Comparative Study of Data Compression Methods for Large Aperture Static Imaging Spectrometer.

Facing the problem of choosing different data source as compressing object results in different compression effect, several techniques are investigated to explore a better data source which can reduce the loss of image and spectral information while getting higher compression ratio in the compression work of the large aperture static imaging spectrometer. In this paper the optical path difference dimension data source of LASIS was proposed after analyzing the characteristic of LASIS and then compared with the LASIS and LAMIS data source in detail. The SWIR data collected with the principle prototype of LASIS were used in our experiment. Firstly, three forms of data sources were extracted after detailedly introducing their data characteristic and extracting methods. Secondly, the mature algorithms in engineering JPEG and JPEG2000 were employed to compress and reconstruct the three forms of data sources respectively. Finally, the compression effect was evaluated in the aspect of image content, interference dimension, spectral dimension and compression ratio respectively, and the original spectral curves of three materials choosing from the field of view and those after reconstruction were extracted next, then the loss of spectral information of these three materials were measured by using the SA (Spectral Angle) and RQE (Relative Quadratic Error) values of the spectral curves to evaluate the compression effect. It is demonstrated that using the optical path difference dimension data as compressing object shows obvious advantages compared with LASIS and LAMIS, which achieves a combination of higher compression ratio, lower mean square error, lower peak signal noise ratio and less information loss that is competitive with the best results from the literature. The results show that the proposed optical path difference dimension data source has good performance in preserving the spatial and spectral information during the compression of LASIS than the other two common forms data sources of LASIS.

[Experiment Research and Analysis of Spectral Prediction on Soil Leaking Oil Content].

The spectral analysis method was applied experimentally to extract the spectral indices, measure and analyze the spectral characteristics and their difference of the mixture which are composed in soil in Central Shaanxi Plain and the diesel and motor oil respectively, aiming to provide solutions to practical difficulties in detecting, analyzing the spectral characteristics and difference between the soil leaking with equal content diesel and motor oil and predicting the leaking content of diesel in the soil. The spectral response curves of the soil leaking with different oil respectively and the soil leaking with diesel with different content were collected. Then the spectral prediction model for the leaking content of diesel in the soil was built based on the reflectance characteristics. The coefficient of the detection (R2) was introduced to evaluate the stability of the built model，and the parameter root mean squared error (RMSE) was introduced to estimate the precision and the predictability of the model built in this work. It is demonstrated that : (1) The reflectance of soil leaking with diesel is less than that of the equal content motor oil. And there is a double absorption trough of the reflectance curve of both soil leaking with diesel and motor oil at 1 740 and 2 328 nm. The spectral absorption indices and absorption depth of the soil leaking with diesel keep less than the equal content motor oil. (2) The built spectral prediction model for the leaking content of diesel in the soil demonstrates good stability with the coefficient of determination at R2=0.854, and performs favorable predictability (Root-Mean-Square Error, RMSE=0.016), which can benefit the effective prediction and quick estimation methods of the leaking content of diesel in the soil, enrich and progress the experimental method and theoretical research work of spectral prediction on soil leaking oil content and promote the application of remote sensing in safety production and environmental protection.

[Spatial domain display for interference image dataset].

The requirements of imaging interferometer visualization is imminent for the user of image interpretation and information extraction. However, the conventional researches on visualization only focus on the spectral image dataset in spectral domain. Hence, the quick show of interference spectral image dataset display is one of the nodes in interference image processing. The conventional visualization of interference dataset chooses classical spectral image dataset display method after Fourier transformation. In the present paper, the problem of quick view of interferometer imager in image domain is addressed and the algorithm is proposed which simplifies the matter. The Fourier transformation is an obstacle since its computation time is very large and the complexion would be even deteriorated with the size of dataset increasing. The algorithm proposed, named interference weighted envelopes, makes the dataset divorced from transformation. The authors choose three interference weighted envelopes respectively based on the Fourier transformation, features of interference data and human visual system. After comparing the proposed with the conventional methods, the results show the huge difference in display time.

[Hadamard transform spectrometer mixed pixels' unmixing method].

Hadamard transform imaging spectrometer is a multi-channel digital transform spectrometer detection technology, this paper based on digital micromirror array device (DMD) of the Hadamard transform spectrometer working principle and instrument structure, obtained by the imaging sensor mixed pixel were analyzed, theory derived the solution of pixel aliasing hybrid method, simulation results show that the method is simple and effective to improve the accuracy of mixed pixel spectrum more than 10% recovery.

[Spatially modulated Fourier transform imaging spectrometer data compression research].

Fourier transform imaging spectrometer is a new technic, and has been developed very fast in recent ten years. When it is used in satellite, because of the limit by the data transmission, the authors need to compress the original data obtained by the Fourier transform imaging spectrometer, then, the data can be transmitted, and can be incepted on the earth and decompressed. Then the authors can do data process to get spectrum data which can be used by user. Data compression technic used in Fourier transform imaging spectrometer is a new technic, and few papers introduce it at home and abroad. In this paper the authors will give a data compression method, which has been used in EDIS, and achieved a good result.

Electrocardiographic alterations after chronic right ventricular apical pacing in patients with sinus node dysfunction.

OBJECTIVE: The purpose of this study is to investigate the potential to induce electrical remodeling by chronic right ventricular apical (RVA) in patients with sinus node dysfunction. METHODS: Ninety-two patients with sinus node dysfunction who underwent initial pacemaker implantation were included in the study. During routine clinic visits, electrocardiograms and echocardiograms were recorded. Forty-five patients were also studied as controls. RESULTS: During a mean follow-up time of 3.3 +/- 0.5 years, the intrinsic QRS duration increased from 87 +/- 9 milliseconds before device implantation to 94 +/- 10 milliseconds (P < .001). The left ventricular end-diastolic diameter increased from 46 +/- 3 to 50 +/- 4 mm (P < .001), and the left ventricular ejection fraction decreased from 63% +/- 4% to 57% +/- 5% (P < .001). Logistic regression analysis revealed that elderly age at the time of pacemaker implantation (odds ratio [OR], 3.41; 95% confidence interval [CI], 1.07-10.90; P = .04), RVA pacing (OR, 3.91; 95% CI, 1.10-13.89; P = .03), and coronary artery disease (OR, 7.33; 95% CI, 1.09-50.29; P = .04) were independent predictors of the prolongation of intrinsic QRS duration. CONCLUSIONS: The present study indicated that chronic RVA pacing may lead to a prolongation of intrinsic QRS duration, which could be independently predicted by elderly age, chronic RVA pacing, and the presence of coronary artery disease.

Polypyrrole/polylactic acid nanofibrous scaffold cotransplanted with bone marrow stromal cells promotes the functional recovery of spinal cord injury in rats.

AIMS: The objective of this study was to analyze the efficacy of polypyrrole/polylactic acid (PPy/PLA) nanofibrous scaffold cotransplanted with bone marrow stromal cells (BMSCs) in promoting the functional recovery in a rat spinal cord injury (SCI). METHODS: Female Sprague-Dawley rats were randomly divided into three groups (n = 18/group): control group, PPy/PLA group, and PPy/PLA/BMSCs group. The SCI was induced in all rats. Consequently, rats in PPy/PLA/BMSCs group were transplanted with 1 × 105 BMSCs after implantation of PPy/PLA, while those in the PPy/PLA group were implanted with PPy/PLA only; no implantation was performed in the control group. Six weeks after surgery, immunofluorescence microscopy, electron microscope, and polymerase chain reaction (PCR) techniques were performed to assess the changes in the injured spinal cord tissues. RESULTS: Electrophysiology and locomotor function testing suggested that PPy/PLA nanofibrous scaffold cotransplanted with BMSCs could promote the functional recovery of the spinal cord. Six weeks after the operation, lower amount of scar tissue was found in the PPy/PLA group compared with the control group. Abundant neurofilament (NF) and neuron-specific marker (NeuN) positive staining, and myelin formations were detected in the injured area. In addition, the transplantation of BMSCs not only improved the efficacy of PPy/PLA but also managed to survive well and was differentiated into neural and neuroglial cells. CONCLUSIONS: The implantation of PPy/PLA nanofibrous scaffold and BMSCs has a great potential to restore the electrical conduction and to promote functional recovery by inhibiting the scar tissue formation, promoting axon regeneration, and bridging the gap lesion.

lncRNA-ES3/miR-34c-5p/BMF axis is involved in regulating high-glucose-induced calcification/senescence of VSMCs.

Vascular calcification/aging is common in diabetes and is associated with increased morbidity and mortality of patients. MiR-34c-5p, not miR-34c-3p, was suppressed significantly in calcification/senescence of human aorta vascular smooth muscle cells (HA-VSMCs) induced by high glucose, which was proven by the formation of mineralized nodules and staining of senescence associated-ß-galactosidase staining (SA ß-gal) positive cells. Overexpression of miR-34c-5p alleviated calcification/senescence of HA-VSMCs, whereas inhibition of miR-34c-5p received the opposite results. Bcl-2 modifying factor (BMF) was a functional target of miR-34c-5p and it was involved in the process of calcification/senescence of HA-VSMCs. Besides, lncRNA-ES3 acted as a competing endogenous RNAs (ceRNA) of miR-34c-5p to enhance BMF expression. Further, lncRNA-ES3 inhibited miR-34c-5p expression by direct interaction and its knockdown suppressed the calcification/senescence of HA-VSMCs. Our results showed for the first time that the calcification/senescence of VSMCs was regulated by lncRNA-ES3 /miR-34c-5p/BMF axis.

[Lovastatin protects mesenchymal stem cells against hypoxia and serum deprivation-induced apoptosis through activation of PI3K/Akt and ERK1/2 signaling pathways].

OBJECTIVE: To investigated the effect of lovastatin on hypoxia and serum deprivation (Hypoxia/SD) induced rat MSCs apoptosis in vitro and associated signaling pathway changes. METHODS: MSCs were isolated from Sprague-Dawley rats. The anti-apoptotic effects of lovastatin were detected using Hoechst33342 and annexin V-FITC/PI binding assay by Flow cytometric analysis. The phosphorylation of Akt and ERK1/2, the cytochrome C and the cleaved caspase-3 were detected by Western blot. RESULTS: Lovastatin (0.01 - 1 micromol/L) significantly reduced Hypoxia/SD-induced MSCs apoptosis and increased Akt phosphorylation, reduced caspase-3 activation and cytochrome c release from mitochondria to cytosol in a time dependent manner. These effects could be significantly blocked by both PI3K inhibitor, LY294002 and ERK1/2 inhibitor, U0126. CONCLUSIONS: Our results showed that lovastatin protects MSCs from Hypoxia/SD-induced apoptosis via activating PI3K/Akt and ERK1/2 signaling pathways suggesting a potential role of statins as an adjunct therapeutic agent during transplanting MSCs into damaged heart after myocardial infarction.

Anatomical mechanism of spontaneous recovery in regions caudal to thoracic spinal cord injury lesions in rats.

BACKGROUND: The nerve fibre circuits around a lesion play a major role in the spontaneous recovery process after spinal cord hemisection in rats. The aim of the present study was to answer the following question: in the re-control process, do all spinal cord nerves below the lesion site participate, or do the spinal cord nerves of only one vertebral segment have a role in repair? METHODS: First we made a T7 spinal cord hemisection in 50 rats. Eight weeks later, they were divided into three groups based on distinct second operations at T7: ipsilateral hemisection operation, contralateral hemisection, or transection. We then tested recovery of hindlimbs for another eight weeks. The first step was to confirm the lesion had role or not in the spontaneous recovery process. Secondly, we performed T7 spinal cord hemisections in 125 rats. Eight weeks later, we performed a second single hemisection on the ipsilateral side at T8-T12 and then tested hindlimb recovery for another six weeks. RESULTS: In the first part, the Basso, Beattie, Bresnahan (BBB) scores and the electrophysiology tests of both hindlimbs weren't significantly different after the second hemisection of the ipsilateral side. In the second part, the closer the second hemisection was to T12, the more substantial the resulting impairment in BBB score tests and prolonged latency periods. CONCLUSIONS: The nerve regeneration from the lesion area after hemisection has no effect on spontaneous recovery of the spinal cord. Repair is carried out by all vertebrae caudal and ipsilateral to the lesion, with T12 being most important.

Identification of MicroRNAs involved in hypoxia- and serum deprivation-induced apoptosis in mesenchymal stem cells.

The use of bone marrow mesenchymal stem cell- (MSC) transplantation therapy for cardiac diseases is limited due to poor survival of implanted cells. MicroRNAs (miRNAs) have been reported to be involved in regulating almost all cellular processes, including apoptosis. In this study, we found that the miRNA profile was altered during apoptosis induced by hypoxia and serum deprivation (hypoxia/SD). We further revealed that over-expression of miR-21, miR-23a and miR-210 could promote the survival of MSCs exposed to hypoxia/SD. In contrast, down-regulation of miR-21, miR-23a and miR-503 aggravated apoptosis of MSCs. It was indicated that these miRNAs may play important roles during MSC apoptosis induced by hypoxia/SD.