Search

Purpose Glaucoma is the world's most common cause of irreversible blindness, which makes early diagnosis, with the goal of preserving vision, essential. The current medical intervention is to reduce intraocular pressure (IOP) to slow down progression of the disease. The main goal of this study was to test a novel handheld acoustic self-tonometer on humans. Methods A sound pressure pulse generated by a loudspeaker causes the eye to vibrate. A pressure chamber is placed on the human orbit to form a coupled system comprised of the patient's eye, the enclosed air, and the loudspeaker. A displacement sensor in front of the loudspeaker membrane allows the dynamic behavior of the entire system to be detected. Results For this clinical trial series, a prototype of the acoustic self-tonometer principle was applied. The resulting membrane oscillation data showed sensitivity of patient IOP, but direct allocation of the measured damping and frequency to the IOP was not significant. For this reason, an artificial neural network was used to find relationships among the subjects’ biometric eye parameters in combination with the self-tonometer data for the IOP reference. An expanded measurement uncertainty (kp = 2) equal to 6.53 mm Hg was determined for the self-tonometer in a Bland–Altman analysis using Goldmann applanation tonometer reference measurements. Conclusions The usability and success rate of producing valid measurement values with the device during self-measurements by test subjects was nearly 92%. The cross-sensitivities observed require compensation in a possible redesign phase to reduce the measurement uncertainty by at least 25% to the maximum of 5 mm Hg required to seek medical device approval. Translational Relevance Building on successful laboratory experiments with pig eyes, this article reports the results of testing the acoustic tonometer on humans.

This essay argues that one structural feature of the law is its working as an expectations machinery that generates and protects legitimate expectations at the same time. The vindication of expectations becomes apparent when we focus on the ex post-dimension of legal norms. In their ex post-dimension, legal norms vindicate legitimate expectations, in their ex ante-dimension, they generate them. This paper identifies three categories of expectations: Mere hopes, legitimate expectations and vindicated (legitimate) expectations. In the practice of legal discourse, this categorisation is of crucial importance and decisive for our legal rights. This will be illustrated with examples concerning contract and property. The essay further shows that the classification of expectations faces an uncertainty problem. Building on Brandom, the essay argues that the rationality of the law’s classification of expectations can be ensured through the practice of legal discourse. Brandom’s theory of mutual recognition as a normative social structure must be supplemented by justice as a virtue (JAV), however. It will be argued that JAV strengthens the mutual recognition of the players of the law in their permanent reconstruction of legal content. JAV must be included in legal discourse to ensure the rationality of the law’s quest for the classification of expectations.

Quantum sensors based on matter-wave interferometry are promising candidates for high-precision gravimetry and inertial sensing in space. The favorable sources for the coherent matter waves in these devices are Bose–Einstein condensates. A reliable prediction of their dynamics, which is governed by the Gross–Pitaevskii equation, requires suitable analytical and numerical methods, which take into account the center-of-mass motion of the condensate, its rotation, and its spatial expansion by many orders of magnitude. In this chapter, we present an efficient way to study their dynamics in time-dependent rotating traps that meet this objective. Both an approximate analytical solution for condensates in the Thomas–Fermi regime and dedicated numerical simulations on a variable adapted grid are discussed. We contrast and relate our approach to previous alternative methods and provide further results, such as analytical expressions for the one- and two-dimensional spatial density distributions and the momentum distribution in the long-time limit that are of immediate interest to experimentalists working in this field of research.

Sensorless online temperature measurement of lithium-ion cells based on electrochemical impedance spectroscopy (EIS) measurements is introduced and applied to a commercial 2 Ah pouch cell. The method's sensitivity on temperature and state of charge (SOC) is investigated, taking a closer look to the selection of measurement frequency. The internal temperature is determined as precise as ±0.17 K with SOC status known and ±2.5 K with SOC status unknown at isothermal conditions. Furthermore, the influence of a temperature gradient, as it will develop during cell operation, is studied in detail and the simulation results are validated experimentally. Finally, the method's ability to monitor the temperature is demonstrated during a thermal cool down.

Purpose: To determine the interaction between corneal topographic and tomographic parameters and dry eye syndrome (DES) in keratoconus (KC) patients. Methods: Seventy-seven eyes of 49 patients with KC (age 34.4 � 11.6 years) were enrolled in this study. In these 77 eyes we recorded surface regularity index (SRI), surface asymmetry index (SAI) and Klyce/Maeda KC index (KCI) using the Topographic Modeling System (TMS-5, Tomey, Tennenlohe, Germany), Index of Surface Variance (ISV), Index of Vertical Asymmetry (IVA), KC Index (KI), Center KC Index (CKI), Index of Height Asymmetry (IHA) and Index of Height Decentration (IHD) using Pentacam (Pentacam HR, Oculus, Germany). Patients were subdivided into mild (grade 1–2) and severe stage (grade 3–4) KC groups according to Pentacam grading. To analyse tear film parameters we assessed in 77 KC eyes McMonnies questionnaire, Schirmer test and breakup time and in 26 eyes (10 eyes with mild KC, 16 eyes with severe KC) high-speed videokeratoscopy (during interblinking interval) using a novel commercially not available system (Tear Inspect). With Tear Inspect the analysed tear film parameters were (1) time of first irregularities of Placido rings and (2) time of eyelid closure. Patients were also subdivided into McMonnies questionnaire positive and negative groups. Results: We did not find significant difference between patients with mild and severe KC in any of the examined tear film parameters (p40.66). There was no significant difference in SRI, SAI, KCI, ISV, IVA, KI, CKI, IHA and IHD in McMonnies test positive and negative KC patients (p40.07). There was no correlation between SRI, SAI, KCI, ISV, IVA, KI, CKI, IHA and IHD and any of the examined tear film parameters (without high-speed videokeratoscopy) neither in 77 KC patients nor in mild or severe KC eyes (r50.3). Conclusions: There is no interaction between DES and topographic/tomographic changes in KC-patients.

Clouds of ultra-cold atoms and especially Bose–Einstein condensates (BEC) provide a source for coherent matter-waves in numerous earth bound experiments. Analogous to optical interferometry, matter-wave interferometers can be used for precision measurements allowing for a sensitivity orders of magnitude above their optical counterparts. However, in some respects the presence of gravitational forces in the lab limits experimental possibilities. In this article, we report about a compact and robust experiment generating Bose–Einstein condensates in the drop tower facility in Bremen, Germany. We also present the progress of building the succeeding experiment in which a two species atom interferometer will be implemented to test the weak equivalence principle with quantum matter.

This article presents a non-invasive sensor setup for objective analysis of the pre-corneal human tear-film involving a time-resolved videokeratoscopy and simultaneous imaging of the lipid layer of the tear-film by a second CMOS-camera. This paper describes in detail the mechanical and optical design of the sensor setup, the realization of the entire illumination component with an integrated Placido grid projection, and the calculation of the image formation using the Placido grid. This concept is demonstrated here with a test subject in the full inter-blink period. All images were taken under physiological conditions. The sensor can assist the ophthalmologist in diagnosing Dry-Eye Syndrome. Results and other potential applications are discussed.

We describe a series of interfacial biomolecular architectures employed for studies aimed at elucidating the structural and dynamical factors governing biorecognition and binding reactions between surface-attached biotin-derivatives and analogues and streptavidin from solution. We compare binding matrices based on mixed lipid monolayers transferred to a solid support from the water/air-interface and surface coatings based on binary mixed self-assembled monolayers. The analytical techniques used to monitor the various layers and the binding events are based on surface-plasmon spectroscopy and microscopy, in some cases in combination with electrochemical methods controlling, in particular, the surface potential of electrode surfaces in contact with aqueous electrolyte solutions. Finally, an example is given for the sensitivity enhancement obtainable by combining the field-enhancement of surface-plasmon resonances with fluorescence detection schemes.

In refractory temporal lobe epilepsy (TLE) temporal lobe structures and functions are continuously or intermittently affected by abnormal brain electrical events, noxious neurochemical agents, and metabolic disturbances. There is conflicting evidence regarding the relationship between the duration of refractory mesial TLE and quantitative measures of temporal lobe functions and volumes of the hippocampi. Twenty patients (aged 28 +/- 7 years, 14 males) with an initial precipitating injury before the age of 5 years were subjected to high-resolution magnetic resonance imaging, fluoro-2-deoxy-d-glucose positron-emission tomography (PET), and the Wada test. We investigated whether the duration of unilateral refractory TLE (12 left, 8 right) affects hippocampal volume, glucose metabolism, or Wada hemispheric memory performance. Ipsilateral to the epileptogenic zone the hippocampal volume, metabolism, and Wada hemispheric memory performance were reduced compared to the corresponding contralateral measures. The duration of epilepsy controlled for age at investigation, side of seizure origin, underlying cause, and sex were negatively correlated with ipsi- and contralateral hippocampal volume, hippocampal metabolism, and Wada hemispheric memory performance. Moreover, ipsilateral Wada hemispheric memory performance and contralateral hippocampal glucose metabolism were correlated with the frequency of habitual seizures. Refractory TLE seems to be associated with a slow but ongoing bilateral temporal lobe damage. These cross-sectional results require verification by longitudinal studies carried out over a period of more than two decades.

Interleukin-4 (IL-4) triggers cellular responses by interaction with the bipartite interleukin-4 receptor (IL-4R). IL-4-responsive cells specifically endocytose IL-4. We studied the ligand internalization properties of the human IL-4R and analyzed the specific functions of its two subunits IL-4Ralpha and gammac in this process. IL-4 mutant RY, which binds to IL-4Ralpha but does not recruit gammac into the receptor complex was used as a tool to show that IL-4Ralpha can promote independent ligand uptake in human T cells. Internalization was limited, however, by rapid IL-4 dissociation, suggesting that one important function of gammac in IL-4 endocytosis is to retain the ligand sufficiently long within the ternary receptor complex. We then measured IL-4 internalization by murine Ba/F3 cells that were stably transfected with various human IL-4R constructs. Efficient IL-4 uptake required the cytoplasmic section of the receptor. The intracellular domains of IL-4Ralpha and gammac were responsible for independent endocytosis processes with distinct kinetics. IL-4Ralpha-mediated internalization resulted in long-term intracellular maintainance of IL-4, whereas gammac directed the associated radioligand to intracellular breakdown and rapid release in the form of degraded protein. Mutants of either IL-4R subunit deficient in Janus kinase activation were not impaired in internalization, indicating that IL-4 endocytosis is not functionally connected to signal transduction.

The combination of surface plasmon spectroscopy (SPS) and atomic force microscopy (AFM) with electrochemical methods (cyclic voltammetry, potential step) is used to (i) probe the film/substrate interaction in alkanethiol monolayers formed on gold surfaces and (ii) monitor the electrochemically driven deposition of organic molecules onto a metal surface. The reductive desorption of alkanethiols at single crystal and polycrystalline gold surfaces was investigated by SPS and AFM. These experiments demonstrate the possibility of desorbing a self-assembled monolayer at a well-defined potential with all the consequences for selective (re)-functionalization. The self-assembly of alkanethiols on gold under potential control was also monitored by SPS. The results show that the surface derivatization of gold electrodes can be actively controlled by the manipulation of the electrode potential. Finally, the immobilization of biotin on gold surfaces has been carried out by the electropolymerization of a water-soluble, biotinylated derivative of 3-hydroxyphenylacetic acid. The molecular recognition of the biotinylated polyphenol film by the bacterial protein streptavidin was monitored by SPS. The packing density of the biotin labels in the polymer film leads to a very fast diffusion-controlled docking of the streptavidin to the surface. These studies clearly prove the usefulness of electrochemically controlled deposition to produce ultrathin film organic surfaces with specific function.

Horse heart cytochrome c was immobilized on mixed self-assembled monolayers (SAMs) of carboxyl- and methyl-terminated alkanethiolates (HOOC(CH2)10S + CH3(CH2)9S) on Au(111) electrodes. The apparent standard rate constant kobs of electron transfer for the electrode system of cytochrome c⧹mixed SAM⧹gold electrode was measured by a.c. impedance and a.c. modulated UV-visible electro reflectance techniques. A strong dependence of kobs on the composition of the mixed alkanethiol solution, from which the monolayers had been assembled, was observed. A maximum of kobs ≈ 200s−1 was found for SAMs formed from solutions containing a mole fraction χ ≈ 0.8 of carboxyl-terminated alkanethiols. This rate constant is about six times faster than that of a system with a single-component monolayer of HOOC(CH2)10S (ξ = 1). Reductive desorption suggested that the two alkane thiolates mix homogeneously in the monolayer and there is no sizable phase separation on the Au(111) electrode. Double-layer capacitance measurements determined the degree of protonation of the mixed SAMs in the pH range 6–9. The enhancement of electron-transfer rate is attributed to a favorable distribution of protein binding sites in the mixed monolayers.