Traceability of Geographic Origin Using Human Skin and Oral Microbiota / 法医学杂志

OBJECTIVES@#To explore the possibility of using human skin and oral microorganisms to estimate the geographic origin of an individual through the sequencing analysis of bacterial 16S rRNA gene.@*METHODS@#Microbial DNA was extracted from the palm and oral microorganisms of the Han population in Shanghai and Chifeng, Inner Mongolia, and the composition and diversity of the microbiota were analyzed by full-length 16S rRNA gene sequencing. Then, differential species were screened and a geographic location prediction model was constructed.@*RESULTS@#The compositions of palm and oral microorganisms between Shanghai and Chifeng samples were both different. The abundance and uniformity of palm side skin microorganisms were higher in Chifeng samples than in Shanghai samples, while there was no significant difference in oral microorganisms. Permutational multivariate analysis of variance (PERMANOVA) confirmed that th e β -diversity between the samples from the two places were statistically significant, and the coefficients of determination (R2) for skin and oral samples were 0.129 and 0.102, respectively. Through principal co-ordinates analysis (PCoA), the samples from the two places could be preliminarily distinguished. The predictive model had the accuracies of 0.90 and 0.83 for the geographic origin using the skin and oral samples, respectively.@*CONCLUSIONS@#There are differences in the compositions of palm and oral microbiota between Han populations in Shanghai and Chifeng. The prediction model constructed by the random forest algorithm can trace the unknown individuals from the above two places.

Three-dimensional broadband acoustic illusion cloak for sound-hard boundaries of curved geometry.

Acoustic illusion cloaks that create illusion effects by changing the scattered wave have many potential applications in a variety of scenarios. However, the experimental realization of generating three-dimensional (3D) acoustic illusions under detection of broadband signals still remains challenging despite the paramount importance for practical applications. Here we report the design and experimental demonstration of a 3D broadband cloak that can effectively manipulate the scattered field to generate the desired illusion effect near curved boundaries. The designed cloak simply comprises positive-index anisotropic materials, with parameters completely independent of either the cloaked object or the boundary. With the ability of manipulating the scattered field in 3D space and flexibility of applying to arbitrary geometries, our method may take a major step toward the real world application of acoustic cloaks and offer the possibilities of building advanced acoustic devices with versatile functionalities.

Acoustic one-way metasurfaces: Asymmetric Phase Modulation of Sound by Subwavelength Layer.

We theoretically design and numerically demonstrate an acoustic one-way metasurface, which is a planar and acoustically subwavelength layer behaving like a nearly-reflectionless surface with arbitrary wave-steering capability for incident wave impinging on one side, while virtually blocking the reversed wave. The underlying mechanism is based on an asymmetric phase modulation by coupling a phase array and a near-zero-index medium. We exemplify a metastructure-based implementation by combining the hybrid metastuctures and labyrinthine structures. Moreover, the performance of the proposed implementation is demonstrated via three distinct phenomena of anomalous refraction, wave splitting and conversion of propagation wave to surface wave. Our findings may offer more possibilities for sound manipulation and improve the application potential of acoustic artificial devices in situations such as ultrasonic imaging and therapy.

Usefulness of the heart-rate variability complex for predicting cardiac mortality after acute myocardial infarction.

BACKGROUND: Previous studies indicate that decreased heart-rate variability (HRV) is related to the risk of death in patients after acute myocardial infarction (AMI). However, the conventional indices of HRV have poor predictive value for mortality. Our aim was to develop novel predictive models based on support vector machine (SVM) to study the integrated features of HRV for improving risk stratification after AMI. METHODS: A series of heart-rate dynamic parameters from 208 patients were analyzed after a mean follow-up time of 28 months. Patient electrocardiographic data were classified as either survivals or cardiac deaths. SVM models were established based on different combinations of heart-rate dynamic variables and compared to left ventricular ejection fraction (LVEF), standard deviation of normal-to-normal intervals (SDNN) and deceleration capacity (DC) of heart rate. We tested the accuracy of predictors by assessing the area under the receiver-operator characteristics curve (AUC). RESULTS: We evaluated a SVM algorithm that integrated various electrocardiographic features based on three models: (A) HRV complex; (B) 6 dimension vector; and (C) 8 dimension vector. Mean AUC of HRV complex was 0.8902, 0.8880 for 6 dimension vector and 0.8579 for 8 dimension vector, compared with 0.7424 for LVEF, 0.7932 for SDNN and 0.7399 for DC. CONCLUSIONS: HRV complex yielded the largest AUC and is the best classifier for predicting cardiac death after AMI.

[Chronic effects of percutaneous transmyocardial laser revascularization in patients with refractory angina].

OBJECTIVE: Conflicting results exist on the therapeutic effects of percutaneous myocardial laser revascularization (PMR) in patients with refractory angina pectoris. This study assessed the effects of PMR on myocardial innervation and perfusion in patients with refractory angina pectoris. METHODS: Patients with refractory angina unsuitable for standard revascularization treatment (PTI and CABG) were randomly divided into medication plus PMR (PMR, n = 17) and medication group (M, n = 13). Coronary sinus noradrenaline (NE) and epinephrine (E) levels, heart rate variability (HRV), total ischemic burden (TIB), and ischemic ST segmental events (STI), myocardial perfusion were evaluated at pre-, immediately post and 12 months post treatment (mean followed up time = 11.6 +/- 4.9 months). RESULTS: In PMR group, one patient developed non-persistent ventricular tachycardia, 2 developed pericardial tamponade and another one patient developed heart failure at 24 h after operation. Coronary sinus NE and E were significantly lower 60 min post PMR compared to pre-PMR and HRV was significantly increased 24 h post PMR. One year post treatments, angina grade was significantly decreased in PMR (1.7 +/- 0.3) than that in M group (0.4 +/- 0.2, P < 0.05) while other parameters were similar between the groups. CONCLUSIONS: PMR induced an early transient denervation and decreased angina grade one year post treatment in patients with refractory angina.