Spontaneously Sliding Multipole Spin Density Waves in Cold Atoms

We report on the observation of spontaneously drifting coupled spin and quadrupolar density waves in the ground state of laser driven Rubidium atoms. These laser-cooled atomic ensembles exhibit spontaneous magnetism via light mediated interactions when submitted to optical feedback by a retroreflecting mirror. Drift direction and chirality of the waves arise from spontaneous symmetry breaking. The observations demonstrate a novel transport process in out-of-equilibrium magnetic systems.

Topological Constraints on the Dynamics of Vortex Formation in a Two-Dimensional Quantum Fluid

We present experimental and theoretical results on formation of quantum vortices in a laser beam propagating in a nonlinear medium. Topological constrains richer than the mere conservation of vorticity impose an elaborate dynamical behavior to the formation and annihilation of vortex-antivortex pairs. We identify two such mechanisms, both described by the same fold-Hopf bifurcation. One of them is particularly efficient although it is not observed in the context of liquid helium films or stationary systems because it relies on the compressible nature of the fluid of light we consider and on the nonstationarity of its flow.

Clinical and radiological results of TLIF surgery with titanium-coated PEEK or uncoated PEEK cages: a prospective single-centre randomised study

BACKGROUND

A comparison of fusion rates and clinical outcomes of instrumented transforaminal interbody fusion (TLIF) between polyetheretherketone (PEEK) and titanium-coated PEEK (Ti-PEEK) cages is not well documented.

METHODS

A single-centre, prospective, randomised study included patients who underwent one-level TLIF between L3-S1 segments. Patients were randomised into one of two groups: TLIF surgery with the PEEK cage and TLIF surgery with the Ti-PEEK cage. Clinical results were measured. All patients were assessed by repeated X-rays and 3D CT scans. Cage integration was assessed using a modified Bridwell classification. The impact of obesity and smoking on fusion quality was also analysed. Patients in both groups were followed up for 2 years.

RESULTS

Altogether 87 patients were included in the study: of these 87 patients, 81 (93.1%) completed the 2-year follow-up. A significant improvement in clinical outcome was found in the two measurements scales in both groups (RM: p = 0.257, VAS: p = 0.229). There was an increase in CobbS and CobbL angle in both groups (p = 0.172 for CobbS and p = 0.403for CobbL). Bony fusion was achieved in 37 of 40 (92.5%) patients in the TiPEEK group and 35 of 41 (85.4%) in the PEEK group (p = 0.157). Cage subsided in 2 of 40 patients (5%) in the TiPEEK group and 11 of 41 (26.8%) in the PEEK group (p = 0.007). Body mass index > 30 and smoking were not predictive factors of bony fusion achievement.

CONCLUSION

There is no significant advantage of TiPEEK cages over PEEK cages in clinical outcome and fusion rate 2 years after surgery.

Brain-based graph-theoretical predictive modeling to map the trajectory of transdiagnostic symptoms of anhedonia, impulsivity, and hypomania from the human functional connectome

Clinical assessments often fail to discriminate between unipolar and bipolar depression and identify individuals who will develop future (hypo)manic episodes. To address this challenge, we developed a brain-based graph-theoretical predictive model (GPM) to prospectively map symptoms of anhedonia, impulsivity, and (hypo)mania. Individuals seeking treatment for mood disorders (n = 80) underwent an fMRI scan, including (i) resting-state and (ii) a reinforcement-learning (RL) task. Symptoms were assessed at baseline as well as at 3- and 6-month follow-ups. A whole-brain functional connectome was computed for each fMRI task, and the GPM was applied for symptom prediction using cross-validation. Prediction performance was evaluated by comparing the GPM's mean square error (MSE) to that of a corresponding null model. In addition, the GPM was compared to the connectome-based predictive modeling (CPM). Cross-sectionally, the GPM predicted anhedonia from the global efficiency (a graph theory metric that quantifies information transfer across the connectome) during the RL task, and impulsivity from the centrality (a metric that captures the importance of a region for information spread) of the left anterior cingulate cortex during resting-state. At 6-month follow-up, the GPM predicted (hypo)manic symptoms from the local efficiency of the left nucleus accumbens during the RL task and anhedonia from the centrality of the left caudate during resting-state. Notably, the GPM outperformed the CPM, and GPM derived from individuals with unipolar disorders predicted anhedonia and impulsivity symptoms for individuals with bipolar disorders, highlighting transdiagnostic generalization. Taken together, across DSM mood diagnoses, efficiency and centrality of the reward circuit predicted symptoms of anhedonia, impulsivity, and (hypo)mania, cross-sectionally and prospectively. The GPM is an innovative modeling approach that may ultimately inform clinical prediction at the individual level. ClinicalTrials.gov identifier: NCT01976975.

The effect of smoking and elderly age on digital replantation - a multivariate analysis

INTRODUCTION

It is often questioned whether to perform replantation or revision amputation for amputation injuries in elderly patients and smokers. According to the current indication criteria, neither old age nor smoking in the absence of other risk factors are considered to be risk factors for replantation failure. However, many microsurgeons still may make the decision not to perform digital replantation based solely on these factors.

MATERIAL AND METHODS

In order to evaluate the influence of both factors, we provided univariate and multivariate analyses of patients who underwent replantation at our centre during a 10-year period. We divided patients in two groups according to age (< and ≥ 60 years) and smoking status.

RESULTS

In the univariate analysis, there were no differences in immediate results between the two age groups. In the multivariate analysis, no statistical difference was found in neither long-term nor short-term results between the two age groups and between smokers and non-smokers.

CONCLUSION

Smoking and age should not be considered the only risk factors when deciding whether to perform digital replantation.

[Surgical Treatment of Degenerative Lumbar Stenosis and Spondylolisthesis: Clinical Practice Guideline]

PURPOSE OF THE STUDY This article presents the evidence and the rationale for the recommendations for surgical treatment of degenerative lumbar stenosis (DLS) and spondylolisthesis that were recently developed as a part of the Czech Clinical Practice Guideline (CPG) "The Surgical Treatment of the Degenerative Diseases of the Spine". MATERIAL AND METHODS The Guideline was drawn up in line with the Czech National Methodology of the CPG Development, which is based on the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. We used an innovative GRADE-adolopment method that combines adoption and adaptation of the existing guidelines with de novo development of recommendations. In this paper, we present three adapted recommendations on DLS and a recommendation on spondylolisthesis developed de novo by the Czech team. RESULTS Open surgical decompression in DLS patients has been evaluated in three randomized controlled trials (RCTs). A recommendation in favour of decompression was made based on a statistically significant and clinically evident improvement in the Oswestry Disability Index (ODI) and leg pain. Decompression may be recommended for patients with symptoms of DLS in the event of correlation of significant physical limitation and the finding obtained via imaging. The authors of a systematic review of observational studies and one RCT conclude that fusion has a negligible role in the case of a simple DLS. Thus, spondylodesis should only be chosen as an adjunct to decompression in selected DLS patients. Two RCTs compared supervised rehabilitation with home or no exercise, showing no statistically significant difference between the procedures. The guideline group considers the post-surgery physical activity beneficial and suggests supervised rehabilitation in patients who have undergone surgery for DLS for the beneficial effects of exercise in the absence of known adverse effects. Four RCTs were found comparing simple decompression and decompression with fusion in patients with degenerative lumbar spondylolisthesis. None of the outcomes showed clinically significant improvement or deterioration in favour of either intervention. The guideline group concluded that for stable spondylolisthesis the results of both methods are comparable and, when other parameters are considered (balance of benefits and risks, or costs), point in favour of simple decompression. Due to the lack of scientific evidence, no recommendation has been formulated regarding unstable spondylolisthesis. The certainty of the evidence was rated as low for all recommendations. DISCUSSION Despite the unclear definition of stable/unstable slip, the inclusion of apparently unstable cases of DS in stable studies limits the conclusions of the studies. Based on the available literature, however, it can be summarized that in simple degenerative lumbar stenosis and static spondylolisthesis, fusion of the given segment is not justified. However, its use in the case of unstable (dynamic) vertebral slip is undisputable for the time being. CONCLUSIONS The guideline development group suggests decompression in patients with DLS in whom previous conservative treatment did not lead to improvement, spondylodesis only in selected patients, and post-surgical supervised rehabilitation. In patients with degenerative lumbar stenosis and spondylolisthesis with no signs of instability, the guideline development group suggests simple decompression (without fusion). Key words: degenerative lumbar stenosis, degenerative spondylolisthesis, spinal fusion, Clinical Practice Guideline, GRADE, adolopment.

Measurement of the Charge-Averaged Elastic Lepton-Proton Scattering Cross Section by the OLYMPUS Experiment

We report the first measurement of the average of the electron-proton and positron-proton elastic scattering cross sections. This lepton charge-averaged cross section is insensitive to the leading effects of hard two-photon exchange, giving more robust access to the proton's electromagnetic form factors. The cross section was extracted from data taken by the OLYMPUS experiment at DESY, in which alternating stored electron and positron beams were scattered from a windowless gaseous hydrogen target. Elastic scattering events were identified from the coincident detection of the scattered lepton and recoil proton in a large-acceptance toroidal spectrometer. The luminosity was determined from the rates of Møller, Bhabha, and elastic scattering in forward electromagnetic calorimeters. The data provide some selectivity between existing form factor global fits and will provide valuable constraints to future fits.

Photon thermalization and a condensation phase transition in an electrically pumped semiconductor microresonator

We report on an experimental study of photon thermalization and condensation in a semiconductor microresonator in the weak-coupling regime. We measure the dispersion relation of light and the photon mass in a single-wavelength, broad-area resonator. The observed luminescence spectrum is compatible with a room-temperature, thermal-equilibrium distribution. A phase transition, identified by a saturation of the population at high energies and a superlinear increase of the occupation at low energy, takes place when the phase-space density is of order unity. We explain our observations by Bose-Einstein condensation of photons in equilibrium with a particle reservoir and discuss the relation with laser emission.

Subradiance with Saturated Atoms: Population Enhancement of the Long-Lived States

Dipole-dipole interactions are at the origin of long-lived collective atomic states, often called subradiant, which are explored for their potential use in novel photonic devices or in quantum protocols. Here, we study subradiance beyond the single-excitation regime and experimentally demonstrate a 200-fold increase in the population of these modes, as the saturation parameter of the driving field is increased. We attribute this enhancement to a mechanism similar to optical pumping through the well-coupled superradiant states. The lifetimes are unaffected by the pump strength, as the system is ultimately driven toward the single-excitation sector. Our study is a new step in the exploration of the many-body dynamics of large open systems.

Pretreatment Reward Sensitivity and Frontostriatal Resting-State Functional Connectivity Are Associated With Response to Bupropion After Sertraline Nonresponse

BACKGROUND

Standard guidelines recommend selective serotonin reuptake inhibitors as first-line antidepressants for adults with major depressive disorder, but success is limited and patients who fail to benefit are often switched to non-selective serotonin reuptake inhibitor agents. This study investigated whether brain- and behavior-based markers of reward processing might be associated with response to bupropion after sertraline nonresponse.

METHODS

In a two-stage, double-blinded clinical trial, 296 participants were randomized to receive 8 weeks of sertraline or placebo in stage 1. Individuals who responded continued on another 8-week course of the same intervention in stage 2, while sertraline and placebo nonresponders crossed over to bupropion and sertraline, respectively. Data from 241 participants were analyzed. The stage 2 sample comprised 87 patients with major depressive disorder who switched medication and 38 healthy control subjects. A total of 116 participants with major depressive disorder treated with sertraline in stage 1 served as an independent replication sample. The probabilistic reward task and resting-state functional magnetic resonance imaging were administered at baseline.

RESULTS

Greater pretreatment reward sensitivity and higher resting-state functional connectivity between bilateral nucleus accumbens and rostral anterior cingulate cortex were associated with positive response to bupropion but not sertraline. Null findings for sertraline were replicated in the stage 1 sample.

CONCLUSIONS

Pretreatment reward sensitivity and frontostriatal connectivity may identify patients likely to benefit from bupropion following selective serotonin reuptake inhibitor failures. Results call for a prospective replication based on these biomarkers to advance clinical care.

Photon Blockade with Ground-State Neutral Atoms

We show that induced dipole-dipole interactions allow for photon blockade in subwavelength ensembles of two-level, ground-state neutral atoms. Our protocol relies on the energy shift of the single-excitation, superradiant state of N atoms, which can be engineered to yield an effective two-level system. A coherent pump induces Rabi oscillation between the ground state and a collective bright state, with at most a single excitation shared among all atoms. The possibility of using clock transitions that are long-lived and relatively robust against stray fields, alongside new prospects on experiments with subwavelength lattices, makes our proposal a promising alternative for quantum information protocols.

Pretreatment resistance mutations and treatment outcomes in adults living with HIV-1: a cohort study in urban Malawi

Background

Pre-treatment drug resistance (PDR) among antiretroviral drug-naïve people living with HIV (PLHIV) represents an important indicator for the risk of treatment failure and the spread of drug resistant HIV variants. We assessed the prevalence of PDR and treatment outcomes among adults living with HIV-1 in Lilongwe, Malawi.

Methods

We selected 200 participants at random from the Lighthouse Tenofovir Cohort Study (LighTen). Serum samples were drawn prior to treatment initiation in 2014 and 2015, frozen, and later analyzed for the presence of HIV-1 drug resistance mutations. Amplicons were sequenced and interpreted by Stanford HIVdb interpretation algorithm 8.4. We assessed treatment outcomes by evaluating clinical outcome and viral suppression at the end of the follow-up period in October 2019.

Results

PDR testing was successful in 197 of 200 samples. The overall NNRTI- PDR prevalence was 13.7% (27/197). The prevalence of intermediate or high level NNRTI- PDR was 11.2% (22/197). The most common mutation was K103N (5.6%, 11/197), followed by Y181C (3.6%, 7/197). In one case, we detected an NRTI resistance mutation (M184V), in combination with multiple NNRTI resistance mutations. All HIV-1 isolates analyzed were of subtype C. Of the 27 patients with NNRTI- PDR, 9 were still alive, on ART, and virally suppressed at the end of follow-up.

Conclusion

The prevalence of NNRTI- PDR was above the critical level of 10% suggested by the Global Action Plan on HIV Drug Resistance. The distribution of drug resistance mutations was similar to that seen in previous studies from the region, and further supports the introduction of integrase inhibitors in first-line treatment in Malawi. Furthermore, our findings underline the need for continued PDR surveillance and pharmacovigilance in Sub-Saharan Africa.

Use of nuclear medicine methods in surgical treatment of lumbar spine degeneration

INTRODUCTION

Chronic back pain (CBP) is a very common symptom. Multiple modalities are used in its evaluation. However, according to current evidence, none of them can be used with certainty to predict the success of fusion surgery. Given the growing experience with bone tissue examination using the methods of nuclear medicine, we have used this possibility in patients with CBP without disc herniation, degenerative spinal stenosis or instability.

CASE REPORTS

We present case reports of 11 patients who underwent lumbar fusion (during two years period) for degenerative disc disease or facet arthropathy with adequate activity on PET or SPECT/CT examination. Rolland-Morris Questionnaire (RMQ), Oswestry Disability Index (ODI), and Visual Analogue Scale (VAS) were filled out pre-operatively and 24 months after surgery.

RESULTS

Six patients after one-level stabilization for active osteochondrosis and one for active facet arthropathy improved on average by 82% (64-92%) in RMQ, by 72% (48-100%) in ODI and 75% (55-100%) in VAS. Results in cases after multilevel stabilizations were slightly worse, but still very significant in most parameters. Only one patient with the most severe morphological and clinical findings did not benefit from surgery.

CONCLUSION

In 10 out of 11 patients, the lower back pain and quality of life improved significantly after lumbar fusion performed in levels diagnosed by PET or SPECT/CT. These methods certainly have their place in the evaluation of CBP, especially in the case of unclear findings or multiple degenerative changes.

History, development and use of classification of thoracolumbar spine fractures

The main goal of this comprehensive paper is to clarify the way of thoracolumbar spine The main goal of this summary paper is to describe the way of thoracolumbar spine injury classification development and to provide a detailed description of two of the most commonly used classifications - the Thoracolumbar Injury Classification and Severity Scale (TLICS) and the AOSpine Classification for Traumatic Fracture of the Thoracolumbar Spine, including their comparison and clarification of the merits introduced by the second one. The paper also formulates a recommendation of a simple algorithm enabling even less experienced clinicians to distinguish between an injury indicated for conservative treatment and one that requires surgery.

Liquid Chromatographic Method for the Determination of Nine Phenolic Antioxidants in Butter Oil: Collaborative Study

Ten laboratories collaboratively studied a liquid chromatographic (LC) method for the determination of propyl, octyl, and dodecyl gallate (PG, OG, and DG, respectively), 2,4,5-trihydroxybutyrophenone (THBP), ferf-butylhydroquinone (TBHQ), nordihydroguaiaretic acid (NDGA), 2- and 3-tert-butyl-4- hydroxyanisole (BHA), 2,6-di-ferf-butyl-4-hydroxymethylphenol (lonox-100), and 3,5-di-terf-butyl-4- hydroxytoluene (BHT) in butter oil. The 10 samples analyzed were spiked in matched pairs at about 100,50, and 10 μg/g. In the method studied, antioxidants are extracted as in AOAC LC method 983.15, but different LC eluants are used to separate the 9 antioxidants. Results from 1 laboratory were rejected as not valid and were not included in any calculations. For the remaining 9 laboratories, the overall mean recoveries for PG, THBP, TBHQ, NDGA, BHA, OG, lonox, BHT, and DG were 100.9, 97.8,103.4,95.4, 97.4,93.6,95.5,79.0, and 96.2%, respectively. The overall reproducibility relative standard deviations were 8.55,17.4,25.6,14.5,6.60, 9.64,10.8,11.4, and 7.35%, respectively. The method was adopted first action by AOAC International as a modification of AOAC method 983.15.

Collective Multimode Vacuum Rabi Splitting

We report the experimental observation of collective multimode vacuum Rabi splitting in free space. In contrast to optical cavities, the atoms couple to a continuum of modes, and the optical thickness of the cloud provides a measure of this coupling. The splitting, also referred as normal mode splitting, is monitored through the Rabi oscillations in the scattered intensity, and the results are fully explained by a linear-dispersion theory.

Robust Coherent Transport of Light in Multilevel Hot Atomic Vapors

Using a model system, we demonstrate both experimentally and theoretically that coherent scattering of light can be robust in hot atomic vapors despite a significant Doppler effect. By operating in a linear regime of far-detuned light scattering, we also unveil the emergence of interference triggered by inelastic Stokes and anti-Stokes transitions involving the atomic hyperfine structure.

Rapid Detection and Quantitation of Precipitating Streptokinase-Antibodies

Streptokinase-therapy is regularly followed by a marked increase of precipitating streptokinase-antibodies. These antibodies cause a significant inhibition of streptokinase-induced plasminogen activation. Counterelectrophoresis is a useful method of tracing the antibodies in serum. For quantitative estimation a modified radial immunodiffusion method is presented. The antibodies were identified as IgG.

Serological and Virological Markers of Human Parvovirus B19 Infection in Sera of Hemophiliacs

It is known that parvovirus B19 (B19) is transmitted to hemophiliacs by clotting factors prepared from human plasma. However, it is not clear whether B19 is also transmitted by the more recently used inactivated clotting factor preparations. Therefore, we investigated 69 hemophiliacs, mostly children, receiving only virus-inactivated clotting factors. 49 of them (71%) were B19 IgG-positive and 18 of the IgG-positive hemophiliacs (37%) were also B19 IgM-positive. In contrast, out of 73 age-matched controls only 10 (14%) were IgG-positive, two of them being also IgM-positive. In hemophiliacs treated before 1984 with noninactivated clotting factors, seroprevalence was very similar: 94/136 (69%) presented B19 IgG antibodies as compared to their age-matched controls with 16/50 (32%). Out of the 94 IgG-positive patients 24 (26%) were IgM-positive, whereas IgM antibodies were never found in 16 sera of 16 IgG-positive controls. In 4 out of 24 IgM positive hemophiliacs, B19 DNA was detected in the sera by using the polymerase chain reaction. However, B19 DNA was also found in 3/69 anti-B19 IgM-negative, HIV-infected hemophiliacs (all three patients in CDC stage IV). Since it seems unlikely that the results only represent passive acquisition of B19 DNA from blood products and induction of antibodies by immunization with inactivated antigen, the observations rather suggest that infection with B19 is transmitted by clotting factors, including those treated for virus inactivation.

Meralgia paresthetica

Meralgia paresthetica is a compression neuropathy of the lateral femoral cutaneous nerve. Despite its rarity, it is the most common nerve entrapment of the lower limbs. It produces similar symptoms as those associated with the more common L4 or L5 radiculopathy. Therefore, it is often diagnosed late (sometimes only after several years of latency) or not at all. This diagnosis should be considered especially in patients with obesity and diabetes who have chronic irritation of the ventrolateral areas of the thigh not responding to conservative therapy and a negative finding on lumbar MRI. We present our experience with surgical nerve decompression in three patients with pain, paresthesias, and sensory loss within the distribution of the lateral cutaneous nerve of the thigh. They all suffered from severe abdominal obesity. All conservative treatments, including weight reduction attempts, were unsuccessful. Nerve release caused an immediate effect in two cases. One patient experienced a temporary worsening of pain, which gradually improved within one month. In spite of the controversy surrounding the surgical treatment of meralgia (neurolysis or nerve resection), it can be concluded that nerve decompression has a good effect. Nerve resection is, in our view, considered to be a reserve option when primary surgery fails. Key words: meralgia paresthetica - nerve entrapment - peripheral nerve.

Qualitative Assessment of Vaccination Hesitancy Among Members of the Apostolic Church of Zimbabwe: A Case Study

Vaccine hesitancy or lack of confidence in vaccines is considered a threat to the success of vaccination programs. The rise and spread of measles outbreaks in southern Africa in 2009-2010 were linked to objections among Apostolic Church members, estimated at about 3.5 million in Zimbabwe as of 2014. To inform planning of interventions for a measles-rubella vaccination campaign, we conducted an assessment of the factors contributing to vaccine hesitancy using data from various stakeholders. Among nine districts in three regions of Zimbabwe, we collected data on religious attitudes toward, and perceptions of, vaccines through focus group discussions with health workers serving Apostolic communities and members of the National Expanded Programme on Immunization; semi-structured interviews with religious leaders; and open-ended questions in structured interviews with Apostolic parents/caregivers. Poor knowledge of vaccines, lack of understanding and appreciation of the effectiveness of vaccinations, religious teachings that emphasize prayers over the use of medicine, lack of privacy in a religiously controlled community, and low levels of education were found to be the main factors contributing to vaccine hesitancy among key community members and leaders. Accepting vaccination in public is a risk of sanctions. Poor knowledge of vaccines is a major factor of hesitancy which is reinforced by religious teachings on the power of prayers as alternatives. Because parents/caregivers perceive vaccines as dangerous for their children and believe they can cause death or disease, members of the Apostolic Church have more confidence in alternative methods such as use of holy water and prayers to treat diseases. Under these circumstances, it is important to debunk the myths about the power of holy water on the one hand and disseminate positive information of the efficacy of vaccines on the other hand in order to reduce hesitancy. Education about vaccines and vaccination in conjunction with government intervention, for example, through the use of social distancing policies can provide a framework for reducing hesitancy and increasing demand for vaccination.

Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering Determined by the OLYMPUS Experiment

The OLYMPUS Collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R_{2γ}, a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01 GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of ≈20° to 80°. The relative luminosity between the two beam species was monitored using tracking telescopes of interleaved gas electron multiplier and multiwire proportional chamber detectors at 12°, as well as symmetric Møller or Bhabha calorimeters at 1.29°. A total integrated luminosity of 4.5  fb^{-1} was collected. In the extraction of R_{2γ}, radiative effects were taken into account using a Monte Carlo generator to simulate the convolutions of internal bremsstrahlung with experiment-specific conditions such as detector acceptance and reconstruction efficiency. The resulting values of R_{2γ}, presented here for a wide range of virtual photon polarization 0.456<ε<0.978, are smaller than some hadronic two-photon exchange calculations predict, but are in reasonable agreement with a subtracted dispersion model and a phenomenological fit to the form factor data.

CURRENT CONCEPTS IN PERIPHERAL NERVE INJURY REPAIR

Even though reconstructive surgery of the nerves underwent significant progress due to experimental and clinical research over the past 40 years, injuries to the peripheral nerves still remain a great challenge for microsurgery. Literature results of these procedures are often evaluated as very good but the final result is often characterized by an achievement of only a useful and not full function, which is rather rare. It is not only a simple suture; the success is also based on functional regeneration and interconnection of the nerve fibres. This is limited by correct surgical technique, the age of the patient, delay from the time of injury and the mechanism or localization of the injury. Some injuries even now remain untreatable (such as the most severe brachial plexus injuries or long traction injuries of the peroneal nerve). Apart from standard neurolysis and epi- or perineural suture with or without nerve grafts, distal nerve transfers (in case of proximal injuries) and end-to-side neurorrhaphy (mainly in trauma of sensitive nerves) have recently been frequently used. The future is however based on influence of nerve regeneration at the cellular level using substances with growth potential. The main prerequisite of successful surgery is however early indication of surgical revision in a specialized centre.

Kibble-Zurek Mechanism in the Self-Organization of a Cold Atomic Cloud

When applying two counterpropagating laser beams to a cold cloud of rubidium atoms, we observe the spontaneous formation of intensity patterns associated with a spatial structuration of the atomic spins. We study the average number of defects in these patterns as a function of the sweep time employed to cross the instability threshold. We observe a power-law decrease of the number of defects with increasing sweep time, typical of the Kibble-Zurek mechanism. The measured exponent is consistent with the prediction for a supercritical bifurcation.

Paraspinal muscle volume in patients with Scheuermann's Kyphosis

To measure the cross-sectional area (CSA) of para-spinal muscles in Scheuermann's kyphosis patients. Preoperative MRI images of 16 Scheuermann's kyphosis patients were analysed and compared to 16 patients with normal MRI images (control group). The CSAs were measured at L3-4 and L4-5. Both groups showed similar demographics and patient characteristics. The multifidus muscles CSA were found to be significantly smaller at L3/4 level in Scheuermann's kyphosis patients (p = 0.022 on the left and p = 0.016 on the right side compared to control group). There was no significant change in multifidus CSA found at L4/5. The mean CSA of the extensor spinae muscles group were significantly smaller at all levels in Scheuermann's kyphosis patients : p = 0.001 bilaterally at L3/4 and p = 0.015 right side and p = 0.009 left side at L4/5 level. This study shows that patients with Scheuermann's kyphosis deformity have significantly smaller CSA of lumbar multifidus and extensor spinae muscles.