Biodegradable Polymers in Veterinary Medicine-A Review.

During the past two decades, tremendous progress has been made in the development of biodegradable polymeric materials for various industrial applications, including human and veterinary medicine. They are promising alternatives to commonly used non-degradable polymers to combat the global plastic waste crisis. Among biodegradable polymers used, or potentially applicable to, veterinary medicine are natural polysaccharides, such as chitin, chitosan, and cellulose as well as various polyesters, including poly(ε-caprolactone), polylactic acid, poly(lactic-co-glycolic acid), and polyhydroxyalkanoates produced by bacteria. They can be used as implants, drug carriers, or biomaterials in tissue engineering and wound management. Their use in veterinary practice depends on their biocompatibility, inertness to living tissue, mechanical resistance, and sorption characteristics. They must be designed specifically to fit their purpose, whether it be: (1) facilitating new tissue growth and allowing for controlled interactions with living cells or cell-growth factors, (2) having mechanical properties that address functionality when applied as implants, or (3) having controlled degradability to deliver drugs to their targeted location when applied as drug-delivery vehicles. This paper aims to present recent developments in the research on biodegradable polymers in veterinary medicine and highlight the challenges and future perspectives in this area.

Systematic Review and Meta-Analysis of the Incidence of Rupture, Repair, and Death of Small and Large Abdominal Aortic Aneurysms under Surveillance.

BACKGROUND: The ultimate goal of treating patients with abdominal aortic aneurysms (AAAs) is to repair them when the risk of rupture exceeds the risk of repair. Small AAAs demonstrate a low rupture risk, and recently, large AAAs just above the threshold (5.5-6.0 cm) seem to be at low risk of rupture as well. The present review aims to investigate the outcomes of AAAs under surveillance through a comprehensive systematic review and meta-analysis. METHODS: PubMed, Embase, and the Cochrane Central Register were searched (22 March 2022; PROSPERO; #CRD42022316094). The Cochrane and PRISMA statements were respected. Blinded systematic screening of the literature, data extraction, and quality assessment were performed by two authors. Conflicts were resolved by a third author. The meta-analysis of prevalence provided estimated proportions, 95% confidence intervals, and measures of heterogeneity (I2). Based on I2, the heterogeneity might be negligible (0-40%), moderate (30-60%), substantial (50-90%), and considerable (75-100%). The primary outcome was the incidence of AAA rupture. Secondary outcomes included the rate of small AAAs reaching the threshold for repair, aortic-related mortality, and all-cause mortality. RESULTS: Fourteen publications (25,040 patients) were included in the analysis. The outcome rates of the small AAA group (<55 mm) were 0.3% (95% CI 0.0-1.0; I2 = 76.4%) of rupture, 0.6% (95% CI 0.0-1.9; I2 = 87.2%) of aortic-related mortality, and 9.6% (95% CI 2.2-21.1; I2 = 99.0%) of all-cause mortality. During surveillance, 21.4% (95% CI 9.0-37.2; I2 = 99.0%) of the initially small AAAs reached the threshold for repair. The outcome rates of the large AAA group (>55 mm) were 25.7% (95% CI 18.0-34.3; I2 = 72.0%) of rupture, 22.1% (95% CI 16.5-28.3; I2 = 25.0%) of aortic-related mortality, and 61.8% (95% CI 47.0-75.6; I2 = 89.1%) of all-cause mortality. The sensitivity analysis demonstrated a higher rupture rate in studies including <662 subjects, patients with a mean age > 72 years, >17% of female patients, and >44% of current smokers. CONCLUSION: The rarity of rupture and aortic-related mortality in small AAAs supports the current conservative management of small AAAs. Surveillance seems indicated, as one-fifth reached the threshold for repair. Large aneurysms had a high incidence of rupture and aortic-related mortality. However, these data seem biased by the sparse and heterogeneous literature overrepresented by patients unfit for surgery. Specific rupture risk stratified by age, gender, and fit-for-surgery patients with large AAAs needs to be further investigated.

Fast strain mapping in abdominal aortic aneurysm wall reveals heterogeneous patterns.

Abdominal aortic aneurysm patients are regularly monitored to assess aneurysm development and risk of rupture. A preventive surgical procedure is recommended when the maximum aortic antero-posterior diameter, periodically assessed on two-dimensional abdominal ultrasound scans, reaches 5.5 mm. Although the maximum diameter criterion has limited ability to predict aneurysm rupture, no clinically relevant tool that could complement the current guidelines has emerged so far. In vivo cyclic strains in the aneurysm wall are related to the wall response to blood pressure pulse, and therefore, they can be linked to wall mechanical properties, which in turn contribute to determining the risk of rupture. This work aimed to enable biomechanical estimations in the aneurysm wall by providing a fast and semi-automatic method to post-process dynamic clinical ultrasound sequences and by mapping the cross-sectional strains on the B-mode image. Specifically, the Sparse Demons algorithm was employed to track the wall motion throughout multiple cardiac cycles. Then, the cyclic strains were mapped by means of radial basis function interpolation and differentiation. We applied our method to two-dimensional sequences from eight patients. The automatic part of the analysis took under 1.5 min per cardiac cycle. The tracking method was validated against simulated ultrasound sequences, and a maximum root mean square error of 0.22 mm was found. The strain was calculated both with our method and with the established finite-element method, and a very good agreement was found, with mean differences of one order of magnitude smaller than the image spatial resolution. Most patients exhibited a strain pattern that suggests interaction with the spine. To conclude, our method is a promising tool for investigating abdominal aortic aneurysm wall biomechanics as it can provide a fast and accurate measurement of the cyclic wall strains from clinical ultrasound sequences.

One-year volume growth of abdominal aortic aneurysms measured by extended field-of-view ultrasound.

BACKGROUND: Measurement of volume has the potential to detect subtle growth not recognized in the current surveillance paradigm of abdominal aortic aneurysms (AAAs). Currently available three-dimensional ultrasound allows for estimation of AAA volume, but for most patients, the AAA extends beyond the ultrasound field-of-view and only allows visualization of a partial AAA volume. A new extended field-of-view three-dimensional ultrasound protocol (XFoV US) has been found to improve the proportion of patients with visualization of the full AAA volume. METHODS: To investigate the applicability of the XFoV US protocol in estimating AAA volume growth in follow-up, 86 patients with AAAs were recruited from the surveillance program at a university hospital. All were imaged by XFoV US at baseline and at one-year follow-up. RESULTS: Assessment of full volume, based on visualization of the AAA neck and bifurcation at both baseline and one-year follow-up, was achieved in 67/86 (78%) of patients. One-year mean growth in maximum diameter was 2.8 mm (6%/year), in centerline length 2.9 mm (4%/year), and in volume 15.9 mL (19%/year). In 17/67 (25%) of patients, volume growth was detected in diameter-stable AAAs. Baseline XFoV US volume was associated with one-year AAA volume growth, while, conversely, maximum baseline diameter was not associated with one-year AAA diameter growth. CONCLUSIONS: This study concludes that the XFoV US protocol provides a safe and repeatable modality for assessing AAA volume growth, and that AAA volume is a promising predictive measure of AAA growth.

Limb graft occlusion after endovascular aneurysm repair with the Cook Zenith Alpha abdominal graft.

OBJECTIVE: Prior reports of the low profile Zenith Alpha abdominal graft (Cook Medical Inc, Bloomington, IN) have shown impaired limb graft patency to be the primary causes of reintervention. Special notices from the manufacturer have indicated certain instructions for use (IFU) violations as the main reasons for these complications. In the present study, we assessed the incidence of limb graft occlusion (LGO) and analyzed the effects of the detailed anatomic risk factors for LGO highlighted in the IFU and previously reported studies. METHODS: A retrospective study was performed of 241 patients treated with the low profile Zenith Alpha at a single institution from October 1, 2015 to September 30, 2018. All computed tomography angiograms were analyzed using three-dimensional software. Data were extracted from the electronic medical records until the end of the study period (December 31, 2020). The cumulative incidence of LGO and LGO-related reinterventions were assessed. A regression analysis was performed to evaluate the possible risk factors associated with the development of LGO at specified time points. These included aortic and iliac diameters, graft component oversizing, iliac tortuosity and calcification, overlap of graft components, proximal alignment of ipsilateral and contralateral legs, and sealing zone in the external iliac artery. Reader agreement of iliac calcification and tortuosity was assessed in patients with LGO. RESULTS: A total of 33 limbs (7%) in 27 patients (11%) had become occluded. The cumulative incidence of LGO was 7% (95% confidence interval [CI], 5%-9%) per limb up to 3 years postoperatively. The previously described risk factors for LGO were studied using regression analysis; however, no positive association with LGO was identified. Heavily calcified common iliac arteries (CIAs) and external iliac arteries were protective against LGO compared with noncalcified vessels up to 3 years postoperatively (decreased risk, 17% [95% CI, -27% to -7%]; P = .001; and 15% [95% CI, -26 to -5]; P = .005, respectively). The reader agreement of iliac calcification and tortuosity showed substantial agreement (CIA intrareader kappa = 0.75; CIA interreader kappa = 0.62) and almost perfect agreement (intrareader kappa = 0.85; interreader kappa = 0.84), respectively. CONCLUSIONS: The cumulative incidence of LGO after endovascular aneurysm repair with the Zenith Alpha graft was 7% per limb up to 3 years postoperatively. None of the analyzed risk factors suggested by the IFUs or current literature were positively associated with LGO.

Anticoagulants and reduced thrombus load in abdominal aortic aneurysms assessed with three-dimensional contrast-enhanced ultrasound examination.

OBJECTIVE: The relationship between intraluminal thrombus (ILT) and abdominal aortic aneurysm (AAA) growth and rupture risk remains ambiguous. Studies have shown a limited effect of antiplatelet therapy on ILT size, whereas the impact of anticoagulant therapy on ILT is unresolved. This study aims to evaluate an association between antithrombotic therapy and ILT size assessed with three-dimensional contrast-enhanced ultrasound (3D-CEUS) examination in a cohort of patients with AAA. METHODS: In a cross-sectional study, 309 patients with small AAAs were examined with 3D-CEUS. Patients were divided into three groups based on prescribed antithrombotic therapy: anticoagulant (n = 36), antiplatelet (n = 222), and no antithrombotic therapy (n = 51). Patient ILT size was calculated in volume and thickness and compared between the three groups. RESULTS: Patients on anticoagulants had a significantly lower estimated marginal mean ILT volume of 16 mL (standard error [SE], ±3.2) compared with 28 mL (SE, ±2.7) in the no antithrombotic group and 30 mL (SE, ±1.3) in the antiplatelet group when adjusting for AAA volume (P < .001) and comorbidities (P < .001). In addition, patients on anticoagulant therapy had significantly lower estimated marginal mean ILT thickness of 10 mm (SE, ±1.1) compared with 13 mm (SE, ±0.9) in the no antithrombotic group of and 13mm (SE, ±0.4) in the antiplatelet group when adjusting for AAA diameter (P = .03) and comorbidities (P = .035). CONCLUSIONS: A 3D-CEUS examination is applicable for ILT assessment and demonstrates that patients with AAA on anticoagulant therapy have lower ILT thickness and volume than patients with AAA on antiplatelet therapy and those without antithrombotic therapy. Causality between anticoagulants and ILT size, and extrapolation to AAA growth and rupture risk, is unknown and merits further investigations, to further nuance US-based AAA surveillance strategy.

Bioethanol Production from Lignocellulosic Biomass-Challenges and Solutions.

Regarding the limited resources for fossil fuels and increasing global energy demands, greenhouse gas emissions, and climate change, there is a need to find alternative energy sources that are sustainable, environmentally friendly, renewable, and economically viable. In the last several decades, interest in second-generation bioethanol production from non-food lignocellulosic biomass in the form of organic residues rapidly increased because of its abundance, renewability, and low cost. Bioethanol production fits into the strategy of a circular economy and zero waste plans, and using ethanol as an alternative fuel gives the world economy a chance to become independent of the petrochemical industry, providing energy security and environmental safety. However, the conversion of biomass into ethanol is a challenging and multi-stage process because of the variation in the biochemical composition of biomass and the recalcitrance of lignin, the aromatic component of lignocellulose. Therefore, the commercial production of cellulosic ethanol has not yet become well-received commercially, being hampered by high research and production costs, and substantial effort is needed to make it more widespread and profitable. This review summarises the state of the art in bioethanol production from lignocellulosic biomass, highlights the most challenging steps of the process, including pretreatment stages required to fragment biomass components and further enzymatic hydrolysis and fermentation, presents the most recent technological advances to overcome the challenges and high costs, and discusses future perspectives of second-generation biorefineries.

Reactivity of Waterlogged Archeological Elm Wood with Organosilicon Compounds Applied as Wood Consolidants: 2D 1H-13C Solution-State NMR Studies.

Some organosilicon compounds, including alkoxysilanes and siloxanes, proved effective in stabilizing the dimensions of waterlogged archaeological wood during drying, which is essential in the conservation process of ancient artifacts. However, it was difficult to determine a strong correlation between the wood stabilizing effect and the properties of organosilicon compounds, such as molecular weight and size, weight percent gain, and the presence of other potentially reactive groups. Therefore, to better understand the mechanism behind the stabilization effectiveness, the reactivity of organosilicons with wood polymers was studied using a 2D 1H-13C solution-state NMR technique. The results showed an extensive modification of lignin through its demethoxylation and decarbonylation and also the absence of the native cellulose anomeric peak in siloxane-treated wood. The most substantial reactivity between wood polymers and organosilicon was observed with the (3-mercaptopropyl)trimethoxysilane treatment, showing complete removal of lignin side chains, the lowest syringyl/guaiacyl ratio, depolymerization of cellulose and xylan, and reactivity with the C6 primary hydroxyls in cellulose. This may explain the outstanding stabilizing effectiveness of this silane and supports the conclusion that extensive chemical interactions are essential in this process. It also indicates the vital role of a mercapto group in wood stabilization by organosilicons. This 2D NMR technique sheds new light on the chemical mechanisms involved in organosilicon consolidation of wood and reveals what chemical characteristics are essential in developing future conservation treatments.

Effects of Biological and Chemical Degradation on the Properties of Scots Pine Wood-Part I: Chemical Composition and Microstructure of the Cell Wall.

Research on new conservation treatment for archaeological wood requires large amounts of wooden material. For this purpose, artificial wood degradation (biological-using brown-rot fungus Coniophora puteana, and chemical-using NaOH solution) under laboratory conditions was conducted to obtain an abundance of similar samples that mimic naturally degraded wood and can serve for comparative studies. However, knowledge about its properties is necessary to use this material for further study. In this study, the chemical composition and microstructure of degraded cell walls were investigated using FT-IR, XRD, helium pycnometry and nitrogen absorption methods. The results show that biological degradation caused the loss of hemicelluloses and celluloses, including the reduction in cellulose crystallinity, and led to lignin modification, while chemical degradation mainly depleted the amount of hemicelluloses and lignin, but also affected crystalline cellulose. These changes affected the cell wall microstructure, increasing both surface area and total pore volume. However, the chemical degradation produced a greater number of mesopores of smaller size compared to fungal decomposition. Both degradation processes weakened the cell wall's mechanical strength, resulting in high shrinkage of degraded wood during air-drying. The results of the study suggest that degraded wood obtained under laboratory conditions can be a useful material for studies on new consolidants for archaeological wood.

Midterm outcomes of aneurysm repair with the Cook Zenith Alpha abdominal endovascular graft.

OBJECTIVE: Outcome reports after endovascular aneurysm repair (EVAR) using the low-profile Zenith Alpha Abdominal Endovascular grafts (Cook Medical, Bjæverskov, Denmark) are sparse. We present results from a single-center cohort treated with the Zenith Alpha, from a period where the graft was the primary EVAR device choice. The aim of the study was to evaluate short- and midterm outcomes of patients treated with the Zenith Alpha. METHODS: A retrospective single-center study was performed including all patients treated with the Zenith Alpha graft from October 1, 2015 to September 30, 2018. All patients underwent computed tomography angiography (CTA) imaging preoperatively as well as at 3 and 12 months postoperatively. Hereafter, patients were followed yearly with duplex ultrasound and clinical exams. Additional imaging was performed on indication. All CTAs were analyzed using three-dimensional reconstruction software (Aquarius, TeraRecon, Durham, NC). Data was extracted from electronic charts according to a protocol that remained unchanged until the end of the study (December 31, 2020). The following outcomes were assessed according to Society for Vascular Surgery/International Society of Cardiovascular Surgeons reporting criteria: aortic-related and all-cause mortality, reinterventions, instruction for use (IFU) violations, endoleaks (ELs), and aneurysm shrinkage. RESULTS: A total of 241 patients were treated with the Zenith Alpha, and 214 (89%) were asymptomatic repairs. Technical success was achieved in 238 patients (99%). One hundred fifty-seven patients (65%) received implantation outside IFU. The median hospital length of stay was 2 days (interquartile range, 2-3 days). The median clinical follow-up was 35.1 months (interquartile range, 28.8-47.5 months). The 4-year Kaplan-Meier estimate of freedom from reintervention was 66% (95% confidence interval, 59%-73%). The main reasons for reinterventions were iliac limb stenosis and occlusion (n = 30; 12%) and type 2 EL (n = 13; 5%). Overall, significantly more patients with grafts implanted outside distal IFU developed type 1B ELs (n = 10/11; P = .009). Aneurysm sac shrinkage was observed in 48 patients (25%) 1 year postoperatively. The Kaplan-Meier estimate of freedom from aortic-related mortality was 99% (95% confidence interval, 98%-100%) 4 years postoperatively. CONCLUSIONS: EVAR with the Zenith Alpha shows acceptable freedom from aortic-related mortality up to 4 years postoperatively. The majority of patients were treated outside IFU, and significantly more type 1B ELs appeared in this subgroup of patients. The leading cause for reintervention was impaired limb patency. The root cause for impaired limb patency requires further investigation.

Profiling abdominal aortic aneurysm growth with three-dimensional ultrasound.

BACKGROUND: Profiling is a new method based on three-dimensional ultrasound (3D-US) allowing for direct comparison of baseline and follow-up diameters along the AAA length. This study aimed to evaluate the feasibility of profiling to visualize AAA changes at submaximum diameters, and to categorize the growth profiles. METHODS: This is a retrospective analysis of prospectively and consecutively included patients under AAA surveillance at a tertiary referral center. 3D-US images of AAAs at baseline and at one-year follow-up were segmented, generating a centerline and a mesh of the aneurysm geometry. The mesh was processed to illustrate diameter changes of a given AAA. Three growth profiles were identified: 1) peak growth (the largest, significant [≥3.6 mm] diameter difference occurred within a 10 mm margin to either side of the maximum baseline diameter); B) edge growth (at least one significant diameter difference and the criteria for peak growth did not apply); and 3) no growth (all diameter differences were nonsignificant). A centerline length of ≥60 mm was assumed to capture a comparable segment of the wall geometry at baseline and follow-up. Cohen's kappa and Kaplan Meier analysis were used to analyze data. RESULTS: In total, 186 patients had growth profiles generated. Of these, 28 (15%) were discarded, mainly based on inadequate centerline lengths (N.=21, 11.3%). The remaining patients were categorized into edge growth (N.=83, 52%), no growth (N.=47, 30%), and peak growth (N.=28, 18%). CONCLUSIONS: Profiling interprets AAA growth at submaximum diameters. Half of the cohort had edge growth. These AAAs risk being classified as stable.

Factors That Affect the Mechanical Strength of Archaeological Wood-A Case Study of 18th-Century Wooden Water Pipes from Bóznicza Street in Poznan, Poland.

Large amounts of archaeological wood are often excavated during groundworks in cities and towns. Part of the unearthed artefacts is usually saved, conserved and then presented in museums. However, if the finding contains several similar objects, some of them could potentially be further employed for some other practical purposes. The research aimed to determine the mechanical performance of the remains of wooden water mains excavated at Bóznicza street in Poznan, Poland and evaluate its potential usefulness for any practical purposes. First, wood density was determined along with its mechanical strength in compression. The density of archaeological wood identified as Scots pine was lower than contemporary pinewood (383 kg × m-3 vs. 572 kg × m-3); therefore, its mechanical properties in compression tests were also lower, as expected, making the wood unsuitable for any practical applications. However, the differences in modulus of elasticity and compressive strength were not justified by the differences in wood density. Further infrared spectroscopy and X-ray diffraction analyses revealed additional differences in chemical composition and cellulose crystallinity between archaeological and contemporary wood. The results indicated the decrease in carbohydrate content and cellulose crystallinity in degraded wood, which, in addition to wood density, apparently contribute to the deterioration in mechanical strength of archaeological wood. The case study of the excavated archaeological wooden pipes shows that they have historical value but are not useful for practical purposes. It also revealed that not only wood density but also its chemical composition and cellulose crystallinity level has a substantial impact on the wood mechanical properties, particularly in compression.

The Viscoelastic Behaviour of Waterlogged Archaeological Wood Treated with Methyltrimethoxysilane.

Waterlogged wood treatment with methyltrimethoxysilane (MTMS) proved effective in stabilising wood dimensions upon drying (anti-shrink efficiency of 76-93%). Before the method can be proposed as a reliable conservation treatment, further research is required that includes the evaluation of the mechanical properties of treated wood. The aim of the study was to characterise the effect of the treatment on the viscoelastic behaviour of archaeological waterlogged elm and oak wood differing in the degree of degradation. Dynamic mechanical analysis in the temperature range from -150 to +150 °C was used for the study. To better understand the viscoelastic behaviour of the treated wood, pore structure and moisture properties were also investigated using Scanning Electron Microscopy, nitrogen sorption, and Dynamic Vapour Sorption. The results clearly show that methyltrimethoxysilane not only prevents collapse and distortions of the degraded cell walls and decreases wood hygroscopicity (by more than half for highly degraded wood), but also reinforces the mechanical strength by increasing stiffness and resistance to deformation for heavily degraded wood (with an increase in storage modulus). However, the MTMS also has a plasticising effect on treated wood, as observed in the increased value of loss modulus and introduction of a new tan δ peak). On the one hand, methyltrimethoxysilane reduces wood hygroscopicity that reflects in lower wood moisture content, thus limiting the plasticising effect of water on wood polymers, but on the other hand, as a polymer itself, it contributes to the viscous behaviour of the treated wood. Interestingly, the effect of silane differs with both the wood species and the degree of wood degradation.

Comparison of Contemporary Elm (Ulmus spp.) and Degraded Archaeological Elm: The Use of Dynamic Mechanical Analysis Under Ambient Moisture Conditions.

This paper describes dynamic mechanical analysis (DMA) experiments on archaeological and contemporary elm tested under air-dry conditions, to explore the suitability of this technique for increasing understanding of the viscoelastic behaviour of archaeological wood. A strong reduction of storage modulus of archaeological elm (AE) was seen in comparison with contemporary wood (CE), resulting from the high degree of wood degradation, notably the reduction in hemicelluloses and cellulose content of AE, as demonstrated by Attenuated Total Reflection-Fourier Transform Infra-Red spectroscopy (ATR-FTIR). The γ relaxation peak was observed in all samples. The γ peak in AE shifted to a higher temperature, and the activation energy for γ-peak motions was lower in AE (29 kJ/mol) than in CE (50 kJ/mol) indicating that motion is less restricted within the degraded AE cell wall, or possibly a difference in the monomer undergoing rotation. Detection of changes in storage modulus are well known, but the DMA temperature scan technique proved to be useful for probing the degree of wood degradation, relating to the changes in location and intensity of secondary relaxation peaks. The γ peak in loss factor can be used to confirm that cell wall degradation is at an advanced stage, and to improve understanding of the internal spatial structure of the degraded wood cell wall.

Prevention of anastomotic leak following surgical treatment for rectal cancer.

INTRODUCTION: Anastomotic leak (AL) is a major complication to surgical treatment of colorectal cancer affecting approximately 12% of patients. AL is associated with a 6-30% mortality. Finding methods that may reduce the incidence of AL is therefore important. In this study, we aimed to examine the effect of mechanical bowel preparation (MBP) and oral antibiotics on the rate of AL. METHODS: This was a retrospective, single-centre analysis of patients undergoing surgical treatment for rectal cancer. We included 150 consecutive patients treated from July 2014 to October 2018. From June 2017 onwards, 50 patients comprised the study group (receiving MBP and oral antibiotics), while the preceding 100 patients served as a control group (receiving a rectal enema). RESULTS: Two cases (4%) of AL were found in the study group and 20 cases (20%) in the control group (p lesser-than 0.01). Converting from laparoscopy to open surgery or having a World Health Organization performance score 2-3 were also associated with AL in univariate analysis. CONCLUSION: Administrating MBP and oral antibiotics prior to surgery seems to reduce the incidence of AL following rectal cancer surgery. FUNDING: none. TRIAL REGISTRATION: not relevant.

Natural Compounds for Wood Protection against Fungi-A Review.

Wood is a renewable, versatile material with multiple applications and the largest terrestrial pool of sequestered carbon. However, it is susceptible to degradation, mainly caused by wood-decaying fungi. Since several traditional wood preservatives have been banned owing to their detrimental effects on humans and the environment, extending the lifespan of wood products using new generation natural preservatives is an imperative from the perspectives of human health and environmental protection. Several natural compounds of plant and animal origin have been tested for their fungicidal properties, including essential oils, tannins, wood extractives, alkaloids, propolis or chitosan; and their enormous potential in wood protection has been shown. Although they are not free of limitations, the potential methods to overcome their drawbacks and enhance their bioactivity already exist, such as co-impregnation with different polymers, cross-linkers, metal chelators or antioxidants. The presence of the discrepancies between laboratory tests and the field performance, as well as legislation-related problems resulting from the lack of standards defining the quality and performance of natural protective formulations, however, create an urgent need for further thorough research and arrangements. The collaboration with other industries interested in the utilisation of natural active compounds will reduce the associated costs, thus, will facilitate the successful implementation of alternative antifungal agents.

Moisture-Dependent Strength Properties of Thermally-Modified Fraxinus excelsior Wood in Compression.

European ash (Fraxinus excelsior L.) is one of the species commonly used for wood thermal modification that improves its performance. The presented research aimed to investigate a moisture-dependent strength anisotropy of thermally-modified European ash in compression. Wood samples were modified at 180 °C and 200 °C. Their mechanical parameters were determined in the principal anatomical directions under dry (moisture content of 3%) and wet (moisture content above fibre saturation point) conditions. Effect of heat treatment temperature and moisture content on the ash wood mechanical parameters concerning each anatomical direction were determined. The results show that thermal treatment kept the intrinsic anisotropy of wood mechanical properties. It decreased wood hygroscopicity, which resulted in improved strength and elasticity measured for wet wood when compared to untreated and treated samples. Higher treatment temperature (200 °C) increased wood elasticity in compression in all the anatomical directions despite wood moisture content during the measurements. Multivariate analysis revealed that the modification temperature significantly affected the modulus of elasticity perpendicular to the grain, while in the case of compression strength, the statistically significant effect was observed only parallel to the grain. The results obtained can be useful from an industrial perspective and can serve as part of a database for further modelling purposes.

Organosilicons of different molecular size and chemical structure as consolidants for waterlogged archaeological wood - a new reversible and retreatable method.

Ineffectiveness of the chemicals applied so far for waterlogged wood conservation created the need to develop new more, efficient and reliable agents. As an alternative, a new method with the use of organosilicon compounds differing in chemical composition and molecular weight has been investigated. The results obtained show the potential of organosilicons as consolidants in waterlogged wood conservation able to effectively stabilise wood dimensions upon drying. The best wood stabilisers were low-molecular organosilicons enable to penetrate the cell wall as well as chemicals with functional groups capable of interacting with wood polymers and forming stabilising coatings on the cell wall surface. The best anti-shrink efficiency values were obtained for (3-Mercaptopropyl)trimethoxysilane, (3-Aminopropyl)triethoxysilane, 1,3-Bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, reaching 98, 91 and 91%, respectively. Most of the applied organosilicons reduced wood hygroscopicity, which limits the risk of further dimensional changes of wood exposed to a variable air moisture content and potentially reduces wood biodegradation. In the light of our studies, the proposed method of waterlogged wood conservation with organosilicons is potentially reversible in the case of siloxanes and amino-silanes as well as retreatable, which complies with the requirements of the conservation ethics.

Perigraft seroma penetrating the aortic sac and rupturing into the intraperitoneal cavity.

We present a case of a 66-year-old woman who developed perigraft seroma after having undergone elective, open abdominal aortic aneurysm repair with a polytetrafluoroethylene graft 5 years previously. One year after graft implantation, she started to suffer from abdominal discomfort and was therefore offered surgical intervention, which she declined owing to the fear of postoperative complications. Instead, an observational strategy was used. Five years later, the patient presented with sudden severe abdominal pain. Subsequent laparotomy revealed that the pseudomembrane lining the perigraft seroma had penetrated through the native aortic wall and into the intraperitoneal cavity, where it had ruptured. The patient was successfully treated by replacing the polytetrafluoroethylene graft with a polyethylene terephthalate (Dacron) graft.

Natural decay of archaeological oak wood versus artificial degradation processes - An FT-IR spectroscopy and X-ray diffraction study.

Wood has been extensively used as a material for different applications over the years, therefore the understanding of different degradation processes in various environments is of great importance. In this study, the infrared spectroscopy, X-ray diffraction and chemometric methods were used to evaluate and compare the structure of archaeological and artificially degraded oak wood. The results clearly show that modifications in the structure of archaeological wood are related to the position of the material in the log (sapwood and heartwood), thus the extent of wood degradation. To identify the possible factors influencing these effects, the control wood samples were exposed to artificial white rot biodegradation with Coriolus (Trametes) versicolor and to alkali treatment (with NaOH solution). Due to the structural similarities between biodegraded wood and control or archaeological samples, this type of decay is likely to occur during natural ageing along with degradation produced by other environmental factors. Further, no real similarity was identified between the alkali treated wood and archaeological samples, indicating that such degradation does not affect wood under natural conditions.