Importance of spin-orbit interaction for the electron spin relaxation in organic semiconductors.

Despite the great interest organic spintronics has recently attracted, there is only a partial understanding of the fundamental physics behind electron spin relaxation in organic semiconductors. Mechanisms based on hyperfine interaction have been demonstrated, but the role of the spin-orbit interaction remains elusive. Here, we report muon spin spectroscopy and time-resolved photoluminescence measurements on two series of molecular semiconductors in which the strength of the spin-orbit interaction has been systematically modified with a targeted chemical substitution of different atoms at a particular molecular site. We find that the spin-orbit interaction is a significant source of electron spin relaxation in these materials.

Identification of the novel allele Cw*040110 in a German patient.

We report here the identification of a novel human leukocyte-Cw*040110 allele detected by polymerase chain reaction sequence-based typing in a German patient.

Capacitance of the double layer formed at the metal/ionic-conductor interface: how large can it be?

The capacitance of the double layer formed at a metal/ionic-conductor interface can be remarkably large, so that the apparent width of the double layer is as small as 0.3 A. Mean-field theories fail to explain such large capacitance. We propose an alternate theory of the ionic double layer which allows for the binding of discrete ions to their image charges in the metal. We show that at small voltages the capacitance of the double layer is limited only by the weak dipole-dipole repulsion between bound ions, and is therefore very large. At large voltages the depletion of bound ions from one of the capacitor electrodes triggers a collapse of the capacitance to the mean-field value.

Hand luggage in the train toilet.

BACKGROUND: The train toilet can form a barrier for those wishing to travel by train as it is perceived as being dirty, and therefore its use as being unpleasant. In addition, Dutch train toilet users have the additional issue of storing their hand luggage in the toilet's confined spaceOBJECTIVE:In this article, we examine the issue of Dutch travelers with hand luggage in relation to their use of train toilets. We investigate the type of hand luggage train travelers have with them and lastly, we study what travelers do with their hand luggage when using the toilet. METHODS: As part of an overarching study, we asked two specific questions on what travelers do with their hand luggage in a train toilet environment, followed by 22 observations from observational research. RESULTS: In the questionnaire, train travelers reported that bringing hand luggage into the train toilet is a problem because of the lack of storage space, and their fear of losing their seat. From the observational research, we noted that the participants mainly held their hand luggage on their bodies, and to a lesser extent, they placed it on the floor of the train toilet itself. None of the 22 participants used the hook to hang up their bag and/ or their coat. CONCLUSIONS: Travelers need a facility in the train toilet to store their hand luggage. Women have a stronger need for this than men, as they almost always carry an item with them. In addition, they use the toilet in hovering position or seated, with their backs to the wall, so they have limited space to store hand luggage on their backs or shoulders as men do. Most participants kept their hand luggage at a distance from the bowl, and the majority kept it off the floor (14 of the 22) because they were aware of the hygiene. The positioning of the coat/luggage hook at 1840 mm above the floor was considered to be too high, out of people's comfort area.

Theory of volumetric capacitance of an electric double-layer supercapacitor.

Electric double-layer supercapacitors are a fast-rising class of high-power energy storage devices based on porous electrodes immersed in a concentrated electrolyte or ionic liquid. As yet there is no microscopic theory to describe their surprisingly large capacitance per unit volume (volumetric capacitance) of ~100 F/cm(3), nor is there a good understanding of the fundamental limits on volumetric capacitance. In this paper we present a non-mean-field theory of the volumetric capacitance of a supercapacitor that captures the discrete nature of the ions and the exponential screening of their repulsive interaction by the electrode. We consider analytically and via Monte Carlo simulations the case of an electrode made from a good metal and show that in this case the volumetric capacitance can reach the record values. We also study how the capacitance is reduced when the electrode is an imperfect metal characterized by some finite screening radius. Finally, we argue that a carbon electrode, despite its relatively large linear screening radius, can be approximated as a perfect metal because of its strong nonlinear screening. In this way the experimentally measured capacitance values of ~100 F/cm(3) may be understood.

Anomalously large capacitance of an ionic liquid described by the restricted primitive model.

We use Monte Carlo simulations to examine the simplest model of a room-temperature ionic liquid (RTIL), called the "restricted primitive model," at a metal surface. We find that at moderately low temperatures the capacitance of the metal-RTIL interface is so large that the effective thickness of the electrostatic double layer is up to three times smaller than the ion radius. To interpret these results we suggest an approach which is based on the interaction between discrete ions and their image charges in the metal surface and which therefore goes beyond the mean-field approximation. When a voltage is applied across the interface, the strong image attraction causes counterions to condense onto the metal surface to form compact ion-image dipoles. These dipoles repel each other to form a correlated liquid. When the surface density of these dipoles is low, the insertion of an additional dipole does not require much energy. This leads to a large capacitance C that decreases monotonically with voltage V, producing a "bell-shaped" curve C(V). We also consider what happens when the electrode is made from a semimetal rather than a perfect metal. In this case, the finite screening radius of the electrode shifts the reflection plane for image charges to the interior of the electrode, and we arrive at a "camel-shaped" C(V). These predictions seem to be in qualitative agreement with experiment.

Non-mean-field theory of anomalously large double layer capacitance.

Mean-field theories claim that the capacitance of the double layer formed at a metal/ionic conductor interface cannot be larger than that of the Helmholtz capacitor, whose width is equal to the radius of an ion. However, in some experiments the apparent width of the double layer capacitor is substantially smaller. We propose an alternate non-mean-field theory of the ionic double layer to explain such large capacitance values. Our theory allows for the binding of discrete ions to their image charges in the metal, which results in the formation of interface dipoles. We focus primarily on the case where only small cations are mobile and other ions form an oppositely charged background. In this case, at small temperature and zero applied voltage dipoles form a correlated liquid on both contacts. We show that at small voltages the capacitance of the double layer is determined by the transfer of dipoles from one electrode to the other and is therefore limited only by the weak dipole-dipole repulsion between bound ions so that the capacitance is very large. At large voltages the depletion of bound ions from one of the capacitor electrodes triggers a collapse of the capacitance to the much smaller mean-field value, as seen in experimental data. We test our analytical predictions with a Monte Carlo simulation and find good agreement. We further argue that our "one-component plasma" model should work well for strongly asymmetric ion liquids. We believe that this work also suggests an improved theory of pseudocapacitance.

Non-mean-field screening by multivalent counterions.

Screening of a strongly charged macroion by its multivalent counterions cannot be described in the framework of a mean-field Poisson-Boltzmann (PB) theory because multivalent counterions form a strongly correlated liquid (SCL) on the surface of the macroion. It was predicted that a distant counterion polarizes the SCL as if it were a metallic surface and creates an electrostatic image. The attractive potential energy of the image is the reason why the charge density of counterions decreases faster with distance from the charged surface than in PB theory. Using the Monte Carlo method to find the equilibrium distribution of counterions around the macroion, we confirm the existence of the image potential energy. It is also shown that, due to the negative screening length of the SCL, -2ξ, the effective metallic surface is actually above the SCL by |ξ|.

Ionic conductivity on a wetting surface.

Recent experiments measuring the electrical conductivity of DNA molecules highlight the need for a theoretical model of ion transport along a charged surface. Here we present a simple theory based on the idea of unbinding of ion pairs. The strong humidity dependence of conductivity is explained by the decrease in the electrostatic self-energy of a separated pair when a layer of water (with high dielectric constant) is adsorbed to the surface. We compare our prediction for conductivity to experiment and discuss the limits of its applicability.

Neonatal alloimmune thrombocytopenia caused by human leucocyte antigen-B27 antibody.

Neonatal alloimmune thrombocytopenia (NAIT) occurs when maternal alloantibodies to antigens presented on foetal platelets cause their immune destruction. Whether human leucocyte antigen (HLA) antibodies can cause NAIT is controversial. Here, a patient was described who suffered from a NAIT caused by an HLA-B27 antibody. Sera from the mother and the newborn were tested for human platelet antigen antibodies and HLA antibodies by monoclonal antibody-specific immobilization of platelet antigens (MAIPA) assay, solid phase-linked immunosorbent assay (ELISA), lymphocytotoxicity assay (LCT) and flow cytometric analysis. No antibodies against cluster designation (CD)109 and platelet glycoproteins of the father were found in patient's and mother's serum. However, HLA ELISA was used to identify HLA antibody in both sera. The antibody was specified as HLA-B27 antibody. Typing results showed that the father descended HLA-B27 antigen on patient and his brother. The mother was HLA-B27 negative. It is most conceivable that the previous pregnancy of the mother induced the production of anti-HLA-B27 antibody, which crossed the placenta and subsequently caused an NAIT in the case presented.

[Christ-Siemens-Touraine syndrome]. / Christ-Siemens-Touraine-Syndrom.

The Christ-Siemens-Touraine syndrome (CST syndrome) is the rare an- or hypohidrotic form of the ectodermal dysplasia. During embryonic development, the formation and maturation of the central nervous system and the epithelia of the sense organs, skin, teeth, hair (and less frequently the nails) are disturbed. In addition to the cosmetic impairment, insufficient or absent secretion of sweat and sebum is particularly discomforting as it leads to extreme heat intolerance. The decreased number of apocrine sweat glands and mucous glands in the upper nasopharynx results in diminished resistance to respiratory infections. We describe typical features of the disease in a 60 year old female patient, distinguishing this disease from other forms of ectodermal dysplasia. Diagnostic criteria as well as therapeutic options are discussed.

[Bacteriuria screening in gynecologic practice: what is the value of mid-stream urine?]. / Bakteriurie-Screening in der gynäkologischen Praxis: Welchen Stellenwert hat der Mittelstrahlurin?

In 55 healthy women corresponding urine proofs were taken by suprapubic punction and by mid stream technique from the same content of the urinary bladder. For detection or exclusion of bacteriuria both collection-methods are of equal value. In 96% of the cases the microbiological results were corresponding. The leucocyte-count is of no value to detect indirectly a bacteriuria as well in punction- and in mid stream urine. A pathologic count is just as little pathognomonic for infection as a normal count excludes a bacteriuria. Therefore the counting of leucocytes should be given up to the favour of a better microbiological observation in gynecological outpatient departments.

[Diagnosis of urinary tract infections in puerperium]. / Diagnostik von Harnweginfektionen im Wochenbett.

In 225 puerperant urine proofs were taken both by suprapubic puncture and by mid stream technique. The corresponding proofs were examined culturally and microscopically. 42% of the mid stream proofs containing more than 10(5) germs/ml were evaluated to be false-positive. The corresponding urine taken by suprapubic puncture was uninfected. A pathologic leucocyte-count is just a little representative for urinary tract infection as a normal leucocyte count excludes an infection. Therefore, the counting of leucocytes is worthless and should be given up to the favour of bacteriologic examinations. Every ward for puerperant should presuppose the technique to take urine proofs by suprapubic puncture.

[Mid-stream versus bladder puncture urine in the diagnosis of urinary tract infection in pregnant patients]. / Mittelstrahl- versus Blasenpunktionsurin zur Diagnostik von Harnwegsinfektionen in graviditate.

150 healthy women being pregnant in the 1st, 2nd and 3rd trimester were examined. From the same content of urinary bladder suprapubic puncture urine (BPU) and mid-stream urine (MSU) were collected. The results concerning microbiological and microscopical analysis of urine proofs were compared. For qualitative and quantitative germ analysis MSU is sufficiently clean enough. In 95.3 there is a good correspondence of the microbiological results of both proofs. Exceptionally in 4.7% the MSU-results were not confirmed by BPU. With respect to the findings in sediment there is no good correspondence of the results. In case of sterile bladder content the BPU sediment - findings are significantly more frequent normal and significantly more seldom abnormal than in MSU. The sediment findings in MSU are more frequent false positive than in BPU. In case of an infected bladder content there are no significant differences in the sediment findings of both techniques in taking urine proofs. The rate of normal sediment findings in case of an infected bladder content is unrealistic high: In MSU in 11% and in BPU in 26%. For microbiologic germ diagnosis MSU and BPU proofs are equivalent. But, for detection or for exclusion of urinary tract infections the sediment finding is poorly pathognomonic for a urinary tract infection. A normal sediment finding does not exclude the existance of an urinary tract infection. Therefore, in the system of prenatal care we should waive of the sediment finding as a guide for the diagnosis of urinary tract infections.

The functional value of electrical muscle stimulation for the rehabilitation of the hand in stroke patients.

The influence of suprathreshold electrical stimulation of the extensor and flexor carpi radialis muscles on biomechanical and functional movement parameters is compared with the effect of a standardized active repetitive training of hand and fingers. Twelve patients suffering from ischaemic lesions in the territory of the middle cerebral artery participated in the study, which was conducted using a multiple baseline design. Following a baseline phase that lasted between one and three weeks all patients received electrical muscle stimulation for 20 minutes twice daily. In a third phase the repetitive training of hand and fingers was conducted for 20 minutes twice daily. Both interventions were applied in addition to conventional occupational therapy and physiotherapy. With the exception of spasticity in hand and finger flexors, repetitive electrical muscle stimulation does not improve biomechanical or functional motor parameters of the centrally paretic hand and arm. The repetitive motor training, however, is appropriate to improve biomechanical and functional movement parameters significantly. Apart from a possible effect on the muscle cell itself, the electrical muscle stimulation is thought to represent a mainly sensory, i.e. proprioceptive, and cutaneous intervention, whereas the active motor training is characterized by a continuous sensorimotor coupling within motor centres of the brain. The underlying neurophysiological mechanisms as well as basic principles concerning the role of afferent input for motor learning and recovery are discussed.