Lumbar Intradural Disc Herniation Caused by Injury: A Case Report and Literature Review.

BACKGROUND: Intradural disc herniation(IDH) caused by trauma is a rare type of disease，which is difficult to diagnose clinically and is easily misdiagnosed. We received a patient with the disease, reported the case to share the process of diagnosis and treatment and put forward our own opinions, so as to increase the probability of correct diagnosis. CASE PRESENTATION: We report the case of a 48-year-old male who fell from a scaffold at a height of 2 m. Later, he developed low back pain, restricted movement, numbness and hyperalgesia of the lower left limb, and decreased left muscle strength. He was diagnosed with IDH. Treatment with posterior decompression and intramedullary decompression with pedicle screw internal fixation was performed. His postoperative course was uneventful, and he underwent regular follow up for 1 year. Good neurologic symptom improvement was achieved. CONCLUSIONS: IDH is rare, and comprehensive consideration and film reading can improve the correct diagnosis rate. Accurate diagnosis and early decompression of laminae and intramedullary decompression can lead to good recovery after neurologic impingement.

Clinical Efficacy Analysis of the New PRUNUS Spine Plate System for Anterior Cervical Spine Surgery.

OBJECTIVE: Although the role of anterior cervical titanium plate system in stabilizing the spine sequence and promoting bone graft fusion has been widely recognized, more and more attention has been paid to the design of the plate itself and the complications caused by it. In order to solve the problems of poor stability of internal fixation, plate displacement and screw looseness, we designed the new PRUNUS spine plate system. Hence, the present study was conducted to describe observe and evaluate the clinical efficacy of a new type of three-leaf reinforced cervical anterior screw plate system (PRUNUS nailing system) developed for anterior cervical surgery. METHODS: A retrospective analysis of 56 patients from June 2018 to October 2019 was used. Twenty-seven patients with cervical spine disease treated with new PRUNUS nail plate internal fixation were selected as the observation group, and 29 patients with cervical spine disease treated with conventional cervical anterior screw fixation were selected as the control group. Postoperative follow-up was performed. Cervical stability, internal fixation position and bone graft fusion were evaluated according to imaging data. The operative time, intraoperative blood loss, cervical Cobb angle, pain visual analogue scale (VAS), and Japanese orthopaedic association (JOA) were compared between the two groups. Spinal function scores and neurological improvement rates were used to evaluate the clinical efficacy of the new PRUNUS spine plate. RESULTS: The patients were followed up for 5-18 months, with an average of 7.33 months. The average operative time of the observation group was 98.4 ± 9.2 min, and the mean intraoperative blood loss was 65.3 ± 10.6 ml, which were significant different from the control group's 109.7 ± 9.4 minutes (P < 0.05), 72.9 ± 15.6 ml (P < 0.05). Comparison between the two groups in postoperative and final follow-up of cervical Cobb angle, JOA score and improvement rate, VAS score and preoperative comparison showed no significant differences (P > 0.05). CONCLUSION: The new PRUNUS spine plate system can be applied to the anterior cervical spine surgery, and its clinical efficacy was similar to the traditional cervical anterior plate. But PRUNUS simplified the operation process, especially suitable for the surgical treatment of anterior cervical revision and osteoporosis patients.

Aerosol-into-liquid capture and detection of atmospheric soluble metals across the gas-liquid interface using Janus-membrane electrodes.

The soluble fraction of atmospheric transition metals is particularly associated with health effects such as reactive oxygen species compared to total metals. However, direct measurements of the soluble fraction are restricted to sampling and detection units in sequence burdened with a compromise between time resolution and system bulkiness. Here, we propose the concept of aerosol-into-liquid capture and detection, which allowed one-step particle capture and detection via the Janus-membrane electrode at the gas-liquid interface, enabling active enrichment and enhanced mass transport of metal ions. The integrated aerodynamic/electrochemical system was capable of capturing airborne particles with a cutoff size down to 50 nm and detecting Pb(II) with a limit of detection of 95.7 ng. The proposed concept can pave the way for cost-effective and miniaturized systems, for the capture and detection of airborne soluble metals in air quality monitoring, especially for abrupt air pollution events with high airborne metal concentrations (e.g., wildfires and fireworks).

On-Site Quantification and Infection Risk Assessment of Airborne SARS-CoV-2 Virus Via a Nanoplasmonic Bioaerosol Sensing System in Healthcare Settings.

On-site quantification and early-stage infection risk assessment of airborne severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with high spatiotemporal resolution is a promising approach for mitigating the spread of coronavirus disease 2019 (COVID-19) pandemic and informing life-saving decisions. Here, a condensation (hygroscopic growth)-assisted bioaerosol collection and plasmonic photothermal sensing (CAPS) system for on-site quantitative risk analysis of SARS-CoV-2 virus-laden aerosols is presented. The CAPS system provided rapid thermoplasmonic biosensing results after an aerosol-to-hydrosol sampling process in COVID-19-related environments including a hospital and a nursing home. The detection limit reached 0.25 copies/µL in the complex aerosol background without further purification. More importantly, the CAPS system enabled direct measurement of the SARS-CoV-2 virus exposures with high spatiotemporal resolution. Measurement and feedback of the results to healthcare workers and patients via a QR-code are completed within two hours. Based on a dose-responseµ model, it is used the plasmonic biosensing signal to calculate probabilities of SARS-CoV-2 infection risk and estimate maximum exposure durations to an acceptable risk threshold in different environmental settings.

The Role of Histone H3 Methylation in Acute Kidney Injury.

Acute kidney injury (AKI) is a clinical syndrome in which kidney function declines sharply due to various reasons. Although the morbidity and mortality of AKI are high, the mechanism of occurrence and development of AKI has not been fully elucidated, and precise prevention and treatment measures are lacking. Epigenetics is a branch of genetics that provides a new perspective to explore the pathophysiology of AKI and renal repair. A large amount of literature shows that the methylation mechanism of H3 in histones is closely related to the development of kidney diseases. The sorting out of histone H3 methylation mechanism in AKI and kidney repair can help understand the pathophysiological process of the disease more deeply. It may also provide new ideas for diagnosing and treating of the disease.

Correlation Analysis for Selection of Microtitanium Plates with Different Specifications for Use in a Cervical Vertebral Dome Expansion Laminoplasty.

OBJECTIVE: To analyze correlations between the selection of microtitanium plates with different specifications for use in a cervical vertebral dome expansion laminoplasty. METHODS: Sixteen patients that underwent the cervical vertebral dome expansion laminoplasty with a cervical spinal stenosis angioplasty procedure for treatment of their cervical spinal cords were recruited at our hospital. From February 2017 to September 2018, medical records confirmed that all patients underwent cervical CT and MRI tests pre- and postsurgery. The anteroposterior diameter of the spinal canal, changes in the cross-sectional area of the spinal canal, and the pre- and postsurgery distance of the cervical spinal cord after applying microtitanium plates with different lengths were measured by Mimics version 17.0 software (Materialise NV, Leuven, Belgium). A statistical regression and correlation analysis of relevant specification parameters of the microtitanium plate was then studied. RESULTS: As the size of the microtitanium plate increased, we found that the cross-sectional area of cervical spinal canal and distance between the descendants of the lamina and the distance of cervical spinal cord concordantly increased, and these data changes linearly. The regression equation associated with sagittal diameter, cross-sectional area, and posterior movement distance of the cervical spinal cord was obtained. CONCLUSION: According to the correlation analysis of imaging data changes, the regression equation was obtained to guide the selection of microtitanium plates with appropriate specifications in a cervical vertebral dome expansion laminoplasty.

Mid- and Long-Term Follow-Up Efficacy Analysis of 3D-Printed Interbody Fusion Cages for Anterior Cervical Discectomy and Fusion.

OBJECTIVE: To evaluate the safety and stability of 3D-printed interbody fusion cages (3D-printed cages) in anterior cervical discectomy and fusion (ACDF) by investigating the mid- and long-term follow-up outcomes. METHODS: In this prospective study, the clinical data of 30 patients with CSM admitted to the Second Hospital of Shanxi Medical University from May 2012 to May 2014 were analyzed. The cohort comprised 18 males and 12 females with an average age of 60.22 ± 3.2 years. All patients were examined by X-ray, CT and MRI before the operation. A total of 30 cases of CSM were treated by ACDF with 3D printed cage implantation. Mid- and long-term follow-ups were performed after the surgery. Clinical efficacy was evaluated by comparing the JOA score, SF-36 score, change in neurological function, cervical curvature index (CCI), vertebral intervertebral height (VIH) and fusion rate before the operation, 6 months after the operation, and at the last follow-up. RESULTS: Two of the 30 patients were lost to follow-up. The remaining patients were followed up for 48-76 (65.23 ± 3.54) months. The patients recovered satisfactorily with a significant clinical effect. The JOA score increased meanfully and the improvement rate was 89.4% at the final follow-up. The SF-36 score increased significantly from pre- to postoperatively. The height of the intervertebral space at the last follow-up was not statistically significantly different from that at 6 months after surgery (P > 0.05), showing that the height of the intervertebral space did not change much and the severity of cage subsidence (CS) decreased. The CCI improved from pre- to postoperatively. The CCI did not change much from the 6-month follow-up to the last follow-up. and the cage rate (CR) was 100% at the 6-month and last follow-ups. No severe complications, such as spinal cord injury, esophageal fistula, cerebrospinal fluid leakage, cervical hematoma or wound infection, occurred in any of the patients. CONCLUSION: The clinical and radiological results show that the application of 3D-printed cages in ACDF can significantly relieve symptoms. Moreover, 3D-printed cages can restore the curvature of the cervical spine, effectively maintain the intervertebral height for a long time, and prevent complications related to postoperative subsidence.

Comparison of Imaging Parameters between a New Cervical Full Lamina Back Shift Spinal Canal Enlargement Technique and Single Open-Door Laminoplasty for Multisegment Cervical Spondylotic Myelopathy.

PURPOSE: To provide imaging evidence of the feasibility and clinical efficacy of a new full lamina back shift spinal canal enlargement technique. METHODS: A retrospective analysis was conducted on 64 patients with multisegment cervical spondylotic myelopathy caused by cervical stenosis. Of these, 32 patients underwent the new full lamina back shift spinal canal enlargement technique (as observation group) and 32 patients underwent single open-door miniature titanium plate internal fixation (as control group). The computed tomography (CT) data of both groups were imported into Mimics 17.0 software to measure the median sagittal diameter and cross-sectional area of the spinal canal. Photoshop CS5 was employed to measure the drift distance of the spinal cord on MR images to perform a comparative study of the imaging parameters from the two groups. RESULTS: The T2-weighted MR images in both groups showed continuous recovery of the cerebrospinal fluid signal in the C3 -C7 range. The enlarged spinal canal cross-sectional area (mm2 ) of each segment after the new full lamina back shift spinal canal enlargement technique was 130.90 ± 20.52 (C3 ), 180.81 ± 18.86 (C4 ), 240.48 ± 35.43 (C5 ), 145.93 ± 36.94 (C6 ), and 153.16 ± 36.28 (C7 ), and the enlarged median sagittal diameter (mm) was 5.31 ± 1.13 (C3 ), 8.8 ± 1.28 (C4 ), 10.28 ± 1.68 (C5 ), 9.46 ± 1.48 (C6 ), and 9.22 ± 1.12 (C7 ). Both parameters were significantly superior to single open-door miniature titanium plate internal fixation (P < 0.05). No significant difference was detected in the drift distance of the spinal cord between the two groups (P > 0.05). CONCLUSION: The new full lamina back shift spinal canal enlargement technique achieved a thorough spinal canal decompression effect on imaging while ensuring a reasonable spinal drift distance and few surgical complications. The clinical curative effect of the new technique was precise.

Flexible and Ultrathin Waterproof Cellular Membranes Based on High-Conjunction Metal-Wrapped Polymer Nanofibers for Electromagnetic Interference Shielding.

Ultrathin, lightweight, and flexible electromagnetic interference (EMI) shielding materials are urgently demanded to address EM radiation pollution. Efficient design to utilize the shields' microstructures is crucial yet remains highly challenging for maximum EMI shielding effectiveness (SE) while minimizing material consumption. Herein, novel cellular membranes are designed based on a facile polydopamine-assisted metal (copper or silver) deposition on electrospun polymer nanofibers. The membranes can efficiently exploit the high-conjunction cellular structures of metal and polymer nanofibers, and their interactions for excellent electrical conductivity, mechanical flexibility, and ultrahigh EMI shielding performance. EMI SE reaches more than 53 dB in an ultra-broadband frequency range at a membrane thickness of merely 2.5 µm and a density of 1.6 g cm-3 , and an SE of 44.7 dB is accomplished at the lowest thickness of 1.2 µm. The normalized specific SE is up to 232 860 dB cm2 g-1 , significantly surpassing that of other shielding materials ever reported. More, integrated functionalities are discovered in the membrane, such as antibacterial, waterproof properties, excellent air permeability, high resistance to mechanical deformations and low-voltage uniform heating performance, offering strong potential for applications in aerospace and portable and wearable smart electronics.

Development and Clinical Application of a New Open-Powered Nail Anterior Cervical Plate System.

OBJECTIVE: To observe and evaluate the clinical curative effect of a new type of open-powered cervical spine system developed for anterior cervical surgery. METHODS: A retrospective analysis was performed in our hospital in 2015-2017 of 329 orthopaedic patients treated with cervical anterior decompression, cage or titanium mesh graft fusion, new open-powered nail plate or traditional cervical anterior screw plate. A total of 154 (control group) and 175 (observation group) cases were fixed with conventional cervical- and new open-powered nail plates, respectively. Postoperative follow-up was performed. Cervical stability, internal fixation position, and bone graft fusion were evaluated by imaging. Operative time, intraoperative blood loss, cervical Cobb angle, pain visual analogue scale (VAS) score, and Japanese orthopaedic association (JOA) score were compared between the groups. JOA scoring (spinal cord function) and neurological function improvement rate (IR) were used to assess clinical efficacy. RESULTS: The patients were followed up for 8-36 months with an average of 19.48 months. There was no significant difference in the operation time and intraoperative blood loss between the two groups (P > 0.05). In the control group, the Cobb angles of the cervical spine were 5.13° ± 1.28°, 10.46° ± 1.07°, and 9.72° ± 1.43° before and after the operation. The observation group was followed by the Cobb angle of the cervical spine before and after the operation. They were 4.96° ± 1.39°, 11.67° ± 0.93°, and 11.13° ± 1.19°, respectively; the JOA scores before the operation, 1 week after the operation, and at the last follow-up were (8.07 ± 1.13) points and (13.57 ± 0.82) points, and (14.19 ± 0.96) points, respectively; the IR was 86.52% ± 9.33%. The preoperative, postoperative 1 week, and last follow-up JOA scores in the observation group were (8.37 ± 1.29) points, (14.11 ± 0.93) points, and (14.95 ± 0.78) points respectively. The IR was 88.74% ± 8.16% in the scores; the VAS scores were (5.54 ± 0.89) points, (1.73 ± 0.71) points, and (1.48 ± 0.52) points in the preoperative, postoperative 1 week, and last follow-up in the control group. The VAS scores were (5.81 ± 0.94) points, (1.82 ± 0.61) points, and (1.16 ± 0.49) points before, 1 week, and after the final follow-up. The JOA score and IR, VAS score and preoperative comparison between the two groups were statistically significant (P < 0.05), but there was no statistically significant difference between the two groups (P > 0.05). CONCLUSION: The new open-powered nail anterior cervical plate system can achieve the same clinical effect as the traditional anterior cervical plate fixation in anterior cervical surgery, but it can simplify the operation process, effectively make up for the shortcomings of the traditional anterior cervical plate operation, and obtain satisfactory clinical application effect, which is worthy of clinical promotion.

Development and Biomechanical Study of a New Open Dynamic Anterior Cervical Nail Plate System.

OBJECTIVE: To develop a new type of open dynamic cervical spine system and study its biomechanical properties. METHODS: Ten fresh goat spine specimens were used in this study. Using high precision digital display grating displacement sensor system, a new type of open dynamic nail plate fixation was compared with Atlantis nail plate fixation in terms of the stability of cervical vertebrae, pull-out strength, and fatigue strength. RESULTS: Biomechanical tests showed: (i) the new type of open dynamic cervical anterior nail plate system has similar three-dimensional stability as the Atlantis nail plate system, and can ensure the stability of anterior cervical fixation surgery; (ii) the fatigue life and fatigue strength of this new open dynamic anterior cervical nail plate and Atlantis nail plate are similar, and can adequately maintain the cervical stability after anterior bone graft fusion, to ensure long-term safety and efficacy of the nail plate system in the body; and (iii) the overall fixed performance of the new type of open dynamic cervical nail system is satisfactory. CONCLUSION: The new type of open dynamic anterior cervical nail plate system has satisfactory biomechanical characteristics and cervical spine stability effect.

Influence of extending expansive open-door laminoplasty to C1 and C2 on cervical sagittal parameters.

BACKGROUND: For patients with spinal canal stenosis in the upper cervical spine who undergo C3-7 laminoplasty alone, it remains impossible to achieve full decompression due to its limited range. This study explores the extension of expansive open-door laminoplasty (EODL) to C1 and C2 for the treatment of cervical spinal stenosis of the upper cervical spine and its effects on cervical sagittal parameters. METHODS: A retrospective analysis of 33 patients presenting with symptoms of cervical spondylosis myelopathy (CSM) and ossification in the posterior longitudinal ligament (OPLL) of the upper cervical spine from February 2013 to December 2015 was performed. Furthermore, the changes in the C0-2 Cobb angle, C1-2 Cobb angle, C2-7 Cobb angle, C2-7 SVA, and T1-Slope in lateral X-rays of the cervical spine were measured before, immediately after, and 1 year after the operation. JOA and NDI scores were used to evaluate spinal cord function. RESULTS: The C0-2 and C1-2 Cobb angles did not significantly increase (P = 0.190 and P = 0.081), but the C2-7 Cobb angle (P = 0.001), C2-7 SVA (P < 0.001), and T1-Slope (P < 0.001) significantly increased from preoperative to 1 year postoperative. In addition, C2-7 SVA was significantly correlated with the T1-Slope (Pearson = 0.376, P < 0.001) and C0-2 Cobb angle (Pearson = 0.287, P = 0.004), and the C2-7 SVA was negatively correlated with the C2-7 Cobb angle (Pearson = - 0.295, P < 0.001). The average preoperative and postoperative JOA scores were 8.3 ± 1.6 and 14.6 ± 1.4 points, respectively, indicating in a postoperative neurological improvement rate of approximately 91.6%. The average preoperative and final follow-up NDI scores were 12.62 ± 2.34 and 7.61 ± 1.23. CONCLUSIONS: The sagittal parameters of patients who underwent EODL extended to C1 and C2 included loss of cervical curvature, increased cervical anteversion and compensatory posterior extension of the upper cervical spine to maintain visual balance in the field of vision. However, the changes in cervical spine parameters were far less substantial than the alarm thresholds reported in previous studies. We believe that EODL extended to C1 and C2 for the treatment of patients with spinal canal stenosis in the upper cervical spine is a feasible and safe procedure with excellent outcomes.

Total Bioaerosol Detection by a Succinimidyl-Ester-Functionalized Plasmonic Biosensor To Reveal Different Characteristics at Three Locations in Switzerland.

Bioaerosols consisting of biologically originated airborne particles such as microbes, metabolites, toxins, and fragments of microorganisms are present ubiquitously in our living environment. The international interests in bioaerosols have rapidly increased because of their many potential health effects. Thus, accurate and fast detection of total bioaerosols in different environments has become an important task for safeguarding against biological threats and broadening the pool of bioaerosol knowledge. To quickly evaluate the total bioaerosol concentration, we developed a localized surface plasmon resonance biosensor based on succinimidyl-ester-functionalized gold nanoislands (SEF-AuNIs) for quantitative bioaerosol detection. The detection limit of our proposed SEF-AuNI sensors for model bacteria Escherichia coli and Bacillus subtilis can go to 0.5119 and 1.69 cells/mL, respectively. To demonstrate the capability of this bioaerosol sensing technique, we tested aerosol samples collected from Bern (urban station), Basel (suburban station), and Rigi mountain (rural and high altitude station) in Switzerland and further investigated the correlation with endotoxin and PM10. The results substantiated that our SEF-AuNI sensors could be a reliable candidate for total bioaerosol detection and air quality assessment.

Efficacy and Safety Analysis of Ultrasonic Bone Curette in the Treatment of Thoracic Spinal Stenosis.

OBJECTIVE: To investigate the efficacy and safety of ultrasonic bone curette in treating thoracic spinal stenosis. METHODS: A total of 30 patients of thoracic spinal stenosis who underwent posterior thoracic decompression in the hospital from December 2015 to 2017 were enrolled. Of these, 18 patients (group A) underwent posterior thoracic decompression using ultrasonic bone curette; and 12 patients underwent the treatment using a high-speed drill (group B). The time of laminectomy, amount of intraoperative blood loss, presence or absence of cerebrospinal fluid leakage, and nerve root injury were recorded. All patients underwent X-ray, computed tomography with three-dimensional reconstruction, and magnetic resonance imaging before and after surgery. The Frankel classification and the Japanese Orthopaedic Association (JOA) scores were used to assess the neurological function and neurological recovery in patients. The measured data were statistically processed and analyzed using SPSS21.0 software, and the measurement data were expressed as mean ± SD. RESULTS: In groups A and B, the average time for single-segment laminectomy was 3.3 ± 1.2 min and 6.0 ± 1.8 min and the mean bleeding volume was 105.5 ± 43.3 mL and 177.4 ± 54.7 mL, respectively, with a statistically significant difference between the groups. The difference in JOA scores before and after surgery in groups A and B was statistically significant. No significant difference was found between the groups, in group A, the improvement rate of nerve function at the last follow-up was 71% and in group B, the improvement rate at the last follow-up was 70%. In group A, at last follow-up, two patients had Frankel grade B injury, one had grade C injury, seven had grade D injury, and eight had grade E injury. In group B, at last follow-up, one patient had Frankel grade B injury, one had grade C injury, five had grade D injury, and five had grade E injury. The Frankel classification of both groups A and B significantly improved. Four patients experienced cerebrospinal fluid leakage in group A and five in group B, with no significant difference between the groups. There was no nerve root injury in both groups, and no complications, such as pulmonary infection and urinary tract infection, occurred after operation. CONCLUSIONS: With the use of ultrasonic bone curette in posterior thoracic decompression, the decompression surgery could be completed relatively safely and quickly. It effectively reduced the amount of intraoperative blood loss.

Optimization of surgical protocol for laser iridotomy based on the numerical simulation of aqueous flow.

Primary angle-closure glaucoma (PACG) is a major cause of blindness worldwide, with a particularly high prevalence in Asian populations. Laser iridotomy (LI) has been the standard therapeutic modality for treating PACG to avoid blindness. However, the complex structure of the eyeball, the aqueous fluidity, and the limitation of detecting equipment will cause difficulty in surgery and the probability of complications. Numerical simulation was conducted to investigate aqueous humor (AH) flow under different physiological structures before and after laser surgery. When the anterior chamber depth decreases from 2.8 mm to 2.0 mm (caused by angle-closure glaucoma), the maximum velocity of natural convection is doubled, and the pressure difference between the posterior and anterior chambers increases by 20%. Therefore, a shallow anterior chamber depth is crucial for the accurate investigation of glaucoma. Pupil block sharply increases the intraocular pressure (IOP). When the gap between the lens and iris decreases from 10 µm to 0.5 µm, P between the posterior and anterior chambers is approximately 37 times higher than before, thereby damaging intraocular tissues. LI can effectively reduce the IOP caused by pupil block, but the velocity of AH after operation is 40 times the normal condition, and the increased corneal shear stress could lead to corneal damage, which can be solved by adjusting the incident angle of laser beam On the basis of the allowable angle range of surgical equipment and the effect of different incident angles on the cornea and iris, the optimum angle of laser drilling is 45°.

Environmental benefits of electronic commerce over the conventional retail trade? A case study in Shenzhen, China.

Electronic commerce has been becoming the new driver of the retail industry. The large-scale expansion of electronic commerce with additional packaging certainly increases stress on the environment. However, a comparative analysis of environmental impacts of electronic commerce and conventional retail trade channels is unavailable. In this study, an Average Package Difference Model (APDM) was developed to evaluate CO2 emissions difference via the two retail channels in Shenzhen, China based on a life-cycle perspective. In the meanwhile, the national emission was estimated by the above results. Our results suggest that conventional retail has a higher environmental cost than that of electronic commerce, especially during shopping trips. Specifically, average CO2 emission difference per package in terms of product returns, packaging, buildings and transportation were 0.14 ±â€¯0.03, 0.84 ±â€¯0.08, 0.67 ±â€¯0.04, 1.3 ±â€¯0.26 kg, respectively. CO2 is mainly emitted from buildings and consumer trips in conventional retail trade, whereas packaging is mainly responsible for CO2 emission in e-commerce. In China, the total CO2 emission difference between conventional retail and electronic commerce was 124 million tons in 2016. Growth of the proportion of electronic commerce will contribute to lower CO2 emissions induced by the entire retail industry. Actually, carbon emissions can be reduced in both conventional retail and electronic commerce, such as the reusable packaging, opening shopping centers in dense population zones and promoting the usage of public transportation.

Solvent-based separation and recycling of waste plastics: A review.

Since the creation of first man-made plastic, the global production and consumption of plastics have been continuously increasing. However, because plastic materials are durable and very slow to degrade, they become waste with high staying power. The over-consumption, disposal, and littering of plastics result in pollution, thus causing serious environmental consequences. To date, only a fraction of waste plastics is reused and recycled. In fact, recycling plastics remains a great challenge because of technical challenges and relatively insufficient profits, especially in mixed plastics. This review focuses on an environmentally friendly and potentially profitable method for plastics separation and recovery and solvents extraction. It includes the dissolution/reprecipitation method and supercritical fluid extraction, which produce high-quality recovered plastics comparable to virgin materials. These methods are summarized and discussed taking mass-produced plastics (PS, PC, Polyolefins, PET, ABS, and PVC) as examples. To exploit the method, the quality and efficiency of solvent extraction are elaborated. By eliminating these technical challenges, the solvent extraction method is becoming more promising and sustainable for plastic issues and polymer markets.

Incidence of real-world automotive parent and halogenated PAH in urban atmosphere.

This study reports results from a tunnel experiment impact of real-world traffic-related particle and gas parent and halogenated polycyclic aromatic hydrocarbons (PAHs and HPAHs) on urban air. The traffic related emission characteristics and subsequent environmental behavior of these compounds were investigated. To understand the significance of real-world transport emissions to the urban air, traffic-related mass emissions of PAHs and HPAHs were estimated based on measured emission factors. According to our results, PAHs and HPAHs emissions via particulate phase were greater than those via gaseous phase; particles in 2.1-3.3 µm size fraction, have the major contribution to particulate PAHs and HPAHs emissions. Over all, contribution of traffic-related emission of PAHs (only ∼3% of the total PAHs emission in China) is an overstated source of PAHs pollution in China. Actually, exhaust pipe emission contributed much less than the total traffic-related emission of pollutants.

Vehicle exhaust: An overstated cause of haze in China.

Overall, total exhaust emissions of NOX, VOC and particulate matter (PM) declined, though vehicles in use continued to increase in China. This suggested that contribution of motor vehicle exhaust to haze in China may be exaggerated. A higher frequency of haze episodes in China with lower total emissions fraction from vehicle exhaust compared with those in the USA confirmed that there exists no strict causality between vehicle and haze. No significant correlation (p<0.05) between haze days and the contribution of vehicles to airborne PM2.5 (particulates that are <2.5µm in aerodynamic diameter) or car ownerships. All results revealed again that vehicle exhaust is an overstated cause for haze formation in China.

Size-dependent emission characteristics of airborne parent and halogenated PAHs from municipal solid waste incinerators in Shenzhen, China.

Two waste incinerators were selected for investigation of size-dependent emission characteristics of airborne parent and halogenated PAHs (PAHs and HPAHs) and incidence of these pollutants from trash incineration. The concentrations of total PAHs (gas and particles with aerodynamic diameter 0.43-10 µm) in ambient air of Shenzhen incinerators were at the lower end of the global range while those of HPAHs were higher than those of urban air in other studies. High-ring PAHs dominated in PM2.5 (66%-86%), while low-ring PAHs dominated in PM10 (83%-86%). As for PAHs in gaseous phase, low-ring PAHs were collectively account for 86%-97%. ΣHPAH mainly enriched in coarse particles (>83%). The size distributions of ΣPAH and ΣHPAH were both characterized by bimodal peaks dominate in 9.0-10 µm and subordinate in 4.7-5.8 µm. PAHs and HPAHs enrichment in the coarse particles indicates that particle-bound PAHs and HPAHs from incinerators cannot travel great distances. Model simulation results showed the peak of airborne PAHs and HPAHs occurred in approximate 300 m from incinerator, then their concentrations reduced sharply. The extent of affected areas by municipal solid waste incinerators (MSWIs) seem very large, intensity of impacts can be neglected for the very low level of pollutants. Although waste incineration is perceived as most polluting way to manage waste, our study found the damage from incinerator to be far less than originally feared.