Search

ABS plastics, as the name indicates, are a family of thermoplastics which are composed of acrylonitrile (A), butadiene (B), and styrene (S). The properties of ABS are determined by these constituent monomers: acrylonitrile imparts chemical and heat resistance; styrene imparts rigidity, hardness, and process-ability; and butadiene imparts impact strength. By varying the proportions of these constituents and the manner by which they are combined, ABS can be tailored to satisfy the requirements of a wide variety of applications. [ABSTRACT FROM PUBLISHER]

Objective: To investigate whether early postoperative walking is associated with "best outcome" and no opioid use at 1 year after lumbar spine surgery and establish a threshold for steps/day to inform clinical practice., Design: Secondary analysis from randomized controlled trial., Setting: Two academic medical centers in the United States., Participants: We enrolled 248 participants undergoing surgery for a degenerative lumbar spine condition (N=248). A total of 212 participants (mean age, 62.8±11.4y, 53.3% female) had valid walking data at baseline., Interventions: Not applicable., Main Outcome Measures: Disability (Oswestry Disability Index), back and leg pain (Brief Pain Inventory), and opioid use (yes vs no) were assessed at baseline and 1 year after surgery. "Best outcome" was defined as Oswestry Disability Index ≤20, back pain ≤2, and leg pain ≤2. Steps/day (walking) was assessed with an accelerometer worn for at least 3 days and 10 h/d at 6 weeks after spine surgery, which was considered as study baseline. Separate multivariable logistic regression analyses were conducted to determine the association between steps/day at 6 weeks and "best outcome" and no opioid use at 1-year. Receiver operating characteristic curves identified a steps/day threshold for achieving outcomes., Results: Each additional 1000 steps/d at 6 weeks after spine surgery was associated with 41% higher odds of achieving "best outcome" (95% confidence interval [CI], 1.15-1.74) and 38% higher odds of no opioid use (95% CI, 1.09-1.76) at 1 year. Walking ≥3500 steps/d was associated with 3.75 times the odds (95% CI, 1.56-9.02) of achieving "best outcome" and 2.37 times the odds (95% CI, 1.07-5.24) of not using opioids., Conclusions: Walking early after surgery may optimize patient-reported outcomes after lumbar spine surgery. A 3500 steps/d threshold may serve as an initial recommendation during early postoperative counseling., (Copyright © 2021 The American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Extracts from white birch have been reported to possess antimicrobial properties, but no study has linked the chemical composition of bark extract with antimicrobial activity. This study aimed to identify white birch (Betula papyrifera Marshall) bark extracts with antimicrobial activity and elucidate its composition. In order to obtain the highest extraction yield, bark residues >3 mm were retained for extraction. A total of 10 extraction solvents were used to determine the extraction yield of each of them. Methanol and ethanol solvents extracted a greater proportion of molecules. When tested on eight microorganism species, the water extract proved to have the best antimicrobial potential followed by the methanol extract. The water extract inhibited all microorganisms at low concentration with minimal inhibitory concentration between 0.83 and 1.67 mg/ml. Using ultraperformance liquid chromatography coupled to a time-of-flight quadrupole mass spectrometer, several molecules that have already been studied for their antimicrobial properties were identified in water and methanol extracts. Catechol was identified as one of the dominant components in white birch bark water extract, and its antimicrobial activity has already been demonstrated, suggesting that catechol could be one of the main components contributing to the antimicrobial activity of this extract. Thus, extractives from forestry wastes have potential for new applications to valorize these residues., (© 2019 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.)

Lignocellulosic biomass is a sustainable source of renewable substrate to produce low carbon footprint energy and materials. Biomass conversion is usually performed in two steps: a biomass pretreatment for improving cellulose accessibility followed by enzymatic hydrolysis of cellulose. In this study we investigated the efficiency of a bioextrusion pretreatment (extrusion in the presence of cellulase enzyme) for production of reducing sugars from corn crop agricultural residues. Our results demonstrate that bioextrusion increased the reducing sugar conversion yield by at least 94% at high solid/liquid ratio (14%-40%). Monitoring biomass surface with carbohydrate-binding modules (FTCM-depletion assay) revealed that well known negative impact of high solid/liquid ratio on conversion yield is not due to the lack of exposed cellulose which was abundant under such conditions. Bioextrusion was found to be less efficient on alkaline pretreated biomass but being a mild and solvent limiting pretreatment, it might help to minimize the waste stream., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The continual emergence of pathogen resistance is a recurring challenge and pushes for the development of antimicrobial compounds. Here, we investigated compounds from quaking aspen trees ( Populus tremuloides ) as potential antimicrobial agents. Several extractions using different solvents were realized, and corresponding antimicrobial activity was tested against eight microorganisms. Results revealed that polar extraction solvents including water, ethanol and methanol gave the best extraction yields (>15.07%). Minimal inhibition concentration (MIC) and minimal bactericidal/fungicidal concentration (MBC/MFC) demonstrated that water extracts had the best antimicrobial activity by a weak to moderate inhibition of growth of all eight tested microorganisms in addition to having a bactericidal effect on three of them. The quaking aspen methanol extract also displayed antimicrobial activity but to a lower level than the water extract. Ultra-performance liquid chromatography quadrupole time-of flight mass spectrometry (UPLC-QTOF-MS) analysis led to the identification of 92 compounds, mainly polyphenols in both extracts, with 22 molecules previously known for their antimicrobial properties. According to the relative abundance, 4-hydroxybenzaldehyde (5.44% in methanol extract) and kaempferol (5.03% in water extract) were the most abundant antimicrobial compounds. Among antimicrobial molecules identified, nine were from the flavonoid family. The results of our study demonstrate the interest of using quaking aspen as source of antimicrobial compounds.

Purpose: To compare the dynamic elongation, stiffness behavior, and ultimate failure load of standard with small diameter soft tissue grafts for anterior cruciate ligament (ACL) reconstruction with and without high-strength suture tape reinforcement., Methods: Both a tripled "small" diameter and a "standard" quadrupled tendon graft with and without suture tape reinforcement were tested using suspensory fixation (n = 8 each group). The suture tape was passed through the suspensory fixation button on the femur and tibia to ensure independent (safety belt) fixation from the graft in vitro. The testing of the constructs included position-controlled cyclic loading, force-controlled cyclic loading at 250 N and 400 N as well as pull to failure (50 mm/min)., Results: Reinforcement of a small diameter graft significantly reduced dynamic elongation of 38% (1.46 ± 0.28 mm vs 2.34 ± 0.44 mm, P < .001) and 50% (2.55 ± 0.44 mm vs 5.06 ± 0.67 mm, P < .001) after the 250 N and 400 N load protocol, respectively. Reinforcement of a standard diameter tendon graft decreased dynamic elongation of 15% (1.59 ± 0.34 mm vs 1.86 ± 0.17 mm, P = .066) and 26% (2.62 ± 0.44 mm vs 3.55 ± 0.44 mm, P < .001). No significant difference was found between both reinforced models. The ultimate failure loads of small and standard diameter reinforced grafts were 1592 ± 105 N and 1585 ± 265 N, resulting in a 64% (P < .001) and 40% (P < .001) increase compared with their respective controls., Conclusions: Independent suture tape reinforcement of soft tissue grafts for ACL reconstruction leads to significantly reduced elongation and higher ultimate failure load according to in vivo native ACL function data without stress-shielding the soft tissue graft., Clinical Relevance: If in vitro results are translational to human knees in vivo, the suture tape reinforcement technique for ACL reconstruction may decrease the risk of graft tears, particularly in the case of small diameter soft tissue grafts., (Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

California is home to more than one out of eight American women of reproductive age. Because California has a large, diverse and growing population, national statistics do not necessarily describe the reproductive health of California women. This article presents risk for pregnancy and sexually transmitted infections among women in California based on the California Women's Health Survey. Over 8900 women of reproductive age who participated in this survey between 1998 and 2001 provide estimates of access to care and use of family-planning methods in the state. We find that 49% of the female population aged 18-44 in California is at risk of unintended pregnancy. Nine percent (9%) of women at risk of an unintended pregnancy are not using any method of contraception, primarily for method-related reasons, such as a concern about side effects or a dislike of available contraceptive methods. Among women at risk for unintended pregnancy, we find disparities by race/ethnicity and education in use of contraceptive methods.

Carotid loop (CL) surgery involves the permanent externalization of a common carotid artery in a skin tube. The CL facilitates repeated access to the systemic arterial system for blood sampling and blood pressure measurement in laboratory sheep. It eliminates the need for arterial cut-downs and chronic indwelling catheters, reduces the risk of sepsis and infection, and adds flexibility to research protocols. The surgical procedure is aseptically performed under general anesthesia and involves isolation of the common carotid artery, creation of a bipedicled skin tube, and permanent envelopment of the artery in the skin tube. The primary complication is ischemic necrosis with sloughing of the middle of the loop and is usually due to failure to adhere to the critical length-to-width ratio (2.5:1). We have performed 150 CL procedures with an overall success rate of 94%. Nine CL ablations were required, due to necrosis with exposure of the artery (7/9) or stricture formation with loss of patency (2/9). Twenty-two CLs developed complications secondary to partial necrosis, but did not require ablation. Results indicate that the CL is a reliable method to ensure repeated access to the systemic arterial system in sheep. A modification of the standard CL procedure in which the artery is surrounded by a skin tunnel rather than enclosed in a skin loop was performed in 10 sheep. Preliminary results indicate significant reduction in the incidence of complications associated with the standard CL.

To assess the role of high-frequency ventilator strategy in the propagation of airway injury, we compared the tracheobronchial histologic alterations in 20 newborn piglets ventilated for 8 hours with high-frequency flow interruption (HFFI). Ten animals were assigned to HFFI with a strategy of continuous pulsations at a frequency of 10 Hz and a mean airway pressure of 16 cm H2O. Ten piglets were treated at identical settings except for 10 one-second baseline pauses per minute to a positive end-expiratory pressure of 5 cm H2O. A semiquantitative scoring system was used to grade light microscopic tissue alterations in the trachea, carina, and mainstem bronchi. Ultrastructural changes were evaluated with scanning electron microscopy. The HFFI-continuous-treated piglets had significantly more damage in all areas than the HFFI-baseline pause group (P less than .001). The upper tracheas of animals in both groups were altered to a greater extent than the lower tracheas (P less than .007). In addition, numerous "skip" areas of injury were noted throughout the tracheas. High-frequency ventilator strategy is a determinant of the severity of airway histologic changes. Factors that adversely affect tissue oxygenation or cause direct mechanical trauma may also influence the degree of injury. Optimal operating characteristics and limitations of different high-frequency devices must be assessed before their use in human neonates.

It was hypothesized that diverse mechanisms may influence upper airway injury during mechanical ventilation. To assess the roles of several factors in the propagation of such injury, the tracheobronchial histologic changes in 53 newborn piglets were compared following conventional positive pressure ventilation. Eight animals were assigned to each of four positive pressure ventilation groups at "low" settings (an FiO2 of 0.25, a frequency of 10 breaths per minute, a peak inspiratory pressure of 20 cm H2O, a positive end-expiratory pressure of 4 cm H2O, a flow rate of 10 L/min, and an inspiratory time to expiratory time ratio of 1:2): (1) positive pressure ventilation with no hypotension or hypoxemia; (2) positive pressure ventilation with hypotension; (3) positive pressure ventilation with hypoxemia; and (4) positive pressure ventilation with both hypotension and hypoxemia. In addition, eight piglets were assigned to each of two positive pressure ventilation groups at "high" settings (greater frequency [40 breaths per minute], higher peak inspiratory pressure [40 cm H2O], and greater flow rate [17 L/min]): (1) positive pressure ventilation with no hypotension or hypoxemia; and (2) positive pressure ventilation with both hypotension and hypoxemia. The changes were mild and similar among the first three positive pressure groups at low settings. However, the injury scores of the combined hypotension and hypoxemia group (group 4) were greater than those of the former three positive pressure ventilation groups (P less than .004). The piglets receiving positive pressure ventilation at high settings with no hypotension or hypoxemia (group 5) had no more injury than those in the first three groups receiving positive pressure ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Reported in this paper are pregnancy, delivery, puerperium, premature birth rate as well as perinatal and peripartal mortality in 353 somewhat aged primigravidae (32 years and more) in three groups counted by years. Reference is made to complications during pregnancy, delivery, and puerperium for all three groups of probands (K I between 1959 and 1961, K II between 1969 and 1971, K III between 1977 and 1979). High incidence of EPH gestosis (31.1 per cent), more frequent need for surgical delivery (28.1 per cent), and relatively high premature birth rate (10.5 per cent) were found to be the major problems with elderly primigravidae.