145 research outputs found
Thermodynamics and scattering in 2D for 4D theories
Considering classical open string solutions with a null polygonal contour at the boundary of AdS3, the geometric problem of minimal surfaces related to gluon scattering amplitudes at strong coupling is developed and solved in a set of TBA-like integral equations. Their form resembles that of a TBA system whose free energy yields the dynamic contribution to the area. The corresponding set of functional relations, the so called Y-system, is derived and extensively analyzed in the cases of octagon and decagon together with the set of integral equations. Useful rewrites of the latter establish the connection with a particular class of HSG models and allow us to identify their Y-system (related to a universal TBA) with the one derived in AdS3 when the algebra level k is set to 2. A useful insight that clarifies how to properly reduce to the An series is offered. Thanks to a well defined change of reference frame, whose mathematical structure has been studied in detail, the dynamic part of the remainder function coincides with the extremum of the Yang-Yang functional for the modified TBA equations. Explicit examples have been treated in terms of Y-functions and pseudo-energies, extrapolating useful links with several works concerning null WLs, Hitchin systems and integrable perturbations of CFTs corresponding to Gk-parafermions
Surgical evolution in the treatment of mandibular condyle fractures
Background: In Literature fractures of the mandible that involve the condyle ranges from 20% to 35% and various possible surgical options are described according to the varying pathological situations. Up to the present, numerous techniques have been used for the surgical treatment of condylar fractures. In this article we are proposing the combination of two surgical techniques as therapy for extra-capsular condylar fractures with dislocation.
Methods: From June 2003 to July 2007 30 patients were treated for condylar fractures with the application of a Rigid External Fixator under endoscopic assistance. This method includes a surgical reduction of the fracture with the aid of an endoscope, performing a transcutaneous insertion of a Rigid External Fixator to stabilize the fracture.
Results: Out of the total number of patients, 28 reached an optimal result without the need for temporary immobilization of the temporal mandibular joint and pre-auricular cutaneous access, thanks to the decisive aid of the video-endoscope.
Conclusions: The endoscope allows perfect control over both the positioning of the external fixator and the surgical reduction, restoring the normal movement of the mandible with a return to full anatomical functioning of the temporo-mandibular joint. This approach avoids possible damages to the facial nerve branches. The rigid external fixation system is better than an internal one, because it is less restrictive in precise anatomical reduction, since with an REF the condylar fragment is kept in the correct anatomical position but is not obliged to maintain that exact position, and therefore it is possible to carry out all the repair mechanisms listed above. Endoscopic assistance allows a good positioning control of the REF although the endoscopy permits an optimal control of the condylemeniscal complex mobility after REF application
A convenient preparation of La2CuO4 from molecular precursors
Exhaustive hydrolysis of a mixture of [La4(CO3)(O2CNBu2)10] and [Cu(O2CNBu2)(pyâ)2] (pyâ = 4-dimethylamino pyridine) in molar ratio 1/2 corresponding to a La/Cu molar ratio 2/1 was carried out in toluene at room temperature. The carbamato derivatives of lanthanum and copper can be easily prepared by extraction of the metal ions from aqueous solution into heptane by the NHBu2/CO2 system, according to a method previously reported. The copper precursor was selected among a number of derivatives in respect of its easy tractability. The tetragonal modification Tâ of La2CuO4 was obtained by treatment at 600 °C of the intermediate mixed carbonate. The thermal treatment of Tâ-La2CuO4 at 850 °C, followed by cooling down to room temperature, afforded the orthorhombic modification of the mixed oxide
Comparison between early-onset and late-onset alzheimer's disease patients with amnestic presentation: CSF and 18F-FDG PET study
BACKGROUND/AIMS
To investigate the differences in brain glucose consumption between patients with early onset of Alzheimer's disease (EOAD, aged â€65 years) and patients with late onset of Alzheimer's disease (LOAD, aged >65 years).
METHODS
Differences in brain glucose consumption between the groups have been evaluated by means of Statistical Parametric Mapping version 8, with the use of age, sex, Mini-Mental State Examination and cerebrospinal fluid values of AÎ1-42, phosphorylated Tau and total Tau as covariates in the comparison between EOAD and LOAD.
RESULTS
As compared to LOAD, EOAD patients showed a significant decrease in glucose consumption in a wide portion of the left parietal lobe (BA7, BA31 and BA40). No significant differences were obtained when subtracting the EOAD from the LOAD group.
CONCLUSIONS
The results of our study show that patients with EOAD show a different metabolic pattern as compared to those with LOAD that mainly involves the left parietal lobe
Severity of experimental traumatic brain injury modulates changes in concentrations of cerebral free amino acids
In this study, concentrations of free amino acids (FAA) and amino group containing compounds (AGCC) following graded diffuse traumatic brain injury (mild TBI, mTBI; severe TBI, sTBI) were evaluated. After 6, 12, 24, 48 and 120 hr aspartate (Asp), glutamate (Glu), asparagine (Asn), serine (Ser), glutamine (Gln), histidine (His), glycine (Gly), threonine (Thr), citrulline (Cit), arginine (Arg), alanine (Ala), taurine (Tau), Îł-aminobutyrate (GABA), tyrosine (Tyr), S-adenosylhomocysteine (SAH), l-cystathionine (l-Cystat), valine (Val), methionine (Met), tryptophane (Trp), phenylalanine (Phe), isoleucine (Ile), leucine (Leu), ornithine (Orn), lysine (Lys), plus N-acetylaspartate (NAA) were determined in whole brain extracts (n = 6 rats at each time for both TBI levels). Sham-operated animals (n = 6) were used as controls. Results demonstrated that mTBI caused modest, transient changes in NAA, Asp, GABA, Gly, Arg. Following sTBI, animals showed profound, long-lasting modifications of Glu, Gln, NAA, Asp, GABA, Ser, Gly, Ala, Arg, Citr, Tau, Met, SAH, l-Cystat, Tyr and Phe. Increase in Glu and Gln, depletion of NAA and Asp increase, suggested a link between NAA hydrolysis and excitotoxicity after sTBI. Additionally, sTBI rats showed net imbalances of the Glu-Gln/GABA cycle between neurons and astrocytes, and of the methyl-cycle (demonstrated by decrease in Met, and increase in SAH and l-Cystat), throughout the post-injury period. Besides evidencing new potential targets for novel pharmacological treatments, these results suggest that the force acting on the brain tissue at the time of the impact is the main determinant of the reactions ignited and involving amino acid metabolism
Open reduction and internal fixation of extracapsular mandibular condyle fractures: a long-term clinical and radiological follow-up of 25 patients
Background: During the last 2 decades, many studies on the treatment of mandibular condyle fracture have been published. The incidence of mandibular condyle fractures is variable, ranging from 17.5% to 52% of all mandibular fractures. This retrospective study evaluated the long-term clinical and radiological outcomes after surgical treatment of 25 patients with a total of 26 extracapsular condyle fractures.
Methods: We used 2 types of surgical approaches, the retromandibular retroparotid or preauricular approach. Three kinds of rigid internal fixation plates were usedâsingle plate, double plate, and trapezoidal plate. The following post-operative clinical parameters were evaluated: dental occlusion, facial nerve functionality, skin scarring, and temporomandibular joint functionality. All patients underwent post-operative orthopanoramic radiography and computed tomography. The patients were also monitored for complications such as Freyâs syndrome, infection, salivary fistula, plate fracture, and permanent paralysis of the facial nerve; the patientâs satisfaction was also recorded.
Results: Of the 25 patients, 80% showed occlusion recovery, 88% had no facial nerve injury, and 88% presented good surgical skin scarring. The patients showed early complete recovery of temporomandibular joint functionality and 72% of them were found to be asymptomatic. The postoperative radiographs of all patients indicated good recovery of the anatomical condylar region, and 80% of them had no postoperative complications. The average degree of patient satisfaction was 8.32 out of 10. Our results confirm that the technique of open reduction and internal fixation in association with postoperative functional rehabilitation therapy should be considered for treating patients with extracapsular condylar fractures.
Conclusion: The topic of condylar injury has generated more discussion and controversy than any other topic in the field of maxillofacial trauma. We confirm that open reduction and internal fixation is the treatment of choice for patients with neck and sub-condylar mandibular fractures
Low molecular weight dextran sulfate (ILBÂź) administration restores brain energy metabolism following severe traumatic brain injury in the rat
Traumatic brain injury (TBI) is the leading cause of death and disability in people less than 40 years of age in Western countries. Currently, there are no satisfying pharmacological treatments for TBI patients. In this study, we subjected rats to severe TBI (sTBI), testing the effects of a single subcutaneous administration, 30 min post-impact, of a new low molecular weight dextran sulfate, named ILB\uae, at three different dose levels (1, 5, and 15 mg/kg body weight). A group of control sham-operated animals and one of untreated sTBI rats were used for comparison (each group n = 12). On day 2 or 7 post-sTBI animals were sacrificed and the simultaneous HPLC analysis of energy metabolites, N-acetylaspartate (NAA), oxidized and reduced nicotinic coenzymes, water-soluble antioxidants, and biomarkers of oxidative/nitrosative stress was carried out on deproteinized cerebral homogenates. Compared to untreated sTBI rats, ILB\uae improved energy metabolism by increasing ATP, ATP/ adenosine diphosphate ratio (ATP/ADP ratio), and triphosphate nucleosides, dose-dependently increased NAA concentrations, protected nicotinic coenzyme levels and their oxidized over reduced ratios, prevented depletion of ascorbate and reduced glutathione (GSH), and decreased oxidative (malondialdehyde formation) and nitrosative stress (nitrite + nitrate production). Although needing further experiments, these data provide the first evidence that a single post-injury injection of a new low molecular weight dextran sulfate (ILB\uae) has beneficial effects on sTBI metabolic damages. Due to the absence of adverse effects in humans, ILB\uae represents a promising therapeutic agent for the treatment of sTBI patients
Towards a better understanding of debris flow sediment sources: Monitoring of an active rock slope at Spitze Stei, Switzerland
Rapid process cascades can lead to destructive debris flows. Identifying and characterizing the processes conditioning debris-flow occurrence will strongly contribute to the mitigation of debris-flow hazards. In recent years, the rock slope near âSpitze Steiâ, in the Kandersteg region, Switzerland, has exhibited elevated displacement rates exceeding 10 cm per day, suggesting a growing instability up to 20 million m3. The accumulated sediments at the bottom of the Spitze Stei slope are mobilized as debris flows by melting snow and heavy summer precipitations. Here, we use seismology combined with an intelligent algorithm to automatically detect rockfall and landslides at the Spitze Stei rock slope. These mass movements act as primary sediment sources delivering sediments to a debris-prone channel. Our initial results quantify mass movement activity before two debris flow events that occurred in 2022 and identify their triggers. Such analysis can contribute towards mitigating debris flow hazards and extending warning time, especially for debris flows triggered by factors other than precipitation
Exclusive Seismoacoustic Detection and Characterization of an Unseen and Unheard Fireball Over the North Atlantic
Small meteoroids that enter Earth's atmosphere often go unnoticed because their detection and characterization rely on human observations, introducing observational biases in space and time. Acoustic shockwaves from meteoroid ablation convert to infrasound and seismic energy, enabling fireball detection using seismoacoustic methods. We analyzed an unreported fireball in 2022 near the Azores, recorded by 26 seismometers and two infrasound arrays. Through polarization analyses, array methods, and 3âD rayâtracing, we determined that the terminal blast occurred at 40 km altitude, âŒ60 km NE of SĂŁo Miguel Island. This location matches an unidentified flash captured by a lightning detector aboard the GOESâ16 satellite. The estimated kinetic energy is âŒ10â3 kT TNT equivalent, suggesting a 10â1 m object diameter, thousands of which enter the atmosphere annually. Our results demonstrate how geophysical methods, in tandem with satellite data, can significantly improve the observational completeness of meteoroids, advancing our understanding of their sources and entry processes
ILBÂź attenuates clinical symptoms and serum biomarkers of oxidative/nitrosative stress and mitochondrial dysfunction in patients with Amyotrophic Lateral Sclerosis
Oxidative/nitrosative stress and mitochondrial dysfunction is a hallmark of amyotrophic lateral sclerosis (ALS), an invariably fatal progressive neurodegenerative disease. Here, as an exploratory arm of a phase II clinical trial (EudraCT Number 2017-005065-47), we used high performance liquid chromatography(HPLC) to investigate changes in the metabolic profiles of serum from ALS patients treated weekly for 4 weeks with a repeated sub-cutaneous dose of 1 mg/kg of a proprietary low molecular weight dextran sulphate, called ILBÂź. A significant normalization of the serum levels of several key metabolites was observed over the treatment period, including N-acetylaspartate (NAA), oxypurines, biomarkers of oxidative/nitrosative stress and antioxidants. An improved serum metabolic profile was accompanied by significant amelioration of the patients' clinical conditions, indicating a response to ILBÂź treatment that appears to be mediated by improvement of tissue bioenergetics, decrease of oxidative/nitrosative stress and attenuation of (neuro)inflammatory processes
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