Poor man's understanding of kinks originating from strong electronic correlations

By means of dynamical mean field theory calculations, it was recently discovered that kinks generically arise in strongly correlated systems, even in the absence of external bosonic degrees of freedoms such as phonons. However, the physical mechanism behind these kinks remained unclear. On the basis of the perturbative and numerical renormalization group theory, we herewith identify these kinks as the effective Kondo energy scale of the interacting lattice system which is shown to be smaller than the width of the central peak.

Necrotising fasciitis of the thigh

Necrotising fasciitis (NF) is an extremely virulent form of infectious fasciitis. It affects skin, subcutaneous fat and superficial and deep muscular fascia by rapidly progressive necrosis. Expeditious diagnosis and radical debridement is necessary to prevent the onset of sepsis, multisystem organ failure and possible death. Perforated rectal cancer resulting in NF can spread to the perineum and genitals known as Fournier gangrene. This case describes an unusual case of NF of the right thigh as first presentation highly suggestive for rectal cancer.

Validation of methods for the detection and quantification of engineered nanoparticles in food

The potential impact of nanomaterials on the environment and on human health has already triggered legislation requiring labelling of products containing nanoparticles. However, so far, no validated analytical methods for the implementation of this legislation exist. This paper outlines a generic approach for the validation of methods for detection and quantification of nanoparticles in food samples. It proposes validation of identity, selectivity, precision, working range, limit of detection and robustness, bearing in mind that each "result" must include information about the chemical identity, particle size and mass or particle number concentration. This has an impact on testing for selectivity and trueness, which also must take these aspects into consideration. Selectivity must not only be tested against matrix constituents and other nanoparticles, but it shall also be tested whether the methods apply equally well to particles of different suppliers. In trueness testing, information whether the particle size distribution has changed during analysis is required. Results are largely expected to follow normal distributions due to the expected high number of particles. An approach of estimating measurement uncertainties from the validation data is given.

Acute pancreatitis in two five-day-old Appaloosa foals

Severe acute pancreatitis (SAP) in foals is rare and treatment has not been documented. This paper describes the clinical, haematological and ultrasonographic findings as well as attempted treatment of SAP in two 5-day-old Appaloosa fillies. Clinical signs, including colic, diarrhoea and coma, may be mistaken for sepsis or neonatal encephalopathy. Hyperlipaemic serum and peritoneal fluid, and elevated serum and peritoneal fluid amylase and lipase activities aided the diagnosis. Severe acute pancreatitis should be included as a differential in an acutely ill foal with diarrhoea, colic, cerebral cortica dysfunction and hyperlipaemia.

CROSS-LINKING OF SATURATED ELASTOMERS WITH DI-AZIDES. PART II: MECHANISTIC STUDY

In the first part, one di-sulfonyl azide: 1,3BDSA, and two di-azidoformates: GDAF and 4,4′DAF, were selected and extensively investigated as curing agents for EP(D)M rubbers. Although the mechanical properties of the vulcanizates vary significantly with the particular di-azide used, all of them act as effective curing agents compared to a peroxide/coagent curing system. To explain the differences in properties as well as to obtain a deeper understanding of the reaction mechanism, model compound experiments are performed with 4-methylheptane as substitute for the saturated ethylene–propylene copolymer rubber backbone. Using gas chromatography/mass spectrometry and high performance liquid chromatography/mass spectrometry as analytical tools, a basic understanding of the reaction mechanisms between sulfonyl azide and azidoformate functionalities and saturated hydrocarbons is obtained.

Blood pressure control in the Hypertension in the Very Elderly Trial (HYVET)

To report blood pressure control in the Hypertension in the Very Elderly Trial, a placebo-controlled trial of hypertensive (systolic blood pressure (SBP) 160-199 mm Hg, diastolic blood pressure (DBP) <110 mm Hg) participants over the age of 80 years, given treatment in three steps: indapamide slow release 1.5 mg alone, indapamide plus 2 mg perindopril and indapamide plus 4 mg perindopril. The difference in control between participants with combined systolic and diastolic hypertension (SDH, DBP90 mm Hg) and those with isolated systolic hypertension (ISH, DBP<90 mm Hg) is determined together with the effects of increments in the treatment regimen. At 2 years, the active treatment lowered blood pressure by 16.5/6.9 mm Hg more than that on placebo in participants with SDH and by 19.3/4.8 mm Hg more in those with ISH. The 2-year falls in pressure on placebo alone were 13.2/8.5 mm Hg in SDH and 8.2/1.5 mm Hg in ISH participants. With full titration of active treatment, 62% of SDH participants achieved goal SBP (<150 mm Hg) by 2 years and 71% of those with ISH. The corresponding results for DBP control (<80 mm Hg) were 40 and 78%. The addition of active perindopril 2 mg roughly doubled the percentage controlled, as did increasing to 4 from 2 mg. Blood pressure control was good with ISH and better than with SDH. The fall in SBP accounted for the observed 30% reduction in strokes, but the 21% reduction in total mortality and 64% reduction in heart failure were greater than predicted.

Low-energy properties of the Kondo lattice model

We study the zero-temperature properties of the Kondo lattice model within the dynamical mean-field theory. As an impurity solver we use the numerical renormalization group. We present results for the paramagnetic case showing the anticipated heavy-fermion physics, including direct evidence for the appearance of a large Fermi surface for antiferromagnetic exchange interaction. Allowing for the formation of a Néel state, we observe at finite doping an antiferromagnetic metal below a critical exchange interaction, which shows a crossover from a local moment antiferromagnet with a small Fermi surface for weak exchange coupling to a heavy-fermion antiferromagnet with a large Fermi surface for increasing exchange. Including lattice degrees of freedom via an additional Holstein term we observe a significant suppression of the Kondo effect, leading to a strongly reduced low-energy scale. For too large electron-phonon coupling we find a complete collapse of the heavy Fermi liquid and the formation of polarons.

Ultrashort pulse generation from diode pumped mode-locked Yb3+:sesquioxide single crystal lasers

We present diode pumped SESAM supported Kerr-lens mode locked laser operation based on Yb3+:Sc2O3 and Yb3+:Lu2O3 single crystals. Pulses as short as 71 fs with an average power of 1.09 W were obtained from an Yb3+:Lu2O3 single crystal. Yb3+:Sc2O3 delivered pulses as short as 81 fs with an average power of 840 mW. The mode locked laser operation was stable for longer than 2 hours.

Immediate and late benefits of treating very elderly people with hypertension: results from active treatment extension to Hypertension in the Very Elderly randomised controlled trial

OBJECTIVE

To assess if very elderly people with hypertension obtain early benefit from antihypertensive treatment.

DESIGN

One year open label active treatment extension of randomised controlled trial (Hypertension in the Very Elderly Trial (HYVET)).

SETTING

Hospital and general practice based centres mainly in eastern and western Europe, China, and Tunisia.

PARTICIPANTS

People on double blind treatment at the end of HYVET were eligible to enter the extension.

INTERVENTIONS

Participants on active blood pressure lowering treatment continued taking active drug; those on placebo were given active blood pressure lowering treatment. The treatment regimen was as used in the main trial-indapamide SR 1.5 mg (plus perindopril 2-4 mg if required)-with the same target blood pressure of less than 150/80 mm Hg.

MAIN OUTCOME MEASURES

The primary outcome was all stroke; other outcomes included total mortality, cardiovascular mortality, and cardiovascular events.

RESULTS

Of 1882 people eligible for entry to the extension, 1712 (91%) agreed to participate. During the extension period, 1682 patient years were accrued. By six months, the difference in blood pressure between the two groups was 1.2/0.7 mm Hg. Comparing people previously treated with active drug and those previously on placebo, no significant differences were seen for stroke (n = 13; hazard ratio 1.92, 95% confidence interval 0.59 to 6.22) or cardiovascular events (n = 25; 0.78, 0.36 to 1.72). Differences were seen for total mortality (47 deaths; hazard ratio 0.48, 0.26 to 0.87; P = 0.02) and cardiovascular mortality (11 deaths; 0.19, 0.04 to 0.87; P = 0.03).

CONCLUSION

Very elderly patients with hypertension may gain immediate benefit from treatment. Sustained differences in reductions of total mortality and cardiovascular mortality reinforce the benefits and support the need for early and long term treatment. Trial registration Clinical trials NCT00122811.

Continuous fluorescence microphotolysis: A sensitive method for study of diffusion processes in single cells

Continuous fluorescence microphotolysis is a sensitive method for the study of translational diffusion in the plasma membrane of single living cells and related systems. In this communication the conceptual basis of the method and its theoretical framework and experimental realization, as well as applications, are reported. In continuous fluorescence microphotolysis a microscopic membrane area of a single fluorescently labeled cell is irradiated by a laser beam while the fluorescence emitted from the area is monitored. The decay of the measuring signal reflects the competition of two processes: (i) the elimination of fluorophores by irreversible photolysis, and (ii) the entrance of new fluorophores into the area by diffusion. Rate constants for the two processes can be derived from the measuring data by mathematical analysis. As compared to our initial approach, fluorescence microphotolysis [Peters, R., Peters, J., Tews, K. H. & Bähr, W. (1974) Biochim. Biophys. Acta 367, 282-294], the main advantage of the method described here is an improvement of data quality and detection limit by orders of magnitude. From the practical point of view the main advantage is a simplification of the experimental setup. Results obtained by this method are encouraging and support the contention that continuous fluorescence microphotolysis may disclose new aspects of diffusion processes in biological systems.

Femtosecond Yb:Lu(2)O(3) thin disk laser with 63 W of average power

We present successful power-scaling of an Yb:Lu(2)O(3) thin disk laser to record high-power levels both in cw and mode-locked operation. In a simple multimode resonator we achieved 149 W of output power in cw operation with 73% optical-to-optical efficiency (eta(opt)). Building an 81 MHz fundamental transverse mode resonator with dispersion compensation and a semiconductor saturable absorber mirror (SESAM) for passive mode locking we achieved 63 W of average power in 535 fs pulses (eta(opt)=35%). The output beam is nearly diffraction limited (M(2)<1.2). The 0.78 microJ pulses with a peak power of 1.28 MW had a central wavelength of 1034 nm and were close to the Fourier transform limit. With an SESAM with a larger modulation depth we obtained pulses as short as 329 fs at 40 W average power corresponding to a pulse energy of 0.49 microJ and a peak power of 1.32 MW.

Wet weather impact on trihalomethane formation potential in tributaries to drinking water reservoirs

During rain storm events, land surface runoff and resuspension of bottom sediments cause an increase in Trihalomethane (THM) precursors in rivers. These precursors, when chlorinated at water treatment facilities will lead to the formation of THMs and hence impact drinking water resources. In order to evaluate the wet weather impact on the potential formation of THMs, river samples were collected before, during and after three rain storms ranging from 15.2 to 24.9 mm precipitation. The samples were tested for THM formation potential and other indicators including UV254 absorbance, turbidity and volatile suspended solid (VSS). Average levels of THMs increased from 61 microg/l during dry weather to 131 microg/l during wet weather, and then went back to 81 microg/l after rain ended. Wet weather values of THM are well above the maximum contaminant level (MCL) 80 microg/l, set by EPA for drinking water. THM indicators also exhibited similar trends. Average levels increased from 0.6 to 1.8 abs; 2.6 to 6 ntu; and 7.5 to 15 mg/l respectively for UV254, turbidity and VSS. A positive correlation was observed between THM formation and THM indicators. The t-test of significance (p-value) was less than 0.05 for all indicators, and R values ranged from 0.85 to 0.92 between THMs and the indicators, and 0.72 to 0.9 among indicators themselves.

Performance of a dedicated light delivery and dosimetry device for photodynamic therapy of nasopharyngeal carcinoma: phantom and volunteer experiments

The objective of this study was to develop a light delivery and measurement device for photodynamic therapy (PDT) in the nasopharyngeal cavity, which achieves a homogeneous and reproducible fluence rate distribution to a target area and provides proper shielding of predefined risk areas.

MATERIALS AND METHODS

A flexible silicone applicator was developed, incorporating light delivery and dosimetry fibers. The applicator can be inserted through the mouth and fixed in the nasopharyngeal cavity. Tissue optical phantoms were prepared on the basis of optical properties measured in vivo using diffuse reflectance spectroscopy (DRS). The fluence rate over the length of the applicator surface was measured in air, in tissue optical phantoms and in five healthy volunteers.

RESULTS

The fluence rate distribution over the applicator surface in air and tissue optical phantom was found to be more homogeneous (SD/mean 3.8% and 18.3%, respectively) than the fluence rate distribution in five volunteers (SD/mean ranging from 19% up to 52%). The maximum observed fluence rate build-up in the nasopharynx varied between subjects and ranged from a factor of 4.1-6.9. Shielding of the risk area such as the soft palate and tongue was effective.

CONCLUSIONS

In air and in tissue optical phantoms the fluence rate distribution of the device was highly homogeneous. The observed inter-subject and intra-subject variations in fluence rate in healthy volunteers originated from differences in optical properties and nasopharyngeal geometry. Light delivery based on a single tissue surface measurement will not be adequate. In situ dosimetric measurements are required to determine the light fluence delivered to a geometrically complex site such as the nasopharynx. These observations should be taken in consideration when developing light applicators for PDT of the nasopharynx and other non-uniform surfaces.

Efficient femtosecond high power Yb:Lu(2)O(3) thin disk laser

We demonstrate the first passively mode-locked thin disk laser based on Yb:Lu(2)O(3). The laser generates 370-fs pulses with 20.5 W of average power in a diffraction-limited beam (M(2) < 1.1). The nearly transform-limited pulses have a spectral bandwidth of 3.4 nm centered near 1034 nm. With slightly longer pulses (523 fs) we obtained 24 W of average power at a pump power of 56 W, resulting in an optical-to-optical efficiency of 43%, which is higher than for any previously mode-locked thin disk laser.

[Guidelines based on decision support software. Quality management in neurological outpatient schizophrenia treatment]

The positive effect of greater adherence to evidence-based guidelines on possibilities of optimizing diagnosis and therapy has been shown various times. Electronic systems for interactive support and systematization of physicians' decision-making represent a relatively new method for implementing guidelines. Introducing the "schizophrenia module", newly developed decision support software is presented combining electronic data processing-based, quality-oriented documentation and interactive decision support in the outpatient treatment for schizophrenic disorders. Structure, functionality, and options of use are presented. Besides classic measures of quality management (benchmarking), electronic decision support systems can contribute to improve process quality and outcome in the treatment of mental diseases.

Characterisation of UV-cured acrylate networks by means of hydrolysis followed by aqueous size-exclusion combined with reversed-phase chromatography

UV-cured networks prepared from mixtures of di-functional (polyethylene-glycol di-acrylate) and mono-functional (2-ethylhexyl acrylate) acrylates were analysed after hydrolysis, by aqueous size-exclusion chromatography coupled to on-line reversed-phase liquid-chromatography. The mean network density and the fraction of dangling chain ends of these networks were varied by changing the concentration of mono-functional acrylate. The amount and the molar-mass distribution of the polyethylene-glycol chains between cross-links (M(XL)) and polyacrylic acid (PAA) backbone chains (the so-called kinetic chain length (kcl)) in the different acrylate networks were determined quantitatively. The molar-mass distribution of kcl revealed an almost linear dependence on the concentration of mono-functional acrylate. Analysis of the starting materials showed a significant concentration of mono-functional polyethylene-glycol acrylate. In combination with the analysis of the extractables of the UV-cured networks (polymers not attached to the network, impurities that originate from the photo-initiator and unreacted monomers), more insight in the total network structure was obtained. It was shown that the UV-cured networks contain only small fractions of residual compounds. With these results, the chemical network structure for the different UV-cured acrylate polymers was expressed in network parameters such as the number of PAA units which are cross-linked, the degree of cross-linking, and the network density, which is the molar concentration of effective network chains between cross-links per volume of the polymers. The mean molar mass of chains between chemical network junctions (M(C)) was calculated and compared with results obtained from solid-state NMR and DMA. The mean molar mass of chains between network junctions as determined by these methods was similar.

In vivo fluence rate measurements during Foscan-mediated photodynamic therapy of persistent and recurrent nasopharyngeal carcinomas using a dedicated light applicator

The objective of this study was to evaluate the performance of a dedicated light applicator for light delivery and fluence rate monitoring during Foscan-mediated photodynamic therapy of nasopharyngeal carcinoma in a clinical phase I/II study. We have developed a flexible silicone applicator that can be inserted through the mouth and fixed in the nasopharyngeal cavity. Three isotropic fibers, for measuring of the fluence (rate) during therapy, were located within the nasopharyngeal tumor target area and one was manually positioned to monitor structures at risk in the shielded area. A flexible black silicon patch tailored to the patient's anatomy is attached to the applicator to shield the soft palate and oral cavity from the 652-nm laser light. Fourteen patients were included in the study, resulting in 26 fluence rate measurements in the risk volume (two failures). We observed a systematic reduction in fluence rate during therapy in 20 out of 26 illuminations, which may be related to photodynamic therapy-induced increased blood content, decreased oxygenation, or reduced scattering. Our findings demonstrate that the applicator was easily inserted into the nasopharynx. The average light distribution in the target area was reasonably uniform over the length of the applicator, thus giving an acceptably homogeneous illumination throughout the cavity. Shielding of the risk area was adequate. Large interpatient variations in fluence rate stress the need for in vivo dosimetry. This enables corrections to be made for differences in optical properties and geometry resulting in comparable amounts of light available for Foscan absorption.

Ageing and the brain

Ageing causes changes to the brain size, vasculature, and cognition. The brain shrinks with increasing age and there are changes at all levels from molecules to morphology. Incidence of stroke, white matter lesions, and dementia also rise with age, as does level of memory impairment and there are changes in levels of neurotransmitters and hormones. Protective factors that reduce cardiovascular risk, namely regular exercise, a healthy diet, and low to moderate alcohol intake, seem to aid the ageing brain as does increased cognitive effort in the form of education or occupational attainment. A healthy life both physically and mentally may be the best defence against the changes of an ageing brain. Additional measures to prevent cardiovascular disease may also be important.

[An auricle prosthesis for a boy with the Vater association]

A nearly 7-year-old boy suffered from psychosocial problems because of aplasia of the left auricle. The auricle aplasia was a symptom of the VATER association. It was decided to conduct a purely problem-oriented treatment in preparing an auricle prosthesis, firmly fixed using an adhesive. Wearing the auricle prosthesis, the boy improved very quickly and substantially in being more free and self-confident.

[An individual facial shield for a sportsman with an orofacial injury]

Facial shields are used when practising contact sports, high speed sports, sports using hard balls, sticks or bats, sports using protective shields or covers, and sports using hard boardings around the sports ground. Examples of facial shields are commercially available, per branch of sport standardised helmets. Fabricating individual protective shields is primarily restricted to mouth guards. In individual cases a more extensive facial shield is demanded, for instance in case of a surgically stabilised facial bone fracture. In order to be able to fabricate an extensive individual facial shield, an accurate to the nearest model of the anterior part of the head is required. An accurate model can be provided by making an impression of the face, which is poured in dental stone. Another method is producing a stereolithographic model using computertomography or magnetic resonance imaging. On the accurate model the facial shield can be designed and fabricated from a strictly safe material, such as polyvinylchloride or polycarbonate.

Securing the prehospital airway: a comparison of laryngeal mask insertion and endotracheal intubation by UK paramedics

OBJECTIVES

The recent introduction of a disposable laryngeal mask airway has provided paramedics with an alternative to endotracheal intubation. Time taken to secure the airway with each device was compared in patients undergoing elective surgery.

METHODS

Patients undergoing general anaesthesia were studied. Paramedics trained in laryngeal mask use and endotracheal intubation participated in the study. A Portex disposable laryngeal mask was inserted and removed, followed by a Portex endotracheal tube. Time taken from beginning of the procedure to ventilation of the patient was recorded.

RESULTS

Laryngeal mask insertion and endotracheal intubation was attempted on 52 patients. Median age was 63.5 years (range 39-83). Laryngeal mask insertion was successful in 88.5% (46 of 52) patients; endotracheal intubation was successful in 71.2% (37 of 52) patients (after no more than two attempts), p = 0.049. Intubation success was related to laryngoscopic view (87.5% grade 1, 56.3% grade 2, 0.0% grade 3. p<0.0001). When laryngeal mask/endotracheal tube insertion were both successful (n = 35 of 52), there was no significant difference in median time to secure the airway (laryngeal mask 47.0 seconds (range 24-126) compared with endotracheal tube 52.0 seconds (range 27-148) p = 0.22). Laryngeal mask insertion was successful in 80.0% (12 of 15) patients in whom endotracheal intubation had failed.

CONCLUSIONS

Even under optimal conditions, 30% of attempts at intubation by paramedics were unsuccessful. A disposable laryngeal mask has a higher success rate in securing the airway and overall, secures the airway more reliably than endotracheal intubation.

High-resolution near-field optical imaging of single nuclear pore complexes under physiological conditions

Scanning near-field optical microscopy (SNOM) circumvents the diffraction limit of conventional light microscopy and is able to achieve optical resolutions substantially below 100 nm. However, in the field of cell biology SNOM has been rarely applied, probably because previous techniques for sample-distance control are less sensitive in liquid than in air. Recently we developed a distance control based on a tuning fork in tapping mode, which is also well-suited for imaging in solution. Here we show that this approach can be used to visualize single membrane protein complexes kept in physiological media throughout. Nuclear envelopes were isolated from Xenopus laevis oocytes at conditions shown recently to conserve the transport functions of the nuclear pore complex (NPC). Isolated nuclear envelopes were fluorescently labeled by antibodies against specific proteins of the NPC (NUP153 and p62) and imaged at a resolution of approximately 60 nm. The lateral distribution of epitopes within the supramolecular NPC could be inferred from an analysis of the intensity distribution of the fluorescence spots. The different number densities of p62- and NUP153-labeled NPCs are determined and discussed. Thus we show that SNOM opens up new possibilities for directly visualizing the transport of single particles through single NPCs and other transporters.