Search

When native blood flow through the aorta from the adult heart and lungs meets retrograde blood flow from an artificial heart and lung during venoarterial extracorporeal membrane oxygenation (VA-ECMO), the result is the creation of two separate circulations on either side of the blood flow mixing point. This phenomenon is known as dual circulation and is characterized by different content of oxygen and carbon dioxide between the circulations. There is currently a lack of clarity surrounding the nomenclature to describe this physiologic phenomenon in VA-ECMO and thus we endeavor to name and define these terms to facilitate clear communication and proper clinical management of these patients. [ABSTRACT FROM AUTHOR]

Snow cover is a key element in the water cycle, global heat balance and in the condition of glaciers. Characterised by high temporal and spatial variability, it is subject to short- and long-term changes in climatic conditions. This paper presents a unique dataset of snow measurements on Hansbreen, an Arctic glacier in Svalbard. The dataset includes 79 archived snow profiles performed from 1989 to 2021. It presents all available observations of physical properties for snow cover, such as grain shape and size, hardness, wetness, temperature and density, supplemented with organised metadata. All data has been revised and unified with current protocols and the present International Classification for Seasonal Snow on the Ground, allowing comparison of data from different periods and locations. The information included is essential for estimations of glacier mass balance or snow depth using indirect methods, such as ground-penetrating radar. A wide range of input data makes this dataset valuable to the greater community involved in the study of snow cover evolution and modelling related to glaciology, ecology and hydrology of glacierised areas. Measurement(s) snow cover, snow stratigraphy Technology Type(s) snow pit analyses, automatic weather stations Factor Type(s) Hansbreen Sample Characteristic - Environment seasonal snow cover, cryosphere, polar environment Sample Characteristic - Location glacier, Hansbreen, Hornsund, Spitsbergen, Svalbard, Arctic [ABSTRACT FROM AUTHOR]

Purpose: The significance and management of pediatric pneumatosis intestinalis (PI) remains poorly defined. We sought to add clarity in children beyond the neonatal period. Methods: Pediatric patients 3 months–18 years admitted to a quaternary children's hospital with a diagnosis of PI were included in this retrospective study. Pathologic PI was defined as irreversible, transmural intestinal ischemia. Results: 167 children were identified with PI. Of these children, 155 (92.8%) had benign PI and 12 (7.2%) developed pathologic PI. The most common underlying diagnosis for pathologic PI was global developmental delay (75%), although we identified a spectrum of underlying diagnoses at risk for PI. Physical exam notable for abdominal distension (p = 0.023) or guarding (p = 0.028), and imaging with portal venous gas (p < 0.001) or bowel distension (p = 0.001) were significantly associated with pathologic PI. Only 6.6% of all children underwent an operation. For those undergoing non-surgical management of benign PI, 75% of children received antibiotics and average duration of bowel rest was 6.8 days. Conclusions: PI in children is primarily a benign phenomenon and often does not warrant surgical intervention. Bowel rest and antibiotics are therapeutic strategies frequently used in the treatment of this finding. [ABSTRACT FROM AUTHOR]

We determine the Hausdorff dimension of the set of k-multiple points for a symmetric operator semistable Lévy process X = { X (t) , t ∈ R + } in terms of the eigenvalues of its stability exponent. We also give a necessary and sufficient condition for the existence of k-multiple points. Our results extend to all k ≥ 2 the recent work (Luks and Xiao in J Theor Probab 30(1):297–325, 2017) where the set of double points (k = 2) was studied in the symmetric operator stable case. [ABSTRACT FROM AUTHOR]

Objectives: Treatment-induced lesions represent a great challenge in neuro-oncology. The aims of this study were (i) to characterize treatment induced lesions in glioblastoma patients treated with chemoradiotherapy and heat-shock protein (HSP) vaccine and (ii) to evaluate the diagnostic accuracy of diffusion weighted imaging for differentiation between treatment-induced lesions and tumor progression. Methods: Twenty-seven patients with newly diagnosed glioblastoma treated with HSP vaccine and chemoradiotherapy were included. Serial magnetic resonance imaging evaluation was performed to detect treatment-induced lesions and assess their growth. Quantitative analysis of the apparent diffusion coefficient (ADC) was performed to discriminate treatment-induced lesions from tumor progression. Mann–Whitney U-test and receiver operating characteristic (ROC) curves were used for analysis. Results: Thirty-three percent of patients developed treatment-induced lesions. Five treatment-related lesions appeared between end of radiotherapy and the first vaccine administration; 4 lesions within the first 4 months from vaccine initiation and 1 at 3.5 years. Three patients with pathology proven treatment-induced lesions showed a biphasic growth pattern progressed shortly after. ADC ratio between the peripheral enhancing rim and central necrosis showed an accuracy of 0.84 (95% CI 0.63–1) for differentiation between progression and treatment-induced lesions. Conclusion: Our findings do not support the iRANO recommendation of a 6-month time window in which progressive disease should not be declared after immunotherapy initiation. A biphasic growth pattern of pathologically proven treatment-induced lesions was associated with a dismal prognosis. The presence of lower ADC values in the central necrotic portion of the lesions compared to the enhancing rim shows high specificity for detection of treatment-induced lesions. [ABSTRACT FROM AUTHOR]

Background: Current consensus guidelines do not recommend routine follow-up imaging for blunt splenic injury (BSI) in children. However, repeat imaging is recommended based on persistent symptoms. Wide variation of practice continues to exist among surgeons. By defining the natural evolution of BSI, we sought to identify patients at higher risk for delayed healing who could benefit from outpatient imaging.Methods: A retrospective review of all children with BSI at a Level 1 Pediatric Trauma Center was completed. Grade of injury, hospital course, laboratory values and follow-up imaging results were obtained. Injured spleens were classified as 'healed', 'healing' (with echogenic scar), or 'non-healing' with persistence of parenchymal abnormalities.Results: Between 2000 and 2014, 222 patients with BSI were identified. Seven patients (3%) underwent immediate splenectomy. Packed red blood cell transfusion was required in 13 (6%) of the 222 patients, and 3 (2%) of 145 with isolated splenic injuries. Seventy-one percent of patients underwent additional imaging 2-74 weeks post-injury. A receiver operating characteristics (ROC) curve was used to establish the relationship between sensitivity and specificity of capturing non-healing spleens over time. Optimal timing for post-injury imaging for grades I-II was 7-8 weeks; healing of higher-grade injuries could not accurately be predicted.Conclusions: If return to full physical activity, in particular contact sports, is contingent upon documented healing of the splenic parenchyma after blunt trauma in the pediatric population, follow-up imaging for low-grade injuries is best obtained around 7-8 weeks. No such recommendations can be made for high-grade splenic injuries, as the exact time to healing cannot be predicted based on initial data.Level Of Evidence: IV. Diagnostic test. [ABSTRACT FROM AUTHOR]

Genetic diseases can be diagnosed early during pregnancy, but many monogenic disorders continue to cause considerable neonatal and pediatric morbidity and mortality. Early intervention through intrauterine gene editing, however, could correct the genetic defect, potentially allowing for normal organ development, functional disease improvement, or cure. Here we demonstrate safe intravenous and intra-amniotic administration of polymeric nanoparticles to fetal mouse tissues at selected gestational ages with no effect on survival or postnatal growth. In utero introduction of nanoparticles containing peptide nucleic acids (PNAs) and donor DNAs corrects a disease-causing mutation in the β-globin gene in a mouse model of human β-thalassemia, yielding sustained postnatal elevation of blood hemoglobin levels into the normal range, reduced reticulocyte counts, reversal of splenomegaly, and improved survival, with no detected off-target mutations in partially homologous loci. This work may provide the basis for a safe and versatile method of fetal gene editing for human monogenic disorders. [ABSTRACT FROM AUTHOR]

We prove the existence and study properties of the Green function of the unit ball for the Dunkl Laplacian △k in ℝd. As applications we derive the Poisson-Jensen formula for △k-subharmonic functions and Hardy-Stein identities for the Poisson integrals of △k. We also obtain sharp estimates of the Newton potential kernel, Green function and Poisson kernel in the rank one case in ℝd. These estimates contrast sharply with the well-known results in the potential theory of the classical Laplacian. [ABSTRACT FROM AUTHOR]

The proximal tubule is the primary site for renal solute reabsorption and secretion and thus a main target for drug-induced toxicity. Current nonclinical methods using 2D cell cultures are unable to fully recapitulate clinical drug responses mainly due to limited in vitro functional lifespan. Since extracellular matrices are known to be key regulators of cell development, culturing cells on classic 2D plastic surfaces inevitably results in loss of differentiation. Hence, 3D models of the human proximal tubule that recapitulate the in vivo morphology would allow for improved drug screening and disease modeling. Here, the development and characterization of a 3D proximal tubule model using RPTEC/TERT1 cells is presented. RPTEC/TERT1 cells self-assembled in matrigel to form highly differentiated and stable 3D tubular structures characterized by a branched network of monolayered cells encircling a cell-free lumen, thus mimicking the proximal tubule. In vitro tubuli resembled the polarity of a proximal tubule epithelium as indicated by polar expression of Na+/K+-ATPase and ZO-3. Furthermore, 3D cultured RPTEC/TERT1 cells showed overall increased mRNA expression of xenobiotic transporters, e.g., OCTs and MATEs and de novo expression of OAT3 when compared to cultures on plastics or membrane inserts. Finally, this model was used to assess delayed cisplatin-induced nephrotoxicity and demonstrated increased sensitivity when compared to 2D culture. Thus, the easyto- use model described here may prove to be useful for mechanistic investigations, e.g., in discovery of compounds interfering with tubule formation, differentiation and polarization, as well for the detection and understanding of pharmaceutical induced nephrotoxicity. [ABSTRACT FROM AUTHOR]

Introduction: Infiltrating gliomas are primary brain tumors that express significant biological and clinical heterogeneity in adults, which complicates their treatment and prognosis. Characterization of tumor subtypes using spectroscopic analysis may assist in predicting malignant transformation and quantification of response to therapy. Study objective: To implement an automated algorithm for classification of metabolomic profiles for the classification of glioma pathological grades and the prediction of malignant progression using spectra obtained by high-resolution magic angle spinning (HR-MAS) spectroscopy of patient-derived tissue samples. Methods: 237 image-guided tissue samples were obtained from 152 patients who underwent surgery for newly diagnosed or recurrent glioma and analyzed via HR-MAS spectroscopy. Orthogonal projection to latent structures discriminant analysis was used as a classifier and the variable-influence-on-projection values were evaluated to identify signature spectral regions. Results: The accuracy of classifiers developed for discriminating glioma subtypes was 68% for newly diagnosed grade II versus III samples; 86 and 92% for new and recurrent grade III versus IV, respectively; 95% for newly diagnosed grade II versus IV; and 88% for recurrent grade II versus IV lesions. Classifiers distinguished between samples from newly diagnosed vs. recurrent lesions with an accuracy of 78% for grade III and 99% for grade IV glioma. Conclusion: Classifying metabolomic profiles for new and recurrent glioma without prior assumptions regarding spectral components identified candidate in vivo biomarkers for use in assessing changes that are likely to impact treatment decisions. [ABSTRACT FROM AUTHOR]

Proper subcellular trafficking is essential to prevent protein mislocalization and aggregation. Transport of the peroxisomal enzyme d-amino acid oxidase (DAAO) appears dysregulated by specific pharmaceuticals, e.g., the anti-overactive bladder drug propiverine or a norepinephrine/serotonin reuptake inhibitor (NSRI), resulting in massive cytosolic and nuclear accumulations in rat kidney. To assess the underlying molecular mechanism of the latter, we aimed to characterize the nature of peroxisomal and cyto-nuclear shuttling of human and rat DAAO overexpressed in three cell lines using confocal microscopy. Indeed, interference with peroxisomal transport via deletion of the PTS1 signal or PEX5 knockdown resulted in induced nuclear DAAO localization. Having demonstrated the absence of active nuclear import and employing variably sized mCherry- and/or EYFP-fusion proteins of DAAO and catalase, we showed that peroxisomal proteins ≤134 kDa can passively diffuse into mammalian cell nuclei-thereby contradicting the often-cited 40 kDa diffusion limit. Moreover, their inherent nuclear presence and nuclear accumulation subsequent to proteasome inhibition or abrogated peroxisomal transport suggests that nuclear localization is a characteristic in the lifecycle of peroxisomal proteins. Based on this molecular trafficking analysis, we suggest that pharmaceuticals like propiverine or an NSRI may interfere with peroxisomal protein targeting and import, consequently resulting in massive nuclear protein accumulation in vivo. [ABSTRACT FROM AUTHOR]

Low-grade gliomas can vary widely in disease course and therefore patient outcome. While current characterization relies on both histological and molecular analysis of tissue resected during surgery, there remains high variability within glioma subtypes in terms of response to treatment and outcome. In this study we hypothesized that parameters obtained from magnetic resonance data would be associated with progression-free survival for patients with recurrent low-grade glioma. The values considered were derived from the analysis of anatomic imaging, diffusion weighted imaging, and H magnetic resonance spectroscopic imaging data. Metrics obtained from diffusion and spectroscopic imaging presented strong prognostic capability within the entire population as well as when restricted to astrocytomas, but demonstrated more limited efficacy in the oligodendrogliomas. The results indicate that multi-parametric imaging data may be applied as a non-invasive means of assessing prognosis and may contribute to developing personalized treatment plans for patients with recurrent low-grade glioma. [ABSTRACT FROM AUTHOR]

We determine the Hausdorff dimension of the set of double points for a symmetric operator stable Lévy process $$X=\left\{ X(t),t\in \mathbb {R}_+\right\} $$ in terms of the eigenvalues of its stability exponent. [ABSTRACT FROM AUTHOR]

Chronic exposure to propiverine, a frequently prescribed pharmaceutical for treatment of overactive bladder and incontinence, provokes massive protein accumulation in the cytosol and nucleus of renal proximal tubule epithelial cells in rats. Previously, the accumulating protein was identified as d-amino acid oxidase (DAAO), a peroxisomal flavoenzyme expressed in kidney, liver and brain. The cellular mechanism of propiverine-induced DAAO accumulation, however, remains unexplained and poorly characterized. Therefore, to further increase the understanding of DAAO accumulation in rat kidney, this study aimed to characterize DAAO accumulations using differential immunofluorescent staining of rat kidney sections as well as in vitro binding analyses and proteasomal activity studies. We demonstrated that propiverine is neither a ligand of DAAO nor an inhibitor of the proteasome in vitro. However, propiverine treatment resulted in a significant decrease of peroxisomal size in rat proximal tubule epithelial cells. Moreover, peroxisomal catalase also accumulated in the cytosol and nuclei of propiverine-treated rats concurrently with DAAO. Taken together, our study indicates that propiverine treatment affects the trafficking and/or degradation of peroxisomal proteins such as DAAO and catalase by a so far unique and unknown mechanism. [ABSTRACT FROM AUTHOR]

Arctic regions experience metal pollution, despite their remote location, and the distribution and migration of those metals determine their potential impact on the local environment. Here, a High-Arctic catchment (Revelva, Svalbard) located remotely from human-induced pollution sources is studied with respect to the distribution and migration of chosen trace elements (Ag, Al, As, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Cs, Mo, Ni, Pb, Sb, Se, Sr, Tl, U, V and Zn) in surface waters. The metal concentrations fluctuated in 2010-2012 between 0.01 and 354 μg L, the highest mean-weighted concentration noted for Sr (42.5 μg L). The concentrations in the river water were likely influenced by both natural and human-activity-related processes. These factors can produce substances of the same chemical composition (e.g. carbon dioxide, sulphur dioxide and metals may be emitted both by a volcanic eruption and by industrial sources). Therefore, chemometric techniques were used in the current paper to distinguish the multiple sources of pollution in the Revelva catchment. The authors were seeking to determine whether there is indeed evidence for contamination, sufficient to cause environmental damage in polar region. As a result, it was shown that the long-range transport could play an important role in shaping the metal concentration profile of this Arctic tundra environment, capturing both the influence of volcanic eruptions within the region and the human activity in a range of distances from the study site. [ABSTRACT FROM AUTHOR]

Objectives: Our aim was to evaluate differences in metabolite levels between unmedicated patients with major depressive disorder (MDD) and healthy controls, to assess changes in metabolites in patients after they completed an 8-week course of mindfulness-based cognitive therapy (MBCT), and to exam the correlation between metabolites and depression severity. Materials and methods: Sixteen patients with MDD and ten age- and gender-matched healthy controls were studied using 3D short echo-time (20 ms) magnetic resonance spectroscopic imaging (MRSI) at 7 Tesla. Relative metabolite ratios were estimated in five regions of interest corresponding to insula, anterior cingulate cortex (ACC), caudate, putamen, and thalamus. Results: In all cases, MBCT reduced severity of depression. The ratio of total choline-containing compounds/total creatine (tCr) in the right caudate was significantly increased compared to that in healthy controls, while ratios of N-acetyl aspartate (NAA)/tCr in the left ACC, myo-inositol/tCr in the right insula, and glutathione/tCr in the left putamen were significantly decreased. At baseline, the severity of depression was negatively correlated with my-inositol/tCr in the left insula and putamen. The improvement in depression severity was significantly associated with changes in NAA/tCr in the left ACC. Conclusions: This study has successfully evaluated regional differences in metabolites for patients with MDD who received MBCT treatment and in controls using 7 Tesla MRSI. [ABSTRACT FROM AUTHOR]

Lymphatic malformations (LM) are characterized by abnormal formation of lymphatic vessels and tissue overgrowth. The lymphatic vessels present in LM lesions may become blocked and enlarged as lymphatic fluid collects, forming a mass or cyst. Lesions are typically diagnosed during childhood and are often disfiguring and life threatening. Available treatments consist of sclerotherapy, surgical removal and therapies to diminish complications. We isolated lymphatic endothelial cells (LM-LEC) from a surgically removed microcystic LM lesion. LM-LEC and normal human dermal-LEC (HD-LEC) expressed endothelial (CD31, VE-Cadherin) as well as lymphatic endothelial (Podoplanin, PROX1, LYVE1)-specific markers. Targeted gene sequencing analysis in patient-derived LM-LEC revealed the presence of two mutations in class I phosphoinositide 3-kinases (PI3K) genes. One is an inherited, premature stop codon in the PI3K regulatory subunit PIK3R3. The second is a somatic missense mutation in the PI3K catalytic subunit PIK3CA; this mutation has been found in association with overgrowth syndromes and cancer growth. LM-LEC exhibited angiogenic properties: both cellular proliferation and sprouting in collagen were significantly increased compared with HD-LEC. AKT-Thr308 was constitutively hyper-phosphorylated in LM-LEC. Treatment of LM-LEC with PI3-Kinase inhibitors Wortmannin and LY294 decreased cellular proliferation and prevented the phosphorylation of AKT-Thr308 in both HD-LEC and LM-LEC. Treatment with the mTOR inhibitor rapamycin also diminished cellular proliferation, sprouting and AKT phosphorylation, but only in LM-LEC. Our results implicate disrupted PI3K-AKT signaling in LEC isolated from a human lymphatic malformation lesion. [ABSTRACT FROM AUTHOR]

Tracheal occlusion in utero has been shown to cause accelerated fetal lung growth and is now being considered as a therapeutic modality for pulmonary hypoplasia. We report the effects of tracheal ligation on the surfactant-producing type II pneumocyte population. Three groups of fetal lambs underwent tracheal ligation of 2 weeks', 4 weeks' and 6 weeks' duration, respectively, and all were sacrificed at 136 days' gestation (9 days pre-term). Nonoperated twins served as controls. The type II pneumocyte population was studied morphometrically using a combination of anti-surfactant protein B immunohistochemistry and computer-assisted stereologic morphometry at light and electron microscopic levels. Single-factor ANOVA was used for statistical analysis. Two weeks of tracheal ligation resulted in doubling of the total lung volume as a result of airspace distension and, to lesser extent, growth of the tissue compartment. With increasing duration of tracheal ligation, there was no additional lung growth. However, more prolonged tracheal occlusion was found to result in significant reduction of the surfactant system, as reflected in the marked decrease of total pneumocyte type II volume (3.14 cm3, 0.95 cm3, and 0.46 cm3, after 2, 4, and 6 weeks of ligation, compared with 5.96 cm3 for controls) and total pneumocyte type II number (13.9 x 10(9), 3.8 x 10(9), and 2.4 x 10(9), compared with 53.2 x 10(9) for controls). Ultrastructural analysis of the type II cells in obstructed lungs showed vacuolar degenerative changes that, after 6 weeks of ligation, were apparently irreversible. In utero tracheal ligation causes fetal lung hyperplasia, but results in reduction of and injury to the surfactant-producing cell population. Before tracheal occlusion can find wide-spread clinical application, its pathophysiology needs to be further elucidated. [ABSTRACT FROM AUTHOR]

This paper presents results of a field investigation conducted to examine the bed sediment, riverbed morphology and flow structure over dunes in natural and regulated channels. Field measurements using an acoustic Doppler current profiler (ADCP) have been carried out on two parts of lowland Wilga River in Poland. It is shown that the bedforms with a low angle of lee side develop more frequently than asymmetrical dunes with high lee-side angles, which are mostly associated with the occurrence of local scours and river meanders. Wavenumber analysis of bed elevation confirms the existence of scaling region in the longitudinal wavenumber spectrum, with '−3' scaling exponents for the natural and regulated channels as well. Moreover, the results of flow velocity field are presented in the form of a 2-D streamwise-vertical vector field, showing several similarities to previous laboratory and field investigations conducted on much deeper rivers than the Wilga. The experimental campaign and methods used to obtain the results are also presented briefly. In addition, a short database of fluvial dunes statistics is provided. [ABSTRACT FROM AUTHOR]

Let $$L=\Delta ^{\alpha /2}+ b\cdot \nabla $$ with $$\alpha \in (1,2)$$ . We prove the Martin representation and the Relative Fatou Theorem for non-negative singular L-harmonic functions on $$\mathcal{C }^{1,1}$$ bounded open sets. [ABSTRACT FROM AUTHOR]

We study α-harmonic functions on the complement of the sphere and on the complement of the hyperplane in Euclidean spaces of dimension bigger than one, for α ∈ (1,2). We describe the corresponding Hardy spaces and prove the Fatou theorem for α-harmonic functions. We also give explicit formulas for the Martin kernel of the complement of the sphere and for the harmonic measure, Green function and Martin kernel of the complement of the hyperplane for the symmetric α-stable Lévy processes. Some extensions for the relativistic α-stable processes are discussed. [ABSTRACT FROM AUTHOR]

2,6-diacetylpyridinediphenylhydrazone perchlorate was prepared and characterized by spectroscopic (IR, ESI–MS, UV–Vis, 1H NMR) and analytical data and its crystal structure was determined by single X-ray analysis. The lanthanum(III), praseodymium(III), and neodymium(III) perchlorate complexes of 2,6-diacetylpyridinediphenylhydrazone were prepared in a direct reaction of the ligand with appropriate metal perchlorates. The spectroscopic and analytical data indicate 1:2 metal to ligand stoichiometry. In all the complexes the hydrazones act as monodeprotonated terdentate NNN donor chelators. The same lanthanum(III) complex was also obtained in a one-step condensation reaction between 2,6-diacetylpyridine and phenylhydrazine in the presence of lanthanum(III) perchlorate. [ABSTRACT FROM AUTHOR]

Brain-based models of visual attention hypothesize that attention-related benefits afforded to imperative stimuli occur via enhancement of neural activity associated with relevant spatial and non-spatial features. When relevant information is available in advance of a stimulus, anticipatory deployment processes are likely to facilitate allocation of attention to stimulus properties prior to its arrival. The current study recorded EEG from humans during a centrally-cued covert attention task. Cues indicated relevance of left or right visual field locations for an upcoming motion or orientation discrimination. During a 1 s delay between cue and S2, multiple attention-related events occurred at frontal, parietal and occipital electrode sites. Differences in anticipatory activity associated with the non-spatial task properties were found late in the delay, while spatially-specific modulation of activity occurred during both early and late periods and continued during S2 processing. The magnitude of anticipatory activity preceding the S2 at frontal scalp sites (and not occipital) was predictive of the magnitude of subsequent selective attention effects on the S2 event-related potentials observed at occipital electrodes. Results support the existence of multiple anticipatory attention-related processes, some with differing specificity for spatial and non-spatial task properties, and the hypothesis that levels of activity in anterior areas are important for effective control of subsequent S2 selective attention. [ABSTRACT FROM AUTHOR]

Symmetry-breaking formulas for a constraint-satisfaction problem are satisfied by exactly one member (e.g., the lexicographic leader) from each set of “symmetrical points” in the search space. Thus, the incorporation of such formulas can accelerate the search for a solution without sacrificing satisfiability. We study the computational complexity of generating lex-leader formulas. We show, even for abelian symmetry groups, that the number of essential clauses in the “natural” lex-leader formula could be exponential. Furthermore, we show the intractability (NP-hardness) of finding any expression of lex-leadership without reordering the variables, even for elementary abelian groups with orbits of size 3. Nevertheless, using techniques of computational group theory, we describe a reordering relative to which we construct small lex-leader formulas for abelian groups. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to evaluate prospectively whether laparoscopic (LA) and open appendectomy (OA) are equally safe and feasible in the treatment of pediatric appendicitis.Methods: A total of 517 children with acute appendicitis were randomly assigned to undergo LA or OA appendectomy, based on the schedule of the attending surgeon on call. Patient age, sex, postoperative diagnosis, operating time, level of training of surgical resident, length of postoperative hospitalization, and minor and major postoperative complications were recorded. Chi-square analysis and the Student t-test were used for statistical analysis.Results: In all, 376 OA and 141 LA were performed. The two groups were comparable in terms of patient demographics and the incidence of perforated appendicitis. The operative time was also similar (47.3 +/- 19.7 vs 49.9 +/- 12.9 min). The overall incidence of minor or major complications was 11.2% in the OA group and 9.9% in the LA group.Conclusion: Pediatric patients with appendicitis can safely be offered laparoscopic appendectomy without incurring a greater risk for complications. Nevertheless, a higher (but not significantly higher) abscess rate was found in patients with perforated appendicitis who underwent laparoscopy. [ABSTRACT FROM AUTHOR]

Background: Laser ablation of placental vessels effectively halts severe twin-to-twin transfusion syndrome (TTTS), but fetal surgery remains a dangerous approach. The authors present the technical aspects of endoscopic fetal surgery in their initial clinical experience.Methods: Altogether, 11 women underwent endoscopic fetal surgery for severe TTTS. Access to the recipient's sac was obtained by the Seldinger technique via minilaparotomy. A 12-Fr peel-away introducer was used as a cannula to accommodate a custom-curved 9-Fr sheath containing a 1.9-mm semirigid fiber endoscope. Laser ablation was performed on all unpaired vessels crossing the intertwin membrane using a 400- micro m neodymium: yttrium-aluminum-garnet (Nd: YAG) fiber. The cannula was removed over a gelatin sponge plug.Results: The median operating time was 65 min (range, 45-105 min). No patient experienced amniotic leak postoperatively. The length of hospital stay was 2.8 +/- 1.6 days. Immediate improvement of the TTTS was noted in all but two patients. Pneumonia developed, in one mother leading to premature labor. There were no other major surgical complications. Fetal survival at 2 weeks was 73%.Conclusions: The safety and efficacy of endoscopic fetal surgery for severe TTTS can be optimized with the application of current minimal-access techniques. The superiority of this approach over less invasive means is still being evaluated through prospective studies. [ABSTRACT FROM AUTHOR]

Focuses on ecological economic policy for sustainable development. Elements of ecological economic policy; Dematerialization of industrialized economies through economic growth; Focus on eco-efficient services over production/acquisition of material goods.