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Perivascular epithelioid cell tumor (PEComa) is a rare type of mesenchymal neoplasm, which occurs most commonly in uterus and gastrointestinal tract. PEComa with perirenal manifestation is an extremely rare entity. To the best of our knowledge, only four cases have been reported up to now. In this case, we reported a patient with both a pulmonary mass and a perirenal mass. Two resections were performed successively and postoperative pathology suggested pulmonary micro invasive adenocarcinoma (MIA) and perirenal PEComa. This is the first case of perirenal PEComa with pulmonary MIA. Combining the present case and prior literature, we summarized the crucial role of immunohistochemistry in the diagnosis and consider that complete operation might be conducive to patients with perirenal PEComa that presents a benign phenotype, regardless of complications with other tumors.

Background: Polycystic ovarian syndrome (PCOS) is one of the most common endocrine disease affecting the reproductive age women. Objective: To investigate the relationship between PCOS and breast, ovarian, and endometrial cancer. Search Strategy: Systematic search of PubMed, EMBASE using keywords ‘PCOS’, ‘ovarian cancer’, ‘breast cancer’ and ‘endometrial cancer’. Selection Criteria: The study providing the relative risk (RR) in the cohort study, odds risk(OR) in the case-control study, and 95%confidence interval (95%CI) were included. The single-case report and the non-English study were excluded. Data Collection and Analysis: This meta-analysis was performed by calculating RR, OR and 95%CI using random-effect models. Main Result: A total of 21 studies (8 cohort studies,13 case-control studies) involving 3831083 participants fulfilled the inclusion criteria. Based on the results of cohort studies and case-control studies, the prevalence of breast cancer among PCOS and non-PCOS women was not significant increased, the RR and OR were 0.959 (95%CI, 0.806-1.112) and 0.991 (95%CI, 0.626-1.35), respectively. Evidence from case-control studies showed that PCOS did not increase the risk of endometrial and ovarian cancer, the summary ORs of case-control studies were 1.288 (95%CI,0.763-1.814) and 1.219 (95%CI, 0.816-1.623). The risk of endometrial and ovarian cancer was significantly increased based on cohort studies, the overall RRs of cohort studies were 2.542 (95%CI, 1.755-3.328) and 1.818 (95%CI, 1.222-2.414). Conclusion: The meta-analysis demonstrate that PCOS will not increase the risk of breast cancer. Evidence from the cohort studies suggests that PCOS significantly increases the risk of endometrial and ovarian cancer, although the case-control studies did not.

The paper studies two moving vehicles exchanging messages assisted by another vehicle which is used as a relay. All the vehicle-to-vehicle (V2V) links are modeled as flat double-Rayleigh fading. Based on this particular channel model, the OPA (optimal power allocation) solutions are derived through maximizing source-to-destination channel capacity on the assumptions of amplify-and-forward relaying strategy. Then, the outage probability is discussed and the lower bound on it is acquired. Simulation results manifest that the OPA method improves the average throughput of the IVC (inter-vehicular communication) system by about 2 dB at low SNR (signal-to-noise ratio) and has no less than 2 dB gains on outage probability at medium to high SNR over equal power allocation (EPA) scheme. They also show that the lower bound on outage probability approximates to the Monte Carlo numerical calculations at low to medium SNR region and, as the exact outage probability is not easy to obtain, it can be used to estimate the outage performance of the relay-assisted IVC system roughly.

The paper explores the relay-assisted IVC (inter-vehicular communication) systems with double-Rayleigh fading V2V (vehicle-to-vehicle) links for both APA (access point assisted) and VA (vehicle assisted) schemes. The OPA (optimal power allocation) solutions are derived through maximizing source-to-destination channel capacity assuming amplify-and-forward relaying. Furthermore, the outage performance is discussed and the lower bounds on outage probabilities at medium to high SNRs (signal-to-noise ratios) are presented for both APA and VA systems. Simulations manifest that the outage performance can be improved about 2dB gains through OPA method over EPA (equal power allocation) solution and the lower bounds coincide with the exact outage probabilities well at medium SNRs. These bounds can be used to evaluate the outage performance of the cooperative IVC systems roughly.

This paper explores the relay-assisted transmission system with mobile-to-mobile links undergo cascaded Rayleigh fading. The BER (bit error rate) bounds of the system are derived through mathematic analysis assuming amplify-and-forward relaying. And the OPA (optimal power allocation) method is discussed which is based on minimizing Chernoff bound on BER performance. The paper presents two classical cases based on geometrical topology and gets optimized power distribution parameters by numerical calculations. It further emphasizes useful insights which are as bellows: when the relay is closer to destination terminal (e.g., d R2 ≤d 12 /10), it should spend more than 97% power to source terminal for the first phase transmission, whereas the relay approaches to the source, an equal power method (EPA) is adopted between the source and the relay during two transmissions. Simulation results manifest that through OPA power savings can be achieved as large as 3dB.