The influence of hydrothermal treatment (HTT) on the hemicellulose, i.e. glucomannan/galactoglucomannan (GM/GGM) and arabinoglucurono-xylan (AGX) in Japanese cedar was examined using mild ...temperatures (95 °C and 120 °C) for its kiln drying. Based on infrared spectra, only a slight change due to HTT was observed in the hemicellulose chemical structure. The quantitative changes of the major chemical components including lignin, cellulose, and hemicellulose also exhibited slight differences among samples. However, the molecular chain-length composition of GM/GGM and AGX in the cell walls decreased clearly with HTT, as well as with an increase in temperature. Also, it was found that the strength of the interaction between cellulose and hemicellulose molecules such as GM/GGM and AGX in cell walls decreased depending on the increase in HTT temperature. These results showed that the polymeric structure of GM/GGM and AGX was degraded by hydrolysis at 95 °C of HTT and proceeded further at 120 °C of HTT.
Parallel grafting presents a viable method for treating patients with complex aortic aneurysms. The current literature is limited to mostly pararenal configurations. We examined our results in ...patients with SMA and/or Celiac artery involvement.
A retrospective analysis was performed for all patients undergoing parallel grafting during the period of 2014 to 2018 at a single institution. All patients had at least SMA with and/or without Celiac artery parallel grafting.
Seventy-nine patients (65% male, median age 74) were treated with 208 parallel grafts. Median ASA score is 4. Forty-nine cases were elective, 22 urgent, and 8 emergent. Mean pre-operative aneurysm diameter was 7.1 cm (4.6-15 cm). Self-expanding covered stents were used for the renal arteries (mean 6.3mm), and balloon-expandable covered stents were used for the SMA and Celiac (mean SMA 8.6 mm, mean celiac 8.3 mm). Axillary exposure was the choice of access in 68 patients (86%). Technical success was achieved in all cases. We defined this as aneurysm sac exclusion with patent visceral stent grafts, and absent to mild gutter leaks. Mean aortic graft proximal seal achieved was 48mm. Coverage extended above the celiac artery in 75% (10% stented and 65% covered). Median contrast volume was 145ml, operative duration was 4 hours, fluoroscopy time was 56 min, and EBL was 250 ml. Perioperative mortality was 6.1%. 4.5%, and 25%, for the elective, urgent, and emergent groups, respectively. There was no incidence of spinal cord ischemia. Axillary access was complicated in 4 patients, requiring patch closure of the axillary artery. One patient developed postprocedural ESRD from a rupture and ATN despite patent renal stents. Of those patients with a patent GDA and celiac coverage, 2 required a cholecystectomy. Nine patients had a persistent gutter leak at the conclusion of the procedure. Median follow-up was 12 months. On follow-up imaging, all SMA and Celiac stents were patent. Six renal stents were occluded and 2 patients progressed to ESRD, both solitary renal periscope configurations at the index procedure. Only 4 patients had persistent gutter leaks with 2 requiring reintervention. Ninety-five percent of patients demonstrated sac regression or stabilization with a mean sac size of 6.5 cm.
Parallel grafting presents a safe, efficacious and off the shelf alternative to conventional repair of complex aortic aneurysms involving the visceral aorta.
We determined whether temporal variation and succession were similar among sites with similar species composition by sampling unmanipulated and cleared plots in a high intertidal assemblage dominated ...by
Endocladia muricata and
Mastocarpus papillatus. Sampling was done for 6 years at six sites spanning over 4° of latitude in California. Ten 1×2-m permanent plots were chosen in the central portion of the assemblage at each site. Four of these served as unmanipulated controls, three were cleared (scraped and burned) in the spring of 1985, and three were cleared in the fall of 1985. The cover of sessile and density of motile species were determined by subsampling within the plots from 1985 until 1991. Recovery of the clearings was determined by their similarity to the controls. The algae
E. muricata,
M. papillatus, and
Fucus gardneri, and the barnacle
Balanus glandula, were the most abundant sessile organisms in the control plots, although the latter never exceeded 12% cover at any site. The grazing gastropods
Littorina scutulata/
plena, various limpets, and
Tegula funebralis were the most common mobile organisms. The species composition of the common species remained constant in the control plots over the study period and there were few large changes in relative abundance. Significant seasonal variation was detected in 11 species but variation was commonly site-specific.
Ephemeral algae were abundant during early succession at only two of the six sites, and barnacle cover was low (<15% cover) at four sites and moderate (15–50% cover) at the remaining two throughout succession. Recovery rate varied considerably among sites and between times of clearing (1–10%/month). Correlations between ephemeral algae and grazer abundance, and between these variables and recovery rate were not significant. The effects of grazers on recovery rate were only evident at one site where they appeared to reduce an initially high cover of ephemeral algae and delay the establishment of perennials. Some of the largest differences in recovery rate were between clearing times, associated with differences in the phenology of the dominant perennial algae. In spite of these differences, most plots recovered by the end of the study period.
These results indicate that the assemblages in the control plots at each site were relatively stable and, while successional pathways and processes varied, the assemblage at most sites still recovered. Current models, based largely on biological interactions, that attempt to explain within assemblage structure and succession were not broadly applicable.
Background
There is a wide ranging incidence of venous thromboembolism after surgery and it continues to be a major cause of morbidity after spinal procedures.This study’s aim was to investigate the ...relationship between timing and administration of venous thromboembolism (VTE) pharmacologic chemoprophylaxis after spinal surgery and the resulting VTE and bleeding complications by reviewing current practices and outcomes at a high-volume single institution to better define opportunities for perioperative intervention to prevent VTE without increasing bleeding complications.
Methods
All patients who underwent elective one or two-stage lumbar spinal fusion procedures were identified. A logistic regression was used to evaluate (1) risk of symptomatic VTE within 30 days of surgery and (2) bleeding-related complications. The odds of developing a VTE as well as bleeding-related complications were compared among the three treatment groups: no chemoprophylaxis, chemoprophylaxis < 24h of surgery and chemoprophylaxis given > 24h post-surgery.
Results
When adjusted for doses administered, the odds of developing a postoperative VTE within 30 days were 0.189 (95% confidence interval (0.044, 0.808)) in patients who received anticoagulation < 24h postoperatively, compared to those who received no anticoagulation (p = 0.025). There was no difference in bleeding rates.
Conclusion
Patients undergoing elective spinal surgery who received anticoagulation within 24h of the conclusion of their procedure had an 81% reduction in the odds of developing a deep vein thrombosis within 30 days with no significant difference in bleeding complications.
Open Surgical Management of Deep Venous Occlusive Disease Kiguchi, Misaki M.; Abramowitz, Steven D.
Techniques in vascular and interventional radiology,
June 2018, 2018-Jun, 2018-06-00, 20180601, Letnik:
21, Številka:
2
Journal Article
Recenzirano
Endovascular techniques have revolutionized the management of deep venous occlusive disease. Open surgery, however, is still required for cases that prove refractory to endovascular interventions. ...The surgical management of deep venous occlusive disease typically involves venous bypass. Preoperative planning before open venous surgery relies upon dynamic imaging to clarify the location and severity of venous obstruction, the assessment of infrainguinal reflux, and the delineation of bypass origination and target vessels. Adjunct arteriovenous fistulas and anticoagulation may improve patency rates of open surgical venous bypass. The timely recognition and management of complications improves secondary patency rates.
Superficial venous disease has a U.S. prevalence of nearly 30%, with advanced disease contributing to a significant healthcare burden. Although the risk factors for venous disease are well known, the ...correlation between race, sex, socioeconomic status, and disease severity on presentation is not well established. The area deprivation index (ADI) is a validated metric with respect to regional geography, social determinants of health, and degree of socioeconomic disadvantage. In the present study, we aimed to identify the disparities and the effect that the ADI, in addition to race and sex, has among patients associated with an advanced venous disease presentation.
A retrospective review between 2012 and 2022 was performed at four tertiary U.S. institutions to identify patients who underwent endovenous closure of their saphenous veins. Patient demographics, state ADI, comorbidities, CEAP (clinical, etiologic, anatomic, pathophysiologic) classification, and periprocedural outcomes were included. Pearson's correlation was performed between the CEAP classification and ADI. Poisson regression analysis was performed to identify factors predicting for an increasing CEAP classification at presentation. Variables with P < .05 were deemed significant.
A total of 2346 patients underwent endovenous saphenous vein closure during the study period, of whom 7 were excluded because of a lack of follow-up data. The mean age was 60.4 ± 14.9 years, 65.9% were women, and 55.4% were White. Of the 2339 patients, 73.3% presented with an advanced CEAP class (≥3). The mean state ADI for the entire cohort was 4.9 ± 3.1. The percent change in the CEAP classification is an increase of 2% and 1% for every level increase in the state ADI for unadjusted (incidence rate ratio IRR = 1.02; P < .001) and adjusted (IRR = 1.01; P < .001) models, respectively. Black race has a 12% increased risk of a higher CEAP class on presentation compared with White race (IRR = 1.12; P = .005). Female sex had a 16% lower risk of a higher CEAP presentation compared with male sex (IRR = 0.84; P < .01).
Low socioeconomic status, Black race, and male sex are predictive of an advanced CEAP classification on initial presentation. These findings highlight the opportunity for improved mechanisms for identification of venous disease and at-risk patients before advanced disease progression in known disadvantaged patient populations.
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Thin film growth of MgO on Ag(0
0
1) was studied using reflection high-energy electron diffraction, Auger electron spectroscopy, electron energy loss spectroscopy (EELS), and ultraviolet ...photoemission spectroscopy (UPS), as a model system of the oxide/metal interface. At a substrate temperature of 450 K, a single-domain MgO film (1
0
0
film//1
0
0
substrate) grew heteroepitaxially on Ag(0
0
1). The in-plane lattice constant of the film changed continuously from the value of the substrate to that of the film, as is the case with the heteroepitaxial growth of alkali halides. The density functional calculations were performed for model clusters in order to investigate the initial adsorption structure. MgO adsorbed preferentially with the O atom above the Ag atom, and the Mg atom on the hollow site. EELS results showed that the band gap energy did not change for MgO thickness from 1 to 20 ML, indicating that the band gap energy of a 1 ML thick MgO film adjacent to a metal substrate was same as that of MgO surface. The UPS results, on the other hand, showed an upward shift of the valence band with decreasing film thickness. These UPS results could be explained by the image charge screening of a hole created by photoionization in the near presence of a metal.
The geometry and chemistry of graphene nanostructures significantly affects their electronic properties. Despite a large number of experimental and theoretical studies dealing with the geometrical ...shape-dependent electronic properties of graphene nanostructures, experimental characterisation of their chemistry is clearly lacking. This is mostly due to the difficulties in preparing chemically-modified graphene nanostructures in a controlled manner and in identifying the exact chemistry of the graphene nanostructure on the atomic scale. Herein, we present scanning probe microscopic and first-principles characterisation of graphene nanostructures with different edge geometries and chemistry. Using the results of atomic scale electronic characterisation and theoretical simulation, we discuss the role of the edge geometry and chemistry on the electronic properties of graphene nanostructures with hydrogenated and oxidised linear edges at graphene boundaries and the internal edges of graphene vacancy defects. Atomic-scale details of the chemical composition have a strong impact on the electronic properties of graphene nanostructures,
i.e.
, the presence or absence of non-bonding π states and the degree of resonance stability.
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