A fine tuning of the Brønsted acidity of the hydrotreatment catalyst (by boron addition) leads to progressive changes of the electronic properties of the Mo and Co–Mo sulfided phases. This change ...markedly improved the hydrogenation activity in HDN test as well as in HDS of refractory molecules for Mo catalysts.
•Support Brønsted acidity monitoring.•Control of the sulfide site electronic properties.•Fit of the hydrogenation activity.
Aluminas with different boron loadings were prepared by impregnation with H3BO3 solutions and then used to prepare pure Mo and CoMo catalysts. According to infrared (IR) spectroscopy of 2,6-dimethylpyridine, the acid properties of the alumina have been finely tuned by boron addition. The effect of alumina acidity change on the properties of sulfided Mo and CoMo has been characterized using transmission electron microscope, X-ray photoelectron spectroscopy, and IR spectroscopy of CO-adsorption as well as model compound reactions as thiophene hydrodesulfurization (HDS), 4,6-dimethyldibenzothiophene (4,6-DMDBT) HDS and 2,6-dimethylaniline (DMA) hydrodenitrogenation (HDN). The acidity change of alumina has a direct influence on the electronic properties of MoS2 and CoMoS sites but not substantially modifies the morphology and dispersion of the sulfide phase. The results point out a relationship between the Brønsted acidity of the support and the electronic properties of the MoS2 and CoMoS phase. The change of the electronic properties of the active sites has a marked positive influence on the hydrogenation activity of the active phase. The performances of the Mo and CoMo catalysts in the reactions of HDS of thiophene and 4,6-DMDBT and HDN of DMA have been related to the variations of the structural and electronic properties resulted from boron addition.
Abstract
Key message
The production of adventitious roots partially counteracts the negative effects of waterlogging on the growth of
Syzygium nervosum
A. Cunn. ex DC. and
Syzygium cumini
(L.) ...Skeels.
S
.
cumini
was more responsive and suffered from larger negative effects than
S
.
nervosum
after the removal of adventitious roots.
Context
Adventitious roots contain gas channels and functionally replace or compensate for the loss of primary roots that usually decay during waterlogging. However, the importance of adventitious roots on growth in waterlogged woody plants varies with species. Therefore, there has been some controversy about whether adventitious roots have beneficial effects on the growth of waterlogged plants.
Aims
We assessed whether
S
.
nervosum
and
S. cumini
differentially responded to the ablation of adventitious roots during waterlogging and whether compensatory responses occurred in the primary roots in both species.
Methods
S
.
nervosum
and
S
.
cumini
saplings were subjected to waterlogging and adventitious root removal for 120 days, and morphological, physiological, biochemical parameters, and biomass were recorded.
Results
All plants survived waterlogging, and produced adventitious roots at the shoot base. Waterlogging had negative effects on the growth of both species, but the effect was more severe in
S
.
cumini
than in
S
.
nervosum
as seen from the values of comprehensive evaluation and total biomass. However,
S
.
nervosum
compensated for the ablation of adventitious roots with increased primary root dry mass, primary root activity, total root length, root tip number, and peroxidase activity.
Conclusions
S
.
nervosum
with a high proportion of adventitious roots would be at an advantage during waterlogging. The removal of adventitious roots was detrimental to the growth of both species, but
S
.
nervosum
exhibited less damage than
S
.
cumini
due to its compensatory physiological responses and its primary roots.
Green tea has many health benefits and is the most consumed type in China. However, the heavy metals and contaminants in tea can also pose a great risk to human health. In this study, mercury (Hg) ...concentration in green tea collected from 11 provinces in China was examined. The leaching characteristics of Hg during brewing and the associated exposure to drinkers were also evaluated. Results indicated a low potential of Hg accumulation in green tea. The Hg content of green tea from Wanshan District, Guizhou Province—which has the largest Hg mine in China and is severely contaminated by Hg—could be limited by controlling the harvest time of tea leaves. The average Hg content of green tea from 43 tea production sites in China was only 6.3 ± 6.4 µg/kg dry weight. The brewing experiments of green tea showed that the leaching ratio of Hg was 22.61 ± 7.58% for 40 min of a single brew, and increased to 32.83 ± 12.37% after four rounds (3 min/ round) of brewing. The leaching of Hg from tea leaves was significantly affected by leaching time, temperature, and solid-liquid ratio but not by water hardness. The risk of Hg exposure from green tea intake was found to be very low, with an average hazard quotient (HQ) value of only 1.82 ± 1.85% for a single brew in 40 min and 2.64 ± 2.68% after four rounds of brewing. However, in some highly contaminated areas, with HQ values as high as 43.12 ± 2.41%, green tea intake may still pose a high risk of Hg exposure, and this risk should not be ignored.
Display omitted
•The Hg content of green tea in China ranged from 1.8 to 102.9 µg/kg.•Green tea Hg content could be control by adjusting the harvest time.•Leaching time, water temperature, and solid-liquid ratio affect the Hg leaching ratios from green tea.•Hg expose risk from green tea was low for most cases.
Sex-specific responses to mycorrhiza have been reported in dioecious plant species, but little attention has been paid to the influence of arbuscular mycorrhizal (AM) fungi on competitive ability ...under intersexual competition. To further address whether this competition is affected by an additional AM fungi supply,
saplings were chosen and subjected to two mycorrhizal treatments inoculated and non-inoculated (control) with an additional AM fungi
while growing with the opposite sex for 3 months. Compared with the control, the additional AM fungi inoculation induced
.
saplings to exhibit significant sexual differences in root structure and nutrient uptake (e.g., cortical layer, cross-section area, radius of root tips, and N, K, and Mg content), and enlarged sexual differences in morphology and biomass accumulation (e.g., leaf number increment, shoot height increment, total leaf area, total specific root length, stem dry mass, leaf dry mass, and total dry mass). Meanwhile, inoculated females presented higher values in most of these traits mentioned above than males under intersexual competition. Therefore, we conclude that the intersexual competition can be increased by an additional AM fungi supply, with females gaining more symbiosis-mediated benefits than males.
Background Unintentional carbon monoxide poisoning occurs frequently after natural disasters. Although the epidemiology of carbon monoxide exposures that occur after power loss storms has been ...reported, few publications detail the characteristics of carbon monoxide exposures after massive snowstorms. Purpose To compare the differences in patient characteristics of carbon monoxide exposures after a snowstorm and power loss storm. Methods In 2013, a retrospective review was conducted of patient characteristics and exposure data from all carbon monoxide cases reported to the Connecticut Poison Control Center in the days following both a major snowstorm in 2013 and a winter storm that caused extensive power outages in 2011. Results Portable generators were the most common source of carbon monoxide exposure after a storm that resulted in power losses; car exhaust was the most frequent source of exposure after an extensive snowstorm. Most exposures occurred within the first day after the snowstorm, and on the second and third days after the power outage storm. There were no significant differences between the two storms in terms of patient age, gender, or median carboxyhemoglobin concentration. Conclusions Future public health and medical education regarding the dangers of carbon monoxide in the aftermath of storms should include attention to the differences in the typical exposure sources and timing.
Neighboring relationships among plants have been extensively reported, but little is known about the effect of waterlogging. In this study, Cleistocalyx operculatus (Roxb.) Merr. and Dalbergia ...odorifera T. Chen saplings were used in investigating the neighboring relationships between legumes and non-leguminous woody plants under different planting and watering regimes. Results showed that C. operculatus and D. odorifera are waterlogging-tolerant species, and C. operculatus with high proportion of adventitious roots would be at an advantage during waterlogging. The growth performance of D. odorifera was better than that of C. operculatus under well-watered single-planting conditions. However, under well-watered mixed-planting conditions, C. operculatus had an obvious inhibitory effect on the growth traits (increments in stem height and leaf number, total leaf area, and total plant fresh weight) and physiological responses (net photosynthesis rate, stomatal conductance, and transpiration) of D. odorifera, whereas the growth of C. operculatus slightly increased in the presence of D. odorifera. Under waterlogging mixed-planting conditions, the facilitative effect was more intensive; the total leaf area, underground fresh weight, and total plant fresh weight of C. operculatus significantly increased, but a negative effect was found in D. odorifer. These results showed that the neighboring relationship between these two species is predominantly favorable to C. operculatus. This research sheds new light on screening waterlogging-tolerant arbor species and species collocation during vegetation restoration and reconstruction activities in wetland systems.
A new unsupported hydrotreating catalyst with binder has been prepared by a reflux method. BET, XRD, TEM characterization results show that the catalysts have high surface area and dense active ...phase. Pilot plant results also show that the new catalyst exhibits much better hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) performance than the traditional supported catalyst.
According to the TEM results, the highly active unsupported Ni–W–Mo catalysts B5 and B8 have more MoS2/WS2 stacking layers than the supported catalyst, which means the increase of active sites in the unsupported catalysts.
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► Highly active unsupported catalysts with binder were prepared. ► BET and XRD show the unsupported catalysts have high surface area and pore volume, highly divided active phase. ► TEM demonstrates the unsupported catalysts have dense active sites. ► Pilot plant test shows the unsupported catalysts exhibit good HDS and HDN performance.
The primary tasks of refineries in the future are to improve the yield of light oil and to produce clean fuels and high-quality chemical raw materials. The efficient conversion of heavy oil is ...necessary to improve the yield of light oil. This conversion requires some crucial technologies, including: (1) residue hydrotreating technology, (2) the research institute of petroleum processing's (RIPP's) integrated combination process for residue hydroprocessing, (3) the integration of selective hydrogenation of fluid catalytic cracking gas oil with selective catalytic cracking process, and (4) the combination of superficial solvent deasphalting, hydrotreatment of deasphalted oil, and fluid catalytic cracking technology. The most important technologies for producing clean fuels such as qualified gasoline and diesel include the RIPP's selective hydrodesulfurization technology, the RIPP's hydrogenation technology for producing ultra-low-sulfur diesel fuel, and catalysts for producing RS-1000 and RS-2000 (grades of ultra-low-sulfur diesel). To produce high quality chemical raw materials, the Sinopec hydroprocessing for maximum propylene of fluid catalytic cracking process is of vital importance. The characteristics and effects of these technologies are summarized in this article.
概述了未来炼油厂主要任务中关键技术的特点和使用效果. (1)提高轻质油收率, 关键在于重油的高效转化, 关键技术包括渣油加氢技术、重油加氢与催化裂化双向组合技术、多产轻质油的催化裂化蜡油选择性加氢工艺与选择性催化裂化工艺集成技术、浅度溶剂脱沥青-脱沥青油加氢处理-催化裂化技术; (2)生产清洁燃料, 主要是生产要求越来越高的清洁汽油和柴油, 关键技术有汽油选择性加氢脱硫技术、柴油超深度加氢脱硫技术、柴油超深度加氢脱硫催化剂; (3)生产优质化工原料, 关键技术主要是催化丙烯技术.
The technologies of efficiently processing heavy oil and producing clean transportation fuel and high-quality chemical raw materials are very crucial support to the future petroleum refining industry. Some technologies with good prospects are cited.
Abstract Objective To compare the safety and efficacy of laparoscopy and laparotomy on clinical outcomes among patients with endometrial cancer. Methods Eligible randomized controlled trials (RCTs) ...conducted between 1966 and June 2010 were analyzed by meta-analysis. Results Eight RCTs were included, with 3599 patients in total. No significant difference was observed between laparoscopy and laparotomy in overall (odds ratio OR, 0.96; 95% confidence interval CI, 0.50–1.82; P = 0.892), disease-free (OR, 0.96; 95% CI, 0.50–1.82; P = 0.892), or cancer-related (OR, 0.90; 95% CI, 0.27–3.08; P = 0.871) survival. More intraoperative complications (OR, 1.33; 95% CI, 1.03–1.73; P = 0.030), fewer postoperative complications (OR, 0.59; 95% CI, 0.46–0.75; P < 0.001), longer operative time (standardized mean difference SMD, 0.80; 95% CI, 0.46–1.15; P < 0.001), lower blood loss (SMD, –2.29; 95% CI, –3.67 to − 0.91; P = 0.001), and shorter hospital stay (SMD, –2.60; 95% CI, –3.47 to − 1.72; P < 0.001) were associated with laparoscopy. There was no significant difference between the groups in pelvic (SMD, 0.22; 95% CI, –0.03 to 0.48; P = 0.086) or para-aortic (SMD, 0.54; 95% CI, –0.04 to 1.11; P = 0.067) lymph node yield. Conclusion Laparoscopy has short-term advantages and seemingly equivalent long-term outcomes and, in experienced hands, might be a feasible alternative to laparotomy for endometrial cancer.
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