Statistical Comparison of Substructures in Pure Aluminum Before and After Creep Deformation, Based on EBSD Image Data.

Electron backscatter diffraction (EBSD) images of extruded pure aluminum were statistically analyzed to investigate creep-induced subgrain structures after applying two different levels of creep stress, corresponding to the power law (PL) and power-law breakdown (PLB) regimes. Kernel average misorientation analysis of EBSD measurements revealed 2D morphologies, which were subdivided by a multi-step segmentation procedure into subgranular arrangements. Various descriptors were employed to characterize the "subgrains" quantitatively, including their size, shape, spatial arrangement, and crystallographic orientation. In particular, the analysis of the orientations of subgrains was conducted by neglecting rotations around the loading axis. This approach facilitated the individual investigation of the {001} and {111} subgrain families with respect to the loading axis for two investigated stress levels plus a reference specimen. For the PL regime, the statistical analysis of subgrain descriptors computed from segmented image data revealed a similar degree of strain accumulation for {111} and {001} subgrains. In contrast, for the PLB regime, the analyzed descriptors indicate that {111} subgrains tend to accumulate significantly more strain than {001} ones. These observations suggest that the mechanisms leading to PLB may be associated with strain localization dependent on intergranular stress, hindering the recovery process within {111} grains.

Microporous Polylactic Acid Scaffolds Enable Fluorescence-Based Perfusion Imaging of Intrinsic In Vivo Vascularization.

In vivo tissue engineering (TE) techniques like the AV loop model provide an isolated and well-defined microenvironment to study angiogenesis-related cell interactions. Functional visualization of the microvascular network within these artificial tissue constructs is crucial for the fundamental understanding of vessel network formation and to identify the underlying key regulatory mechanisms. To facilitate microvascular tracking advanced fluorescence imaging techniques are required. We studied the suitability of microporous polylactic acid (PLA) scaffolds with known low autofluorescence to form axial vascularized tissue constructs in the AV loop model and to validate these scaffolds for fluorescence-based perfusion imaging. Compared to commonly used collagen elastin (CE) scaffolds, the total number of vessels and cells in PLA scaffolds was lower. In detail, CE-based constructs exhibited significantly higher vessel numbers on day 14 and 28 (d14: 316 ± 53; d28: 610 ± 74) compared to the respective time points in PLA-based constructs (d14: 144 ± 18; d28: 327 ± 34; each p < 0.05). Analogously, cell counts in CE scaffolds were higher compared to corresponding PLA constructs (d14: 7661.25 ± 505.93 and 5804.04 ± 716.59; d28: 11211.75 + 1278.97 and 6045.71 ± 572.72, p < 0.05). CE scaffolds showed significantly higher vessel densities in proximity to the main vessel axis compared to PLA scaffolds (200-400 µm and 600-800 µm on day 14; 400-1000 µm and 1400-1600 µm on day 28). CE scaffolds had significantly higher cell counts on day 14 at distances from 800 to 2000 µm and at distances from 400 to 1600 µm on day 28. While the total number of vessels and cells in PLA scaffolds were lower, both scaffold types were ideally suited for axial vascularization techniques. The intravascular perfusion of PLA-based constructs with fluorescence dye MHI148-PEI demonstrated dye specificity against vascular walls of low- and high-order branches as well as capillaries and facilitated the fluorescence-based visualization of microcirculatory networks. Fluorophore tracking may contribute to the development of automated quantification methods after 3D reconstruction and image segmentation. These technologies may facilitate the characterization of key regulators within specific subdomains and add to the current understanding of vessel formation in axially vascularized tissue constructs.

PARROT: A Pilot Study on the Open Access Provision of Particle-Discrete Tomographic Datasets.

In the present paper, as part of an interdisciplinary research project (Priority Programme SPP2045), we propose a possible way to design an open access archive for particle-discrete tomographic datasets: the PARROT database (https://parrot.tu-freiberg.de). This archive is the result of a pilot study in the field of particle technology and three use cases are presented for illustrative purposes. Instead of providing a detailed instruction manual, we focus on the methodologies of such an archive. The presented use cases stem from our working group and are intended to demonstrate the advantage of using such an archive with concise and consistent data for potential and ongoing studies. Data and metadata merely serve as examples and need to be adapted for disciplines not concerned here. Since all datasets within the PARROT database and its source code are freely accessible, this study represents a starting point for similar projects.

A single-center retrospective comparison of Duplex ultrasonography versus audible Doppler regarding anterolateral thigh perforator flap harvest and operative times.

INTRODUCTION: We reported on the superiority of preoperative Duplex mapping ("Duplex") over audible Dopplers ("Doppler") in anterolateral thigh perforator (ALT) free flaps for upper extremity reconstruction. To corroborate our findings on a larger cohort, we conducted this present study focusing on surgical efficiency and patient safety. METHODS: 150 consecutive ALT free flaps were divided into 65 cases of preoperative Duplex versus 85 Doppler controls. We first compared patient demographics, operative details, and defect and flap characteristics. We then assessed group differences in the number and course of perforators pursued intraoperatively, flap harvest and operative times, and donor-site complications. Additionally, the impact of the training level of the primary microsurgeon was evaluated. RESULTS: Cases and controls were comparable regarding age (p = .48), sex (p = .81), ASA class (p = .48), and BMI (p = .90). Duplex was associated with an increased likelihood of raising flaps on one single dominant perforator of purely septal course and significant reductions of flap harvest (68 ± 10 min, p < .0001) and operative times (74 ± 16 min, p < .0001), regardless of the experience of the primary microsurgeon. There were strong negative linear correlations between preoperative Duplex and both the flap harvest and operative times (p < .0001). Additionally, while there was no effect on the emergency take-back rate (OR = 1.3, p = .60), revisions were significantly less likely among duplexed patients (OR = 0.15, p = .04). CONCLUSIONS: Preoperative Duplex is associated with a significant reduction in ALT free flap harvest and overall operative times, as well as donor-site revisions as opposed to Doppler planning, regardless of the training level of the primary microsurgeon.

Patients Decision-Making Characteristics Affects Gynecomastia Treatment Satisfaction: A Multicenter Study Using the BODY-Q Chest Module.

BACKGROUND: Patient satisfaction is the most critical outcome in gynecomastia treatment. However, patient satisfaction may be affected by the patient's decision-making trait, such as exhaustively searching for the best outcome or being content with an outcome that satisfies a preconceived requirement. OBJECTIVE: To assess whether patient's decision-making characteristic affect their satisfaction with gynecomastia treatment. METHODS: This was a cross-sectional study including patients treated for gynecomastia between January 2009 and December 2019 at two tertiary hospitals in Denmark. Alive patients were sent the BODY-Q: Chest module, the SF-36 questionnaire, and the Maximizer/Satisficer decision-making survey. Patients were classified as Maximizers if they scored more than 40 points on the Maximizer/Satisficer survey. Percentage score differences (PDs) in quality of life scales were calculated between Maximizers and Satisficers. RESULTS: In total, 192 gynecomastia patients were included in this study and classified as Maximizers (n = 152) or Satisficers (n = 40). Maximizers were younger and more had gynecomastia following abuse of anabolic steroids than Satisficers (p < 0.05). With respect to bodily satisfaction, Maximizers showed significantly worse satisfaction with nipples (PDs: - 12.98%), psychological function (PDs: - 13.68%) and social function (PDs: - 8.77%, p < 0.05). In addition, Maximizers had significantly worse emotional role functioning (- 11.03%), vitality (PDs: - 11.72%) and mental health (PDs: - 10.00%, p < 0.05). CONCLUSION: Patients exhibiting maximizing-type decision-making characteristics have worse satisfaction with gynecomastia treatment and poorer psychosocial health. This information may facilitate patient counseling and alignment of treatment expectations. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A Retrospective Comparative Functional and Aesthetic Outcome Study of Muscle versus Cutaneous Free Flaps for Distal Upper Extremity Reconstruction.

BACKGROUND: Function and cosmesis are crucial in upper extremity reconstruction. Yet, there persists a lack of outcome evaluations, particularly regarding differences between free flap types. METHODS: In a single-center retrospective analysis, outcomes were compared between patients with cutaneous or muscle free flaps for distal upper extremity reconstruction between 2008 and 2018. The Disabilities of Arm, Shoulder and Hand -Score, Michigan-Hand (MHQ), and Short Form 36 Health Survey (SF-36) Questionnaires were assessed, motor function was quantified, and self-reported measures of cosmesis were compared, including the Vancouver Scar-Scale (VSS), MHQ aesthetics-subscale (MAS), and Moscona's cosmetic validation-score (CVS). RESULTS: One-hundred forty-one cases were identified, with a shift toward cutaneous flaps over the study period. Muscle flaps were used for larger defects (251 vs. 142 cm2, p = 0.008). Losses, thromboses, and donor-site complications were equally distributed. Partial necroses were more frequent in muscle flaps (11 vs. 1%, p = 0.015). Seventy patients with 53 cutaneous versus 17 muscle flaps were reexamined. There was no difference in the timing of flap coverage (after 16 vs. 15 days, p = 0.79), number of preceding (2 vs. 1.7, p = 0.95), or subsequent operations (19/53 vs. 5/17, p = 0.77). Patients with cutaneous flaps showed higher grip strength (25 vs. 17 kg, p = 0.046) and reported better hand function (MHQ: 58 vs. 47, p = 0.044) and general health (SF-36: 70 vs. 61, p = 0.040), as well as more favorable appearance (MAS: 71 vs. 57, p = 0.044, CVS: 77 vs. 72, p = 0.048), and scar burden (VSS: 0 vs. 3, p < 0.001). CONCLUSION: Cutaneous flaps yielded better motor function, self-perceived cosmesis, patient satisfaction, and quality of life in our cohort of distal upper extremity reconstructions.

Safety of an Intravenous Formulation of Voriconazole as an Intramuscular Injection in Pigeons (Columba livia f. domestica).

Aspergillosis is a common disease in birds. Currently, avian aspergillosis is treated with voriconazole administered orally, although intramuscular (IM) administration increases bioavailability and is more effective in treating generalized aspergillosis. The objective of this study was to evaluate the safety of the intravenous formulation of voriconazole as an IM injection in the pectoral muscles of pigeons (Columba livia f. domestica) as a model for other avian species. Sixteen healthy pigeons received IM injections of voriconazole (12.5 mg/kg) and sterile saline in the right and left pectoral muscles, respectively, twice a day for 7 days. Additionally, 4 birds acted as controls (no injections). Eight birds in the treatment group and 2 of the control pigeons were humanely euthanized 1 day (group 1) and 14 days (group 2) after the final injection. Hematologic and plasma biochemistry panels were performed prior to the birds being euthanized. Gross and histopathological evaluations of the pectoral muscles were completed postmortem. Statistical analysis revealed significant differences in multiple parameters, including aspartate aminotransferase and lactate dehydrogenase, but all biochemical analytes remained within the reference intervals for the species. The group 1 birds had advanced gross and histopathological pectoral muscle lesions associated with the voriconazole injections compared with the contralateral side, the group 2 birds, and the negative controls. After 14 days, the pectoral muscles did not reveal any gross or histopathological changes associated with the voriconazole or sterile saline injections. These results indicate that the intravenous formulation is safe for IM use twice per day for 1 week in pigeons. Further investigation is needed to extrapolate these findings to other avian species and to evaluate the roles of longer treatment periods and higher doses of voriconazole.

Pore constrictions in intervessel pit membranes provide a mechanistic explanation for xylem embolism resistance in angiosperms.

Embolism spreading in angiosperm xylem occurs via mesoporous pit membranes between vessels. Here, we investigate how the size of pore constrictions in pit membranes is related to pit membrane thickness and embolism resistance. Pit membranes were modelled as multiple layers to investigate how pit membrane thickness and the number of intervessel pits per vessel determine pore constriction sizes, the probability of encountering large pores, and embolism resistance. These estimations were complemented by measurements of pit membrane thickness, embolism resistance, and number of intervessel pits per vessel in stem xylem (n = 31, 31 and 20 species, respectively). The modelled constriction sizes in pit membranes decreased with increasing membrane thickness, explaining the measured relationship between pit membrane thickness and embolism resistance. The number of pits per vessel affected constriction size and embolism resistance much less than pit membrane thickness. Moreover, a strong relationship between modelled and measured embolism resistance was observed. Pore constrictions provide a mechanistic explanation for why pit membrane thickness determines embolism resistance, which suggests that hydraulic safety can be uncoupled from hydraulic efficiency. Although embolism spreading remains puzzling and encompasses more than pore constriction sizes, angiosperms are unlikely to have leaky pit membranes, which enables tensile transport of water.

Allogeneic hematopoietic stem cell transplantation improves long-term outcome for relapsed AML patients across all ages: results from two East German Study Group Hematology and Oncology (OSHO) trials.

Relapse of acute leukemia is a frequent complication with uncertain outcome and poorly defined risk factors. From 1621 patients entered into two prospective clinical trials (AML02; n = 740 and AML04; n = 881), 74.2% reached complete remission (CR) 1 after induction(s) and 59 patients after additional induction ± hematopoietic cell transplantation (HCT). Of the non-refractory patients, 48.4% with a median age of 63 (range 17-85) years relapsed. Relapses occurred within 6 months after CR in 46.5%, between 7 and 18 months in 38.7%, and after 18 months in 14.8% of patients. Relapse treatment resulted in CR2 in 39% of patients depending upon age (54.5% of ≤ 60 and 28.6% of > 60 years), duration of CR1, and treatment of relapse. Overall survival (OS) was 10.9 (7.4-16.2) %, but OS after HCT ± intensive chemotherapy (ICT) was 39.3% (31.8-48.6) at 5 years and not different in younger and older patients. Donor lymphocyte infusion ± chemotherapy and ICT alone resulted only in OS of 15.4% and of 5%, respectively. Independent favorable factors for OS were long CR1 duration, and HCT, while non-monosomal disease was beneficial for OS in elderly patients. Leukemia-free survival [LFS; 24.9 (19.5-31.7) % at 10 years] was affected by similar risk factors. In a competing risk model, the relapse incidence at 5 years was 53.5 ± 3.5% and the non-relapse mortality rate 21.7 ± 2.9%. Lower relapse incidence was observed in patents with HCT, long CR1 duration, and female gender. Risk factors for non-relapse mortality were HCT in younger and type of AML in elderly patients. In conclusion, allogeneic HCT ± IC improved the results in relapsed AML in younger and elderly patients. Increasing CR2 rates and HCT frequency will be the challenge for the next years. Relapse of the disease remains the major problem.

Usutu virus infection in aviary birds during the cold season.

The mosquito-borne flavivirus Usutu virus (USUV) is responsible for countless deaths in both resident populations and birds kept in outdoor aviaries. Since 2001, USUV outbreaks have attracted increased attention due to the rapid geographical spread of the virus and its close relationship to West Nile virus (WNV), an emerging pathogen in humans and animals. Similar to WNV, the USUV enzootic transmission cycle predominantly involves Culex spp. as vectors, whereas birds serve as amplifying reservoir hosts. In Europe, USUV-associated disease outbreaks in birds are almost exclusively described during late spring and early autumn (early April to late October). Contagiousness of virus particles excreted by infected birds has not yet been proven, so that the role of non-vector-borne transmission, as it is known for the closely related WNV, remains unclear. Here we report the diagnosis of USUV infection in 15 of 24 birds from mortality outbreaks that occurred during the cold season between late October 2018 and early April 2019, in eight different aviaries located in Germany. Detection of USUV was performed using standardized molecular biological methods and immunohistochemistry for verification of the infection. USUV infection in a parrot species, a tropical finch and two estrildid finches are reported for the first time. Further research on the occurrence of USUV infection during the cold season is key to understanding the dynamics of viral transmission as well as for a profound health risk assessment for aviary birds as well as humans.

Expression of Connexin43 Stimulates Endothelial Angiogenesis Independently of Gap Junctional Communication In Vitro.

Connexins (Cx) form gap junctions (GJ) and allow for intercellular communication. However, these proteins also modulate gene expression, growth, and cell migration. The downregulation of Cx43 impairs endothelial cell migration and angiogenetic potential. Conversely, endothelial Cx43 expression is upregulated in an in vivo angiogenesis model relying on hemodynamic forces. We studied the effects of Cx43 expression on tube formation and proliferation in HUVECs and examined its dependency on GJ communication. Expectedly, intercellular communication assessed by dye transfer was linked to Cx43 expression levels in HUVECs and was sensitive to a GJ blockade by the Cx43 mimetic peptide Gap27. The proliferation of HUVECs was not affected by Cx43 overexpression using Cx43 cDNA transfection, siRNA-mediated knockdown of Cx43, or the inhibition of GJ compared to the controls (transfection of an empty vector, scrambled siRNA, and the solvent). In contrast, endothelial tube and sprout formation in HUVECs was minimized after Cx43 knockdown and significantly enhanced after Cx43 overexpression. This was not affected by a GJ blockade (Gap27). We conclude that Cx43 expression positively modulates the angiogenic potential of endothelial cells independent of GJ communication. Since proliferation remained unaffected, we suggest that Cx43 protein may modulate endothelial cell migration, thereby supporting angiogenesis. The modulation of Cx43 expression may represent an exploitable principle for angiogenesis induction in clinical therapy.

Superomedial Reduction Mammoplasty Affects Patients' Ability to Breastfeed in a Distinct Manner: A Multicenter Study of 303 Patients.

BACKGROUND: Breast reduction by the superomedial technique can relieve symptoms related to breast hypertrophy; however, as the lateral and inferior portion of the breast parenchyma is removed and displaced, reduction mammoplasty may lead to an impaired ability to breastfeed. OBJECTIVES: The aim of this study was to assess patients' ability to breastfeed after superomedial reduction mammoplasty. METHODS: This was a cross-sectional study including patients treated with superomedial reduction mammoplasty between January 2009 and December 2018 at 2 tertiary hospitals in Denmark. Patients were stratified into 2 cohorts, depending on whether they had experienced childbirth before or after their reduction mammoplasty. Patients were sent specific questionnaires regarding maternity, breastfeeding before and after reduction mammoplasty, nipple sensitivity, and current demographic information. Operative details were retrieved from electronic medical records. RESULTS: In total, 303 patients were identified as eligible for this study (37 patients giving birth after and 266 before reduction mammoplasty). Fewer patients were able to breastfeed exclusively for the recommended 6 months after reduction mammoplasty (2/37, 5.41%) compared with before (92/266, 34.59%; P < 0.05). In addition, fewer patients were able to breastfeed at all after reduction mammoplasty (18/37, 48.64%) compared with before mammoplasty (241/266, 90.60%; P < 0.001). Patients unable to breastfeed after reduction mammoplasty had lower nipple sensitivity and more breast tissue excised (P < 0.05). CONCLUSIONS: Superomedial reduction mammoplasty seems to impair the patient's ability to breastfeed exclusively for the recommended 6 months. Patients of childbearing age considering reduction mammoplasty should be made aware that reduction mammoplasty reduces their breastfeeding capacity.

Age and Body Mass Index Affect Patient Satisfaction Following Reduction Mammoplasty: A Multicenter Study Using BREAST-Q.

BACKGROUND: Reduction mammoplasty effectively improves quality of life for women with macromastia. However, little is known whether surgical- or patient-related factors affect satisfaction. OBJECTIVE: The authors sought to investigate factors associated with altered patient satisfaction following reduction mammoplasty. METHODS: A cross-section study was performed by sending the BREAST-Q Reduction module to all patients who had undergone reduction mammoplasty between January 2009 and December 2018 at 2 tertiary Danish hospitals. Demographics and pre-, peri-, and postoperative details were gathered from electronic medical records. RESULTS: A total of 393 patients returned the questionnaire and were eligible for the study. Increasing age at the time of surgery was associated with higher satisfaction with breasts nipples, headache, psychosocial well-being, and outcome. Increased body mass index at the time of surgery negatively affected satisfaction with breasts and psychosocial well-being. Increase in body mass index after surgery was further associated with lower satisfaction with breasts, nipples, sexual well-being, and more pain in the breast area. Postoperative scar revision and wound infection was more common following inferior pedicle technique than superomedial technique and negatively affected satisfaction with outcome and pain in the breast area. CONCLUSIONS: Patients should be motivated to optimize their weight prior to reduction mammoplasty to achieve optimal satisfaction. Age was associated with improved patient satisfaction, which should considered when operating on younger patients. Postoperative complications affect patient satisfaction, and the superomedial technique seems to be a better choice than the inferior pedicle technique in medium-large breasts.

High porosity with tiny pore constrictions and unbending pathways characterize the 3D structure of intervessel pit membranes in angiosperm xylem.

Pit membranes between xylem vessels play a major role in angiosperm water transport. Yet, their three-dimensional (3D) structure as fibrous porous media remains unknown, largely due to technical challenges and sample preparation artefacts. Here, we applied a modelling approach based on thickness measurements of fresh and fully shrunken pit membranes of seven species. Pore constrictions were also investigated visually by perfusing fresh material with colloidal gold particles of known sizes. Based on a shrinkage model, fresh pit membranes showed tiny pore constrictions of ca. 20 nm, but a very high porosity (i.e. pore volume fraction) of on average 0.81. Perfusion experiments showed similar pore constrictions in fresh samples, well below 50 nm based on transmission electron microscopy. Drying caused a 50% shrinkage of pit membranes, resulting in much smaller pore constrictions. These findings suggest that pit membranes represent a mesoporous medium, with the pore space characterized by multiple constrictions. Constrictions are much smaller than previously assumed, but the pore volume is large and highly interconnected. Pores do not form highly tortuous, bent, or zigzagging pathways. These insights provide a novel view on pit membranes, which is essential to develop a mechanistic, 3D understanding of air-seeding through this porous medium.

Automatic identification of crossovers in cryo-EM images of murine amyloid protein A fibrils with machine learning.

Detecting crossovers in cryo-electron microscopy images of protein fibrils is an important step towards determining the morphological composition of a sample. Currently, the crossover locations are picked by hand, which introduces errors and is a time-consuming procedure. With the rise of deep learning in computer vision tasks, the automation of such problems has become more and more applicable. However, because of insufficient quality of raw data and missing labels, neural networks alone cannot be applied successfully to target the given problem. Thus, we propose an approach combining conventional computer vision techniques and deep learning to automatically detect fibril crossovers in two-dimensional cryo-electron microscopy image data and apply it to murine amyloid protein A fibrils, where we first use direct image processing methods to simplify the image data such that a convolutional neural network can be applied to the remaining segmentation problem. LAY DESCRIPTION: The ability of protein to form fibrillary structures underlies important cellular functions but can also give rise to disease, such as in a group of disorders, termed amyloid diseases. These diseases are characterised by the formation of abnormal protein filaments, so-called amyloid fibrils, that deposit inside the tissue. Many amyloid fibrils are helically twisted, which leads to periodic variations in the apparent width of the fibril, when observing amyloid fibrils using microscopy techniques like cryogenic electron microscopy (cryo-EM). Due to the two-dimensional projection, parts of the fibril orthogonal to the projection plane appear narrower than parts parallel to the plane. The parts of small width are called crossovers. The distance between two adjacent crossovers is an important characteristic for the analysis of amyloid fibrils, because it is informative about the fibril morphology and because it can be determined from raw data by eye. A given protein can typically form different fibril morphologies. The morphology can vary depending on the chemical and physical conditions of fibril formation, but even when fibrils are formed under identical solution conditions, different morphologies may be present in a sample. As the crossovers allow to define fibril morphologies in a heterogeneous sample, detecting crossovers is an important first step in the sample analysis. In the present paper, we introduce a method for the automated detection of fibril crossovers in cryo-EM image data. The data consists of greyscale images, each showing an unknown number of potentially overlapping fibrils. In a first step, techniques from image analysis and pattern detection are employed to detect single fibrils in the raw data. Then, a convolutional neural network is used to find the locations of crossovers on each single fibril. As these predictions may contain errors, further postprocessing steps assess the quality and may slightly alter or reject the predicted crossovers.

Low rate of azole resistance in cases of avian aspergillosis in Germany.

Aspergillosis is the most common fungal disease of the avian respiratory tract. Due to delayed diagnosis and treatment failure, the outcome of these infections is often poor. We investigate 159 cases of avian aspergillosis among captive birds in Germany to define clinical features as well as the frequency of in vitro triazole resistance. Adult birds were more likely to present with clinical signs compared to juvenile birds, and dyspnoea was the most common clinical sign, present in 53% of birds. Molecular species identification indicated that all infections were caused by Aspergillus fumigatus. Only one of 159 independent isolates was azole resistant.

Multiscale Tomographic Analysis for Micron-Sized Particulate Samples.

The three-dimensional characterization of distributed particle properties in the micro- and nanometer range is essential to describe and understand highly specific separation processes in terms of selectivity and yield. Both performance measures play a decisive role in the development and improvement of modern functional materials. In this study, we mixed spherical glass particles (0.4­5.8 µm diameter) with glass fibers (diameter 10 µm, length 18­660 µm) to investigate a borderline case of maximum difference in the aspect ratio and a significant difference in the characteristic length to characterize the system over several size scales. We immobilized the particles within a wax matrix and created sample volumes suitable for computed tomographic (CT) measurements at two different magnification scales (X-ray micro- and nano-CT). Fiber diameter and length could be described well on the basis of the low-resolution micro-CT measurements on the entire sample volume. In contrast, the spherical particle system could only be described with sufficient accuracy by combining micro-CT with high-resolution nano-CT measurements on subvolumes of reduced sample size. We modeled the joint (bivariate) distribution of fiber length and diameter with a parametric copula as a basic example, which is equally suitable for more complex distributions of irregularly shaped particles. This enables us to capture the multidimensional correlation structure of particle systems with statistically representative quantities.

Concepts in Early Reconstruction of the Burned Hand.

BACKGROUND: Early reconstruction of burn sequelae of the hand can be challenging owing to high goals for functional and aesthetic outcome. A variety of reconstructive procedures with ascending levels of complexity exists and warrants careful indication. METHODS: In this case series, the main reconstructive techniques for reconstruction of burn defects of the hand are described, illustrated, and discussed: split thickness skin grafting (STSG) with fibrin glue, dermal matrices with STSG, distant random pattern (abdominal bridge) flap, distant pedicled flap (superficial circumflex iliac artery flap), and free microvascular tissue transfer (anterolateral thigh flap). An algorithm for decision making in the reconstructive process is proposed. RESULTS: Split thickness skin grafting provides sufficient coverage for partial thickness defects without exposure of functional structures; fixation with fibrin glue avoids unnecessary stapling. Dermal matrices under STSG provide vascularized granulation tissue on full thickness defects and can be used as salvage procedure on functional structures. Distant random pattern or pedicled flaps provide sufficient coverage of large full thickness defects with exposed functional structures but pose some challenges regarding patient compliance and immobilization. Free tissue transfer allows tailored reconstruction of large full thickness defects with exposed functional structures and can be safely and feasibly performed. Secondary and tertiary procedures are needed with more complex techniques; if applied correctly and consequently, all methods can yield favorable functional and aesthetic outcomes. CONCLUSIONS: Reconstruction of the burned hand may require a broad armamentarium of surgical techniques with different levels of complexity, versatility, and applicability. Excellent results can be achieved with the right procedure for the right patient.

A comparative study of preoperative color-coded Duplex ultrasonography versus handheld audible Dopplers in ALT flap planning.

INTRODUCTION: The anterior lateral thigh (ALT) flap's vascular variability can lead to complications. Thus, the accuracy of numerous planning modalities has been studied. The clinical relevance of competing mapping methods, however, remains unknown. Therefore, we compared the impact of color-coded Duplex ultrasonography and handheld audible Dopplers on surgical efficacy and flap safety. PATIENTS AND METHODS: Forty-four ALT flaps were included in this comparative retrospective monocentric study. Twelve patients received Duplex scans and 32 flaps were designed using Dopplers only. Patient, defect, and flap characteristics of both groups were analyzed. The effect of either planning method on the primary outcome variables - flap harvest and operative times (HT, OT), course of perforator dissection, incidence of flap loss, emergent re-explorations, and donor-site revisions - was then assessed. RESULTS: Patient, defect, and flap characteristics were comparable between both groups, including flap size (Doppler: 134 ± 73 cm2 , Duplex: 131 ± 65 cm2 , p = .90). There was no flap loss. Emergent re-explorations (Doppler: 4/32, Duplex: 1/12, p = .70) and donor-site revisions (Doppler: 2/32, Duplex: 1/12, p = .81) were equally distributed. Duplex rendered septal perforator dissection 10 times more likely (Chi-Square = 8.9, p = .003, OR = 9.7), reaching 50% (n = 6/12), as opposed to only 9% in the Doppler cohort (n = 3/32). This allowed for highly significant HT and OT reductions of 89 minutes, respectively (p < .01): from 255 and 383 min (Doppler) to 166 and 294 min (Duplex). CONCLUSIONS: Preoperative Duplex significantly reduces harvest and operative times of ALT flaps.

Venous bypass grafts versus arteriovenous loops as recipient vessels for microvascular anastomosis in lower extremity reconstructions: A matched-pair analysis.

BACKGROUND: Limb salvage in patients with peripheral vascular disease (PVD) and soft tissue defects often requires both a restoration of blood flow to the lower extremity and soft tissue coverage. Outcomes of free tissue transfer may be affected by vein grafts, which can be used for the placement of an autologous venous bypass or an arteriovenous (AV) loop leading to different hemodynamic situations. The purpose of this study was to investigate whether free flap anastomosis to a bypass or an AV loop can be performed with comparable results. METHODS: We performed a matched-pair analysis of 22 patients with PVD undergoing free flap reconstructions of the lower extremity with end-to-side anastomosis to an autologous venous bypass (n = 11, 1 female and 10 male patients) or an AV loop (n = 11, 2 female and 9 male patients). Defects caused by trauma, infection, ulcer, or fasciotomy were reconstructed in each group with 5 muscle-based flaps, 3 parascapular flaps, 2 anterolateral thigh (ALT) flaps, and 1 conjoined latissimus dorsi and parascapular flap. Postoperative complications including thromboses, flap failures, wound complications, and hematomas were compared. RESULTS: Postoperative complication rates including 1 venous pedicle thrombosis (9%vs. 0%, P = 1.0), minor (18% vs. 9%, P = 1.0) and major wound complications (45% vs. 27%, P = .69) as well as hematomas (27% vs. 36%, P = 1.0) did not show relevant differences between the groups. Flap failures were absent in both groups. CONCLUSION: In patients with PVD, autologous venous bypass grafts may be used for end-to-side anastomoses of free flaps, with postoperative outcomes being comparable to AV loop reconstructions.