Association between cumulative surgeon experience and long-term outcomes in complex abdominal wall reconstruction.

PURPOSE: While many factors have been correlated with lesser outcomes in abdominal wall reconstruction (AWR), the impact of surgeon experience has yet to be elucidated. We sought to evaluate the effect of cumulative surgeon experience on long-term complex AWR outcomes. METHODS: We conducted a comprehensive review of all consecutive patients who underwent AWR using biologic mesh for the repair of ventral hernias or tumor resection defects from March 2005 to June 2019. The primary outcome measure was hernia recurrence (HR). Secondary outcomes were surgical site occurrences (SSOs) and surgical site infections (SSIs). Patients were a priori categorized into the following groups according to the cumulative number of hernia repairs performed by their surgeons: low (< 50), moderate experience (50-100), and high (> 100) experience. RESULTS: We identified 60 surgeons and 650 consecutive patients (62% women) who met our inclusion criteria. In adjusted models, AWR performed by surgeons with high experience was associated with a fourfold lower risk of HR (hazard ratio, 0.28; 95% confidence interval, 0.08 to 0.87), but the odds of surgical site occurrences (odds ratio, 0.72, 95% confidence interval, 0.34 to 1.52) and surgical site infections (odds ratio, 0.89, 95% confidence interval, 0.26 to 2.86) did not differ significantly in the high-experience group. CONCLUSIONS: High surgical experience, defined as > 100 cumulative hernia repairs, is predictive for markedly lower HR rates in complex AWR. These findings have potential implications for preoperative risk assessment, patient-centered surgeon selection, regulatory oversight, specific referral patterns, designations of centers of excellence, and individual provider or trainee quality improvement.

Validation of a mobile app for reducing errors of administration of medications in an emergency.

Medication errors occur frequently and are a risk to patient safety. To reduce mistakes in the medication process in emergencies, a mobile app has been developed supporting the calculation of doses and administration of drugs. A simulation study was performed to validate the app as a tool to reduce medication errors. This was a randomised crossover study conducted in the Academic Hospital. The participants included were residents and attendings in anaesthesiology. 74 Participants performed four simulation scenarios in which they had to calculate and administer drugs for emergencies. Two scenarios were performed with the app ("app scenarios") and the other two scenarios were performed without the use of the app ("control scenarios"). The order of drugs, simulation patients and usage of aid were randomized. The accuracy of administered drug doses were measured. Medications were categorised as either "accurate" ([Formula: see text]% of target dosage) or "wrong" (less than 50% or more than 200% of target dosage). The dosage calculated and the dosage administered were documented separately to differentiate between calculation and handling errors. During app scenarios, there were no "wrong" dosages, whereas 6.8 (95% CI 2.7-10.8%) of dosages in control scenarios were evaluated as "wrong". The probability of giving an "accurate" dosage was increased from 77.7 (70.9-84.5%) in control scenarios to 93.9 (90-97.8%) in app scenarios. Calculation errors were the main cause for wrong dosing. The app is an appropriate and feasible tool to reduce calculation and handling errors and may increase patient safety.

An ultra-high vacuum scanning tunneling microscope operating at sub-Kelvin temperatures and high magnetic fields for spin-resolved measurements.

We present the construction and performance of an ultra-low-temperature scanning tunneling microscope (STM), working in ultra-high vacuum (UHV) conditions and in high magnetic fields up to 9 T. The cryogenic environment of the STM is generated by a single-shot 3He magnet cryostat in combination with a 4He dewar system. At a base temperature (300 mK), the cryostat has an operation time of approximately 80 h. The special design of the microscope allows the transfer of the STM head from the cryostat to a UHV chamber system, where samples and STM tips can be easily exchanged. The UHV chambers are equipped with specific surface science treatment tools for the functionalization of samples and tips, including high-temperature treatments and thin film deposition. This, in particular, enables spin-resolved tunneling measurements. We present test measurements using well-known samples and tips based on superconductors and metallic materials such as LiFeAs, Nb, Fe, and W. The measurements demonstrate the outstanding performance of the STM with high spatial and energy resolution as well as the spin-resolved capability.

Two distinct superconducting phases in LiFeAs.

A non-trivial temperature evolution of superconductivity including a temperature-induced phase transition between two superconducting phases or even a time-reversal symmetry breaking order parameter is in principle expected in multiband superconductors such as iron-pnictides. Here we present scanning tunnelling spectroscopy data of LiFeAs which reveal two distinct superconducting phases: at = 18 K a partial superconducting gap opens, evidenced by subtle, yet clear features in the tunnelling spectra, i.e. particle-hole symmetric coherence peak and dip-hump structures. At Tc = 16 K, these features substantiate dramatically and become characteristic of full superconductivity. Remarkably, the distance between the dip-hump structures and the coherence peaks remains practically constant in the whole temperature regimeT ≤ . This rules out the connection of the dip-hump structures to an antiferromagnetic spin resonance.

LabDisk with complete reagent prestorage for sample-to-answer nucleic acid based detection of respiratory pathogens verified with influenza A H3N2 virus.

Portable point-of-care devices for pathogen detection require easy, minimal and user-friendly handling steps and need to have the same diagnostic performance compared to centralized laboratories. In this work we present a fully automated sample-to-answer detection of influenza A H3N2 virus in a centrifugal LabDisk with complete prestorage of reagents. Thus, the initial supply of the sample remains the only manual handling step. The self-contained LabDisk automates by centrifugal microfluidics all necessary process chains for PCR-based pathogen detection: pathogen lysis, magnetic bead based nucleic acid extraction, aliquoting of the eluate into 8 reaction cavities, and real-time reverse transcription polymerase chain reaction (RT-PCR). Prestored reagents comprise air dried specific primers and fluorescence probes, lyophilized RT-PCR mastermix and stick-packaged liquid reagents for nucleic acid extraction. Employing two different release frequencies for the stick-packaged liquid reagents enables on-demand release of highly wetting extraction buffers, such as sequential release of lysis and binding buffer. Microfluidic process-flow was successful in 54 out of 55 tested LabDisks. We demonstrate successful detection of the respiratory pathogen influenza A H3N2 virus in a total of 18 LabDisks with sample concentrations down to 2.39 × 10(4) viral RNA copies per ml, which is in the range of clinical relevance. Furthermore, we detected RNA bacteriophage MS2 acting as internal control in 3 LabDisks with a sample concentration down to 75 plaque forming units (pfu) per ml. All experiments were applied in a 2 kg portable, laptop controlled point-of-care device. The turnaround time of the complete analysis from sample-to-answer was less than 3.5 hours.

Detection of delayed cerebral ischemia (DCI) in subarachnoid haemorrhage applying near-infrared spectroscopy: elimination of the extracerebral signal by transcutaneous and intraparenchymatous measurements in parallel.

BACKGROUND: Detection of delayed cerebral ischemia (DCI) in high-grade subarachnoid haemorrhage (SAH) is an unsolved issue. Conventional near-infrared spectroscopy (NIRS) with optodes applied over the skin is controversial because the NIRS signal is contaminated by extracerebral tissue. The objective is to quantify and subtract the contribution from extracerebral tissue from the signal by using measurements in parallel with a NIRS brain tissue probe and conventional NIRS. METHODS: In a patient with high-grade SAH, two approaches for NIRS were applied. First, a conventional brain tissue probe for intracranial pressure (ICP) monitoring, supplied by optical fibres, was placed into the brain tissue 2 cm deep from the dura. Second, for conventional NIRS, a plaster-based patch carrying optodes (one emitter, two detectors) was attached to the skin. Central venous injections of 0.3 mg/kg body weight (bw) indocyanine green (ICG) were performed. ICG dye dilution curves obtained with the probe and patch were collected simultaneously and analysed for blood flow values. RESULTS: Twelve measurements in parallel with the probe and patch were performed. Mean cerebral blood flow (CBF) for the probe was higher (24.8 ± 9.1 ml/100 g/min) compared with the values obtained with the patch (for detector 1, extra-cerebral blood flow [ECBF] mean 5.1 ± 1.8 ml/100 g/min; p = 0.002; for detector 2, 6.6 ± 2.1 ml/100 g/min; p = 0.002). CBF values obtained with the probe correlated with blood flow values obtained with the patch (for CBF vs. ECBF detector 1, r = 0.72 [p = 0.008]; ECBF detector 2, r = 0.79 [p = 0.002]). CONCLUSIONS: Blood flow values obtained with conventional NIRS correlated significantly with absolute CBF values obtained directly within the brain tissue. Simultaneous measurements with the NeMo Probe and NeMo Patch allow quantification and subtraction of the contribution from extracerebral tissues from the signal obtained with conventional NIRS.

Design and properties of a cryogenic dip-stick scanning tunneling microscope with capacitive coarse approach control.

We present the design, setup, and operation of a new dip-stick scanning tunneling microscope. Its special design allows measurements in the temperature range from 4.7 K up to room temperature, where cryogenic vacuum conditions are maintained during the measurement. The system fits into every (4)He vessel with a bore of 50 mm, e.g., a transport dewar or a magnet bath cryostat. The microscope is equipped with a cleaving mechanism for cleaving single crystals in the whole temperature range and under cryogenic vacuum conditions. For the tip approach, a capacitive automated coarse approach is implemented. We present test measurements on the charge density wave system 2H-NbSe2 and the superconductor LiFeAs which demonstrate scanning tunneling microscopy and spectroscopy data acquisition with high stability, high spatial resolution at variable temperatures and in high magnetic fields.

[Acquired Gitelman syndrome associated with Sjögren's syndrome and scleroderma]. / Syndrome de Gitelman acquis au cours d'un syndrome de Gougerot-Sjögren associé à une sclérodermie.

Tubulopathy can complicate autoimmune diseases. It is usually a distal tubular acidosis, but Fanconi syndrome or Bartter syndrome has been exceptionally reported. We report a case of acquired Gitelman syndrome in a 32-year-old male who also presented diffuse scleroderma autoimmune thyroiditis, and Sjögren's syndrome. Only three cases of Sjögren syndrome associated with Gitelman syndrome have been previously reported in literature. The absence of other cases in the family and absence of mutation SLC12A3 emphasise the relation between autoimmune disease and this tubulopathy.

Preservation of dendritic cell function upon labeling with amino functionalized polymeric nanoparticles.

Dendritic cells (DCs) are key players in eliciting immunity against antigens, therefore making them the focus of many investigations on immune responses in infections, cancer and autoimmune diseases. Nanosized materials have just recently been investigated for their use as carriers of antigens and as labeling agents for DCs. For this later use nanoparticles should be non-toxic and should most importantly not alter the physiological functions of DCs. Here we demonstrate that by the use of polymeric fluorescent nanoparticles as synthesized by the miniemulsion process immature DCs (iDCs) can be efficiently labeled intracellularly. Amino functionalized nanoparticles are more effective than carboxy functionalized ones. Even after 8 days 95% of DCs have retained nanoparticles with a fluorescence intensity of 67% compared to day 1. Nanoparticle labeling does not influence expression of cell surface molecules on mature DCs (mDCs) like HLA-DR, CD80/83/86, CCR7, CD11c nor does it influence the immunostimulatory capacity of mDCs. This procedure does also not impair the capability of DCs for uptake, processing and presentation of viral antigens as demonstrated by interferon-gamma ELISPOT on T cells stimulated with viral antigens presented by DCs. Therefore polymeric nanoparticles are a promising tool to study migration and homing of DCs in animal studies.

Substantia nigra echomorphology and motor cortex excitability.

The aim of our study was to investigate the relation between substantia nigra (SN) echomorphology and indices of motor cortex excitability. Nigral hyperechogenicity in healthy individuals is thought to represent an SN abnormality or predisposition to Parkinson's disease (PD) and its prevalence is greater in the very old. Our study involved 20 old healthy subjects (aged 72-84 years) known to have normal (n=10) or abnormal (n=10) SN echomorphology. All were in good health with no overt neurological signs. SN morphology was assessed with transcranial sonography through the pre-auricular bone window. Motor cortical excitability and intracortical inhibition were assessed with transcranial magnetic stimulation (TMS) over the first dorsal interosseus motor area. Single stimuli were delivered during relaxation and voluntary contraction and paired stimuli were delivered during relaxation. Each cortical hemisphere was analysed separately. The response to single-pulse TMS (in motor cortex ipsilateral to the target SN) did not differ between groups. However, a significant difference between groups was observed in the paired pulse paradigm (conditioning stimulus intensity: 70% resting motor threshold; interstimulus interval: 2 ms). The conditioned motor evoked potential amplitude was significantly larger ipsilateral to the hyperechogenic SN than in controls (P=0.014). Thus, healthy subjects with SN hyperechogenicity exhibit significantly less intracortical inhibition within the motor cortex than subjects with normal echomorphology. Decreased intracortical inhibition is also observed in PD patients. This study provides further evidence that SN hyperechogenicity in healthy individuals is associated with changes characteristic of PD supporting a role for this feature as a vulnerability marker or state marker for subtle nigral dopaminergic dysfunction.

Investigation of the exclusive 3He(e,e' pn)1H reaction.

Cross sections for the 3He(e,e' pn)1H reaction were measured for the first time at energy transfers of 220 and 270 MeV for several momentum transfers ranging from 300 to 450 MeV/c. Cross sections are presented as a function of the momentum of the recoil proton and the momentum transfer. Continuum Faddeev calculations using the Argonne V18 and Bonn-B nucleon-nucleon potentials overestimate the measured cross sections by a factor 5 at low recoil proton momentum with the discrepancy becoming smaller at higher recoil proton momentum.

A modular implementation of dispersive materials for time-domain simulations with application to gold nanospheres at optical frequencies.

The development of photonic nano-structures can strongly benefit from full-field electromagnetic (EM) simulations. To this end, geometrical flexibility and accurate material modelling are crucial requirements set on the simulation method. This paper introduces a modular implementation of dispersive materials for time-domain EM simulations with focus on the Finite-Volume Time-Domain (FVTD) method. The proposed treatment can handle electric and magnetic dispersive materials exhibiting multi-pole Debye, Lorentz and Drude models, which can be mixed and combined without restrictions. The presented technique is verified in several illustrative examples, where the backscattering from dispersive spheres is calculated. The amount of flexibility and freedom gained from the proposed implementation will be demonstrated in the challenging simulation of the plasmonic resonance behavior of two gold nanospheres coupled in close proximity, where the dispersive characteristic of gold is approximated by realistic values in the optical frequency range.

Dissolution in nasal fluid, retention and anti-inflammatory activity of fluticasone furoate in human nasal tissue ex vivo.

BACKGROUND: Intranasal glucocorticoids represent the most effective pharmacologic treatment of allergic rhinitis. So far, no clinical data are available that compare fluticasone furoate (FF) with other intranasally applied glucocorticoids. OBJECTIVE: Because the pharmacokinetic behaviour of drugs governs their presence at the therapeutic target site we analysed selected in vitro properties of FF in comparison with triamcinolone acetonide (TCA), budesonide (Bud), fluticasone propionate (FP) and mometasone furoate (MF). Additionally, we determined the anti-inflammatory activity of the glucocorticoid fraction residing in human nasal tissue samples after washing. METHODS: We analysed the solubility of the compounds in artificial human nasal fluid and the retention in human nasal tissue as well as typical spray volumes of commercially available drug preparations. As an anti-inflammatory measure, we evaluated the inhibition of IL-8 release from epithelial cells. RESULTS: FF is delivered in the smallest application volume per spray. Despite the low aqueous solubility of glucocorticoids, a fraction of the compounds is already dissolved in the aqueous supernatants of drug preparations (Bud>TCA>FP>MF>FF). The dissolution of FP, MF and FF was significantly enhanced in artificial nasal fluid and FF displayed the most pronounced enhancement of solubility in the presence of proteins. Consistent with this result, the highest retention in nasal tissue was observed for FF, followed by FP>MF>Bud>TCA. After washing of the nasal tissue samples, all compounds inhibited IL-8 release, with FF displaying the highest activity. CONCLUSION: FF displayed beneficial properties for nasal application. Its low application volume per spray is a prerequisite for effective drug utilization by avoiding immediate loss by nose runoff or drip down the throat. Sustained dissolution and high tissue binding of FF should contribute towards an extended presence of compounds in nasal tissue as a basis for a prolonged pharmacologic activity.

A predicted operon map for Mycobacterium tuberculosis.

The prediction of operons in Mycobacterium tuberculosis (MTB) is a first step toward understanding the regulatory network of this pathogen. Here we apply a statistical model using logistic regression to predict operons in MTB. As predictors, our model incorporates intergenic distance and the correlation of gene expression calculated for adjacent gene pairs from over 474 microarray experiments with MTB RNA. We validate our findings with known examples from the literature and experimentation. From this model, we rank each potential operon pair by the strength of evidence for cotranscription, choose a classification threshold with a true positive rate of over 90% at a false positive rate of 9.1%, and use it to construct an operon map for the MTB genome.

A study paradigm allowing comparison of multiple high-resolution rCBV-maps for the examination of drug effects.

Owing to the neuro-vascular coupling, measurement of changes in regional cerebral blood flow and blood volume (rCBV) can be used as surrogates reflecting the effects of central nervous system active drugs on neural transmission. As most such drugs are administered orally or intramuscularly and, in many cases, beneficial effects due to drug treatment can be observed only after chronic administration for days or weeks, the evaluation of drug efficacy requires the development of acquisition and analysis tools that allow for comparison of imaging data sets obtained in multiple sessions and for multiple subjects. In the present study, high-resolution susceptibility contrast MR perfusion imaging using a super-paramagnetic contrast agent (CA) was applied to study the effect of a single oral administration of the acetylcholine-esterase inhibitor rivastigmine (Exelon) on rCBV in rats. rCBV maps were calculated from two T2-weighted three-dimensional fast-spin-echo scans recorded before and after the injection of the CA, respectively. All MRI data sets were mapped to a reference data set obtained from a normal male Sprague-Dawley rat using an automated co-registration procedure prior to the analysis for drug effects. Rivastigmine was orally administered at doses of 2, 4 or 8 mg/kg 1 h prior to the rCBV measurement. Rivastigmine increased rCBV in several brain areas including cortex, caudate putamen and hippocampus. The observed effects were dose-dependent and the changes reached the order of 5-12% as compared with baseline levels. Vehicle-treated animals showed no significant alterations of blood volume, demonstrating the reproducibility and stability of rCBV measurements.

Measurement of the exclusive 3He(e,e'p) reaction below the quasielastic peak.

New, high-precision measurements of the 3He(e,e(')p) reaction using the A1 Collaboration spectrometers at the Mainz microtron MAMI are presented. These were performed in antiparallel kinematics at energy transfers below the quasielastic peak, and at a central momentum transfer of 685 MeV/c. Cross sections and distorted momentum distributions were extracted and compared to theoretical predictions and existing data. The longitudinal and transverse behavior of the cross section was also studied. Sizable differences in the cross-section behavior from theoretical predictions based on the plane wave impulse approximation were observed in both the two- and three-body breakup channels. Full Faddeev-type calculations account for some of the observed excess cross-section, but significant differences remain.

Signs of metastatic disease on thoracic radiographs of dogs suffering from mammary gland tumours: a retrospective study (1990-1998).

A mammary gland tumour (MGT) was clinically diagnosed in 136 dogs. Histologically 71% were malignant and 29% benign. Intrathoracic metastatic disease was noted or suspected radiographically in 13.5% of the dogs with malignant and in 2.5% of the dogs with benign MGT. Six dogs with malignant MGT were necropsied, 5 had pulmonary metastases but only 1 had radiographic signs of intrathoracic metastatic disease. We conclude that radiographs are not very sensitive for detection of early intrathoracic metastatic disease of MGT.

Supercritical carbon dioxide extraction of selected medicinal plants--effects of high pressure and added ethanol on yield of extracted substances.

The possibilities and limitations of supercritical fluid extraction of natural products of low, medium and high polarity under very high pressure and with polar modifiers has been investigated. The medicinal herbs marigold (Calendula officinalis), hawthorn (Crataegus sp.) and chamomile (Matricaria recutita) were used as models in this study. Extraction profiles and the spectra of extractable metabolites were recorded following extraction with mixtures of carbon dioxide:ethanol of varying proportions (0-20% ethanol) and at various pressures in the range 300-689 bar. Components were identified by HPLC-PAD-MS or GC-MS and quantified by HPLC or GC as appropriate. Extraction yields under the varying conditions depended to a large extent on the profiles of secondary metabolites present in the three drugs. Whereas the extractability of lipophilic compounds increased substantially at pressures above 300 bar, the yields of polyphenolic and glycosidic compounds remained low even at 689 bar and with 20% modifier in the extraction fluid.