RNA Interference in the Egg Parasitoid, Trichogramma dendrolimi Matsumura.

The egg parasitoids, Trichogramma spp, are recognized as efficient biological control agents against various lepidopteran pests in agriculture and forests. The immature stages of Trichogramma offspring develop within the host egg, exhibiting remarkable diminutiveness (approximately 0.5 mm in adult length). RNA-interference (RNAi) methodology has emerged as a crucial tool for elucidating gene functions in numerous organisms. However, manipulating RNAi in certain small parasitoid species, such as Trichogramma, has generally posed significant challenges. In this study, we present an efficient RNAi method in Trichogramma denrolimi. The outlined procedure encompasses the acquisition and isolation of individual T. dendrolimi specimens from host eggs, the design and synthesis of double-stranded RNA (dsRNA), the in vitro transplantation and cultivation of T. dendrolimi pupae, the micro-injection of dsRNA, and the subsequent assessment of target gene knockdown through RT-qPCR analysis. This study furnishes a comprehensive, visually detailed procedure for conducting RNAi experiments in T. dendrolimi, thereby enabling researchers to investigate the gene regulation in this species. Furthermore, this methodology is adaptable for RNAi studies or micro-injections in other Trichogramma species with minor adjustments, rendering it a valuable reference for conducting RNAi experiments in other endoparasitic species.

The identification and expression pattern of the sex determination genes and their sex-specific variants in the egg parasitoid Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae).

Introduction: Trichogramma wasps are egg parasitoids of agricultural lepidopteran pests. The sex of Trichogramma is determined by its ploidy as well as certain sex ratio distorters, such as the endosymbiotic bacteria Wolbachia spp. and the paternal sex ratio (PSR) chromosome. The sex determination systems of hymenopterans, such as Trichogramma spp., involve cascades of the genes transformer (tra), transformer-2 (tra2), and doublesex (dsx) and are associated with sex-specific tra and dsx splicing. First, these genes and their sex-specific variants must be identified to elucidate the interactions between the sex ratio disorders and the sex determination mechanism of Trichogramma. Methods: Here, we characterized the sex determination genes tra, tra2, and dsx in Trichogramma dendrolimi. Sex-specific tra and dsx variants were detected in cDNA samples obtained from both male and female Trichogramma wasps. They were observed in the early embryos (1-10 h), late embryos (12-20 h), larvae (32 h and 48 h), pre-pupae (96 h), and pupae (144 h, 168 h, 192 h, and 216 h) of both male and female T. dendrolimi offspring. Results: We detected female-specific tra variants throughout the entire early female offspring stage. The male-specific variant began to express at 9-10 h as the egg was not fertilized. However, we did not find any maternally derived, female-specific tra variant in the early male embryo. This observation suggests that the female-specific tra variant expressed in the female embryo at 1-9 h may not have originated from the maternal female wasp. Discussion: The present study might be the first to identify the sex determination genes and sex-specific gene splicing in Trichogramma wasps. The findings of this study lay the foundation for investigating the sex determination mechanisms of Trichogramma and other wasps. They also facilitate sex identification in immature T. dendrolimi and the application of this important egg parasitoid in biological insect pest control programs.

Posterior concentration of Wolbachia during the early embryogenesis of the host dynamically shapes the tissue tropism of Wolbachia in host Trichogramma wasps.

Introduction: The bacterial endosymbiont, Wolbachia spp. induce thelytokous parthenogenesis in certain parasitoid wasps, such as the egg parasitoid wasps Trichogramma spp. To complete the cycle of vertical transmission, Wolbachia displays efficient transovarial transmission by targeting the reproductive tissues and often exhibits strong tissue-specific tropism in their host. Method: The present study aimed to describe the basic Wolbachia distribution patterns that occur during the development of Wolbachia-infected, thelytokous Trichogramma dendrolimi, and T. pretiosum. We used fluorescence in situ hybridization (FISH) to investigate Wolbachia signal dynamics during early embryogenesis (from 30 to 120 min). Wolbachia titers and distributions from the embryo to adult stages of Trichogramma after early embryogenesis were detected by absolute quantitative polymerase chain reaction (AQ-PCR) and FISH. The symmetry ratios (SR) of the Wolbachia signals were calculated using the SR odds ratios in the anterior and posterior parts of the host. The SR was determined to describe Wolbachia tropism during early embryogenesis and various developmental stages of Trichogramma. Results: Wolbachia was concentrated in the posterior part of the embryo during early embryogenesis and the various developmental stages of both T. dendrolimi and T. pretiosum. Wolbachia density increased with the number of nuclei and the initial mitotic division frequency during early embryogenesis. The total Wolbachia titer increased with postembryogenesis development in both T. dendrolimi and T. pretiosum. However, the Wolbachia densities relative to body size were significantly lower at the adult and pupal stages than they were at the embryonic stage. Discussion: The present work revealed that posterior Wolbachia concentration during early host embryogenesis determined Wolbachia localization in adult wasps. By this mechanism, Wolbachia exhibits efficient vertical transmission across generations by depositing only female Wolbachia-infected offspring. The results of this study describe the dynamics of Wolbachia during the development of their Trichogramma host. The findings of this investigation helped clarify Wolbachia tropism in Trichogramma wasps.

Assessing the characteristics of different-sized particles in the first flush of roof runoff.

The first flush occurs during urban runoff events. In this study, we aimed to assess the characteristics of different-sized particles in the first flush of roof runoff, and runoff was collected from an asphalt roof (AR), metal roof (MR), and cement roof (CR) for analysis. There were no clear patterns in the particle size distributions in the runoff from the three roofs and were affected by several factors. The strength of the first flushes differed significantly for particles in different size categories in AR, MR, and CR runoff and were very different from suspended solids (SS). The comparison showed that it would be possible to meet the SS control design expectation required by the Chinese national standard for runoff pollution control (VFF = 3 mm) for particles <45 µm but not for particles >45 µm. The methods presented provide an alternative for assessing the ability to control the transport of different-sized particles in runoff.

Percutaneous Transforaminal Endoscopic Surgery (PTES) for Treatment of Lumbar Degenerative Disease in Patients with Underlying Diseases: A Retrospective Cohort Study of 196 Cases.

Objective: To evaluate the postoperative outcomes, safety and feasibility of percutaneous transforaminal endoscopic surgery (PTES) for the treatment of lumbar degenerative disease (LDD) in the patients with underlying diseases. Methods: From June 2017 to April 2019, PTES was performed to treat 226 patients of single-level LDD. According to clinical background, the patients were divided into two groups. A total of 102 patients with underlying diseases were included in group A. The other 124 LDD patients without underlying diseases were included in group B. The occurrence of postoperative complications was recorded. Leg pain was assessed before, immediately, 1 month, 2 months, 3 months, 6 months, 1 year, and 2 years after PTES using VAS, and ODI before PTES and 2 years after PTES were recorded. The therapeutic quality (Excellent, Good, Moderate or Poor) was defined according to MacNab grade at 2-year follow-up. Results: No aggravation of underlying diseases or serious complications was observed in all patients within 6 months after the operation. Altogether, 196 patients were followed up for more than 2 years, 89 patients in group A and 107 patients in group B. The VAS score of leg pain and ODI dropped significantly after surgery (P<0.001) in both groups. One case of group B received PTES again due to recurrence 52 months after surgery. According to MacNab, the excellent and good rate was 97.75% (87/89) in group A and 96.26% (103/107) in group B. In operative duration, frequency of intraoperative fluoroscopy, blood loss, incision length, hospital stay, VAS, ODI, and the excellent and good rate, there was no statistical difference between the two groups. Conclusion: PTES is safe, effective and feasible for the treatment of LDD with underlying diseases, which is comparable to PTES for LDD without underlying diseases. The entrance point of PTES (Gu's Point) is located at the corner of the flat back turning to the lateral side. PTES is not only a minimally invasive surgical technique but also includes a postoperative care system for preventing LDD recurrence.

Contralateral bridge fixation of freehand minimally invasive pedicle screws combined with unilateral MIS-TLIF vs. open TLIF in the treatment of multi-segmental lumbar degenerative diseases: A five years retrospective study and finite element analysis.

Objective: To evaluate the efficacy, safety, feasibility and biomechanical stability of contralateral bridge fixation of freehand minimally invasive pedicle screws (Freehand MIPS) combined with unilateral minimally invasive surgery-transforaminal lumbar interbody fusion (MIS-TLIF) (smile-face surgery) and open TLIF for the treatment of multi-segmental lumbar degenerative diseases (LDDs). Methods: From January 2013 to January 2016, clinical data of multi-segmental (2- or 3-level) LDDs receiving smile-face surgery or open TLIF were retrospectively collected and analyzed. The back and leg pain VAS and ODI were used to assess clinical outcomes preoperatively and postoperatively. The MacNab criteria were used to evaluate the satisfaction of patient. The disc height (DH), lumbar lordosis (LL) and segmental lordosis angle (SLA) were measured before and after surgery. We used patient's CT data to establish the finite element model of smile-face surgery and open TLIF, and analyze biomechanical stability of two methods. Results: Smile-face surgery group showed shorter operation time, shorter incision, less blood loss, shorter hospital stay than open TLIF (P < 0.05). The back VAS in smile-face surgery group was significantly lower than that in open TLIF immediately and 3 months after surgery, and no significant difference was observed 1 year, 2 years and 5 years after surgery. There was no significant difference in the leg pain VAS and ODI between both groups after surgery. No significant difference was observed between two groups in the DH, LL and SLA. At 5-year follow-up, grade I or II fusion was achieved in 99.00% (100/101) segments of smile-face surgery group and 97.67% (84/86) segments of open TLIF group according to Bridwell system. The complication rate of open TLIF was higher than that of smile-face surgery (24.32% vs. 0%, P < 0.01). After verification, the established finite element model can accurately simulate the biological structure of lumbar spine and there was no significant difference in biomechanical stability between two methods. Conclusions: Smile-face surgery has some advantages over open TLIF including smaller aggression, less blood loss, and lower cost, indicating that it is a good choice of treatment for multi-segmental LDDs. Both methods can achieve good biomechanical stability.

Influence of urban runoff pollutant first flush strength on bioretention pollutant removal performance.

Bioretention is commonly used for runoff pollution control. The first flush strength of pollutants can affect bioretention performance. To examine the influence of the first flush strength on bioretention performance, bioretention columns filled with garden soil as the main media were established. Activated carbon and water treatment residuals (WTR) were added and compared for their ability to enhance phosphorus removal. Waste edible fungus culture medium (WEFCM) as a carbon source was also explored. When WEFCM was used as a carbon source instead of wood chips, total nitrogen (TN) removal increased from 60.83 ± 21.22 to 62.21 ± 16.43%, but chemical oxygen demand (COD) leaching was observed. WTR was better able than activated carbon to enhance phosphorus removal (87.97 ± 8.87 vs. 81.66 ± 9.27%) without impacting TN removal. NH4+-N removal increased with increasing first flush strength, but there was no trend for suspended solids (SS), COD, TN, or total phosphorus. First leaching phenomenon in bioretention outflow was proposed in this study. A low first leaching was observed in the outflow when the inflow had a uniform pollutant mass (i.e., no first flush) because of media leaching. A weak first leaching outflow was observed for SS and COD when they were present at strong first flush inflow.

Percutaneous transforaminal endoscopic surgery combined with mini-incision OLIF and anterolateral screws rod fixation vs. MIS-TLIF for surgical treatment of single-level lumbar spondylolisthesis.

Objective: Oblique lumbar interbody fusion (OLIF) has been used to treat lumbar spine spondylolisthesis. However, it usually needs posterior pedicle screws fixation for biomechanical stability and possible posterior direct decompression for relieving neurologic symptoms. We use percutaneous transforaminal endoscopic surgery (PTES) combined with mini-incision OLIF and anterolateral screws rod fixation for surgical treatment of lumbar spondylolisthesis. The purpose of study is to evaluate the feasibility, efficacy, and safety of this method compared with minimally invasive surgery-transforaminal lumbar interbody fusion (MIS-TLIF). Methods: From July 2016 to May 2018, 65 patients of lumbar spondylolisthesis (L2-4) with neurologic symptoms were treated using PTES combined with mini-incision OLIF and anterolateral screws rod fixation (31 cases, group A) or MIS-TLIF (34 cases, group B) in this study. Operative duration, blood loss, incision length, fluoroscopy frequency, and hospital stay are compared. Preoperative and postoperative visual analog scale (VAS) pain scores of back and legs, Oswestry disability index (ODI), intervertebral space height, lumbar lordotic angle, operative segmental lordotic angle, and complications are recorded. The fusion status is assessed according to Bridwell's fusion grades. Results: The VAS score of back and leg pain and ODI significantly dropped after surgery in both groups (p < 0.001). There was no statistical difference of back and leg VAS score and ODI between two groups except that back VAS scores in group A were significantly lower than that of group B immediately after surgery (p = 0.000). Group A had significantly more intervertebral space height and operative segmental lordotic angle than group B postoperatively (p = 0.022, p = 0.002). Twenty-three segments (74.2%) were grade I and 8 segments (25.8%) were grade II in group A; 20 segments (58.8%) were grade I and 14 segments (41.2%) were grade II in group B at a 2-year follow-up (p = 0.194). No difference was observed in the complication rate between the two groups (6.5% vs. 5.9%, p = 0.924). Conclusion: The long-term clinical efficacy and complication rates of both groups are comparable. PTES combined with mini-incision OLIF and anterolateral screws rod fixation is a good choice of minimally invasive surgery for lumbar spondylolisthesis, which hardly destroys the paraspinal muscles and bone structures.

How to predict the culprit segment in percutaneous transforaminal endoscopic surgery under local anesthesia for surgical treatment of lumbar degenerative diseases? Radiologic images or clinical symptoms.

Objective: Percutaneous transforaminal endoscopic surgery (PTES) is a novel, minimally invasive technique used to treat lumbar degenerative diseases (LDDs). PTES under local anesthesia was performed to treat the culprit segment of LDDs predicted by radiologic images or clinical symptoms, and the efficacy, security, and feasibility were evaluated. Methods: Eighty-seven cases of LDDs with nerve root symptoms, which were not consistent with lumbar degenerative levels and degrees on MRI and CT, were treated with PTES under local anesthesia in a day surgery ward from January 2015 to December 2019. Forty-two patients, whose culprit segments were predicted by radiologic images, were included in group A. The other 45 patients, whose culprit segments were predicted by clinical symptoms, were included in group B. Leg pain VAS and ODI scores before and after PTES were recorded. The outcome was defined according to the MacNab grade at the 2-year follow-up. Postoperative complications were recorded. Results: In group A, 2 patients underwent PTES for one segment, 37 patients underwent PTES for two segments, and 3 patients underwent PTES for three segments. One of the one-segment PTES patients had no relief from symptoms and underwent another PTES for other culprit segments 3 months after surgery. In group B, 44 of 45 patients were treated using PTES for one segment and 1 patient was treated for two segments. Group B showed significantly less operative duration, less blood loss, and less fluoroscopy frequency than group A (p < 0.001). The leg pain VAS score and the ODI score significantly decreased after the operation in both groups (p < 0.001), and the excellent and good rates were 97.6% (41/42) in group A and 100% (45/45) in group B at the 2-year follow-up. The leg pain VAS score of group B was significantly lower than that of group A immediately and 1 week, 1 month, 2 months, and 3 months after surgery (p < 0.001). There was no statistical difference in ODI scores and the excellent and good rates between the two groups. No complications, such as wound infection or permanent nerve injury, were observed. Conclusion: It is much more accurate to predict the culprit segment according to clinical symptoms than radiologic images in PTES under local anesthesia for surgical treatment of LDDs.

Efficacy and safety of percutaneous transforaminal endoscopic surgery (PTES) compared with MIS-TLIF for surgical treatment of lumbar degenerative disease in elderly patients: A retrospective cohort study.

Objectives: To evaluate the efficacy and safety of PTES for surgical treatment of lumbar degenerative disease (LDD) including lumbar disc herniation, lateral recess stenosis, intervertebral foraminal stenosis and central spinal canal stenosis in elderly patients compared with MIS-TLIF. Methods: From November 2016 to December 2018, 84 elderly patients (>70 years old) of single-level LDD with neurologic symptoms underwent the surgical treatment. 45 patients were treated using PTES under local anesthesia in group 1 and 39 patients treated using MIS-TLIF in group 2. Preoperative, postoperative back and leg pain were evaluated using Visual analog scale (VAS) and the results were determined with Oswestry disability index (ODI) at 2-year follow-up. All complications were recorded. Results: PTES group shows significantly less operation time (55.6 ± 9.7 min vs. 97.2 ± 14.3 min, P < 0.001), less blood loss [11(2-32) ml vs. 70(35-300) ml, P < 0.001], shorter incision length (8.4 ± 1.4 mm vs. 40.6 ± 2.7 mm, P < 0.001), less fluoroscopy frequency [5(5-10) times vs. 7(6-11) times, P < 0.001] and shorter hospital stay[3(2-4) days vs. 7(5-18) days, P < 0.001] than MIS-TLIF group does. Although there was no statistical difference of leg VAS scores between two groups, back VAS scores in PTES group were significantly lower than those in MIS-TLIF group during follow-ups after surgery (P < 0.001). ODI of PTES group was also significantly lower than that of MIS-TLIF group at 2-year follow-up (12.3 ± 3.6% vs. 15.7 ± 4.8%, P < 0.001). Conclusion: Both PTES and MIS-TLIF show favorable clinical outcomes for LDD in elderly patients. Compared with MIS-TLIF, PTES has the advantages including less damage of paraspinal muscle and bone, less blood loss, faster recovery, lower complication rate, which can be performed under local anesthesia.

Pollutant first flush identification and its implications for urban runoff pollution control: a roof and road runoff case study in Beijing, China.

First flush is a common phenomenon in urban runoff pollution. Typical cement roof and asphalt road runoff in Beijing, China were monitored for 2 years. Based on the M(v) curve, the suspended solids (SS), chemical oxygen demand (COD), total phosphorus (TP) and particulate phosphorus in cement roof runoff presented a stronger first flush than those in asphalt road runoff. The first flush volume (VFF) of SS, COD, total nitrogen (TN) and TP in asphalt road runoff differed slightly from the cement roof. There were also differences in the first flush assessment depending on which method was used. We proposed a new method based on the runoff depth versus pollutant cumulative mass curve. According to the national standards in China (VFF = 3 mm), various masses of different pollutants, such as 91.42 ± 9.80% (cement roof) and 78.49 ± 19.41% (asphalt road) of SS and 86.85 ± 13.54% (cement roof) and 72.80 ± 25.79% (asphalt road) of COD, can be effectively controlled, but our mass control efficiencies were 55.91%-66.65% when VFF = 1 mm. The new method proposed in this study provides an alternative approach for assessing runoff pollution control efficiency of different VFF.

Optimal clutch size for quality control of bisexual and Wolbachia-infected thelytokous lines of Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae) mass reared on eggs of a substitutive host, Antheraea pernyi Guérin-Méneville (Lepidoptera: Saturniidae).

BACKGROUND: Trichogramma dendrolimi has been widely used in augmentative biocontrol of lepidopteran pests in China. In mass production of T. dendrolimi using Antheraea pernyi eggs as substitutive hosts, which are large in size, as clutch size is a parameter of importance to produce high quality parasitoids. Here, we aimed to determine the optimal clutch size for the bisexual Wolbachia-uninfected line (TdB) and Wolbachia-infected thelytokous line (TdT) of T. dendrolimi reared on A. pernyi eggs. RESULTS: A medium clutch size of 42.75 to 62.27 for TdB and 52.93 to 57.14 for TdT was optimal to maximize fitness-correlated traits of parasitoid individual. The optimal clutch sizes with maximized parameters included adult emergence rate, adult body size, adult longevity, fecundity, and sum of fecundity of all females per brood were 58.31 (86.00%), 42.75 (231.11 µm), 50.92 (2.69 days), 62.27 (150.89 eggs), and 83.25 (7926.33 eggs) for TdB and 57.14 (94.54%), 52.93 (236.97 µm), 53.64 (2.62 days), 56.80 (161.01 eggs), and 70.10 (8579.71 eggs) for TdT. The TdT had a shorter adult longevity, longer development time, and higher adult emergence rate than did its non-infected bisexual counterpart. CONCLUSION: A medium brood size in a A. pernyi egg host was optimal to produce offspring parasitoids with higher fitness parameters for both bisexual Wolbachia-uninfected and thelytokous Wolbachia-infected lines of T. dendrolimi. The determination of optimal clutch size for T. dendrolimi will provide the reference for the quality control of T. dendrolimi production and improvement of the field performance of the wasps. © 2020 Society of Chemical Industry.

Effects of temperature and superparasitism on quality and characteristics of thelytokous Wolbachia-infected Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae) during mass rearing.

Thelytokous Wolbachia-infected Trichogramma spp. are widely used egg parasitoids against lepidopteran pests in biological control programs. Wolbachia may manipulate host wasps for superparasitism and is sensitive to temperature. To explore effects of temperature and superparasitism, we compared fitness parameters and Wolbachia-mediated phenotype of thelytokous Wolbachia-infected Trichogramma dendrolimi between those emerging from superparasitised or single-parasitised hosts at 17, 21, 25, or 29 °C. Infected mothers of T. dendrolimi showed reduced superparasitism and parasitism increased with temperature. Wolbachia titre decreased with temperature when females emerged from singly-parasitised hosts, but there was no correlation in superparasitised hosts. Females showed higher Wolbachia titres at 21, 25, or 29 °C when developing from superparasitised hosts. The daily male ratio of offspring increased with temperature, and the day-age threshold for 5%, 50%, or 95% daily male ratio decreased with temperature in both parasitism forms. Females that emerged from superparasitised hosts had a shorter life span and reduced fecundity. These results indicate that Wolbachia may affect host behaviour by increasing superparasitism to enhance its spread, but this has negative effects on thelytokous Wolbachia-infected T. dendrolimi.

A pilot bioretention system with commercial activated carbon and river sediment-derived biochar for enhanced nutrient removal from stormwater.

Bioretention is an effective technology for urban stormwater management, but the nutrient removal in conventional bioretention systems is highly variable. Thus, a pilot bioretention column experiment was performed to evaluate the nutrient control of systems with commercial activated carbon and river sediment-derived biochar. Significant chemical oxygen demand (COD) and total phosphorus (TP) leaching were found with the addition of activated carbon and biochar, but total nitrogen (TN) leaching was significantly improved when activated carbon was used as the medium. During a semi-synthetic runoff experiment, the bioretention systems containing two types of fluvial biochar showed relatively better COD and TN control (average mass removal efficiencies and cumulative removal efficiencies) than commercial activated carbon. However, the average TP mass removal efficiency with commercial activated carbon (95% ± 3%) was significantly higher than biochar (48% ± 20% and 56 ± 14%). The addition of biochar in the media increased the nitrogen removal efficiency, and the addition of activated carbon significantly increased the phosphorous removal efficiency. Therefore, both biochar and activated carbon are effective materials for bioretention, and fluvial biochar provides an alternative approach to comprehensively utilize river sediment.

Endovascular Treatment of Iliac Artery Stenosis Caused by Takayasu Arteritis: A 10-Year Experience.

Purpose: To evaluate the safety and efficacy of endovascular treatment for iliac artery stenosis caused by Takayasu arteritis (TA). Methods: Twenty-three consecutive TA patients (mean age 28.6±9.5 years; 17 women) with 30 iliac artery stenoses underwent percutaneous transluminal angioplasty (PTA) and selective stent implantation between January 2007 and December 2016. All had claudication (Rutherford category 2 or 3). The changes in the Rutherford category, ankle-brachial index (ABI), 6-minute walking capacity, and adverse events were assessed. Results: The success rate of endovascular therapy for iliac artery lesions was 93.3% (28/30). Guidewires could not cross either lesion in a patient with bilateral stenoses. Twenty-four lesions were treated by PTA alone and the other 4 lesions with provisional stents. One patient had a puncture site hematoma. Over an average of 4.8±3.3 years, 18 patients remained asymptomatic or had mild intermittent claudication. The other 4 patients developed moderate to severe intermittent claudication due to progression of a previously existing iliac lesion (n=1) or restenosis (n=3); all 4 underwent PTA. At the last follow-up, improvements were seen in the ABI (0.95±0.12 vs 0.51±0.22, p<0.001), 6-minute walking capacity (409.5±46.1 vs 272.6±32.3 m, p<0.001), and the Rutherford category of 22 patients. One patient died of a hemorrhagic stroke at 27 months due to uncontrolled hypertension. Conclusion: Endovascular therapy was safe and effective in treating TA patients with iliac artery stenosis, with good clinical outcomes in the long term.

Nutrient removal from urban stormwater runoff by an up-flow and mixed-flow bioretention system.

Bioretention is one of the most popular technical practices for urban runoff pollution control. However, the efficiency of nutrient removal from urban stormwater runoff by bioretention systems varies significantly. To improve the nutrient removal performance, innovative up-flow and mixed-flow bioretention systems were proposed in this study, and a laboratory study was conducted to investigate the runoff retention and nutrient removal performance. During the leaching experiment using tap water as the inflow, turbidity, chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) leaching phenomenon was obvious. COD and TN leaching controls were obviously improved when the up-flow and mixed-flow bioretention systems were adopted comparing with the conventional bioretention. During the semi-synthetic runoff experiments, after the leaching experiments' performance (accumulated 2.78 times of empty bed volume), there were no significant differences in COD mass removal efficiencies of conventional and up-flow bioretention processes (p > 0.05); however, the COD mass removal efficiencies of the mixed-flow bioretention processes increased by 10% when compared with conventional bioretention. The TN mass removal efficiencies of the up-flow and mixed-flow bioretention increased obviously from 17% ± 13% (conventional) to 41% ± 23% (up-flow) and 31% ± 16% (mixed-flow). However, there were no significant differences in TP mass removal or runoff reduction among the three bioretention columns (p > 0.05). Both up-flow and mixed-flow bioretention can effectively improve TN mass removal, and the mixed-flow bioretention did not show a better TN removal performance than the up-flow bioretention because these two bioretention had almost the same volume of the saturated zone. Overall, the results indicate the mixed-flow bioretention proposed in this study can effectively improve TN mass removal and slightly improve COD mass removal relative to conventional methods via increases in hydraulic retention time and in-flow paths, respectively.

Time trends regarding the etiology of renal artery stenosis: 18 years' experience from the China Center for Cardiovascular Disease.

The time trends regarding the etiology of renal artery stenosis (RAS) are changing, but few investigations have focused on these issues. This study aimed to analyze the time trends regarding the etiology of RAS in a large patient sample from the China Center for Cardiovascular Disease. Consecutive inpatients with RAS from January 1999 to December 2016 were enrolled in this study. The etiologic diagnosis of RAS was based on established criteria. We retrospectively analyzed the time trends regarding the etiology of RAS during an 18-year period. A total of 2905 patients with RAS were enrolled. There were 2393 (82.4%) patients with atherosclerosis (AS), 345 (11.9%) with Takayasu arteritis (TA), 126 (4.3%) with fibromuscular dysplasia (FMD), and 41 (1.4%) with other causes. Among all patients (n = 2905), patients aged ≤ 40 years (n = 450), patients aged >40 years (n = 2455), female patients (n = 1097), male patients (n = 1808), female patients aged >40 years (n = 808), and male patients aged >40 years (n = 1647), there were a gradual increase in the proportion of atherosclerotic RAS (P < 0.05), a gradual decrease in the proportion of RAS caused by TA (P < 0.05), and almost no change in the proportion of RAS caused by FMD during the 18-year period (P > 0.05). The data show that the primary causes of RAS are AS, TA, and FMD. The proportion of RAS caused by AS and TA gradually increased and decreased, respectively, over time, and the proportion of RAS caused by FMD showed no significant change.

Nephrotoxicity of iodixanol versus iopamidol in patients undergoing peripheral angiography with or without endovascular therapy.

PURPOSE: To compare the nephrotoxic effects of iodixanol and iopamidol in patients undergoing peripheral angiography. METHODS: Patients scheduled for peripheral angiography were randomly assigned to the iodixanol group (n = 463) and iopamidol group (n = 458). The primary endpoint was the incidence of contrast associated acute kidney injury (CA-AKI), which was defined as an increase ≥ 25% or ≥ 44.2 µmol/l (0.5 mg/dl) in serum creatinine (SCr) from baseline within 72 h after receiving contrast media (CM). The secondary endpoints were the mean peak SCr increase within 72 h after receiving CM and major adverse renal events (SCr increased by two times after 30 days, the need for dialysis treatment, rehospitalization for acute renal failure, or kidney-related death) during hospitalization and within 30 day postdischarge. RESULTS: The incidence of CA-AKI did not differ significantly between the iodixanol group and iopamidol group (18.1% vs. 16.8%; p = 0.595). There was no significant difference in the mean peak SCr increase between the iodixanol group and iopamidol group (10.4 ± 13.0 vs. 10.6 ± 14.3 µmol/l, p = 0.919). There were four patients [1 (0.2%) patient in the iodixanol group and 1 (0.7%) patients in the iopamidol group, p = 0.609] with doubling of SCr; no other adverse renal events were observed. CONCLUSIONS: Our data showed that the nephrotoxicity of iodixanol was comparable with that of iopamidol in patients undergoing peripheral angiography.

Clinical outcomes and influencing factors of in-stent restenosis after stenting for symptomatic stenosis of the vertebral V1 segment.

OBJECTIVE: The objective of this study was to evaluate 30-day and long-term clinical outcomes and influencing factors of in-stent restenosis (ISR) after stenting for symptomatic stenosis of the vertebral V1 segment. METHODS: The clinical and follow-up data of 301 consecutive patients (mean age, 64 ± 8 years; 252 men) with symptomatic V1 stenosis who underwent stenting at the Fuwai Hospital between January 2010 and June 2016 were collected retrospectively. The 30-day and long-term follow-up of stroke and death after stenting and the recurrence of symptoms, ISR, and repeated revascularization were assessed. RESULTS: Technical success was 100%. The mean stenosis of lesions was reduced from 82.8% ± 7.6% to 4.4% ± 4.0% immediately after 312 stents (165 bare-metal stents [BMSs] and 147 drug-eluting stents) were implanted. The overall risk of combined any stroke and death was 1.0% (3/301) within 30 days after stenting. The rates of freedom from any stroke and death were 98.2%, 96.8%, and 91.4% at 1 year, 3 years, and 5 years, respectively. After a mean follow-up of 2.9 ± 1.5 years, 46 (15.8%) patients developed ISR, of whom 19 (6.5%) were symptomatic. Twenty-two (7.6%) patients with ISR underwent repeated revascularization. The primary and assisted patency rates were 90.0% and 95.4%, 82.6% and 90.3%, and 80.3% and 87.9% at 1 year, 3 years, and 5 years, respectively. BMS (hazard ratio, 2.02; 95% confidence interval, 1.01-4.06; P < .05) and diabetes (hazard ratio, 1.87; 95% confidence interval, 1.04-3.37; P = .04) were independently associated with an increased risk of ISR. CONCLUSIONS: Percutaneous stent placement for symptomatic V1 stenosis is safe and associated with a good long-term patency rate. BMS and diabetes are independent predictive factors of ISR.

Nutrient leaching from extensive green roofs with different substrate compositions: a laboratory study.

To investigate nutrient leaching from extensive green roofs, green roof platforms were established to investigate the effluent quantity and quality during artificial rainfall. When the influent volume reached three times the empty bed volume, for which the cumulative rainfall was around 300 mm, the effluent TP and COD concentrations of green roof platforms filled with peat soil did not tend to stabilize. For a long-term operation, the substrate depths had little significant influence on TN, TP and COD concentrations of the green roof effluents. A normalized cumulative emission process method was proposed to discuss the difference in various pollutant leaching processes. Obvious differences in the leaching process of different contaminants for green roof platforms filled with various substrates were observed. For the green roof filled with modified substrates, the nitrogen and phosphorus pollutant leaching rates were relatively high in the initial stage of green roof operation and the phosphorus leaching rate was higher than that of nitrogen. The green roof is a sink for TN, but not for TP and COD in this study. The outcomes are critical for the selection of green roof substrates and also contribute to green roof maintenance.