence of diastolic dysfunction than male (17.3% vs. 8.4%, P < .01). After adjustment for confounding variables, only central systolic BP, not brachial systolic BP, was significantly associated with E/E' in the total population. Similar result was found in the subgroup analysis (participants without antihypertensive agents treatment, man, woman). Similar findings were obtained for the pulse pressure (PP) analysis. Within central hemodynamics, only central PP, but not central systolic BP or augmentation pressure, was significantly associated with E/E' after adjustment. When LVDD was defined by E/E' and other echocardiographic parameters, our findings remained unaltered in the multivariate logistic regression with similar adjustment in the total population and subgroup analysis. In the Chinese elderly cohort, central hemodynamics, especially central PP, is superior to other BP components in identifying LVDD (NCT02368938).

Comparison of Carotid-Femoral and Brachial-Ankle Pulse-Wave Velocity in Association With Target Organ Damage in the Community-Dwelling Elderly Chinese: The Northern Shanghai Study.

BACKGROUND: Carotid-femoral pulse-wave velocity (cf-PWV) and brachial-ankle PWV (ba-PWV) are the 2 most frequently applied PWV measurements. However, little is known about the comparison of hypertensive target organ damage (TOD) with cf-PWV and ba-PWV. METHODS AND RESULTS: A total of 1599 community-dwelling elderly subjects (age >65 years) in northern Shanghai were recruited from June 2014 to August 2015. Both cf-PWV and ba-PWV were measured using SphygmoCor and VP1000 systems, respectively. Within the framework of comprehensive cardiovascular examinations, risk factors were assessed, and asymptomatic TOD, including left ventricular mass index, peak transmitral pulsed Doppler velocity/early diastolic tissue Doppler velocity (E/Ea), carotid intima-media thickness, arterial plaque, creatinine clearance rate, and urinary albumin-creatinine ratio were all evaluated. Both PWVs were significantly associated with male sex, age, waist/hip circumference, fasting plasma glucose, and systolic blood pressure, and ba-PWV was also significantly related to body mass index. Both PWVs were significantly correlated with most TOD. When cf-PWV and ba-PWV were both or separately put into the stepwise linear regression model together with cardiovascular risk factors and treatment, only cf-PWV, but not ba-PWV, was significantly associated with carotid intima-media thickness and creatinine clearance rate (P<0.05). When cf-PWV and ba-PWV were both or separately put into the same full-mode model after adjustment for confounders, only cf-PWV, but not ba-PWV, showed significant association with carotid intima-media thickness and creatinine clearance rate (P<0.05). Similar results were observed in logistic regression analysis. CONCLUSIONS: Taken together, in the community-dwelling elderly Chinese, cf-PWV seems to be more closely associated with hypertensive TOD, especially vascular and renal TOD, as compared with ba-PWV. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02368938.

Energetic cost of walking with increased step variability.

Step-by-step variations occur during normal human walking, induced in part by imperfect sensorimotor control and naturally occurring random perturbations. These effects might increase energy expenditure during walking, because they differ from the nominal preferred gait, which is typically the most economical, and because of the cost of making active feedback adjustments to maintain gait stability. We tested this hypothesis by artificially inducing greater step variability through visual perturbations from a virtual reality display, and measuring the effect on energy expenditure. Young healthy adult subjects (N=11) walked on a treadmill while viewing a virtual hallway, to which virtual perturbations were applied in fore-aft or medio-lateral directions. The greatest effect on gait was achieved with medio-lateral visual perturbations, which resulted in a 65% increase in step width variability and a 5.9% increase (both P<0.05) in net metabolic rate compared to walking without perturbations. Perturbations generally induced greater variability in both step width and (to a lesser degree) step length, and also induced slightly wider and (to a lesser degree) shorter mean steps. Each of these measures was found to correlate significantly with each other, regardless of perturbation direction and magnitude. They also correlated with metabolic rate (P<0.05 for each separate measure), despite explaining only a modest proportion of overall energetic variations (R(2)<0.40). Step variability increases with some gait disorders and with increasing age. Our results suggest that imperfect sensorimotor control may contribute to the increased metabolic cost of walking observed with such conditions.