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Ammonium sulfate and ammonium chloride are widely used in daily production and life. They can be used as nitrogen fertilizer in agricultural fields and as raw materials for other chemical products in factories. Under the action of precipitation and other factors, these compounds can have a certain impact on water ecology when they enter natural water bodies. In the paper, the acute toxicity of ammonium sulfate and ammonium chloride was investigated using water fleas as indicator organisms. According to GB/T 16125- 2012 test method for acute toxicity of water flea, the 24h-LC50 values of the acute toxicity of ammonium sulfate and ammonium chloride to water flea were 469. 894mg/L and 546. 720mg/L respectively, which were classified as slightly toxic according to the toxicity class.

Glioblastoma multiforme (GBM) is one of the most aggressive and therapy-resistant brain tumors prevalent in both adults and children. Despite extensive research to understand GBM pathology, it remains unclear how neural cells in the human brain interact with GBM cells to support their brain propagation and therapy resistance and whether GBM cells exert any influence on the properties of human neural cells. In this study, we co-culture human stem cell-derived subpallial telencephalic organoids with patient-derived proneural or mesenchymal GBM spheroids to investigate their reciprocal interactions. We show that both proneural and mesenchymal GBM spheroids readily fuse and propagate with human organoids, forming organoid-GBM chimeras, without the need for exogenous growth factors. GBM cells within the chimeras adapt by modulating gene expression profiles consistent with diminished proliferation, heightened hypoxia, increased angiogenesis, and proneural-to-mesenchymal transition in proneural GBM. Both proneural or mesenchymal GBMs also exert an impact on the properties of neural cells in the chimeras, leading to the suppression of neuronal genes and an upregulation expression of genes associated with hypoxia and angiogenesis. Collectively, this study identifies specific genes and molecular pathways that can be altered in GBM and neural cells by reciprocal interactions in a human developing brain-like environment for an increased understanding of GBM pathology and future therapy development.

Open and comminuted mid-distal fractures often result from high-energy trauma, and a concomitant poor blood supply often leads to skin necrosis, infection, and bone union. To circumvent such complications, we used limited-reduction and bilateral-external fixators to treat open and comminuted mid-distal tibial fractures with compromised soft tissue. A retrospective series of 34 patients who had open and comminuted mid-distal tibial fractures and treated by bilateral-external fixators with limited-internal fixation were analyzed. Patients were followed for 10-25 months (mean: 12 months) post-treatment and osseous union was achieved in each case. The average union time was 16.3 weeks. Based on the Johner- Wruhs criteria, the retrospective series consisted of 21 ‘excellent’ cases, 8 ‘good’ cases, 4 ‘fair’ cases, and a ‘poor’ case. The total percentage of ‘excellent’ and ‘good’ cases of fracture recovery was 85.29%. Bilateral-external and limited-internal fixators pro- vided high bone union rate and excellent ankle-joint motion. Hence, it is an appropriate surgical approach for treating open and comminuted mid-distal tibial fractures with compromised soft tissue.

This paper develops an artificial intelligence based automated valuation model (AI-AVM) using the boosting tree ensemble technique to predict housing prices in Singapore. We use more than 300,000 private and public housing transactions in Singapore for the period from 1995 to 2017 in the training of the AI-AVM models. The boosting model is the best predictive model that produce the most robust and accurate predictions for housing prices compared to the decision tree and multiple regression analysis (MRA) models. The boosting AI-AVM models explain 91.33% and 94.28% of the price variances, and keep the mean absolute percentage errors at 8.55% and 5.34% for the public housing market and the private housing market, respectively. When subject the AI-AVM to the out-of-sample forecasting using the 2018 housing sale samples, the prediction errors remain within a narrow range of between 5% and 9%.

Objectives The objectives of this study were to describe trajectories of pelvic floor symptoms and support from the third trimester to 1 year postpartum in primiparous women after vaginal delivery and to explore factors associated with their resolution between 8 weeks postpartum and 1 year postpartum. Methods Five hundred ninety-seven nulliparous women 18 years or older who gave birth vaginally at term completed the Epidemiology of Prolapse and Incontinence Questionnaire and the Pelvic Organ Prolapse Quantification examination at the third trimester, 8 weeks postpartum, and 1 year postpartum. Results At 1 year postpartum, 41%, 32%, and 23% of participants reported stress urinary incontinence, nocturia, and flatus incontinence, respectively, and 9% demonstrated maximal vaginal descent (MVD) ≥ 0 cm. For more common symptoms, incidence rates between the third trimester and 8 weeks postpartum ranged from 6% for urinary frequency to 22% for difficult bowel movements, and resolution rates between 8 weeks postpartum and 1 year postpartum ranged from 23% for stress urinary incontinence to 73% for pain. Between the third trimester and 8 weeks postpartum, 13% demonstrated de novo MVD ≥ 0 cm. For most symptoms, the presence of the same symptom before delivery decreased the probability of resolution between 8 weeks postpartum and 1 year. However, the sensitivities of predelivery vaginal bulge and MVD of 0 cm or greater for those outcomes at 1 year postpartum was overall low (10-12%). Conclusions One year postpartum, urinary and bowel symptoms are common in primiparous women who gave birth vaginally. A substantial portion of this burden is represented by symptoms present before delivery, while most of the prevalence of worse anatomic support is accounted for by de novo changes after delivery.

OBJECTIVE: To determine whether oxytocin for induction or augmentation of labor impacts the incidence or persistence of pelvic floor symptoms and support 5–10 weeks after first vaginal delivery. METHODS: Participants in this prospective cohort study were nulliparous women ≥ 18 years that delivered vaginally at ≥ 37 weeks gestation, completed the Epidemiology of Prolapse and Incontinence Questionnaire (EPIQ) and the Pelvic Organ Prolapse Quantification examination (POP-Q) in third trimester and 5–10 weeks postpartum. We compared the incidence and persistence of symptomatic EPIQ domains and worse vaginal support (maximal vaginal descent ≥ 0 cm) between women who received oxytocin to those that did not (with or without prostaglandin or mechanical methods in both groups). We performed modified binomial regression to calculate adjusted relative risks of each outcome with 95% confidence intervals. RESULTS: Mean age of the 722 participants was 28.3 (SD 5.2) years; 20% were Hispanic. There were no significant differences according to oxytocin exposure in either incidence or persistence of symptomatic EPIQ domains or worse vaginal support. We found similar results in sensitivity analyses comparing women who received oxytocin as the sole pharmacologic agent to women who received no pharmacologic agent. After adjusting for demographic and obstetric factors associated with incidence and persistence of symptoms and support, oxytocin exposure continued to have no effect. CONCLUSIONS: Oxytocin during labor does not significantly increase the risks for the incidence or persistence of pelvic floor symptoms or worse vaginal support in the early postpartum period, though power for less frequent outcomes was limited. SINGLE SENTENCE SUMMARY: Oxytocin during labor does not significantly increase the risks for the incidence or persistence of pelvic floor symptoms or worse vaginal support in the early postpartum period.

Hydrofluoroolefins (HFO) are considered as substitute to HFC refrigerant in the Organic Rankine cycle, however, the lack of studies on HFO refrigerant-lubricant mixtures hampers their further applications. This reported computational work aims to provide guidance for the development of suitable lubricants for new refrigerants. We use ab initio and large scale molecular dynamics (MD) modeling to gain insight into the molecular mechanism of interaction between polypropylene glycol dimethyl ether (PPGDE) and R1233zd(E). The ab initio calculated stable structures, interaction energies and charge distribution analysis indicate that the oxygen atoms in PPGDE and chlorine atom in R1233zd(E) play a major role in the solubility, the calculated interaction energy is -13.97 kJ mol−1 for the most stable configuration; The MD simulated density of R1233zd(E) agrees well with experimental data over a wide range of temperatures and pressures, the obtained cohesive energy density, solubility parameter, Flory−Huggins parameter and radial distribution functions (RDF) allow a characterization of the solubility properties and reveal the solvation mechanism and structure as well, PPGDE molecules begin to be attached to the Cl atoms in R1233zd(E) from the first neighbor shell of radius 2.925 A.

BACKGROUND Minocycline blocks microglial TNF signaling and downstream NF-κB activation, which reduces the mesenchymal phenotype in preclinical models of GBM. Primary analysis of the D-TERMINED trial identified a maximal tolerated dose (MTD) of oral minocycline at 150 mg BID in combination with temozolomide and radiation. In the overall population, the secondary objective of improved PFS was not met. Here, response is further stratified by biomarkers delineating mesenchymal subtype (OLIG2, CD44), microglial activation (IBA-1), and NF-κB signaling (P-p65). METHODS Patients with newly diagnosed high-grade glioma received continuous oral minocycline during concurrent chemoradiation and adjuvant temozolomide. Twenty patients were included in the MTD efficacy population. Within this cohort, immunohistochemistry for OLIG2, CD44, IBA-1, and P-p65 was performed on nineteen patient tumor samples. For each biomarker, the mean percent positivity or number/HPF was compared between patients who exceeded or did not exceed expected PFS. Spearman correlation coefficients were also generated for pairwise comparison of these biomarkers. RESULTS In patients with high PFS, 12.7% of tumor cells were positive for OLIG-2, 36.5% for CD44, and 23.9% for P-p65, with 41.7 cells/HPF positive for IBA-1. Comparatively, in patients with low PFS, 9.4% of tumor cells were positive for OLIG-2 (p = 0.59), 34.1% for CD44 (p = 0.77), and 22.3% for P-p65 (p = 0.85), with 31.1 cells/HPF positive for IBA-1 per HPF (p = 0.38). The only biomarkers demonstrating significant relationship were P-p65 and IBA-1, with a rank correlation of 0.637 (p = 0.007). CONCLUSIONS Exploratory analysis of D-TERMINED concludes that OLIG-2, CD44, IBA-1, and P-p65 are not predictive of improved PFS within high-grade glioma patients treated with SOC and minocycline. Concurrent use of minocycline with chemoradiation is therefore not indicated in these or unselected populations. Significant correlation is seen between IBA-1 and P-p65, biomarkers of microglial activation and NF-κB signaling. SPONSORSHIP: Funding provided by the Musella Foundation and NIH grant P30CA042014.

For the prevailing CO2 micro-channel gas-cooler (MCGC) mathematical modeling research, a big challenge for an efficient numerical model is the trade-off between fast calculation and high-precision considering the specific properties of CO2. The main purpose of this work is to propose a regression method with multiple variables for CO2 MCGC model based on the combination of Distributed Parameter Model (DPM) and Genetic algorithm (GA). The GA based prediction model of MCGC is established, which takes correlation coefficients and mean squared error into consideration. A test rig of CO2 MCGC is developed, and the experimental data used to validate the MCGC model are collected. The fixed-point iteration algorithm is utilized to reduce the complexity of simulation to accelerate the iteration speed. Moreover, an improved Taylor series expansion-based method for fast calculation of working fluid properties was proposed. The model precision was analyzed by comparing the prediction results with conducted experimental data. The improved CO2-to-air MCGC model enables to predict refrigerant outlet temperature and pressure drop within a maximum deviation of 1.2 °C and 2 kPa against the experimental data.

This study primarily aims to evaluate the cooling and heating characteristics and provide a performance comparison of CO2, R41, and several CO2/R41 blends for applications in automobile air-conditioning and heat pump systems. Experiments were conducted to reveal the effects of the refrigerant charge, compositions, ambient temperatures, and compressor speeds among the trans-critical and subcritical cycles. The performance merits of the environmental friendliness, energy efficiency, and safety of using CO2/R41 blends are emphasized. The results demonstrate that, at an optimum charge amount, the coefficient of performance of pure CO2 in the heating and cooling modes can be improved up to a maximum of 14.5% and 25.7%, respectively, by increasing the R41 mass fraction. The heating and cooling capacities were both decreased with an increasing R41 mass fraction, as the system mass flow rates decreased owing to the reduction in suction density. The overall system operation pressure, gas cooler outlet temperature, and high- and low-side pressure drops in both the heating and cooling modes were reduced significantly when the mass fraction of R41 increased from 0% to 100%. Furthermore, the effect of the CO2 mass fraction on the flammability of CO2/R41 blends was studied to discuss the advantages of its safety application. Finally, based on the experimental data, a correlation of the optimum high-side pressure for the trans-critical CO2/R41 cycle was developed, showing a deviation of ±5% from the data.

The aim of this work is to evaluate the cabin heating energy consumption and driving range for a battery electric vehicle. The vehicle was tested in climatic wind tunnel laboratory under Worldwide Harmonized Light-duty vehicle Test Cycle. A heating load model was established and used to predict the heating requirements of the vehicle in different climate conditions. Three different heat pump systems and five refrigerants are also investigated. Results show an error within 5% for the established heating load model. Compared with PTC heating, the heat pump systems lead to much lower energy consumption between 41% and 72% for different scenarios. Besides, 20% and 30% recirculation air can reduce the overall consumed energy by an average of 28.5% and 36.6%, respectively. Finally, the driving range of all the heat pump systems are much higher than that of PTC, which is between 14.2% and 31%.

Micro-scale organic Rankine cycle (ORC) enables to convert low-temperature waste heat into electricity, which is presented as one of combined heat and power (CHP) technologies. The commonly utilized working fluid R245fa will be phased out in the near future because of significant impact to the climate change. In that case, new HFOs (hydrofluoroolefins) refrigerants are suggested as potential alternatives to R245fa because of extremely low GWPs (Global Warming Potential) and zero ODP (Ozone Depletion Potential). This paper experimentally analyzed the applicability of three HFO refrigerants as drop-in replacements to R245fa for micro-scale ORC application including R1234ze(Z), R1233zd(E) and R1336mzz(E). Control options were assigned to the refrigerant mass flow rate and the expander rotational speed. System performance indicators including cycle thermal efficiency and net power output were compared. Besides, the expansion behavior along with the heat transfer performance and pump work were also analyzed. For the whole range of operating conditions, comparing the maximum cycle thermal efficiency, R245fa is 4.6% while R1233zd(E), R1234ze(Z) and R1336mzz(E) are 4.7%, 4.5% and 3.1%, respectively; Comparing the maximum net power output, R245fa generates 11.4% more than R1233zd(E) and 3.1% than R1234ze(Z). Limited range of pressure ratio contributes to the extremely low electricity of R1336mzz(E).

Background: Venous thromboembolism events (VTEs) continue to be of the most widespread severe complication following total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, there are no optimal accurate monitoring methods to assess the changes in coagulability after anticoagulation and anti-fibrinolysis during the perioperative period. Therefore, the objective of this study is to determine changes in coagulability as measured by thromboelastography (TEG) following revision total hip arthroplasty when the patients received rivaroxaban and tranexamic acid in perioperative period during enhanced recovery after surgery (ERAS). Methods: We retrospectively reviewed 70 revision TKA patients (mean age 63.69±10.17 years). Perioperative management of each patient was conducted in accordance with ERAS. The patients received tranexamic (TXA) to control perioperative bleeding. TEG was performed pre-operatively and on post-operative days (POD) 1, 3, 5 and 7. TEG-hypercoagulability was classified into three types: enzymatic hypercoagulability, platelet hypercoagulability and mixed hypercoagulability. Screening for coagulation-related complications at three months of follow-up. Results: The mean duration of surgery was 2.91±0.99 h. the mean intraoperative blood loss of patients was 486.43±346.92 ml. And 55.71% (39) patients received transfusion, the mean blood transfusion volume was 482.86 ± 458.79 ml. There only were 4 (5.71%) patients who suffered postoperative coagulation-related complications. 1 patient with hypercoagulable on preoperative developed intramuscular venous thrombosis at 1 month postoperatively. 1 patient with hypercoagulability at POD5 and POD7 suffered melena at POD5. 2 patients with hypocoagulability developed ecchymosis at POD3. The proportion of postoperative hypercoagulable state is gradually increasing. The distribution of different hypercoagulable states on the postoperative day (POD) 5 and 7 were significantly different from that pre-operation (Pre) and POD1 (POD5 vs Pre: p=0.011; POD5 vs POD1: p=0.001; POD7 vs Pre: p=0.001; POD7 vs POD5: p

R410A has been widely applied in air-to-water heat pumps for space heating, but its phase-out process is accelerated due to the high GWP. This paper investigates the heating performances of low GWP HFO mixtures (R452B and R447B) as substitutions in a sub-cooler vapor injection cycle. The results illustrate that the capacities of R452B and R447B systems are lower by 0.7–5% and 6–15% in the measured conditions, respectively. The attenuation with the ambient temperature of R452B is slower than that of R410A, while R447B is faster. The COP improvements of R452B are 4–9% and 1.4–2.4% with and without vapor injection, respectively. The COP increases of R447B are 3–12% and 0.4–3.8% with and without vapor injection, respectively. In view of injection characteristics, the optimal injection pressure ratios of R452B and R447B are slightly higher. Synthetically R452B and R447B perform more excellent in the high outlet water temperature conditions and R452B is also suitable for low ambient temperatures.

To help reduce the warming impacts, this study evaluates the drop-in performances of R-427A, R-161 and R-290 in R-22 air source heat pump with EVI (Economized Vapor Injection). The results show that the IPLV(H) of R-161 and R-290 arises 5∼8% relative to R-22 with EVI on. A reversal occurs between R-290 and the baseline with EVI on, making the IPLV(H) of R-290 superior to that of R-22 by 3.6∼5.2% from worse performance with EVI off. At -20/41 °C condition, the capacity and COP of R-290 increase by 38% and 19%, respectively. Considering COP and discharge temperatures, R-290 is better-performed to replace R-22 in high pressure ratio conditions. Based on LCCP (Life Cycle Climate Performance) model, 11% of the equivalent CO2 emission can be reduced by using R-161 and R-290. However, the discharge temperature of R-161 is high in the high pressure ratio condition. R-290 is the most synthetically beneficial alternative.

Heat pump and its efficiency are of great significance to the energy saving of electric vehicle in cold climate. This paper proposes a modified autocascade heat pump (ACHP) system using natural CO2-propane mixture. The main purpose is to enhance the heating performance compared with that of conventional heat pump. Using a thermodynamic model of the proposed ACHP cycle, the transcritical and subcritical cycle performance under various conditions are carried out from the perspective of first and second law of thermodynamics, and the transcritical operating characteristics of ACHP system is introduced for the first time. Additionally, an exergy performance comparison has been carried out. Results indicate that the ACHP system can produce more heating capacity, lower compression pressure ratio, lower heat rejection temperature for low ambient temperature conditions and it consumes less compressor work for all the temperature range researched. For transcritical ACHP cycle, the best COP is 2.7 obtained when CO2 mass fraction is 0.8 at −20 °C, which is 12.3% higher than that of CO2 single stage heat pump. For subcritical ACHP cycle, the best COP is 3.97 while heating capacity is much lower than that of transcritical cycle in the same condition. Finally, the exergy analysis confirms the feasibility of the ACHP system and points out exactly the further optimization locations in the ACHP system.

HFCs are suggested to be banned in 2020 because of high GWP (Global Warming Potential). New type of HFO refrigerant R1233zd(E) is proposed as a drop-in replacement to R245fa for organic Rankine cycle application considering the similar thermo-physical properties. In this paper, a description of previous experimental comparison between two refrigerants is presented in the first section. In the second section, further investigation in expansion procedure is implemented with a semi-empirical expander model, which is validated with experimental data based on ‘Genetic Algorithm’. Internal leakage, mechanical friction and heat transfer are presented as main irreversible losses. Input parameters are assigned to mass flow rate, expander rotational speed, supply temperature and exhaust pressure. Supply pressure, exhaust temperature and net power are computed as output results. The maximum deviation between the measured and predicted results are 3.35%, 2.24 K and 6.09% respectively. In the last section, polynomial curve-fittings of dimensionless expander efficiency are conducted for wider prediction of operating range of the expander. Values of filling factor and expander isentropic efficiency are predicted with R 2 = 99.517 % and R 2 = 97.997 % . Curve-fittings of expander efficiency can be integrated into systematic simulation, which is aimed for further optimization of cycle performance to better take advantage of new refrigerants.

The whole-life ratchetting and fatigue failure, as well as the ratchetting-fatigue interaction, of polyamide-6 (PA6) were investigated by performing a set of uniaxial stress-controlled cyclic tests at room temperature and with different stress levels. The effects of mean stress, stress amplitude and stress ratio on the evolution of ratchetting strain and the fatigue life of PA6 are discussed. Simultaneously, the evolution of damage variable, which is defined as a function of equivalent modulus, is summarized to reflect the interaction of ratchetting and fatigue damage. The experimental results show that the uniaxial whole-life ratchetting and fatigue life of PA6 are sensitive to the mean stress, stress amplitude and stress ratio. The evolution of damage variable and its dependence on the stress level are similar to that of whole-life ratchetting, and present a tri-phased feature with respect to the damage rate. By comparing the fatigue lives obtained in the asymmetrical and symmetrical tests, a detrimental effect of ratchetting deformation on the fatigue life of PA6 is found.

It is well-known that conventional multiaxial fatigue life prediction models are generally limited to specific materials and loading conditions. To remove this limitation, a novel attempt is proposed in this work based on the deep learning (i.e., an improvement of artificial neural network in machine learning approaches, which is powerful to learn representations of data with multiple levels of abstraction). To comprehensively evaluate the prediction capability of proposed deep learning-based method, six series of existing fatigue data of different materials are, respectively, analyzed, in which the main loading conditions concerned in the low-cycle and high-cycle fatigue researches are included, such as loading modes (stress-controlled/strain-controlled modes), loading levels (stress/strain amplitude and mean stress/strain), and loading paths (uniaxial/multiaxial and proportional/non-proportional paths), as well as for low-cycle and high-cycle fatigue regimes. Comparison of the predicted and experimental results shows that: all the loading conditions mentioned above can be handled satisfactorily by the proposed deep learning-based method; excellent prediction accuracy is achieved, and the predicted lives in each study case fall almost within the scatter band of 1.5 times. In addition, four groups of specifically designed data are used to evaluate the extrapolation capability of the proposed method, and the results show that the extrapolation capability gets weaker if the distinctions between the loading paths involved in the training dataset and test one increase.

Medulloblastoma (MB) is the most common malignant primary pediatric brain tumor. The Group 3 molecular subgroup of Medulloblastoma (Group 3 MB) is the deadliest with only 30% long term survival. Irradiation for Group 3 Medulloblastoma is required for long term survival of children. Methods to enhance the effect of irradiation against Group 3 MB are an active area of investigation. Immunotherapy using the anti-CD47 treatment has shown promise in treating Group 3 MB. We recently demonstrated that irradiation significantly enhanced anti-CD47-mediated phagocytosis of high-grade glioma cells in vitro. Furthermore, mice engrafted with human high-grade glioma that received anti-CD47 combined with irradiation showed a significant increase in the survival rate and a significant decrease in tumor growth than those that received a single treatment. We have now extended these studies to demonstrate the enhancement of anti-CD47-dependent phagocytosis of human Group 3 MB with irradiation. We also analyzed normal human neural stem cells exposed to the same treatments to assess for the potential toxicity that uniquely exists with this treatment combination.

This paper develops an artificial intelligence-based automated valuation model (AI-AVM) using the decision tree and the boosting techniques to predict residential property prices in Singapore. We use more than 300,000 property transaction data from Singapore’s private residential property market for the period from 1995 to 2017 for the training of the AI-AVM models. The two tree-based AI-AVM models show superior performance over the traditional multiple regression analysis (MRA) model when predicting the property prices. We also extend the application of the AI-AVM to more homogenous public housing prices in Singapore, and the predictive performance remains robust. The boosting AI-AVM models that allow for inter-dependence structure in the decision trees is the best model that explains more than 88% of the variance in both private and public housing prices and keep the prediction errors to less than 6% for HDB and 9% for the private market. When subject the AI-AVM to the out-of-sample forecasting using the 2017-2019 testing property sale samples, the prediction errors remain within a narrow range of between 5% and 9%.

Objective: Most studies about truncal pain during and after pregnancy focus on low back pain, few prospectively define change in pain, and even fewer evaluate pain in all three major truncal areas: upper back, lower back, and pelvic girdle. Thus, the objective of this prospective cohort study was to describe, in primiparous women delivered vaginally, prevalence rates and severities of upper back, lower back, and pelvic girdle pain during pregnancy and 6–10 weeks postpartum and to describe the trajectory of pain constellations between time points. Study design: Participants completed questionnaires at each time point. Pain intensity was rated on a visual analogue scale ranging from 0 to 100. Results: Of the 288 participants, 94% reported truncal pain during pregnancy, while 75% did so postpartum. Prevalence rates of upper back, lower back, and pelvic girdle pain with or without other types of pain during pregnancy were 42%, 77%, and 74% and postpartum were 43%, 52%, and 41%, respectively. Pain severity was highest for women endorsing pain in three locations (median 55–60). Of women with the most common pain constellation during pregnancy, lower back and pelvic girdle (32%), 18% had persistent low back and pelvic girdle pain postpartum, 20% had no pain, and the remainder had pain in a different location. Of women with pain in all three locations during pregnancy (27%), 34% had persistent pain in three locations postpartum, 13% had no pain, and the remainder had pain in at least one location. Conclusion: More women experience pain in a constellation of locations than in a single location. Severity increases as number of pain sites increase. Women with pain in three sites during pregnancy are least likely to have pain resolve. Interventions should focus on the entire trunk and not simply one site of pain.

Organic Rankine cycle (ORC) enables to harness waste heat resource to generate electrical power. R245fa is assumed as an appropriate working fluid for low-temperature waste heat recovery. However, strict regulations of CO2 emissions stimulate scientists to search for potential alternatives to R245fa. This paper presents a comparative analysis of various latest low-GWP refrigerants for ORC application. An energetic-economic-environmental evaluation model is established and further integrated into the non-sorted genetic algorithm (NSGA-II) for multi-objective optimization (MOO). A classic decision-making method is employed to screen out the optimal refrigerant for current study. Apart from that, the whole-year ambient conditions in Sydney are taken into consideration to screen refrigerants. Comparing the cycle thermal efficiency, R1224yd(Z) leads to 3.3% higher than R245fa. Comparing the economic cost, it saves 10.4% more than R245fa. Comparing the whole year’s performance, R1224yd(Z) exhibits 11.2% higher cycle thermal efficiency than R245fa while R1234ze(Z) saves 9.85% more economic cost than R245fa. R1224yd(Z) is considered as the optimal working fluid for current ORC system. R1224yd(Z) leads to 16% higher L E C T s than R245fa. Comparing the maximum L E C T s , R1224yd(Z), R1234ze(Z) and R1233zd(E) is 16%, 9.2% and 13.5% higher than R245fa, respectively.

Based on the experimental results in [1,2], a semi-empirical low-cycle fatigue life prediction model is constructed for a polyamide-6 (PA6) polymer, in which the rate dependence of fatigue life and the effect of ratchetting strain on the life are considered. Since the fatigue damage in PA6 is not only loading-cycle-dependent but also time-dependent, a function to describe the complicate effect of stress rate on the fatigue life is obtained. In the proposed model, the detrimental effect of ratchetting strain on the fatigue life is characterized by introducing a function of mean stress. Comparison of the predicted and experimental results shows that the proposed model presents a good prediction. Furthermore, the neural network based method is also used to correlate the low-cycle fatigue data of PA6. The results show that the established neural network based approach achieves a better prediction to the fatigue life of PA6 with the occurrence of ratchetting than that by the proposed semi-empirical model, which demonstrates a possibility to apply the neural network based machine learning method to deal with the fatigue of polymer.

Among various techniques of utilizing waste heat, ORC is receiving more and more attention for its high efficiency and flexibility. One of the toughest tasks in ORC waste heat recovery system is working fluid selection. The aim of the study is to investigate the effect of physical properties on overall ORC system costs and propose a general method of refrigerant’s performance assessment of ORC system. The internal relationship between the enthalpy of vaporization, molecular weight, and molecular complexity, and the impact on investment cost were analyzed theoretically. The analysis and experiment using R12333zd(E), R1234ze(Z) and R1366mzz(E) as well as R245fa explain the internal mechanism of the effect of different working fluids on NPIT, which represents the ratio of the net power output to the total cost. The economic performances of several new environmental-friendly refrigerants are evaluated using the NPIT assessment. The results show that R12333zd(E) has the best performance and its maximal NPIT value is 0.0625, followed by R1234ze(Z), R1366mzz(E) and R245fa. In addition, when R1233zd(E) performs excellently, evaporation and condensation temperature are 127 °C and 30 °C, respectively. The physical properties of R1233zd(E) and R245fa are extremely close, which makes R1233zd(E) be an alternative refrigerant without redesigning components of ORC system. NPIT is the answer to the challenge of complex boundary conditions and system types with various operational parameters and it could guide the selection of operating condition and design of ORC system equipment.

Rate-dependent whole-life ratchetting and fatigue failure of polyamide 6 were explored by conducting a series of stress-controlled uniaxial fatigue tests at room temperature. Meanwhile, the temperature rises on the surface of specimens were recorded to reflect the self-heating occurred during the fatigue tests. The experimental results demonstrate that ratchetting strain rate is sensitive to the variation of prescribed stress rate, and the whole-life ratchetting of PA6 presents a tri-staged evolution feature at high stress rate but a four-staged one at low stress rate. Two failure modes (i.e., the necking controlled by unstable self-heating and resultant large ratchetting strain; and the fracture controlled by the low-cycle fatigue damage) are experimentally observed in the tests at different stress rates. By considering the relationship between ratchetting evolution and temperature rise, it is found that whether increasing the stress rate retards or promotes the ratchetting is dependent on the magnitude of self-heating produced at each fatigue stage, and whether it will be beneficial or detrimental to the total fatigue life is determined by the competition of resultant strain hardening and self-heating softening.

With carbon emission levels on the rise, rapid and far-reaching action is needed to counteract global warming. Among many available strategies, CO2 is nowadays more and more often proposed as a solution for heating, cooling and refrigeration purposes since the extremely low global warming potential and being natural. In order to overcome the inherently low efficiency in high-temperature conditions and high operating pressure especially in transcritical cycles, an updated review of the advances on modified technologies to solve the drawbacks of CO2 refrigeration is provided and recent progress on the energy efficiency improvement is summarized. First, the basic principles of the CO2 refrigeration cycle and important performance characteristics are discussed. Then, a detailed discussion on different modified technologies as well as their operating fundamental, technical features and performance are provided, followed by a summary of previous studies. At the end of this review, conclusion and perspectives on the future development of this field are presented.

Organic Rankine cycle can be used to harness waste heat to generate electricity. The cycle performance is dependent on expander behavior, where the design of lubricant oil loop is significant. The effects of oil on expansion machine rely on the prevention of leakages and friction losses. However, the lubricant oil is inevitably mixed with refrigerant, which may in turn affect system performance. This paper is targeted to investigate the impact of lubricant oil ratios on a 2 kW ORC prototype using R245fa as working fluid. The heat source temperature is fixed at 125 °C. Two degrees of freedom including the mass flow rate and expander rotational speed are adjusted to explore the system performance. Cycle thermal efficiency, expander isentropic efficiency, filling factor and heat transfer performance are analyzed. The results show that injection of lubricant oil has significant influence on the organic Rankine cycle system. The optimum cycle thermal efficiency is 4.7%, which is obtained under high oil ratio. The system efficiency is more sensitive under lower lubricant oil charges, as 10.25% increase in cycle thermal efficiency is observed when oil-concentration varies from 0.12% to 1%. The hermetic scroll expander is more sensitive to various oil-concentration than the plate heat exchanger.

Mesenchymal stem cells (MSCs) possess tumor-tropic properties and consequently have been used to deliver therapeutic agents for cancer treatment. Their potential in cancer therapy highlights the need for a consistent and renewable source for the production of uniform human MSCs suitable for clinical applications. In this study, we seek to investigate whether human embryonic stem cells can be used as a cell source to fulfill this goal. We generated MSC-like cells from two human embryonic stem cell lines, HuES9 and H1, and observed that MSC-like cells derived from human embryonic stem cells were able to migrate into human glioma intracranial xenografts after being injected into the cerebral hemisphere contralateral to the tumor inoculation site. We engineered these cells with baculoviral and lentiviral vectors, respectively, for transient and stable expression of the herpes simplex virus thymidine kinase gene. In tumor-bearing mice the engineered MSC-like cells were capable of inhibiting tumor growth and prolonging survival in the presence of ganciclovir after they were injected either directly into the xenografts or into the opposite hemisphere. Our findings suggest that human embryonic stem cell-derived MSCs may be a viable and attractive alternative for large-scale derivation of targeting vehicles for cancer therapy.

Yeast cells, like mammalian cells, enlarge steadily as they age. Unabated cell growth can promote cellular senescence; however, the significance of the relationship between size and cellular lifespan is not well understood. Herein, we report a genetic link between cell size, growth rate and lifespan. Mutations that increase cell size concomitantly increase growth rate and decrease lifespan. As a result, large cells grow, divide and age dramatically faster than small cells. Conversely, small cell mutants age slowly and are long-lived. Investigation of the mechanisms involved suggests that attainment of a maximal size modulates lifespan. Indeed, cumulative results revealed that life expectancy is size-dependent, and that the rate at which cells age is determined in large part by the amount of cell growth per generation.

Adult stem cells may serve as powerful cellular vehicles to deliver therapeutic genes for cancer therapy. In such applications, effective and safe transduction to load stem cells with genes of interest is essential. To examine whether baculovirus can be used to fulfill this task, we tested a range of baculoviral vectors in human bone marrow mesenchymal stem cells (MSCs). A vector using the human cytomegalovirus immediate-early gene promoter to drive transgene expression and the woodchuck hepatitis virus posttranscriptional regulatory element to enhance translation was able to transduce MSCs with efficiency close to 80%. Following the observation that baculoviral transduction did not significantly affect surface marker expression of the stem cells, we tested the feasibility of using baculovirus-transduced MSCs for targeted cancer therapy. We transduced cells with a baculoviral vector harboring the herpes simplex virus thymidine kinase gene, and performed tail vein injection of the transduced cells into mice preinoculated subcutaneously with human U87 glioma cells. After ganciclovir prodrug injection, we observed inhibition of tumor growth and significantly prolonged survival of tumor-inoculated animals. Our findings suggest that baculoviral transduction of MSCs is an attractive option to generate targeting vehicles for systemic cancer therapy.

Low-energy laser has been widely applied in breeding of microorganisms, treatment of wound healing, and cancer therapy for many years, but the molecular mechanisms of the laser irradiation are still unclear. In this study, the biological effects of the He-Ne laser irradiation on the dibenzothiophene monooxygenase (DszC) were analyzed, comparing the wild-type bacteria strain of Gordonia sp. WQ-01 and its He-Ne laser irradiated strain WQ-01A. First, the gene and protein sequences of the DszC were analyzed. The results indicated that there were ten point mutations on the dszC gene sequences, and four of them further caused alteration of four amino acid residues in DszC protein. Then, the enzymatic activities of the DszC were analyzed. It was indicated that the enzymatic activity of the mutant protein DszC was higher than wild-type protein DszC. Finally, the biodesulfurization (BDS) capacities of both the wild-type strain and the mutant strain in aqueous model oil and light gas oil systems were analyzed. The results indicated that biodesulfurization capacities of the mutant strain WQ-01A were enhanced in all the above systems. Therefore, the He-Ne laser irradiation caused the point mutation in the dszC and alteration of amino acid residues of DszC, and further enhanced the BDS capacities of the mutant strain WQ-01A.

Large, multisubunit Ccr4-Not complexes are evolutionarily conserved global regulators of gene expression. Deletion of CCR4 or several components of Ccr4-Not complexes results in abnormally large cells. Since yeast must attain a critical cell size at Start to commit to division, the large size of ccr4Δ cells implies that they may have a size-specific proliferation defect. Overexpression of CLN1, CLN2, CLN3, and SWI4 reduces the size of ccr4Δ cells, suggesting that ccr4Δ cells have a G1-phase cyclin deficiency. In support of this, we find that CLN1 and CLN2 expression and budding are delayed in ccr4Δ cells. Moreover, overexpression of CCR4 advances the timing of CLN1 expression, promotes premature budding, and reduces cell size. Genetic analyses suggest that Ccr4 functions independently of Cln3 and downstream of Bck2. Thus, like cln3Δbck2Δ double deletions, cln3Δccr4Δ cells are also inviable. However, deletion of Whi5, a transcriptional repressor of CLN1 and CLN2, restores viability. We find that Ccr4 negatively regulates the half-life of WHI5 mRNAs, and we conclude that, by modulating the stability of WHI5 mRNAs, Ccr4 influences the size-dependent timing of G1-phase cyclin transcription.