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The unmanned aerial vehicle (UAV) assisted communication can significantly improve the coverage and spectrum efficiency of the Internet of Things (IoT). One main feature of IoT is short packet communication (SPC), in which the data transmission uses finite block-length codewords. The transmission rate and the packet error rate will affect the effective throughput of the IoT. In this paper, we investigate the impact of SPC on the performance of UAV-enabled spectrum sharing network. Specifically, the optimization of energy efficiency (EE) in the UAV communication system is considered since the battery of the UAV is usually limited. We design the packet error rate, the sensing duration, the normalized sensing threshold and the UAV’s transmit power to maximize the EE under the constraint that the primary user is sufficiently protected. Since the system parameters are intertwined with each other, we employ a successive optimization algorithm to solve the optimization problem by dividing it into three subproblems. Then, an efficient iterative algorithm is proposed to obtain the optimal parameters. Simulation results reveal that the proposed algorithm can converge to global optimal value and has better EE performance than other benchmark schemes. And there is a fundamental tradeoff between the throughput and the EE.

This article prepared a simvastatin-NLCs for the treatment of arteriosclerotic occlusive disease of lower limbs. Taking the size distribution, polydispersity coefficient, encapsulation efficiency and drug loading of simvastatin-NLCs as evaluation indicators, various prescription factors of simvastatin-NLCs were investigated. The in vitro release behavior and stability of simvastatin-NLCs were also investigated. A hyperlipidemia rat model was established using high-fat diets. SD rats fed ordinary diet were set as normal control groups. 20 rats, 20 in the simvastatin group and 20 in the simvastatin nanocarrier group. After 5 weeks of drug intervention, the rats were sacrificed and the aorta was taken to determine the smooth muscle cell apoptosis rate. Studies have shown that simvastatin nanocarriers can more effectively reduce blood lipids in hyperlipidemia rats, increase the rate of smooth muscle cell apoptosis in hyperlipidemia rats, and delay the onset of atherosclerosis.

BACKGROUND Acute arterial embolism of the extremities is a surgical emergency. Atrial fibrillation is the major etiology of acute arterial embolism of the extremities. Emergency femoral artery thrombectomy can successfully treat this issue. However, polycythemia vera (PV) may sometimes explain this medical emergency. Recurrent thrombosis in the lower extremities after thrombectomy can be found in patients with PV, and reoperation is needed for this condition. CASE SUMMARY A 68-year-old man in China suffered from sudden pain in the left lower extremity for 14 h. The examination in the emergency department showed a diagnosis of acute arterial embolism of the extremities combined with PV. The patient’s complaint disappeared after repeat emergency thrombectomy. CONCLUSION Patients with acute arterial embolism of the extremities should be treated carefully, especially those who have recurrent thrombosis after emergency thrombectomy. Clinicians should be aware of PV, a rare cause of acute arterial embolism of the extremities. The combination of thrombectomy, phlebotomy, and antiplatelet and anticoagulant drugs may be a suitable therapeutic regimen for these patients.

Background Death-associated protein kinase (DAPK1) is one of the positive regulators of apoptosis, and it is widely involved in apoptosis induced by multiple pathways. We examined that the function of DAPK1 in Clinical treatment of arterial aneurysm and its underlying mechanisms. Arterial aneurysm is a common cerebrovascular disease with high disability and fatality rate. Objectives Male C57BL/6 mice or DAPK1−/− mice were injected with 50 mg/kg pentobarbital sodium and then were injected with angiotensin II (AngII) infusion for vivo model. hASMCs (Human artery smooth muscle cell) were treated with murine recombinant IL-6 (20 ng ml−1; Cell Signaling) for vitro model. Results DAPK1 gene, mRNA expression, and protein expression were induced in mice of arterial aneurysm. DAPK1 mRNA expression was increased and Area Under Curve was 0.9075 in patients with arterial aneurysm. Knockout of DAPK1 decreased inflammation and vascular injury in mice model of arterial aneurysm. Beclin1/NLRP3 (NACHT, LRR, and PYD domains-containing protein 3) signal pathway is a critical downstream effector of DAPK1 by TAP production. The regulation of Beclin1 participated in the effects of DAPK1 on inflammation of arterial aneurysm by ATP-dependent NLRP3 inflammasome. The regulation of NLRP3 participated in the effects of DAPK1 on inflammation of arterial aneurysm. Conclusion Collectively, our data indicated that DAPK1 may be a potential biomarker for arterial aneurysm in clinical treatment and activated inflammation levels in arterial aneurysm through NLRP3 inflammasome by Beclin1. DAPK1 might be a key pathogenic event underlying excess inflammation of arterial aneurysm.

Hemangiomas, also called infantile hemangiomas (IH), are the most common congenital benign vascular tumors in infants and young children. At present, there are many treatment methods for proliferative hemangiomas, which have different effects and lack predictability. Propranolol has gradually replaced glucocorticoids as the first-line treatment for infants and young children with hemangiomas. However, premature discontinuation is prone to relapse, and the efficacy and safety of medication need to be further studied and determined. The exact pathogenesis of hemangiomas is still unclear. Therefore, in this study, poly(lactic-co-glycolic acid) (PLGA) nanoparticles were used as drug delivery carriers, propranolol was encapsulated, and PLGA-propranolol (PLGA-PP) nanodelivery preparations were prepared and targeted. Anisotropy and pharmacokinetics were preliminary studied. At the same time, after the treatment of HemECs cells with PLGA-PP in gradient concentration in vitro, CCK-8 method was used to detect the cell proliferation, and Anyixin-V/PI double staining method was used to detect the apoptosis rate of cells. The effect of PLGA-PP nano-delivery vector on hemangioma was studied by western blot method to detect the expression level of Id-1 protein in HemECs. The results showed that after PLGA-PP treated HemECs for 24 h, PLGA-PP significantly inhibited HeECs proliferation and promoted their apoptosis, and the intracellular Id-1 protein expression was also reduced. Therefore, this study believes that the mechanism of PLGA-PP nano-targeted delivery preparations in the treatment of hemangiomas is achieved by down-regulating the Id-1 gene, thereby inhibiting the colonization of HemECs and promoting its apoptosis effect.

UAV swarm cooperative situation awareness (SA) and situation sharing is the basis of swarm cooperative decision and control. Swarm cooperative SA consensus is an important factor affecting swarm consistent decision-making. The related studies of consensus analysis do not consider the levels of SA and the uncertainty of situation information carefully, which is not very suitable for complex and antagonistic mission environments. Combined with the Endsley’s SA three-level model, this paper further proposes UAV swarm cooperative SA consensus three-level model, i.e. situation perception consensus, situation comprehension consensus and situation prediction consensus. The definitions and relationships of the SA consensus three-level model are carefully clarified and analysed. Then, the calculation methods of situation perception consensus and situation prediction consensus are described. The reaching process of situation comprehension consensus with a new feedback mechanism is proposed. A case study demonstrates the reaching process of situation comprehension consensus with the proposed feedback mechanism is efficient.

Aiming at the problem that the eigenvalue based spectrum sensing algorithms don't perform well in the situation of low SNR and small sample, based on the difference value between the maximum and minimum eigenvalue spectrum sensing algorithm (DMM), a Difference between the mean and minimum eigenvalue spectrum sensing algorithm (DAM) was proposed via the limiting distribution of minimum eigenvalue and the energy quality of the mean eigenvalue with the Random Matrix Theory (RMT). Analyze the algorithm performance (DAM1 and DAM2) with two different thresholds relatively, which were deducted in different ways. The simulation results show the DAM has the best performance without increasing algorithm complexity over the DMM and current Difference between the Maximum and average Energy spectrum sensing algorithm (ME-S-ED) in the situation of low SNR and sample, the DAM1 suits low SNR better and the DAM2 suits sample better.

Orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) has been proven to be a promising multi-carrier modulation (MCM) technique for the transmission of signals over multipath fading channels. However, OFDM/OQAM has also the intrinsic disadvantage of high peak-to-average-power ratio (PAPR) that should be alleviated. In this paper, a novel selective mapping (SLM) method is proposed for OFDM/OQAM system. Since the pulse shape may cover a few OFDM symbols, the basic principle of the proposed method is to apply the SLM method in the range of the most relevant OFDM symbols. Analysis and simulation results show that, compared to the existing SLM algorithms for OFDM/OQAM system, the proposed method has better PAPR performance and lower computation complexity.

In this paper, we compare the performance between channel estimation based on compressed sensing (CS) and time-domain least square (LS) for single-carrier (SC) communication system. Unlike the conventional channel estimation techniques such as frequency domain LS which is used in the condition that the length of pilot sequence is equal to data sequence, the estimation scheme based on CS requires smaller length of pilot sequence. In this paper, the corresponding system structure is presented. Zadoff-Chu sequence is used to generate the pilot sequence, which is shown to perform better in forming measurement matrix of CS than pseudo random sequence. Simulation results demonstrate that channel estimation based on CS achieves a better bit error rate (BER) performance than time domain LS with a smaller pilot sequence and thus raising data rate of the SC communication system.

Orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) has been proven to be a promising multi-carrier modulation (MCM) technique for the transmission of signals over multipath fading channels. However, OFDM/OQAM has also the intrinsic disadvantage of high peak-to-average-power ratio (PAPR) that should be alleviated. This paper focuses on the reduction of the clipping noise and out-of band radiation caused by the clipping process. The basic principle is to estimate the clipping noise and then eliminate it from the received signal. Analysis and simulation results show that, with one time iteration, the proposed method can effectively improve the bit error ratio (BER) performance.

Orthogonal frequency division multiplex/offset QAM (OFDM/OQAM) and N-continuous OFDM are both improved multi-carrier modulation (MCM) techniques for the transmission of signals over multipath fading channels. In this paper, we aim to compare these two techniques with respect to out-of-band radiation, bit error ratio (BER) and calculation complexity. Analysis and simulation results show that, compared to the N-continuous OFDM, the OFDM/OQAM has lower out-of-band radiation, calculation consumption and similar BER performance.

To compare cardiac adverse events, clinical outcomes and mid-and-long-term effects among massive and sub-massive pulmonary embolism (PE) patients under different periodswho received thrombus fragmentation by pigtail catheter.Two groups of patients who receivedthrombusfragmentation bypigtail catheter in different periods were analyzed retrospectively. Group E: 38 cases received therapy from July 2004 to October 2009 with local anesthesia; Group P: 64 cases with general anesthesia from March 2010 to December 2014. All patients were confirmedPEby CT and angiography. Parts of patients with deep vein thrombosis (DVT) received inferior vena cava filter placement 3 days later. The patients were followed up for 6-24 months after discharge. Cardiac adverse events, clinical outcomes during the thrombusfragmentation process, and mid-and-long-term effects were compared between the two groups.There were no significant differences in preoperative clinical data betweenthe two groups (P0.05). Compared with group E, clinical warning events were significantly improved in group P (odds ratio(OR): 1.24, 98.3, 1.45, 2.50; P0.05). Within group P, there were significant differences inarterial oxygen partial pressure (PaO2) [(98.3±8.7)vs(81.3±7.1)], mean pulmonary artery pressure (mPAP) [(25.3±7.9)vs(37.2±7.6)], heart rate (HR) [(94.3±7)vs(122±9)], airway resistance [(16.7±1.6)vs (22.5±2.1)] and mean arterial pressure (MAP) [(53.4±7)vs(42.5±6)] before and after thrombus fragmentationtreatment (P0.05). The incidence of congestive heart failure and pulmonary arterial hypertension associated with chronic pulmonary thromboembolism (CPEPH) during follow-up were significantly different between group P andgroup E (P0.05).Thrombus fragmentation by pigtail catheter with intraoperativeprecise management under general anesthesia can reduce cardiac adverse events andimprove the mid-and-long-term effects among PE patients.

In this paper, a simple transmit diversity scheme using two transmitting and two receiving antennas for STBC structure is presented. Moreover, a detection algorithm with iterative interference cancellation for STBC-OFDM/OQAM system is proposed to improve bit error ratio performance. Simulation results prove that the proposed detection algorithm is an effective algorithm for STBC-OFDM/OQAM system.

In this paper, an effective preamble structure with only one zero-value guard symbols for OFDM/OQAM systems is proposed to improve spectrum efficiency. Moreover，a preamble interference cancellation (PIC) based channel estimation (CE) scheme is proposed to mitigate the residual ISI in OFDM/OQAM systems. Simulation results prove that the proposed preamble with PIC based channel estimation is an effective structure for OFDM/OQAM systems.