A Robust Interacting Multi-Model Multi-Bernoulli Mixture Filter for Maneuvering Multitarget Tracking under Glint Noise.

In practical radar systems, changes in the target aspect toward the radar will result in glint noise disturbances in the measurement data. The glint noise has heavy-tailed characteristics and cannot be perfectly modeled by the Gaussian distribution widely used in conventional tracking algorithms. In this article, we investigate the challenging problem of tracking a time-varying number of maneuvering targets in the context of glint noise with unknown statistics. By assuming a set of models for the possible motion modes of each single-target hypothesis and leveraging the multivariate Laplace distribution to model measurement noise, we propose a robust interacting multi-model multi-Bernoulli mixture filter based on the variational Bayesian method. Within this filter, the unknown noise statistics are adaptively learned while filtering and the predictive likelihood is approximately calculated by means of the variational lower bound. The effectiveness and superiority of our proposed filter is verified via computer simulations.

Real Aperture Radar Super-Resolution Imaging for Sea Surface Monitoring Based on a Hybrid Model.

In recent years, super-resolution imaging techniques have been intensely introduced to enhance the azimuth resolution of real aperture scanning radar (RASR). However, there is a paucity of research on the subject of sea surface imaging with small incident angles for complex scenarios. This research endeavors to explore super-resolution imaging for sea surface monitoring, with a specific emphasis on grounded or shipborne platforms. To tackle the inescapable interference of sea clutter, it was segregated from the imaging objects and was modeled alongside I/Q channel noise within the maximum likelihood framework, thus mitigating clutter's impact. Simultaneously, for characterizing the non-stationary regions of the monitoring scene, we harnessed the Markov random field (MRF) model for its two-dimensional (2D) spatial representational capacity, augmented by a quadratic term to bolster outlier resilience. Subsequently, the maximum a posteriori (MAP) criterion was employed to unite the ML function with the statistical model regarding imaging scene. This hybrid model forms the core of our super-resolution methodology. Finally, a fast iterative threshold shrinkage method was applied to solve this objective function, yielding stable estimates of the monitored scene. Through the validation of simulation and real data experiments, the superiority of the proposed approach in recovering the monitoring scenes and clutter suppression has been verified.

Purification and Identification of Peptides from Oyster (Crassostrea hongkongensis) Protein Enzymatic Hydrolysates and Their Anti-Skin Photoaging Effects on UVB-Irradiated HaCaT Cells.

This study aimed to purify and identify antiphotoaging peptides from oyster (Crassostrea hongkongensis) protein enzymatic hydrolysates (OPEH) and to investigate the possible mechanism underlying its antiphotoaging effect. Multiple methods (Ultrafiltration, G25 Chromatography, RP-HPLC, and LC/MS/MS) had been used for this purpose, and eventually, two peptides, including WNLNP and RKNEVLGK, were identified. Particularly, WNLNP exerted remarkable antiphotoaging effect on the UVB-irradiated HaCaT photoaged cell model in a dose-dependent manner. WNLNP exerted its protective effect mainly through inhibiting ROS production, decreasing MMP-1 expression, but increasing extracellular pro-collagen I content. Furthermore, WNLNP downregulated p38, JNK, ERK, and p65 phosphorylation in the MAPK/NF-κB signaling pathway and attenuated bax over-expressions but reversed bcl-2 reduction in UVB- irradiated HaCaT cells. The molecular docking analysis showed that WNLNP forms five and seven hydrogen bonds with NF-κB (p65) and MMP-1, respectively. This study suggested that a pentapeptide WNLNP isolated from OPEH had great potential to prevent and regulate skin photoaging.

Gain-Phase Errors Calibration for a Linear Array Based on Blind Signal Separation.

In this paper, a non-iterative blind calibration algorithm for gain-phase errors is proposed. A mixing matrix is first obtained from the received observation data through blind signal separation. The mixing matrix is the product of the gain-phase error matrix and the ideal array manifold matrix. Then, a spatial spectrum is constructed by using the estimated mixed matrix. The direction corresponding to the maximum point of the spectral function is proved to be the azimuth of a certain source. Therefore, after the direction-of-arrival (DOA) is obtained by a one-dimensional spectrum search, the active calibration method can be used to estimate the gain-phase errors. The proposed algorithm is not limited to the calibration for uniform linear array (ULA), but also applicable to a non-uniform linear array. Moreover, the estimation performance of the algorithm will not be affected by the magnitude of the gain errors. Some simulations are given to verify the effectiveness and performance of the algorithm.

Focusing Bistatic Forward-looking Synthetic Aperture Radar Based on An Improved Hyperbolic Range Model and A Modified Omega-K algorithm.

For parallel bistatic forward-looking synthetic aperture radar (SAR) imaging, the instantaneous slant range is a double-square-root expression due to the separate transmitter-receiver system form. The hyperbolic approximation provides a feasible solution to convert the dual square-root expression into a single-square-root expression. However, some high-order terms of the range Taylor expansion have not been considered during the slant range approximation procedure in existing methods, and therefore, inaccurate phase compensation occurs. To obtain a more accurate compensation result, an improved hyperbolic approximation range form with high-order terms is proposed. Then, a modified omega-K algorithm based on the new slant range form is adopted for parallel bistatic forward-looking SAR imaging. Several simulation results validate the effectiveness of the proposed imaging algorithm.

[Treatment of children with femoral subtrochanteric fractures by the external fixation combined with single hip plaster].

OBJECTIVE: To explore curative effects of external fixation combined with single hip plaster in treating children with femoral subtrochanteric fracture. METHODS: Form March 2009 to July 2016, 15 children with femoral subtrochanteric fracture were treated with external fixation combined with single hip plaster, including 9 males and 6 females with a mean age of 8.5 years old ranging from 5 to 14 years old. According to fracture classification of Seinsheimer, 3 cases were type IIA, 4 cases were type IIB, 3 cases were type IIC, 2 cases were type IIIA, 1 case was type IIIB, 1 case was type IV, 1 case was type V. Complications and radiographs were retrospectively reviewed. Postoperative function of hips were evaluated according to Sanders criteria. RESULTS: All children were followed up from 16 to 48 months with an average of 32 months. No early closure of epiphysis, bone nonunion and breakage of screw occurred. According to the Sanders score standard of hip function, the result was excellent in 14 cases, good in 1 case. There were no hip inversion, limb shortening, excessive growth and other malformations. CONCLUSIONS: External fixation combined with single hip plaster for the treatment of children is a safe and effective fixation, which provide a new choice of femoral subtrochanteric fracture.

Parametric down-conversion with nonideal and random quasi-phase-matching.

Quasi-phase-matching (QPM) has enriched the capacity of parametric down-conversion (PDC) in generating biphotons for many fundamental tests and advanced applications. However, it is not clear how the nonidealities and randomness in the QPM grating of a parametric down-converter may affect the quantum properties of the biphotons. This paper intends to provide insights into the interplay between PDC and nonideal or random QPM structures. Using a periodically poled nonlinear crystal with short periodicity, we conduct experimental and theoretical studies of PDC subject to nonideal duty cycle and random errors in domain lengths. We report the observation of biphotons emerging through noncritical birefringent-phasematching, which is impossible to occur in PDC with an ideal QPM grating, and a biphoton spectrum determined by the details of nonidealities and randomness. We also observed QPM biphotons with a diminished strength. These features are both confirmed by our theory. Our work provides new perspectives for biphoton engineering with QPM.

[Short-term efficacy of atrial septostomy in the treatment of idiopathic pulmonary arterial hypertension patients complicating with right heart failure].

OBJECTIVE: To evaluate the efficacy of atrial septostomy in idiopathic pulmonary arterial hypertension (IPAH) patients complicating right ventricular failure. METHODS: This retrospective analysis included 5 IPAH patients (3 males, (29.3±15.2) years old) with right ventricular failure which were refractory to conventional and target-specific medication in Shanghai Chest Hospital from March to July 2014. Graded balloon dilation septostomy procedures were performed in all 5 patients. RESULTS: Successful atrial septostomy was achieved in 5 attempts with no procedure-related complications. Immediately post procedure, the mean systemic oxygen saturation decreased from (98.0±1.8)% to (86.4±3.2)% (P = 0.002), while the mean right atrial pressure decreased from (18.9±1.7) mmHg (1 mmHg = 0.133 kPa) to (16.0±1.3) mmHg (P = 0.039) and the mean cardiac index increased from (2.1±0.3) L · min(-1) · m(-2) to (2.7±0.5) L · min(-1) · m(-2) (P = 0.029). Mean follow-up was (6.2 ±1.8) months. Cardiac functional class (WHO) was 3 in 3 patients and 4 in 2 patients before the procedure, and increased 1 class in all patients during follow-up (P = 0.062). Exercise endurance (6-min walk test) also improved from (289.2±16.9) m to (320.4±19.6) m (P = 0.019), while B-type natriuretic peptide (BNP) level declined from (550.0±35.7) ng/L to (218.0±36.2) ng/L (P < 0.001). Except one patient developed spontaneous closure of created defect, right to left shunt at atrial septal level was evidenced by echocardiography during follow-up in the rest 4 patients. CONCLUSIONS: Atrial septostomy is safe and can improve hemodynamics and heart function in selected IPAH patients with right heart failure. Atrial septostomy can be used as a palliative treatment for IPAH and further study is warranted to evaluate the long-term efficacy of this procedure.

Combined enzymatic and mechanical cell disruption and lipid extraction of green alga Neochloris oleoabundans.

Microalgal biodiesel is one of the most promising renewable fuels. The wet technique for lipids extraction has advantages over the dry method, such as energy-saving and shorter procedure. The cell disruption is a key factor in wet oil extraction to facilitate the intracellular oil release. Ultrasonication, high-pressure homogenization, enzymatic hydrolysis and the combination of enzymatic hydrolysis with high-pressure homogenization and ultrasonication were employed in this study to disrupt the cells of the microalga Neochloris oleoabundans. The cell disruption degree was investigated. The cell morphology before and after disruption was assessed with scanning and transmission electron microscopy. The energy requirements and the operation cost for wet cell disruption were also estimated. The highest disruption degree, up to 95.41%, assessed by accounting method was achieved by the combination of enzymatic hydrolysis and high-pressure homogenization. A lipid recovery of 92.6% was also obtained by the combined process. The combined process was found to be more efficient and economical compared with the individual process.

Platelet-derived growth factor-BB induces matrix metalloproteinase-2 expression and rat vascular smooth muscle cell migration via ROCK and ERK/p38 MAPK pathways.

Matrix metalloproteinases (MMP) play a pivotal role in the pathogenesis of cardiovascular diseases. Their expressions are altered in response to a variety of stimuli, including growth factors, inflammatory markers, and cytokines. In this study, we demonstrated that platelet-derived growth factor-BB (PDGF-BB) induces a dose- and time-dependent increase in MMP-2 expression in rat vascular smooth muscle cells (VSMC). Treatment with either the Rho-associated protein kinase (ROCK) inhibitor Y-27632 or suppression of ROCK-1/2 by small interfering RNA technology significantly reduced the MMP-2 expression, thus suggesting that ROCK regulates such expression. Similar results were observed when VSMC were pretreated with either U0126 or SB203580, which are selective inhibitors of extracellular signal-regulated kinase and p38 mitogen-activated protein kinase, respectively, thus suggesting that these kinases are important for the induction of MMP-2 expression by PDGF-BB. In conclusion, these results described a novel mechanism in atherosclerosis through PDGF-BB signaling in VSMC, in which MMP-2 expression is induced via extracellular signal-regulated kinases and p38 mitogen-activated protein kinase phosphorylation, as well as ROCK.