Transmutation of long-lived fission products in an advanced nuclear energy system

Disposal of long-lived fission products (LLFPs) produced in reactors has been paid a lot attention for sustainable and clean nuclear energy. Although a few transmutation means have been proposed to address this issue, there are still scientific and/or engineering challenges to achieve efficient transmutation of LLFPs. In this study, we propose a novel concept of advanced nuclear energy system (ANES) for transmuting LLFPs efficiently without isotopic separation. The ANES comprises intense photoneutron source (PNS) and subcritical reactor, which consist of lead–bismuth (Pb-Bi) layer, beryllium (Be) layer, and fuel, LLFPs and shield assemblies. The PNS is produced by bombarding radioactive cesium and iodine target with a laser-Compton scattering (LCS) γ-ray beam. We investigate the effect of the ANES system layout on transmutation efficiency by Monte Carlo simulations. It is found that a proper combination of the Pb-Bi layer and the Be layer can increase the utilization efficiency of the PNS by a factor of ~ 10, which helps to decrease by almost the same factor the LCS γ-beam intensity required for driving the ANES. Supposing that the ANES operates over 20 years at a normal thermal power of 500 MWt, five LLFPs including ⁹⁹Tc, ¹²⁹I, ¹⁰⁷Pd, ¹³⁷Cs and ⁷⁹Se could be transmuted by more than 30%. Their effective half-lives thus decrease drastically from ~ 10⁶ to less than 10² years. It is suggested that this successful implementation of the ANES paves the avenue towards practical transmutation of LLFPs without isotopic separation.

[Clinical diagnosis and treatment characteristics of pancreatic cystic neoplasms in pediatric patients: a report of 13 cases]

Objective: To investigate the clinical characteristics of pancreatic cystic neoplasms in pediatric patients. Methods: The clinical data of 13 patients with pancreatic cystic neoplasm at Wuhan Children's Hospital from July 2007 to November 2019 were collected.There were 5 males and 8 females, with a mean age of 133 months(range: 9 to 170 months). Eleven patients presented with abdominal pain, vomiting, and a palpable mass. Tumors were located in the pancreatic head(n=7), body(n=2) and tail(n=4), respectively. Results: The preoperative diagnosis was confirmed by imaging examination in 11 patients, CT and MRI was significantly superior to ultrasound in the exact diagnosis of the tumor types. In this group, surgical methods mainly included pancreaticoduodenectomy(n=3), pylorus-preserving pancreatoduodenectomy(n=1), duodenum-preserving pancreas head resection(n=3), spleen-preserving distal pancreatectomy (n=3), distal pancreatectomy plus splenectomy(n=2), and tumor enucleation(n=1). Postoperative complications including biochemical leakage(n=1), delayed gastric emptying(grade A) (n=1), adhesive intestinal obstruction(n=1), transient elevation of platelet count(n=2), all were cured by conservative treatment. In one patient biliary leakage occurred and later developed into biliary stricture, this patient underwent the second operation 6 weeks later and recovered smoothly. All patients were diagnosed by postoperative pathology, including solid pseudopapillary neoplasm(n=10), serous cystadenoma(n=1), mucinous cystadenoma(n=1) and cystic lymphangiom(n=1). Three cases were lost in this group, the rest of patients were all accepted outpatient or telephones follow-up. There was no evidence of recurrence or metastasis during 3 to 92 months follow-up. Conclusions: The incidence of pancreatic cystic neoplasm is low in the pediatric patients. Symptomatic patients should receive surgical treatment timely. It's safe and effective to choose the organs and functions-preserving surgical method.

[Clinical study of cervical necrotizing fasciitis accompanied with descending necrotizing mediastinitis treated with cervical double parallel incision combined with mediastinoscope or thoracoscope]

Objective: To summarize the experience of applying cervical double parallel incision combined with mediastinoscope or thoracoscope in the treatment of cervical necrotizing fasciitis (CNF) accompanied with descending necrotizing mediastinitis (DNM), so as to provide a reference for clinical practice. Methods: The clinical data of six patients with CNF accompanied with DNM who were admitted to the Department of Stomatology and the Department of Otolaryngology Head and Neck Surgery, The First People's Hospital of Changzhou from September 2014 to September 2018 were retrospectively analyzed. All of the six patients were confirmed by CT of neck and chest, among whom there were two males and four females aged from 48 to 73. Three patients were treated with cervical double parallel incision combined with mediastinoscope to be combined with cervical and thoracic drainage under general anesthesia while the other three with cervical double parallel incision combined with thoracoscope to be combined cervical and thoracic drainage under general anesthesia. The CT of neck and chest as well as infectious indicators including hematology, C-reactive protein (CRP) and procalcitonin (PCT) were reexamined during the postoperative period. Results: The cervical and thoracic combined drainage was unobstructed in all of the six patients, no secondary surgery was performed, and the infectious indicators gradually decreased. All patients had off-bed activities on the first day after the operation, were all cured and discharged after an average of 21 days (16 to 36 days) in hospital and followed up for an average of 18 months (4 to 30 months) after the operation. None of them experienced infection relapse, and they were all satisfied with the appearance of the cervical incision. Conclusions: Cervical double parallel incision combined with mediastinoscope or thoracoscope for the treatment of CNF accompanied with DNM has the advantages of complete drainage, small trauma, excellent efficacy and aesthetic operative area, thus being deserved to be clinically popularized.

[Screening of differentially expressed genes of allergic rhinitis with asthma]

Objective:To detect the differentially expressed genes of allergic rhinitis(AR) with asthma and screen the pathogenic genes. Method: Eight nasal mucosa tissue samples from patients with nasal septum deviation (healthy control group), eight nasal mucosa tissue samples from patients with allergic rhinitis（AR） and eight nasal mucosa tissue samples from patients with AR and asthma were collected. Allergy & Asthma PCR Array was used to analyze allergy related genes expression level. Result: Compared to the control group, there are 84 related genes were found and 15 genes were up-regulated, 69 genes were down-regulated. Furthermore, there are 17 genes（ADAM33, BCL6, IFNGR2, IL12A, IL12B, IL13RA1, IL17A, IL31, IL4R, IL5, KIT, LTB4R, MS4A2, RORC, STAT5A, STAT6, TBX21） differentially expressed. Compared AR with asthma group to the AR group, there was 1 gene differentially expressed(RORC). Conclusion: ADAM33, BCL6, IFNGR2, IL12A, IL12B, IL13RA1, IL17A, IL31, IL4R, IL5, KIT, LTB4R, MS4A2, RORC, STAT5A, STAT6, TBX21 are the possible pathogenic genes of AR with asthma. RORC may be the specific marker gene in asthma induced by allergic rhinitis.

[The treatment of Lemierre syndrome associated with cervical necrotizing fascitis]

Lemierre syndrome is a rare, potentially fatal condition characterized by internal jugular vein thrombosis following an acute oropharyngeal infection, often accompanied with cervical necrotizing fasciitis. This paper reviews 5 cases of Lemierre syndrome with cervical necrotizing fasciitis, extensive cervical drainage and sufficient antibiotics is crucial treatment for Lemierre syndrome, anticoagulation combined with antibiotics is safe and effective for propagation or nonresolution of the thrombus.

Satellite-based entanglement distribution over 1200 kilometers

Long-distance entanglement distribution is essential for both foundational tests of quantum physics and scalable quantum networks. Owing to channel loss, however, the previously achieved distance was limited to ~100 kilometers. Here we demonstrate satellite-based distribution of entangled photon pairs to two locations separated by 1203 kilometers on Earth, through two satellite-to-ground downlinks with a summed length varying from 1600 to 2400 kilometers. We observed a survival of two-photon entanglement and a violation of Bell inequality by 2.37 ± 0.09 under strict Einstein locality conditions. The obtained effective link efficiency is orders of magnitude higher than that of the direct bidirectional transmission of the two photons through telecommunication fibers.

Wire rope tension control of hoisting systems using a robust nonlinear adaptive backstepping control scheme

This paper concerns wire rope tension control of a double-rope winding hoisting system (DRWHS), which consists of a hoisting system employed to realize a transportation function and an electro-hydraulic servo system utilized to adjust wire rope tensions. A dynamic model of the DRWHS is developed in which parameter uncertainties and external disturbances are considered. A comparison between simulation results using the dynamic model and experimental results using a double-rope winding hoisting experimental system is given in order to demonstrate accuracy of the dynamic model. In order to improve the wire rope tension coordination control performance of the DRWHS, a robust nonlinear adaptive backstepping controller (RNABC) combined with a nonlinear disturbance observer (NDO) is proposed. Main features of the proposed combined controller are: (1) using the RNABC to adjust wire rope tensions with consideration of parameter uncertainties, whose parameters are designed online by adaptive laws derived from Lyapunov stability theory to guarantee the control performance and stability of the closed-loop system; and (2) introducing the NDO to deal with uncertain external disturbances. In order to demonstrate feasibility and effectiveness of the proposed controller, experimental studies have been conducted on the DRWHS controlled by an xPC rapid prototyping system. Experimental results verify that the proposed controller exhibits excellent performance on wire rope tension coordination control compared with a conventional proportional-integral (PI) controller and adaptive backstepping controller.

Satellite-to-ground quantum key distribution

Quantum key distribution (QKD) uses individual light quanta in quantum superposition states to guarantee unconditional communication security between distant parties. However, the distance over which QKD is achievable has been limited to a few hundred kilometres, owing to the channel loss that occurs when using optical fibres or terrestrial free space that exponentially reduces the photon transmission rate. Satellite-based QKD has the potential to help to establish a global-scale quantum network, owing to the negligible photon loss and decoherence experienced in empty space. Here we report the development and launch of a low-Earth-orbit satellite for implementing decoy-state QKD-a form of QKD that uses weak coherent pulses at high channel loss and is secure because photon-number-splitting eavesdropping can be detected. We achieve a kilohertz key rate from the satellite to the ground over a distance of up to 1,200 kilometres. This key rate is around 20 orders of magnitudes greater than that expected using an optical fibre of the same length. The establishment of a reliable and efficient space-to-ground link for quantum-state transmission paves the way to global-scale quantum networks.

[Endoscopic surgery and reconstruction for extensive osteoradionecrosis of skull base after radiotherapy for nasopharyngeal carcinoma]

Objective: To investigate the clinical efficacy of endoscopic surgery for extensive osteoradionecrosis (ORN) of skull base in patients with nasopharyngeal carcinoma (NPC) after radiotherapy. Methods: Seventeen patients diagnosed as ORN of skull base after radiotherapy for NPC and underwent endoscopic surgery were retrospectively studied with their clinic data. Results: Based on the CT and endoscopic examination, all patients had large skull base defects with bone defects averaged 7.02 cm² (range, 3.60 - 14.19 cm²). Excepting for curetting the sequestra, endoscopic surgery was also used to repair the wound or to protect the internal carotid artery with flap in 12 patients. No bone reconstructions were conducted in all patients with the bone defects of skull base. CT examinations were taken after endoscopic surgery when required. The postoperative follow-up ranged from 8 months to 6 years (average, 14 months). Aside from 1 patient with delayed cerebrospinal fluid (CSF), others had no related complications. Conclusions: The patients with extensive ORN can be treated with endoscopic surgery to curette the necrotic bone of skull base, and endoscopic reconstruction provides an alternative technique. It may not be necessary to reconstruct the bone defects at skull base, however, the exposed important structures of skull base, such as internal carotid artery, need to repair with soft tissue such as flap.

Effects of Strand Lay Direction and Crossing Angle on Tribological Behavior of Winding Hoist Rope

Friction and wear behavior exists between hoisting ropes that are wound around the drums of a multi-layer winding hoist. It decreases the service life of ropes and threatens mine safety. In this research, a series of experiments were conducted using a self-made test rig to study the effects of the strand lay direction and crossing angle on the winding rope’s tribological behavior. Results show that the friction coefficient in the steady-state period shows a decreasing tendency with an increase of the crossing angle in both cross directions, but the variation range is different under different cross directions. Using thermal imaging, the high temperature regions always distribute along the strand lay direction in the gap between adjacent strands, as the cross direction is the same with the strand lay direction (right cross contact). Additionally, the temperature rise in the steady-state increases with the increase of the crossing angle in both cross directions. The differences of the wear scar morphology are obvious under different cross directions, especially for the large crossing angle tests. In the case of right cross, the variation range of wear mass loss is larger than that in left cross. The damage that forms on the wear surface is mainly ploughing, pits, plastic deformation, and fatigue fracture. The major wear mechanisms are adhesive wear, and abrasive and fatigue wear.

[Skull base metastasis from differentiated thyroid carcinoma: 3 cases report and review of literature]

Skull base metastasis from differentiated thyroid carcinoma (DTC), including papillary and follicular thyroid carcinoma, is a rare manifestation and easily misdiagnosed. In this study, we reported three cases whose initial clinical presentation was skull base metastasis complaints with the presence of silent primary sites. Based on the thyroid ultrasound and histopathology (identifying skull base and primary thyroid tumor), the final diagnoses of DTC metastasis to skull base were confirmed. Two patients underwent removal of metastasizing tumors in the skull base and primary thyroid cancer, and have respectively survived 58 months and 4 months since then. Another patient underwent tumor removal of the metastasizing skull base carcinoma leaving the primary lesion intact. However, the patient died of recurrent carcinoma after 18 months. We compared the diagnosis and treatment processes of three patients with DTC metastasis to skull base, and referenced the reported cases in the literature. In conclusion, DTC metastasis to skull base is a rare occurrence and hence easy to be misdiagnosed as primary skull base carcinoma. Clinical records, imaging tests, histopathology and immunohistochemistry are mandatory for differential diagnosis and final diagnosis. Surgical resection of both the primary and metastatic lesions is the recommended treatment. In cases where tumors are removed completely via surgery, no further treatment is necessary postoperatively when meticulously following up is in place. However, in cases where tumors are postoperative residual, radiation therapy after surgery is a feasible option.

[Analysis and dynamic observation of inhaled and food allergens for people in Pearl River Delta]

Objective:To investigate the distribution of allergens in patients with suspected allergic diseases in Pearl River Delta, analysis the changes of allergens with seasons and years, and provide clinical references for management strategies with regional character.Method:Patients from 9 hospitals in Pearl River Delta, with suspected clinical symptoms and signs of allergic disease, were given serum specific IgE test from September 2012 to April 2016. The positive rate was compared with genders, ages, the dynamic changes of seasons, and years.Result:In 30 003 patients, the positive rate of dust mites, house dust, tree, mugwort, mold, animal dander were 39.3%, 26.1%, 16.9%, 26.1%, 9.0%, 6.0% respectively. In 22748 patients, the positive rate of egg, milk, fish, seafood, meats, fruits, nuts were 13.5%, 14.5%, 10.3%, 14.5%, 10.9%, 15.4%, 10.9%. The positive rate of female patients are higher than male patients in both inhaled and food allergens (P< 0.01). The positive rate of minor group was obviously higher than that of the adult group (P< 0.01). The highest positive rate of dust mite, mold, animal dander, egg, fish occurs in the spring, while trees, mugwort, house dust, milk, seafood, meats, fruits, nuts in summer (P< 0.01). There was an upward trend in the positive rate of dust mite, while the positive rate of house dust, mugwort, mold, egg, milk was on the decline, and positive rate of other allergens changed in volatility from 2013 to 2015 (P< 0.01).Conclusion:The dust mites, house dust, seafood and fruits were the main allergens in Pearl River Delta and should be the key for prevention and treatment of allergic diseases. More attention should be paid to the patients of allergic diseases of minors and major seasonal allergens in clinical prevention and treatment. The changes of allergens with the years and dietary habit in local area for the prevention and control of allergic diseases are also not allowed to be ignored.

Genetic diversity and variability in populations of the white wax insect Ericerus pela, assessed by AFLP analysis

The white wax insect Ericerus pela Chavannes (Hemiptera: Coccoidea) is an economically valuable insect species that has been used for over a thousand years in China. The present study focuses on assessing the genetic variability in different populations of E. pela collected from seven Chinese provinces. The amplified fragment length polymorphism technique was used to generate DNA fingerprints of individuals from each population using nine primer combinations (EcoRI-MseI). A total of 435 polymorphic loci were generated; fragment sizes ranged from 200 to 1000 bp. The percentage of polymorphic loci was 85.29%. Nei's genetic diversity and Shannon index indicated consistency in the results, which showed that the Sichuan population had the highest diversity, followed by Yunnan and Zhejiang populations. Dendrogram analysis showed the shortest genetic distance between the Sichuan and Yunnan populations, suggesting that they probably form sister groups. High genetic differentiation between population values among all sampled populations indicated a low degree of genetic variability within each population (40.85%) and higher variation among populations (59.15%). Gene flow estimate values were low in all samples, suggesting low gene flow from events such as interbreeding and migration. Low gene flow values also suggested that populations among species of E. pela might become genetically heterogeneous, due to counteracting forces such as strong differential selection. Our data support the probability that E. pela will remain localized, and has a low potential to spread beyond current habitats.

Generation of bright attosecond x-ray pulse trains via Thomson scattering from laser-plasma accelerators: errata

We report and correct a couple of calculation errors in the x-ray flux and maximum peak brightness in our paper [Opt. Express 22, 32098 (2014)].

Generation of bright attosecond x-ray pulse trains via Thomson scattering from laser-plasma accelerators

Generation of attosecond x-ray pulse attracts more and more attention within the advanced light source user community due to its potentially wide applications. Here we propose an all-optical scheme to generate bright, attosecond hard x-ray pulse trains by Thomson backscattering of similarly structured electron beams produced in a vacuum channel by a tightly focused laser pulse. Design parameters for a proof-of-concept experiment are presented and demonstrated by using a particle-in-cell code and a four-dimensional laser-Compton scattering simulation code to model both the laser-based electron acceleration and Thomson scattering processes. Trains of 200 attosecond duration hard x-ray pulses holding stable longitudinal spacing with photon energies approaching 50 keV and maximum achievable peak brightness up to 10²⁰ photons/s/mm²/mrad²/0.1%BW for each micro-bunch are observed. The suggested physical scheme for attosecond x-ray pulse trains generation may directly access the fastest time scales relevant to electron dynamics in atoms, molecules and materials.

[Cranioplasty using preserved subaponeurotic bone plate]

Cranial bone defect in 6 patients (5 males and 1 female) was repaired with preserved subaponeurotic bone plate. The defect was caused by evacuation of hematoma (5 patients) and resection of pituitary tumor (1 patient). Bone plates used measured 5-8 x 6-10 cm, and preserved for 57-92 days. Microscopic examination showed that the bone plates was alive, and small blood vessels were connected with two aponeuroses. X-ray examination showed normal density of the bone plates. No complication was noted. The bone plate can be used in postoperative cranioplasty.