• 【颗粒壁附着力对混合器中颗粒带电的影响。】 复制标题 收藏 收藏
    DOI:10.1016/j.ijpharm.2006.07.041 复制DOI
    作者列表:Zhu K,Tan RB,Chen F,Ong KH,Heng PW
    BACKGROUND & AIMS: :In this work, particle electrification in the Turbula and horizontally oscillating mixers were investigated for adipic acid, microcrystalline cellulose (MCC), and glycine particles. MCC and glycine particles acquired positive electrostatic charges, while adipic acid particles attained negative charges in both mixers. Adipic acid (of sieved size larger than 500 microm), MCC, and glycine particles were monotonically charged to saturated values, and had negligible wall adhesion. On the contrary, the adipic acid particles, both unsieved and sieved but of smaller sieved size fraction, exhibited very different charging kinetics in the horizontally oscillating mixer. These adipic acid particles firstly acquired charges up to a maximum value, and then the charges slowly reduced to a lower saturated value with increasing mixing time. Furthermore, these particles were found to adhere to the inner wall of the mixer, and the adhesion increased with mixing time. Surface specific charge densities for adipic acid particles were estimated based on particle size distribution, and were found to increase with particle mean diameters under the conditions investigated. The results obtained from the current work suggested that electrostatic force enhanced particle-wall adhesion, and the adhered particles can have a significant impact on particle electrification.
    背景与目标: : 在这项工作中,研究了湍流和水平振荡混合器中己二酸,微晶纤维素 (MCC) 和甘氨酸颗粒的颗粒带电。MCC和甘氨酸颗粒在两个混合器中均获得正电荷,而己二酸颗粒则获得负电荷。己二酸 (筛分尺寸大于500微米) 、MCC和甘氨酸颗粒单调带电至饱和值,并且具有可忽略的壁粘附力。相反,未过筛和过筛但过筛尺寸分数较小的己二酸颗粒在水平振荡混合器中表现出非常不同的充电动力学。这些己二酸颗粒首先获得的电荷达到最大值,然后随着混合时间的增加,电荷逐渐降低到较低的饱和值。此外,发现这些颗粒粘附在混合器的内壁上,并且粘附力随混合时间而增加。根据粒径分布估算了己二酸颗粒的表面比电荷密度,并发现在所研究的条件下随着颗粒平均直径的增加而增加。从当前工作中获得的结果表明,静电力增强了颗粒壁的附着力,并且粘附的颗粒会对颗粒的起电产生重大影响。
  • 【燕麦花粉管壁的生长。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Dickinson HG,Lawson J
    BACKGROUND & AIMS: :The growth of the pollen tube wall of Oenothera is effected by the expulsion of fibrillar material from the cytoplasm into the developing wall. This material may also be seen in the cytoplasm, contained in membrane-bound vesicles. It is not clear how the content of the vesicles is discharged, but it appears not to involve the participation of microtubules. The source of the cytoplasmic fibrillar bodies depends upon the stage of development of the pollen tube. The earilest growth is derived from the inclusion into the wall of vesicles containing pre-formed materials present in the grain on pollination. During the next stage of growth the wall is derived from the content of double-membraned inclusions also present in the pollen. The content of the former vesicles is not so similar to the wall as the latter, but intermediates between the 2 types of vesicle may be seen in the cytoplasm, indicating that the former are formed from the latter. Most of the tube wall is derived from the products of dictyosomes in the pollen grain or tube. These dicytosomes are few in number and they must be exceedingly active. This, and the observation that dictyosome vesicles are frequently associated with banked complexes of mitochondria, indicates that some steps in the metabolism of the vesicular content, perhaps phosphorylation, take place distant from the dicytosomes. These different sources of fibrillar material presumably permit the rapid starting of tube growth, without any attendant metabolism. However, it would be impossible to include enough pre-formed wall material in the grain to enable the full growth of the tube, so once started, it seems that the tube then relies on the elaboration of simple reserves for the contruction of its wall. These reserves are likely to be held in the pollen, and may be the large numbers of starch grains characteristic of the pollen cytoplasm.
    背景与目标: : 卵生花粉管壁的生长是通过将原纤维物质从细胞质中排出到发育中的壁中而实现的。这种物质也可以在细胞质中看到,包含在膜结合的囊泡中。尚不清楚如何释放囊泡的含量,但似乎不涉及微管的参与。细胞质原纤维体的来源取决于花粉管的发育阶段。最早的生长来自包含在授粉时谷物中存在的包含预形成材料的囊泡壁。在生长的下一阶段,壁来自花粉中也存在的双层包裹体的含量。前者囊泡的含量不像后者那样与壁相似,但在细胞质中可能看到2种囊泡之间的中间体,表明前者是由后者形成的。大部分的管壁来源于花粉粒或管中双子体的产物。这些二胞体数量很少,它们必须非常活跃。这以及观察到dictyosome囊泡经常与线粒体的银行复合物有关,这表明囊泡含量代谢的某些步骤 (可能是磷酸化) 发生在远离二胞体的地方。这些不同的原纤维物质来源可能允许快速开始管生长,而没有任何伴随的代谢。但是,不可能在谷物中包括足够的预成型壁材料以使管完全生长,因此一旦开始,管似乎就依赖于简单的储备来构造其壁。这些储备很可能存在于花粉中,并且可能是花粉细胞质特有的大量淀粉粒。
  • 【烧伤和内脏损伤合并爆炸伤后腹壁全层损失的成功治疗。】 复制标题 收藏 收藏
    DOI:10.1097/01.BCR.0000238090.70355.6D 复制DOI
    作者列表:Başaran O,Karaarslan P,Sakalloğlu AE,Kesik E,Karakayalý H,Haberal M
    BACKGROUND & AIMS: :A 29-year-old man was admitted to our institution 10 days after he had undergone an urgent exploratory laparotomy at a local army hospital after a terrorist bombing attack. On admission, deep second-degree and third-degree burns involving 25% of the upper and lower extremities were present, together with a 25 x 10-cm abdominal full-thickness blast injury defect on the left side, an infected eviscerated midline incision, and a colostomy on the right side of the abdomen. The patient underwent a second laparotomy, at which time the intraabdominal abscess was drained, and the abdominal cavity was irrigated with saline. A jejunal perforation was found and sutured. The abdominal cavity was left open and covered with a Bogota bag for temporary closure. On postburn day 18, the patient underwent débridment and grafting of the third-degree burns to the left and right arm and right lower extremities. After several débridment sessions (postburn days 16, 18, 20, 22, and 24), an abdominal skin release and reapproximation were performed (postburn day 26). On postburn day 36, split-thickness skin grafts were placed directly on the granulated tissue of the intestines and on a defect in the left flank and iliac regions. Postoperatively, the patient did well. He was discharged on postburn day 78 with all wounds well healed. In our opinion, temporary closure followed by direct application of meshed split-thickness skin grafts to exposed abdominal viscera represents a simple method of reconstruction that can be safely performed, with minimal risk, on critically ill patients.
    背景与目标: : 一名29岁的男子在恐怖爆炸袭击后在当地一家军队医院接受紧急剖腹探查术10天后被送入我们的机构。入院时,出现了涉及上下肢25% 的深二度和三度烧伤,左侧有25x10 cm的腹部全层爆炸伤缺损,感染的内脏中线切口,以及腹部右侧的结肠造口术。患者接受了第二次剖腹手术,此时引流了腹腔内脓肿,并用盐水冲洗了腹腔。发现空肠穿孔并缝合。腹腔保持开放状态,并用波哥大袋覆盖,以暂时关闭。在烧伤后第18天,患者接受了三度烧伤的移植,并将其移植到左,右臂和右下肢。经过几次缓解 (烧伤后第16、18、20、22和24天) 后,进行了腹部皮肤释放和重新逼近 (烧伤后第26天)。在烧伤后的第36天,将厚度分开的皮肤移植物直接放置在肠的颗粒状组织以及左侧和ili区的缺损处。术后,患者表现良好。他在烧伤后第78天出院,所有伤口均愈合良好。在我们看来,暂时封闭,然后直接将网状厚度的皮肤移植物应用到暴露的腹部内脏上,代表了一种简单的重建方法,可以对危重病人安全地进行,风险最小。
  • 【转化生长因子-β: 血管生成、血管生成和血管壁完整性。】 复制标题 收藏 收藏
    DOI:10.1016/s1359-6101(96)00048-2 复制DOI
    作者列表:Pepper MS
    BACKGROUND & AIMS: Genetic studies have recently revealed a role for transforming growth factor-beta-1 (TGF-beta 1) and its receptors (TGF-beta Rs I and II as well as endoglin) in embryonic vascular assembly and in the establishment and maintenance of vessel wall integrity. The purpose of this review is threefoldfirst, to reassess previous studies on TGF-beta and endothelium in the light of these recent findings; second, to describe some of the well-established as well as controversial issues concerning TGF-beta and its regulatory role in angiogenesis; and third, to explore the notion of "context' with respect to TGF-beta and endothelial cell function. Although the focus of this review will be on the endothelium, other vascular wall cells are also likely to be important in the pathogenesis of the vascular lesions revealed by genetic studies.

    背景与目标: 遗传研究最近揭示了转化生长因子-beta-1 (TGF-beta 1) 及其受体 (TGF-beta Rs I和II以及endoglin) 在胚胎血管组装以及血管壁完整性的建立和维持中的作用。这篇综述的目的是三重首先,根据这些最新发现重新评估先前关于TGF-β 和内皮的研究; 第二,描述一些关于TGF-β 及其在血管生成中的调节作用的公认的和有争议的问题; 第三,探讨TGF-β 和内皮细胞功能的 “背景” 概念。尽管本综述的重点将放在内皮上,但其他血管壁细胞也可能在遗传学研究揭示的血管病变的发病机理中很重要。
  • 【磨牙全冠制剂中的轴向壁倾斜角和垂直高度相互作用。】 复制标题 收藏 收藏
    DOI:10.1016/j.jdent.2006.06.002 复制DOI
    作者列表:Bowley JF,Kieser J
    BACKGROUND & AIMS: OBJECTIVE:This study has been designed to evaluate the interaction of axial wall heights with inclination angles in full crown tooth preparations. The interaction of these parameters was related to the resulting preparation surface area. MATERIALS AND METHODS:A right regular pyramid was used to simulate a single mandibular molar preparation with known convergence angles and vertical heights. Various combinations of these two variables allowed the calculation of surface areas with a formula for the area of a pyramid and right triangles through trigonometric manipulations. The pyramidal model system had a 9-mm square base with vertical heights from 3- to 5-mm and single-side inclination angles from 2 to 25 degrees. The occlusal surface was a flat, square or rectangular surface and was included in the total area. RESULTS:A percentage of surface area lost or gained served as the dependent variables. The significance levels were set at 10.0% or greater magnitude of loss/gain in a surface area compared to the ideal 2 degree-level. Significant area loss was demonstrated in all alpha-level comparisons. The largest change was found in the 5-mm height grouping compared to the 3-mm height grouping, -36.6% difference between groups at the 2 degree-level. CONCLUSIONS:Axial single-side inclination angles greater than 10 degrees in 3- and 4-mm height-molars are detrimental to maximum surface area in full crown restorations. The 5-mm axial wall height with < or = 10 degree single wall has been shown to maximize the luting agent surface area between restoration and tooth structure.
    背景与目标:
  • 【血管紧张素II体外诱导大鼠和人小肠壁肌肉组织收缩。】 复制标题 收藏 收藏
    DOI:10.1111/j.1748-1716.2006.01600.x 复制DOI
    作者列表:Ewert S,Spak E,Olbers T,Johnsson E,Edebo A,Fändriks L
    BACKGROUND & AIMS: BACKGROUND:Angiotensin II (Ang II) is a well-known activator of smooth muscle in the vasculature but has been little explored with regard to intestinal wall muscular activity. This study investigates pharmacological properties of Ang II and expression of its receptors in small-intestinal smooth muscle from rats and humans. METHODS:Isometric recordings were performed in vitro on small intestinal longitudinal muscle strips. Protein expressions of Ang II typ 1 (AT1R) and typ 2 (AT2R) receptors were assessed by Western blot. RESULTS:Ang II elicited concentration-dependent contractions of rat jejunal and ileal muscle preparations. The concentration-response curve (rat ileum, EC(50): 1.5 +/- 0.9 x 10(-8) M) was shifted to the right by the AT1R receptor antagonist losartan (10(-7) M) but was unaffected by the AT2R antagonist PD123319 (10(-7) M) as well as by the adrenolytic guanethidine (3 x 10(-6) M) and the anticholinergic atropine (10(-6) M). Human duodenal, jejunal and ileal longitudinal muscle preparations all contracted concentration-dependently in response to Ang II. The concentration-response curve (human jejunum, EC(50): 1.5 +/- 0.8 x 10(-8) M) was shifted to the right by losartan (10(-7) M) but was unaffected by PD123319 (10(-7) M). Both AT1R and AT2R were detected in all segments of the rat small intestinal wall musculature, whereas only AT1R was readily detectable in the human samples. CONCLUSION:Ang II elicits contractions of small-intestinal longitudinal muscle preparations from the small intestine of rats and man. The pharmacological pattern and protein expression analyses indicate mediation via the AT1R.
    背景与目标:
  • 【舒张期颈动脉纵向壁运动对衰老和冠状动脉疾病状态均敏感,而与动脉僵硬无关。】 复制标题 收藏 收藏
    DOI:10.1016/j.ultrasmedbio.2017.04.026 复制DOI
    作者列表:Au JS,Valentino SE,McPhee PG,MacDonald MJ
    BACKGROUND & AIMS: :We investigated the ability of systolic and diastolic carotid artery longitudinal wall motion (CALM) to delineate expected differences in arterial health in individuals representing a range of both age and health status. We recruited 161 younger healthy adults (aged 24 ± 5 y), 51 older healthy adults (aged 70 ± 5 y) and 14 adults with coronary artery disease (aged 67 ± 8 y) for resting assessment of CALM and arterial stiffness. All CALM parameters were reduced in the old healthy adults and adults with coronary artery disease compared with the young healthy adults (p < 0.01), with diastolic velocity and maximum diastolic acceleration being further reduced in the adults with coronary artery disease than in the older healthy adults (p < 0.01). Diastolic CALM parameters were more strongly related to age (β range: -0.46 to -0.53) than systolic CALM parameters (β range: -0.24 to -0.44). In contrast to previous examinations of a variety of CALM parameters, diastolic CALM may provide superior promise in terms of characterizing arterial wall properties, with additional sensitivity to cardiovascular disease status.
    背景与目标: : 我们研究了收缩期和舒张期颈动脉纵向壁运动 (CALM) 描绘代表年龄和健康状况范围的个体的动脉健康预期差异的能力。我们招募了161名年轻的健康成年人 (24 ± 5岁),51名老年健康成年人 (70 ± 5岁) 和14名患有冠状动脉疾病的成年人 (67 ± 8岁) 进行静息评估平静和动脉僵硬度。与年轻健康成年人相比,老年健康成年人和患有冠状动脉疾病的成年人的所有CALM参数均降低 (p <0.01),与老年健康成年人相比,患有冠状动脉疾病的成年人的舒张速度和最大舒张加速度进一步降低 (p <0.01)。舒张期平静参数与年龄 (β 范围: -0.46至-0.53) 的相关性高于收缩期平静参数 (β 范围: -0.24至-0.44)。与以前对各种平静参数的检查相比,舒张期平静在表征动脉壁特性方面可能具有出色的前景,并且对心血管疾病状态具有额外的敏感性。
  • 【Isg-geis四肢和躯干壁软组织肉瘤试验中的手术质量和新辅助联合治疗。】 复制标题 收藏 收藏
    DOI:10.1093/annonc/mds501 复制DOI
    作者列表:Gronchi A,Verderio P,De Paoli A,Ferraro A,Tendero O,Majò J,Martin J,Comandone A,Grignani G,Pizzamiglio S,Quagliuolo V,Picci P,Frustaci S,Dei Tos AP,Palassini E,Stacchiotti S,Ferrari S,Fiore M,Casali PG
    BACKGROUND & AIMS: BACKGROUND:To explore correlation between the quality of surgery and outcome in high-risk soft tissue sarcoma (STS) patients treated within a phase III randomized trial. PATIENTS AND METHODS:In the trial, all patients received three cycles of preoperative chemotherapy (CT) with epirubicin 120 mg/m(2) and ifosfamide 9 g/m(2) and were randomly assigned to receive two further postoperative cycles. Radiotherapy (RT) could be delivered in the preoperative or postoperative setting. The association between surgical margins and overall survival (OS) was studied in a univariate and multivariate fashion. RESULTS:Two hundred and fifty-two patients completed the whole treatment and were operated conservatively. At a median follow-up of 60 months (IQR, 45-74 months), the 5-year OS was 0.73, even in patients with positive and negative margins. The 5-year cumulative incidence (CI) of local recurrence (LR) in patients with positive and negative microscopic margins was 0.17 (standard error, SE, 0.08) and 0.03 (SE, 0.01), respectively. In the subgroup of patients receiving combined preoperative CT-RT and with positive surgical margins, the CI of LR was 0. CONCLUSIONS:In this setting of high-risk STS treated by preoperative CT or CT-RT, the negative impact of positive margins on the outcome was limited. When close margins can be anticipated preoperative CT-RT may be a reasonable option to maximize the chance of cure.
    背景与目标:
  • 【布鲁氏菌壁根提取物的体外和体内抗血浆活性。ex Kurz。】 复制标题 收藏 收藏
    DOI:10.1007/s00436-012-3178-1 复制DOI
    作者列表:Prakash A,Sharma SK,Mohapatra PK,Bhattacharjee K,Gogoi K,Gogoi P,Mahanta J,Bhattacharyya DR
    BACKGROUND & AIMS: :Malaria control is compromised worldwide by continuously evolving drug-resistant strains of the parasite demanding exploration of natural resources for developing newer antimalarials. The northeastern region of India is endemic for malaria characterized by high prevalence of drug-resistant Plasmodium falciparum strains. Many plants are used by the indigenous communities living in the northeast India in their traditional system of medicine for the treatment of malarial fever. Folklore claim of antimalarial property of one such plant Brucea mollis was evaluated in vitro and in vivo for antiplasmodial activity. Crude extracts from dried B. mollis root powder were prepared through soxhlet extraction using petroleum ether, methanol, and water sequentially. Methanol extract was further partitioned between chloroform and water. These extracts were tested in vitro against laboratory-adapted chloroquine-sensitive and chloroquine-resistant strains of P. falciparum. In in vitro evaluation, extracts were found more active on the chloroquine-sensitive strain. Methanolic-chloroform (IC(50) 5.1 μg ml(-1)) and methanolic-aqueous (IC(50) 13.9 μg ml(-1)) extracts recorded significant in vitro antiplasmodial activity which was also supported by their promising in vivo activity (ED(50) 72 and 30 mg kg(-1) bw day(-1), respectively) against chloroquine-resistant Plasmodium yoelli N-67 strain in Swiss albino mice. Methanolic-aqueous extract-treated mice survived on average for 14 days that was comparable to the reference drug chloroquine. This is the first report of antiplasmodial activity of B. mollis validating the traditional use of this plant as antimalarial in the northeast India and calls for further detailed investigations.
    背景与目标: : 疟疾控制在世界范围内受到不断发展的寄生虫耐药菌株的损害,需要探索自然资源来开发新型抗疟药。印度东北部地区是疟疾的地方病,其特征是抗药性恶性疟原虫菌株的高流行。生活在印度东北部的土著社区在其传统医学系统中使用了许多植物来治疗疟疾发热。在体外和体内评估了一种此类植物布鲁氏菌的抗疟特性的民间传说声称具有抗疟原虫活性。通过依次使用石油醚,甲醇和水进行索氏萃取,制备了干燥的B. mollis根粉末的粗提取物。甲醇提取物在氯仿和水之间进一步分配。这些提取物在体外针对实验室适应的恶性疟原虫对氯喹敏感和对氯喹耐药的菌株进行了测试。在体外评估中,发现提取物对氯喹敏感的菌株更具活性。甲醇-氯仿 (IC(50) 5.1 μ gml (-1)) 和甲醇-水性 (IC(50) 13.9 μ gml (-1)) 提取物记录了显着的体外抗血浆活性,这也受到其有希望的体内活性的支持 (ED(50) 72和30 mg kg(-1) bw日 (-1),分别) 针对瑞士白化病小鼠中抗氯喹的疟原虫yoelli N-67株。甲醇水提取物处理的小鼠平均存活14天,与参考药物氯喹相当。这是关于B. mollis抗疟原虫活性的第一份报告,证实了该植物在印度东北部作为抗疟药的传统用途,并呼吁进行进一步的详细研究。
  • 【使用支撑技术重建粉碎性后壁骨折: 对32例骨折的回顾。】 复制标题 收藏 收藏
    DOI:10.1007/s00264-006-0246-0 复制DOI
    作者列表:Ebraheim NA,Patil V,Liu J,Sanford CG Jr,Haman SP
    BACKGROUND & AIMS: :Fractures of the posterior wall are the most common of the acetabular fractures. The aim of this study was to assess the medium-term results of reconstruction of comminuted posterior wall fractures of the acetabulum by using the buttress technique. This is a retrospective review conducted at a level 1 trauma centre. Thirty-two patients (25 men, 7 women, mean age 41 years, range 14-80 years) with comminuted posterior wall fracture of the acetabulum underwent reconstruction of the posterior wall during the period of July 1998 to February 2004. The average follow-up was 43 months (range 24-70 months). Clinical evaluation was based on modified Merle d'Aubigne and Postel scoring. Radiographic evaluation was according to criteria developed by Matta. The postoperative reduction was graded as anatomical in 28 patients (88%) and imperfect in 4 patients (12%). The clinical outcome was excellent in 11 (34% ), very good in 9 (28%), good in 4 (12%), fair in 3 (9%) and poor in 5 (15%). Radiological grading at the final follow-up was excellent 12 (37%), good 11 (34%), fair 4 (12%) and poor 5 (15%). Reconstruction of comminuted posterior wall acetabular fractures by buttress technique can be expected to produce good results. It can provide a stable fixation of the posterior wall amenable to early range of motion and weight bearing.
    背景与目标: : 后壁骨折是髋臼骨折中最常见的。这项研究的目的是评估使用支撑技术重建髋臼粉碎性后壁骨折的中期结果。这是在一级创伤中心进行的回顾性审查。在1998年7月至2004年2月期间,对32例髋臼粉碎性后壁骨折患者 (男性25例,女性7例,平均年龄41岁,范围14-80岁) 进行了后壁重建。平均随访43个月 (24-70个月)。临床评估基于改良的Merle d'Aubigne和Postel评分。射线照相评估是根据Matta制定的标准进行的。术后复位分为解剖型28例 (88% 例),不完美的4例 (12% 例)。临床结果优11例 (34% 例),好9例 (28% 例),好4例 (12% 例),好3例 (9% 例),差5例 (15% 例)。最终随访的放射学分级为优秀12 (37%),良好11 (34%),一般4 (12%) 和较差5 (15%)。通过支撑技术重建粉碎性后壁髋臼骨折有望产生良好的效果。它可以提供稳定的后壁固定,适合早期的运动范围和承重。
  • 【用非线性自适应滤波器降低胸部CT的辐射剂量。】 复制标题 收藏 收藏
    DOI:10.1258/ar.2012.120045 复制DOI
    作者列表:Singh S,Digumarthy SR,Back A,Shepard JA,Kalra MK
    BACKGROUND & AIMS: BACKGROUND:CT radiation dose reduction results in increased noise or graininess of images which affects the diagnostic information. One of the approaches to lower radiation exposure to patients is to reduce image noise with the use of image processing software in low radiation dose images. PURPOSE:To assess image quality and accuracy of non-linear adaptive filters (NLAF) at low dose chest CT. MATERIAL AND METHODS:In an IRB approved prospective study, 24 patients (mean age, 63 ± 7.3 years; M:F ratio, 11:13) gave informed consent for acquisition of four additional chest CT image series at 150, 110, 75, and 40 mAs (baseline image series) on a 64-slice MDCT over an identical 10-cm length. NLAF was used to process three low dose (110, 75, and 40 mAs) image series (postprocessed image series). Two radiologists reviewed baseline and postprocessed images in a blinded manner for image quality. Objective noise, CT attenuation values, patient weight, transverse diameters, CTDIvol, and DLP were recorded. Statistical analysis was performed using parametric and non-parametric tests for comparing postprocessed and baseline images. RESULTS:No lesions were missed on baseline or postprocessed CT images (n = 80 lesions, 73 lesions <1 cm). At 40 mAs, subjective noise in mediastinal window settings were graded as unacceptable in baseline images and acceptable in postprocessed images. Visibility of smaller structures improved from suboptimal visibility in baseline images at 40 mAs to excellent in postprocessed images at 40 mAs. No major artifacts were seen due to NLAF postprocessing, except for minor beam hardening artifacts not affecting diagnostic decision-making (14/22) in both baseline and postprocessed image series. Diagnostic confidence for chest CT was improved to fully confident in postprocessed images at 40 mAs. Compared to baseline images, postprocessing reduced objective noise by 26% (14.2 ± 4.7/19.2 ± 6.4), 31.5% (15.2 ± 4.7/22.2 ± 5.7), and 41.5% (16.9 ± 6/28.9 ± 10.2) at 110 mAs, 75 mAs, and 40 mAs tube current-time product levels. CONCLUSION:Applications of NLAF can help reduce tube current down to 40 mAs for chest CT while maintaining lesion conspicuity and image quality.
    背景与目标:
  • 【动脉壁低密度脂蛋白氧化动力学模型及其在动脉粥样硬化病变预测中的应用。】 复制标题 收藏 收藏
    DOI:10.1016/j.chemphyslip.2013.07.006 复制DOI
    作者列表:Karimi S,Dadvar M,Modarress H,Dabir B
    BACKGROUND & AIMS: :Oxidation of low-density lipoprotein (LDL) is one of the major factors in atherogenic process. Trapped oxidized LDL (Ox-LDL) in the subendothelial matrix is taken up by macrophage and leads to foam cell generation creating the first step in atherosclerosis development. Many researchers have studied LDL oxidation using in vitro cell-induced LDL oxidation model. The present study provides a kinetic model for LDL oxidation in intima layer that can be used in modeling of atherosclerotic lesions development. This is accomplished by considering lipid peroxidation kinetic in LDL through a system of elementary reactions. In comparison, characteristics of our proposed kinetic model are consistent with the results of previous experimental models from other researches. Furthermore, our proposed LDL oxidation model is added to the mass transfer equation in order to predict the LDL concentration distribution in intima layer which is usually difficult to measure experimentally. According to the results, LDL oxidation kinetic constant is an important parameter that affects LDL concentration in intima layer so that existence of antioxidants that is responsible for the reduction of initiating rates and prevention of radical formations, have increased the concentration of LDL in intima by reducing the LDL oxidation rate.
    背景与目标: : 低密度脂蛋白 (LDL) 的氧化是动脉粥样硬化过程的主要因素之一。内皮下基质中捕获的氧化LDL (Ox-LDL) 被巨噬细胞摄取,并导致泡沫细胞的产生,从而形成动脉粥样硬化发展的第一步。许多研究人员使用体外细胞诱导的LDL氧化模型研究了LDL氧化。本研究提供了内膜层LDL氧化的动力学模型,可用于模拟动脉粥样硬化病变的发展。这是通过通过基本反应系统考虑LDL中的脂质过氧化动力学来实现的。相比之下,我们提出的动力学模型的特征与其他研究的先前实验模型的结果一致。此外,我们提出的LDL氧化模型被添加到传质方程中,以预测内膜层中的LDL浓度分布,这通常很难通过实验进行测量。根据结果,LDL氧化动力学常数是影响内膜层中LDL浓度的重要参数,因此抗氧化剂的存在负责降低起始速率和防止自由基形成,通过降低LDL氧化速率来增加内膜中LDL的浓度。
  • 【与骨科胸壁重建相关的人肋骨的几何形状。】 复制标题 收藏 收藏
    DOI:10.1016/j.jbiomech.2006.05.017 复制DOI
    作者列表:Mohr M,Abrams E,Engel C,Long WB,Bottlang M
    BACKGROUND & AIMS: :Orthopedic reconstruction of blunt chest trauma can aid restoration of pulmonary function to reduce the mortality associated with serial rib fractures and flail chest injuries. Contemporary chest wall reconstruction requires contouring of generic plates to the complex surface geometry of ribs. This study established a biometric foundation to generate specialized, anatomically contoured osteosynthesis hardware for rib fracture fixation. On human cadaveric ribs three through nine, the surface geometry pertinent to anatomically conforming osteosynthesis plates was characterized by quantifying the apparent rib curvature C(A), the longitudinal twist alpha(LT) along the diaphysis, and the unrolled curvature C(U). In addition, the rib cross-sectional geometry pertinent to intramedullary fixation strategies was characterized in terms of cross-section height, width, area, and cortex thickness. The rib surface exhibited a curvature C(A) ranging from 3.8 m(-1) in the anteromedial section of rib seven to 17.3 m(-1) in the posterior section of rib three. All ribs had in common a longitudinal twist alpha(LT), ranging from 41-60 degrees. The unrolled curvature C(U) decreased gradually from ribs three to five, and increased gradually with reversed orientation from rib six to nine. The cross-sectional area remained constant along the rib diaphysis. However, the medullary canal increased in size from 29.9 mm(2) posteriorly to 41.2 mm(2) in anterior rib segments. Results of this biometric rib characterization describe a novel strategy for intraoperative plate contouring and provide a foundation for the development of specialized rib osteosynthesis strategies.
    背景与目标: : 钝性胸部创伤的矫形重建可以帮助恢复肺功能,以降低与系列肋骨骨折和连枷胸损伤相关的死亡率。当代的胸壁重建需要将通用板轮廓绘制到肋骨的复杂表面几何形状。这项研究建立了生物识别基础,以生成用于肋骨骨折固定的专门的,解剖学轮廓的骨合成硬件。在人体尸体肋骨的三到九个肋骨上,与解剖学上符合的骨接骨板相关的表面几何形状的特征是量化了明显的肋骨曲率C(A),沿骨干的纵向扭曲 α (LT) 和展开的曲率C(U)。此外,与髓内固定策略相关的肋骨横截面几何形状的特征在于横截面高度,宽度,面积和皮质厚度。肋骨表面的曲率C (a) 的范围为7肋的前内侧部分的3.8 m(-1) 至3肋的后部的17.3 m(-1)。所有肋骨的共同纵向扭曲 α (LT) 在41-60度之间。展开的曲率C(U) 从肋骨3逐渐减小到肋骨5,并随着方向从肋骨6逐渐减小到肋骨9。沿肋骨骨干的横截面积保持恒定。然而,前肋骨段的延髓管大小从后29.9毫米 (2) 增加到41.2毫米 (2)。这种生物特征的结果描述了一种用于术中钢板轮廓的新策略,并为开发专门的肋骨骨合成策略提供了基础。
  • 【[主动脉壁夹层的组织病理学研究]。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Niitsuya M,Kuwao S,Sato B,Kameya T,Kikawada R
    BACKGROUND & AIMS: :To determine the etiology of aortic wall dissection, a histopathological study of the aorta in 20 cases with dissecting aortic aneurysm (DA), 3 cases with Marfan syndrome and 3 cases with annulo-aortic ectasia (AAE) was performed. Controls consisted of 348 cases of normally-aging aorta. In cases with aortic wall dissection, the histopathological changes in the undissected media were also carefully examined. In Marfan syndrome and AAE, there was a marked accumulation of acid mucopolysaccharide (AMPS) and its distribution in the wall was diffuse in patients under 50 years old, resulting in changes in elastic fibers including fragmentation, elastolysis and reticulation. In contrast, DA was histopathologically characterized by zonal fibrosis and abnormally-dilated vessels in the aortic media. These lesions were found in 8 (40%) of the 20 DA cases. The remaining 12 cases also had increased vascularization and fragmentation of elastic fibers. This medial fibrosis and increased vascularization were particularly marked in older patients. Among the 3 diseased entities responsible for aortic wall dissection, DA differed distinctly from Marfan syndrome or AAE as to the amount and site of AMPS accumulation in the media as well as fibrosis and hypervascularity in the outer half of the aortic media. In conclusion, aortic wall dissection in younger patients may be etiologically associated with the increased AMPS accumulation in the aortic media which may always be accompanied by degeneration of elastic fibers in this study, however, in older patients zonal fibrosis and abnormal vessels developing in the media are responsible for the dissection.
    背景与目标: : 为了确定主动脉壁夹层的病因,对20例夹层主动脉瘤 (DA),3例Marfan综合征和3例环状主动脉扩张 (AAE) 的主动脉进行了组织病理学研究。对照组包括348例正常老化的主动脉。在主动脉壁夹层的情况下,还仔细检查了未解剖介质的组织病理学变化。在Marfan综合征和AAE中,在50岁以下的患者中,酸性粘多糖 (AMPS) 明显积累,并且其在壁中的分布是弥漫性的,导致弹性纤维的变化,包括碎片,弹性分解和网状。相反,DA的组织病理学特征是主动脉介质中的带状纤维化和异常扩张的血管。在20例DA病例中,有8例 (40% 例) 发现了这些病变。其余12例也有血管化和弹性纤维碎裂的增加。这种内侧纤维化和血管化增加在老年患者中尤为明显。在负责主动脉壁夹层的3个患病实体中,DA与Marfan综合征或AAE在培养基中AMPS积累的数量和部位以及主动脉培养基外半部的纤维化和血管增生方面明显不同。总之,年轻患者的主动脉壁夹层可能与主动脉介质中AMPS积累增加在病因学上有关,在本研究中,这可能总是伴随着弹性纤维的变性,但是,在老年患者中,带状纤维化和异常血管在主动脉介质中发展是造成夹层的原因。
  • 【胸部理疗可延长重症患者通气时间超过48小时。】 复制标题 收藏 收藏
    DOI:10.1007/s00134-007-0762-4 复制DOI
    作者列表:Templeton M,Palazzo MG
    BACKGROUND & AIMS: OBJECTIVE:This study aimed to determine the impact of providing chest physiotherapy after routine clinical assessment on the duration of mechanical ventilation, outcome and intensive care length of stay. DESIGN AND SETTING:Single-centre, single-blind, prospective, randomised, controlled trial in a university hospital general intensive care unit. PATIENTS AND PARTICIPANTS:180 patients requiring mechanical ventilation for more than 48 h. INTERVENTIONS:Patients randomly allocated, one group receiving physiotherapy as deemed appropriate by physiotherapists after routine daily assessments and another group acting as controls were limited to receiving decubitus care and tracheal suctioning. MEASUREMENTS AND RESULTS:Primary endpoints were initial time to become ventilator-free, secondary endpoints included intensive care unit (ICU) and hospital mortality and ICU length of stay. Kaplan-Meier analysis censored for death revealed a significant prolongation of median time to become ventilator-free among patients receiving physiotherapy (p=0.047). The time taken for 50% of patients (median time) to become ventilator-free was 15 and 11 days, respectively, for physiotherapy and control groups. There were no differences between groups in ICU or hospital mortality rates, or length of ICU stay. The number of patients needing re-ventilation for respiratory reasons was similar in both groups.
    背景与目标:

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