degradation rate

降解率
  • 文章类型: Journal Article
    多环芳烃(PAHs),广泛存在的有机污染物,显着影响人类健康和环境完整性。改善PAH污染土壤的最新方法,特别是在寒冷的环境中,已经不够了。本研究调查了使用固定化的耐低温混合微生物(LTRMM)来增强焦化厂和神府灌区土壤中PAHs的降解。我们的结果表明,用固定化混合微生物(MC-HS)处理比用游离细菌(H-S)和对照(CK)处理更有效。具体来说,MC-HS1处理的降解率比CK1和H-S1处理的焦化厂土壤高10.10%-41.13%。同样,在神府灌区土壤中,MC-HS2显示比CK2和H-S2提高6.00%至52.56%。使用动力学模型来分析增强的降解能力,结果表明,与游离细菌(T2)和对照处理(T1)相比,固定化混合微生物处理(T3)下PAHs的半衰期明显较短。这些发现表明,采用固定化LTRMM可以显着提高寒冷气候下PAH污染土壤的修复效率。
    Polycyclic aromatic hydrocarbons (PAHs), widespread organic pollutants, significantly impact human health and environmental integrity. Recent approaches to ameliorate PAH-contaminated soils, particularly in cold environments, have been insufficient. This study investigates the use of immobilized low-temperature-resistant mixed microorganisms (LTRMM) for enhancing the degradation of PAHs in soils from coke plants and the Shenfu irrigation area. Our results demonstrate that treatment with immobilized mixed microorganisms (MC-HS) is more effective than treatments with free bacteria (H-S) and control (CK). Specifically, the degradation rates in the MC-HS1 treatment were 10.10 %-41.13 % higher than those in the coking plant soil treated with CK1 and H-S1. Similarly, in the Shenfu irrigation area soil, MC-HS2 showed improvements of 6.00 % to 52.56 % over CK2 and H-S2. A kinetic model was used to analyze the enhanced degradation capabilities, revealing that the half-life of PAHs under the immobilized mixed microorganism treatment (T3) was significantly shorter compared to the free bacteria (T2) and control treatments (T1). These findings suggest that employing immobilized LTRMM could significantly improve the remediation efficiency of PAH-contaminated soils in cold climates.
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  • 文章类型: Journal Article
    通过水热法合成了异质结纳米复合材料(ZnO:NiO:CuO),并在三种不同的温度(400°C,600°C,和800°C)。结构,光学,和电性能进行了测试,采用XRD,SEM,UV-Vis,FTIR,和LCR计技术来研究退火的影响。提高退火温度导致纳米复合材料(NCP)表现出增强的结晶度,纯度,光学性质,和改善的电气和介电性能。对于退火温度400°C,NCP的计算晶体尺寸(Debye-Scherrer方法)确定为21、26和34nm,600°C,800°C,分别。合成样品的计算带隙在2.92-2.55eV的范围内。这种温度相关的退火过程显著影响颗粒尺寸,形态学,带隙特性,和光催化效率。EDX剖析肯定了样品的纯度,有锌的元素峰,Cu,Ni,和O.这些NCP对各种染料溶液(甲基橙(MO),亚甲蓝(MB),和染料的混合溶液)在阳光下,并且通过圆盘扩散法评估也显示出良好的抗菌性能。值得注意的是,在400°C下退火的纳米复合材料通过在阳光下仅90分钟内降解96%MB和91%MO而表现出特别高的降解效率。
    Heterojunction nanocomposites (ZnO:NiO:CuO) were synthesized via a hydrothermal method and annealed at three different temperatures (400 °C, 600 °C, and 800 °C). The structural, optical, and electrical properties were examined by employing XRD, SEM, UV-Vis, FTIR, and LCR meter techniques to investigate the effects of annealing. Increasing the annealing temperature resulted in the nanocomposites (NCPs) exhibiting enhanced crystallinity, purity, optical properties, and improved electrical and dielectric behavior. The calculated crystalline sizes (Debye-Scherrer method) of the NCPs were determined to be 21, 26 and 34 nm for annealing temperature 400 °C, 600 °C, and 800 °C, respectively. The calculated bandgaps of synthesized samples were found in the range of 2.92-2.55 eV. This temperature-dependent annealing process notably influenced particle size, morphology, band-gap characteristics, and photocatalytic efficiency. EDX analysis affirmed the sample purity, with elemental peaks of Zn, Cu, Ni, and O. These NCPs demonstrated exceptional photocatalytic activity against various dyes solutions (Methyl orange (MO), Methylene Blue (MB), and mixed solution of dyes) under sunlight and also showed good antibacterial properties assessed by the disc diffusion method. Notably, the nanocomposite annealed at 400 °C exhibited a particularly high degradation efficiency by degrading 96% MB and 91% MO in just 90 min under sunlight.
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  • 文章类型: Journal Article
    四环素(TC)在各种水体中应用广泛,其中TC的存在对水生生物的健康构成了重大威胁。此外,抗生素几乎不被生物处理降解。因此,为了增强TC的去除,我们提出了一种新型的紫外线/过碳酸钠(UV/SPC)高级氧化工艺,并进行了深入的研究。研究考察了氧化剂用量的影响,初始pH值,UV强度,和TC浓度对TC去除的影响。结果表明,UV/SPC系统有效地去除TC,去除效率随着SPC浓度的增加而增加。在3-11的pH范围内,TC降解表现出最小的变化,表明UV/SPC系统对pH值变化有较强的适应性。水基质对TC去除影响的研究表明,HCO3-对TC降解有抑制作用,而NO3-促进TC降解。此外,自由基物种的存在(·OH,·CO3-,·O2-)被检测到,并且二级反应的速率常数(k·OH,TC=6.3×109升mol-1·s-1,k·CO3-,计算出TC=3.4×108Lmol-1·s-1),表明·OH与·CO3-相比具有更强的氧化性能。这项研究不仅提出了一种通过UV/SPC去除TC的新策略,而且揭示了·CO3-对污染物去除的独特作用。
    Tetracycline (TC) was widely used and frequently detected in various water bodies, where the presence of TC posed a significant threat to the health of aquatic organisms. Furthermore, antibiotics were hardly degraded by biological treatment. Thus, in order to enhance the removal of TC, we proposed the use of a novel ultraviolet/sodium percarbonate (UV/SPC) advanced oxidation process and initiated an in-depth study. The study investigated the influence of oxidant dosage, initial pH, UV intensity, and TC concentration on the removal of TC. The results demonstrated that the UV/SPC system efficiently removed TC, with removal efficiency increasing as the SPC concentration increased. Within the pH range of 3-11, TC degradation exhibited minimal variation, indicating the UV/SPC system\'s strong adaptability to pH variations. The research on the impact of the water matrix on TC removal revealed that HCO3- had an inhibitory effect on TC degradation, while NO3- promoted TC degradation. Additionally, the presence of free radical species (·OH, ·CO3-, ·O2-) were detected and rate constants for the secondary reactions (k·OH,TC = 6.3 × 109 L mol-1·s-1, k·CO3-,TC = 3.4 × 108 L mol-1·s-1) were calculated, indicating that ·OH exhibited a stronger oxidative performance compared to ·CO3-. This study did not only present a novel strategy via UV/SPC to remove TC but also uncovered the unique role of ·CO3- for contaminant removal.
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  • 文章类型: Journal Article
    连续高温堆肥(CTC)可能有助于缩短堆肥周期。然而,其普遍有效性和所涉及的微生物学机制尚不清楚.这里,比较了常规模型和CTC模型中蒸馏谷物废物堆肥过程中的理化特性和细菌群落动态。CTC加速了有机物降解速率(0.2vs.0.1d-1),并缩短了堆肥周期(24vs.65d),主要由细菌属的协同作用驱动。微生物分析表明,与常规堆肥相比,Firmicutes的丰度显着提高,在整个CTC过程中,Firmicutes成为主要的细菌门(相对丰度>70%)。此外,相关分析表明,细菌成分对种子萌发指数有显著影响。因此,在连续高温条件下控制堆肥过程有利于提高堆肥效率和加强细菌属之间的合作。
    Continuous thermophilic composting (CTC) is potentially helpful in shortening the composting cycle. However, its universal effectiveness and the microbiological mechanisms involved are unclear. Here, the physicochemical properties and bacterial community dynamics during composting of distilled grain waste in conventional and CTC models were compared. CTC accelerated the organic matter degradation rate (0.2 vs. 0.1 d-1) and shortened the composting cycle (24 vs. 65 d), mainly driven by the synergism of bacterial genera. Microbial analysis revealed that the abundance of Firmicutes was remarkably improved compared to that in conventional composting, and Firmicutes became the primary bacterial phylum (relative abundance >70 %) during the entire CTC process. Moreover, correlation analysis demonstrated that bacterial composition had a remarkable effect on the seed germination index. Therefore, controlling the composting process under continuous thermophilic conditions is beneficial for enhancing composting efficiency and strengthening the cooperation between bacterial genera.
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  • 文章类型: Journal Article
    益生元通过与益生菌的相互作用对宿主产生有利的影响,它们的有益影响已经在各种慢性病中得到了广泛的验证,包括糖尿病.这项研究提供了一项病例对照研究的结果,该研究涉及10名2型糖尿病(T2DM)患者和10名健康者。从所有参与者收集新鲜粪便标本。在含有木糖醇和甘露醇的培养基中发酵24小时后,观察到的病例组中乳酸菌丰度的增加超过了对照组。同样,在含有可溶性淀粉的培养基中,胆碱,和左旋肉碱,病例组中双歧杆菌的增加超过了对照组。值得注意的是,病例组和对照组之间的糖降解率出现了统计学上显著的差异,特别是在含有乳果糖和异麦芽寡糖的培养基中。值得注意的是,乳果糖的降解率与双歧杆菌的扩增呈正相关(R2=.147,p=.037)。同样,异麦芽寡糖的降解率与双歧杆菌的增殖呈正相关(R2=.165,p=.041)。总之,诸如木糖醇和甘露醇之类的益生元具有增强新诊断为糖尿病的个体的肠道益生菌群的能力。糖尿病患者肠道菌群稳态的改变可以通过特定益生元底物的降解速率的改变来证明。
    Prebiotics exert favorable effects on the host through interactions with probiotics, and their beneficial impacts have been extensively validated across various chronic ailments, including diabetes. This study presents findings from a case-control investigation involving 10 individuals with type 2 diabetes mellitus (T2DM) and 10 healthy counterparts. Fresh stool specimens were collected from all participants. Following a 24-h fermentation period in mediums containing xylitol and mannitol, the observed increase in Lactobacillus abundance within the case group exceeded that of the control group. Similarly, in mediums containing soluble starch, choline, and L-carnitine, the augmentation of Bifidobacterium within the case group surpassed that of the controls. Notably, a statistically significant divergence in sugar degradation rate emerged between the case and control groups, specifically in the medium harboring lactulose and isomalto-oligosaccharides. Remarkably, the degradation rate of lactulose exhibited a positive correlation with the expansion of Bifidobacterium (R 2 = .147, p = .037). Likewise, the degradation rate of isomalto-oligosaccharides demonstrated a positive correlation with Bifidobacterium proliferation (R 2 = .165, p = .041). In conclusion, prebiotics like xylitol and mannitol exhibit the capacity to enhance intestinal probiotic populations in individuals newly diagnosed with diabetes. The modifications in the intestinal flora homeostasis of diabetic patients may be evidenced by alterations in the degradation rate of specific prebiotic substrates.
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  • 文章类型: Journal Article
    利用引导组织再生膜是增强骨缺损区域骨组织生长的重要方法。生物可降解镁合金由于其突出的成骨性能而越来越多地用作引导组织再生膜。然而,文献中记载的镁合金骨植入物的降解速率趋于快速。此外,许多研究只关注植入后最初的3个月,限制其适用性并阻碍临床采用。此外,镁合金植入物的降解与邻近组织之间的相互作用很少受到关注。为了弥补这些差距,这项研究采用了经过充分研究的镁铝(Mg-Al)合金膜,降解速率较慢。将该膜植入大鼠颅骨骨缺损中,并在长达48周的长时间内进行监测。在植入后以各种间隔(2、4、8、12、24和48周)进行观察。使用组织学切片进行降解行为和组织再生反应的评估,显微CT扫描,和扫描电子显微镜(SEM)。结果表明,在整个观察期间,镁合金膜表现出显著的生物相容性和成骨能力。具体来说,Mg-Al合金膜维持其结构完整性8周。值得注意的是,由于在植入的后期形成腐蚀产物层,它们的成骨能力进一步增强。此外,我们采用镁合金提取物的体外实验显示出显着的成骨作用,伴随着成骨相关基因的表达显着增加。总的来说,这些结果强烈表明Mg-Al合金膜在引导组织再生方面的巨大潜力。
    The utilization of guided tissue regeneration membranes is a significant approach for enhancing bone tissue growth in areas with bone defects. Biodegradable magnesium alloys are increasingly being used as guided tissue regeneration membranes due to their outstanding osteogenic properties. However, the degradation rates of magnesium alloy bone implants documented in the literature tend to be rapid. Moreover, many studies focus only on the initial 3-month period post-implantation, limiting their applicability and impeding clinical adoption. Furthermore, scant attention has been given to the interplay between the degradation of magnesium alloy implants and the adjacent tissues. To address these gaps, this study employs a well-studied magnesium-aluminum (Mg-Al) alloy membrane with a slow degradation rate. This membrane is implanted into rat skull bone defects and monitored over an extended period of up to 48 weeks. Observations are conducted at various intervals (2, 4, 8, 12, 24, and 48 weeks) following the implantation. Assessment of degradation behavior and tissue regeneration response is carried out using histological sections, micro-CT scans, and scanning electron microscopy (SEM). The findings reveal that the magnesium alloy membranes demonstrate remarkable biocompatibility and osteogenic capability over the entire observation duration. Specifically, the Mg-Al alloy membranes sustain their structural integrity for 8 weeks. Notably, their osteogenic ability is further enhanced as a corrosion product layer forms during the later stages of implantation. Additionally, our in vitro experiments employing extracts from the magnesium alloy display a significant osteogenic effect, accompanied by a notable increase in the expression of osteogenic-related genes. Collectively, these results strongly indicate the substantial potential of Mg-Al alloy membranes in the context of guided tissue regeneration.
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  • 文章类型: Journal Article
    三个主要参数的影响包括辐照时间,研究了包括多壁碳纳米管和不同量的TiO2(MCT#1和MCT#2)在内的光催化剂的重量分数和pH值对甲基橙(MO)的降解率。方差分析(ANOVA)和响应面法(RSM)已用于研究主要参数对降解速率的二元和三元相互作用。ANOVA结果证实,所有三个研究的因素在5%的概率水平下对MO的降解速率具有相当大的功效。同时,结果表明,在0.1~0.3%wt的范围内增加重量分数,在5~35min的照射时间内,降解速率提高。在pH=7和pH=3时分别观察到最低和最高的降解。可以使用图形分析来确认残差分布的正态。RSM结果表明,降解速率对辐照时间的依赖性高于光催化剂的重量分数。
    The influence of three main parameters including irradiation time, weight fraction of photocatalysts including multi-walled carbon nanotubes and different amount of TiO2 (MCT#1 and MCT#2) and pH is investigated for the degradation rate of methyl orange (MO). Analysis of variance (ANOVA) and response surface methodology (RSM) have been applied to study the binary and ternary interactions of the main parameters on the degradation rate. The ANOVA results confirm that all of three studied factors have a considerable efficacy on degradation rate of MO at 5% level of probability. Meanwhile, the results show that the degradation rate is enhanced with increasing the weight fraction in range of 0.1 to 0.3%wt and irradiation time in a period of 5 to 35min.The lowest and highest degradation are observed at pH=7 and pH=3, respectively. The normality of residue distribution can be confirmed using graphical analysis. The RSM results reveal that the degradation rate dependency on irradiation time is higher than the weight fraction of photocatalysts.
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  • 文章类型: Journal Article
    C-糖基类黄酮具有多种药理活性。制备C-糖基类黄酮的有效方法是通过代谢工程。因此,为了在重组菌株中产生C-糖基黄酮,重要的是防止C-糖基黄酮的降解。在这项研究中,阐明了C-糖基类黄酮降解的两个关键因素。从大肠杆菌BL21(DE3)中表达槲皮素酶(YhhW)基因,纯化,和特点。YhhW有效降解槲皮素8-C-葡萄糖苷,奥伦丁,和isoorientin,而牡蛎素和异牡蛎素的降解不显著。Zn2+可以通过抑制YhhW的活性来显著降低C-糖基黄酮的降解。pH是导致C-糖基类黄酮降解的另一个关键因素,和C-糖基类黄酮在体外或体内pH超过7.5时显著降解。在此基础上,两种策略,从大肠杆菌基因组中删除YhhW基因,并在生物转化过程中调节pH,被开发以缓解C-糖基化类黄酮的降解。最后,orenin和槲皮素8-C-葡萄糖苷的总降解率从100下降到28%,从65%下降到18%,分别。以木犀草素为底物的奥龙素最大产量达到3353mg/L,以槲皮素为底物,槲皮素8-C-葡萄糖苷的最大产量达到2236mg/L。因此,本文所述的用于缓解C-糖基类黄酮降解的方法可广泛用于重组菌株中C-糖基类黄酮的生物合成。
    C-glycosylflavonoids have a number of pharmacological activities. An efficient method for the preparation of C-glycosylflavonoids is through metabolic engineering. Thus, it is important to prevent the degradation of C-glycosylflavonoids for producing C-glycosylflavonoids in the recombinant strain. In this study, two critical factors for the degradation of C-glycosylflavonoids were clarified. The quercetinase (YhhW) gene from Escherichia coli BL21(DE3) was expressed, purified, and characterized. YhhW effectively degraded quercetin 8-C-glucoside, orientin, and isoorientin, while the degradation of vitexin and isovitexin was not significant. Zn2+ can significantly reduce the degradation of C-glycosylflavonoids by inhibiting the activity of YhhW. pH was another key factor causing the degradation of C-glycosylflavonoids, and C-glycosylflavonoids were significantly degraded with pH exceeding 7.5 in vitro or in vivo. On this basis, two strategies, deleting YhhW gene from the genome of E. coli and regulating pH during the bioconversion, were developed to relieve the degradation of C-glycosylflavonoids. Finally, the total degradation rates for orientin and quercetin 8-C-glucoside decreased from 100 to 28% and 65% to 18%, respectively. The maximum yield of orientin reached 3353 mg/L with luteolin as substrate, and the maximum yield of quercetin 8-C-glucoside reached 2236 mg/L with quercetin as substrate. Therefore, the method described herein for relieving the degradation of C-glycosylflavonoids may be widely used for the biosynthesis of C-glycosylflavonoids in recombinant strains.
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  • 文章类型: Journal Article
    近年来,聚己二酸丁二醇酯-对苯二甲酸酯共聚物(PBAT)地膜已成为农业中最常用的可生物降解地膜之一,以对抗塑料膜污染。然而,其降解特性及其对土壤环境和作物生长的影响受多种因素的影响,土壤和作物类型,当地气候特征,等。在这项研究中,以PBAT地膜和普通聚乙烯(PE)膜为试验材料,以非覆盖处理(CK)为对照,为了研究PBAT薄膜在墨玉县的适用性,南疆地区,以番茄生长为例。结果表明,PBAT膜在60天后开始诱导期,60.98%的PBAT膜在100天内降解。一般来说,在番茄生长的幼苗和开花结实阶段,该膜的土壤温度和湿度保存功能与PE膜相当。在成熟阶段,PBAT膜下的土壤湿度明显低于PE膜,因为其降解率很高。然而,这对番茄生长没有任何显著的负面影响,产量,和质量。用BPAT处理667m2的番茄产量不显著低于PE膜3.14%,均显著高于CK治疗的63.38%和68.68%,分别,表明在南疆干旱地区使用PBAT膜种植番茄等作物是可行的,中国。
    In recent years, polybutylene adipate-co-terephthalate (PBAT) mulch film has become one of the most commonly used biodegradable mulch films in agriculture in an attempt to combat plastic film pollution. However, its degradation characteristics and impact on the soil environment and crop growth are affected by many factors such as its composition, soil and crop types, local climate characteristics, etc. In this study, PBAT mulch film and ordinary polyethylene (PE) film were used as test materials, with non-mulching treatment (CK) as a control, to study the applicability of PBAT film in Moyu County, Southern Xinjiang region, using tomato growth as an example. The results showed that PBAT film started its induction period after 60 days, and 60.98% of the PBAT film was degraded within 100 days. Generally, the soil temperature and humidity preservation functions of this film were comparable to that of PE film in the seedling and flowering-fruiting stages of tomato growth. In the mature stage, the soil humidity under PBAT film was significantly lower than that of PE film due to its substantial degradation rate. However, this did not have any significant negative effects on tomato growth, yield, and quality. The tomato yield of 667 m2 with BPAT was insignificantly lower than that of PE film by 3.14%, and both were significantly higher than that of the CK treatment by 63.38% and 68.68%, respectively, indicating that it is feasible to use PBAT film to cultivate crops such as tomato in the arid region of Southern Xinjiang, China.
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  • 文章类型: Journal Article
    聚(癸二酸甘油酯)(PGS)由于具有良好的生物相容性和可调的机械性能,在组织工程中是一种出色的支架材料。PGS的降解特性已在静态磷酸盐缓冲溶液或酶溶液中进行了初步探索。了解拉伸应力如何影响降解速率至关重要。在这项研究中,采用熔融缩聚法合成了PGS,并对其性能进行了表征。然后精心设计并建立了可以提供不同恒定拉伸应力的体外降解装置,和PGS的酶降解在0-150kPa和37℃下测试。发现PGS表面的孔在2-4天降解后几乎彼此平行且垂直于100kPa和150kPa的拉伸应力方向。降解8天后,PGS在150kPa下的极限拉伸强度(UTS)为0.28MPa,弹性模量为1.11MPa,而PGS的UTS为0.44MPa,降解前的弹性模量为1.63MPa,两者有很大的不同。因此,拉伸应力和降解时间与孔的出现时间和大小成正比,导致质量损失的减少,UTS和弹性模量。通过我们的降解实验定量描述了应力和PGS降解率之间的关系,为未来合适的PGS应用提供指导。
    Poly(glycerol sebacate) (PGS) is an excellent scaffold material in tissue engineering due to good biocompatibility and tunable mechanical properties. The degradation properties of PGS have been primarily explored in static phosphate buffer solution or enzyme solution. It is vital to understand how the tensile stress affect the degradation rate. In this study, PGS was synthetized by melt polycondensation and its properties were characterized. Then an in vitro degradation device which could provide different constant tensile stresses was carefully designed and established, and the enzymatic degradation of PGS was tested under 0-150 kPa at 37°C. It was found that holes of PGS surface arranged almost parallel to each other and perpendicular to the direction of tensile stresses at 100 kPa and 150 kPa after 2-4 days degradation. After 8 days degradation, the ultimate tensile strength (UTS) of PGS at 150 kPa was 0.28 MPa and the elastic modulus was 1.11 MPa, while the UTS of PGS was 0.44 MPa and the elastic modulus was 1.63 MPa before degradation, both of them have significant differences. Hence, the tensile stress and degradation time were proportional to the appear time and size of holes, leading to the decrease of mass loss, UTS and elastic modulus. The relationship between stress and PGS degradation rates was quantitatively described through our degradation experiments, providing guidance for suitable PGS applications in the future.
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