Neuropeptide reporter assay for serum, capillary blood and blood cards.

In the associated main paper (JPBA 2019), substance P was shown to be a valuable neuropeptide reporter substance to monitor the protease activity of serum. The assay was developed based on the predecessor assay using bradykinin (JPBA 2017). Both neuropeptides are of interest in inflammation and pain research and were thus explored for use with capillary blood and blood cards. Here, we present the protocols and set them in perspective to above neuropeptide assays for serum.•Neuropeptide reporter substance protease activity assay for use with fresh and dried blood.•Dabsylated Substance P and bradykinin are substrates of angiotensin-converting enzyme and other proteases.•Neuropeptides of interest in inflammation and pain.

Time and laser ranging: a window of opportunity for geodesy, navigation and metrology.

Recent progress in the domain of time and frequency (T/F) standards requires important improvements of existing time distribution links. Among these, the accuracy of time transfer is actually an important part of the concerns in order to establish and maintain time & space references from ground and/or space facilities. Several time transfers by laser link projects have been carried out over the past 10 years with numerous scientific and metrological objectives. Satellite Laser ranging (SLR) has proven to be a fundamental tool, offering a straightforward, conceptually simple, highly accurate and unambiguous observable. Depending on the mission, LR is used to transmit time over two-way or one-way distances from 500 to several millions of km. The following missions and their objectives employed this technique: European Laser Timing (ELT) at 450 km, Time Transfer by Laser Link (T2L2) at 1,336 km, Laser Time Transfer (LTT) at 36,000 km, Lunar Reconnaissance Orbiter (LRO) at 350,000 km, and MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) at tens of million km. This article describes the synergy between SLR and T/F technologies developed on the ground and in space and as well as the state of the art of their exploitation. The performance and sources of limitation of such space missions are analyzed. It shows that current and future challenges lie in the improvement of the time accuracy and stability of the time for ground geodetic observatories. The role of the next generation of SLR systems is emphasized both in space and at ground level, from the point of view of GGOS and valuable exploitation of the synergy between time synchronization, ranging and data transfer.

Automation of a portable extracorporeal circulatory support system with adaptive fuzzy controllers.

The presented work relates to the procedure followed for the automation of a portable extracorporeal circulatory support system. Such a device may help increase the chances of survival after suffering from cardiogenic shock outside the hospital, additionally a controller can provide of optimal organ perfusion, while reducing the workload of the operator. Animal experiments were carried out for the acquisition of haemodynamic behaviour of the body under extracorporeal circulation. A mathematical model was constructed based on the experimental data, including a cardiovascular model, gas exchange and the administration of medication. As the base of the controller fuzzy logic was used allowing the easy integration of knowledge from trained perfusionists, an adaptive mechanism was included to adapt to the patient's individual response. Initial simulations show the effectiveness of the controller and the improvements of perfusion after adaptation.

Development of an Exergame for individual rehabilitation of patients with cardiovascular diseases.

An Exergame prototype for improved and patient-adapted rehabilitation was developed. A target heart rate for individual users was defined and tracked using a chest belt. Physical activity was tracked by two 3-axis accelerometers, fixed to both wrists. Dependent on the recorded heart rate and by means of a supporting factor and linear regression the movement of the user within the game was supported or hindered. The Exergame was evaluated on 15 healthy users regarding entertaining aspects, physical effort, and impressions concerning the handling of the whole setup. The support factor algorithm to reach the target heart rate was reliable in all subjects.

Pressure shift freezing as potential alternative for generation of decellularized scaffolds.

Background. Protocols using chemical reagents for scaffold decellularization can cause changes in the properties of the matrix, depending on the type of tissue and the chemical reagent. Technologies using physical techniques may be possible alternatives for the production grafts with potential superior matrix characteristics. Material and Methods. We tested four different technologies for scaffold decellularization. Group 1: high hydrostatic pressure (HHP), 1 GPa; Group 2: pressure shift freezing (PSF); Group 3: pulsed electric fields (PEF); Group 4: control group: detergent (SDS). The degree of decellularization was assessed by histological analysis and the measurement of residual DNA. Results. Tissue treated with PSF showed a decellularization with a penetration depth (PD) of 1.5 mm and residual DNA content of 24% ± 3%. HHD treatment caused a PD of 0.2 mm with a residual DNA content of 28% ± .4%. PD in PEF was 0.5 mm, and the residual DNA content was 49% ± 7%. In the SDS group, PD was found to be 5 mm, and the DNA content was determined at 5% ± 2%. Conclusion. PSF showed promising results as a possible technique for scaffold decellularization. The penetration depth of PSF has to be optimized, and the mechanical as well as the biological characteristics of decellularized grafts have to be evaluated.

Automation of an extracorporeal support system with adaptive fuzzy controllers.

For patients suffering from cardiogenic shock cardiopulmonary resuscitation may not be sufficient to restore normal heart function. However, their chances of survival may be increased with the use of an extracorporeal support system. With this system the patient's organs are perfused while being transported to the nearest hospital for proper treatment. In the automation of an extracorporeal support system the patient's vital signals are constantly monitored and proper adjustments are performed to improve organ perfusion. In this paper, an adaptive fuzzy controller is proposed that uses the knowledge and expertise of a perfusionist as a starting point and reference for regulation. Furthermore it is able to adapt to the patient's specific reactions by manipulating the rule base of the fuzzy controller. The performance of the adaptive fuzzy controller is tested with a simulation model of the cardiovascular system.

Design of a fuzzy controller for the automation of an extracorporeal support system with the use of a simulation environment.

The automation of a portable extracorporeal support system may greatly help people who suffer from cardiogenic shock by providing them with an optimal oxygen perfusion and avoid mult-organ failure while being transported to a hospital. This however requires the creation of tools that help in the design of the ideal controller. In this paper a simulation environment is described were a cardiovascular model from the ISR Physiome database was used together with a model of a portable extracorporeal support system. Additionally a model of an oxygenator/blender model is introduced to allow the simulation of oxygen perfusion. Fuzzy controlling was used for automation since it allows a straightforward implementation of expert knowledge. Through the simulation environment different scenarios may be created where intensive testing is possible and constant repetition for control optimization. Initial simulation results are given of the fuzzy controller adjusting the extracorporeal flow rate and oxygen administration for a case of low cardiac output.

[Primary stability of the capsule-labrum complex after reconstruction with the Mitek Bioknotless anchor system in human cadaver models]. / Primärstabilität des Kapsel-Labrum-Komplexes nach Rekonstruktion mit Mitek-Bioknotless-Fadenankern am humanen Schulterkadavermodell.

BACKGROUND: This study examines the postoperative stability of the Mitek Bioknotless anchor system with biomechanical draw-out pulling in human cadaver shoulders. METHOD: With simulation of anterior shoulder dislocation a test group (n=10, Ø 45 years) was tested against a native group (n=8, Ø 47 years). All shoulders were dissected up to the passive stabilizers. In the test group an artificial Bankart lesion was created and repaired with three Mitek Bioknotless anchors. The humeri of both groups were fixed in 60 degrees glenohumeral abduction and 90 degrees external rotation and then dislocated in a ventral direction. For evaluation purposes the ultimate draw-out strength, mode of failure, translation of humeral head, capsular slope, and bone density in the test group were measured. RESULTS: In the test group the ultimate strength was a median of 937 N (min. 554 N, max. 1,294 N) with 28 bony anchor dislocations, 1 suture rupture, and 1 capsular rupture, and in the native group with 6 Bankart and 2 HAGL lesions it was 1,214 N (708 N, 1,471 N). The bone density showed a positive correlation to the draw-out strength regarding cortical density and total density. CONCLUSION: Regarding the high draw-out strength the Mitek Bioknotless anchor system provides enough stability for early functional treatment.

Experiments on robot-assisted navigated drilling and milling of bones for pedicle screw placement.

BACKGROUND: This article presents experimental results for robot-assisted navigated drilling and milling for pedicle screw placement. The preliminary study was carried out in order to gain first insights into positioning accuracies and machining forces during hands-on robotic spine surgery. Additionally, the results formed the basis for the development of a new robot for surgery. METHODS: A simplified anatomical model is used to derive the accuracy requirements. The experimental set-up consists of a navigation system and an impedance-controlled light-weight robot holding the surgical instrument. The navigation system is used to position the surgical instrument and to compensate for pose errors during machining. Holes are drilled in artificial bone and bovine spine. A quantitative comparison of the drill-hole diameters was achieved using a computer. RESULTS: The interaction forces and pose errors are discussed with respect to the chosen machining technology and control parameters. Within the technological boundaries of the experimental set-up, it is shown that the accuracy requirements can be met and that milling is superior to drilling. CONCLUSIONS: It is expected that robot assisted navigated surgery helps to improve the reliability of surgical procedures. Further experiments are necessary to take the whole workflow into account.

The selection of a model microalgal species as biomaterial for a novel aquatic phytotoxicity assay.

A phytotoxicity assay based on the ToxY-PAM dual-channel yield analyser has been developed and successfully incorporated into field assessments for the detection of phytotoxicants in water. As a means of further exploring the scope of the assay application and of selecting a model biomaterial to complement the instrument design, nine algal species were exposed to four chemical substances deemed of priority for water quality monitoring purposes (chlorpyrifos, copper, diuron and nonylphenol ethoxylate). Inter-species differences in sensitivity to the four toxicants varied by a factor of 1.9-100. Measurements of photosystem-II quantum yield using these nine single-celled microalgae as biomaterial corroborated previous studies which have shown that the ToxY-PAM dual-channel yield analyser is a highly sensitive method for the detection of PS-II impacting herbicides. Besides Phaeodactylum tricornutum, the previously applied biomaterial, three other species consistently performed well (Nitzschia closterium, Chlorella vulgaris and Dunaliella tertiolecta) and will be used in further test optimisation experiments. In addition to sensitivity, response time was evaluated and revealed a high degree of variation between species and toxicants. While most species displayed relatively weak and slow responses to copper, C. vulgaris demonstrated an IC10 of 51 microgL-1, with maximum response measured within 25 minutes and inhibition being accompanied by a large decrease in fluorescence yield. The potential for this C. vulgaris-based bioassay to be used for the detection of copper is discussed. There was no evidence that the standard ToxY-PAM protocol, using these unicellular algae species, could be used for the detection of chlorpyrifos or nonylphenol ethoxylate at environmentally relevant levels.

The combined SPE:ToxY-PAM phytotoxicity assay; application and appraisal of a novel biomonitoring tool for the aquatic environment.

Mounting concerns regarding the environmental impact of herbicides has meant a growing requirement for accurate, timely information regarding herbicide residue contamination of, in particular, aquatic systems. Conventional methods of detection remain limited in terms of practicality due to high costs of operation and the specialised information that analysis provides. A new phytotoxicity bioassay was trialled for the detection of herbicide residues in filter-purified (Milli-Q) as well as natural waters. The performance of the system, which combines solid-phase extraction (SPE) with the ToxY-PAM dual-channel yield analyser (Heinz Walz GmbH), was tested alongside the traditional method of liquid chromatography-mass spectrometry (LC-MS). The assay methodology was found to be highly sensitive (LOD 0.1 ng L(-1) diuron) with good reproducibility. The study showed that the assay protocol is time effective and can be employed for the aquatic screening of herbicide residues in purified as well as natural waters.

Osmotic stress induces inactivation of photosynthesis in guard cell protoplasts of Vicia leaves.

Guard cell protoplasts isolated from Vicia leaves showed a strong suppression of the photosynthesis under hypotonic conditions, as reflected by changes in the chlorophyll fluorescence characteristics. The response was reversible as well. Mesophyll cell protoplasts did not show any lowering of photosynthetic activity under hypo-osmotic conditions. This result indicates that the response was guard cell specific.

UV-excited chlorophyll fluorescence as a tool for the assessment of UV-protection by the epidermis of plants.

Recently, a new method for estimating epidermal transmission of UV radiation in higher plants has been proposed. The empirical evidence for the usefulness of this method is reviewed here. Direct comparison with spectroscopically determined epidermal transmission yielded equivalent results. A linear correlation to the concentration of epidermal screening compounds has been shown. Relating UV-A and UV-B absorbance allowed some preliminary conclusions about the chemical nature of the screening compounds. A new portable apparatus is presented for the first time, which allows the non-destructive assessment of UV-A screening even under field conditions. Repeated measurements on identical leaves over a time-course of 6 d demonstrated a strong age-dependence in the capacity for the synthesis of UV-A screening compounds upon exposure to UV-B radiation. It is concluded that the new method may provide a valuable tool for the investigation of the acclimation of plants to UV-B radiation and, when accompanied by HPLC analysis, of the reaction of phenolic metabolism to environmental stimuli.

Nitrogen starvation-induced chlorosis in Synechococcus PCC 7942. Low-level photosynthesis as a mechanism of long-term survival.

Cells of the non-diazotrophic cyanobacterium Synechococcus sp. strain PCC 7942 acclimate to nitrogen deprivation by differentiating into non-pigmented resting cells, which are able to survive prolonged periods of starvation. In this study, the physiological properties of the long-term nitrogen-starved cells are investigated in an attempt to elucidate the mechanisms of maintenance of viability. Preservation of energetic homeostasis is based on a low level of residual photosynthesis; activities of photosystem II and photosystem I were approximately 0.1% of activities of vegetatively growing cells. The low levels of photosystem I activity were measured by a novel colorimetric assay developed from the activity staining of ferredoxin:NADP+ oxidoreductase. Photosystem II reaction centers, as determined by chlorophyll fluorescence measurements, exhibited normal properties, although the efficiency of light harvesting was significantly reduced compared with that of control cells. Long-term chlorotic cells carried out protein synthesis at a very low, but detectable level, as revealed by in vivo [35S]methionine labeling and two-dimensional gel electrophoresis. In conjunction with the very low levels of total cellular protein contents, this implies a continuous protein turnover during chlorosis. Synthesis of components of the photosynthetic apparatus could be detected, whereas factors of the translational machinery were stringently down-regulated. Beyond the massive loss of protein during acclimation to nitrogen deprivation, two proteins that were identified as SomA and SomB accumulated due to an induced expression following nitrogen reduction.

Epidermal transmittance of leaves of Vicia faba for UV radiation as determined by two different methods.

Leaves of Vicia faba were collected from the field and the greenhouse and transmittance of epidermal peels from adaxial and abaxial sides was determined in the wavelength range from 250 to 800 nm using a spectrophotometer equipped for the measurement of turbid samples. From the same leaves, epidermal transmittance was estimated by a recently developed fluorometric method. Both methods gave highly correlated results with a slope of the regression line between both methods close to 1 and an intercept close to 0. Transmittances at around 310 nm as low as 3% were detected in the adaxial epidermis of field-grown leaves, while transmittance could be as high as 70% in the abaxial epidermis of greenhouse-grown leaves. There was a strong correlation between UV-A (ca. 366 nm) and UV-B (ca. 310 nm) transmittance detected by both methods which could be explained by the pigment composition in methanolic extracts where flavonols accounted for 90% of the absorption at 310 nm in the extract, while hydroxycinnamic acid derivatives which absorb only at the shorter wavelength constituted about 5%. It is concluded that the fluorescence method which allows rapid measurements on intact leaves can provide a quantitative estimate of epidermal transmittance for UV-B (280-320 nm) and UV-A (320-400 nm) radiation.

Radon and thoron in cave dwellings (Yan'an, China).

222Rn and 220Rn concentrations were measured in cave dwellings and brick houses in the region of Yan'an (China) during summer 1997. The underground dwellings are built into Quaternary loess, and all investigated houses are founded on it. The median values of indoor 222Rn and 220Rn concentrations are 42 (n = 18) and 77 Bq m(-3) (n = 15) for brick houses and 92 (n = 23) and 215 (n = 17) Bq m(-3) for cave dwellings. To classify the dwellings in respect to their "cave-character," the fraction of walls having a direct contact to the loses is calculated for each dwelling. While the 222Rn concentrations are increasing with higher fractions, the 220Rn concentrations are not correlated with this fraction. On the other hand, due to the short half-life of 220Rn the distance from the measuring point to the walls is negatively correlated with the 220Rn concentration, while there is no correlation with the 222Rn concentration. Therefore, concentric isolines of 220Rn concentrations showing a strong gradient were detected in cave dwellings. An influence of the ventilation rate is distinct for 222Rn but weak for 220Rn. The effective dose rates for 222Rn and 220Rn and their progenies are calculated for brick houses (2.7 mSv y(-1)), cave dwellings (7.1 mSv y(-1)), and for traditional cave dwellings with a bed foundation built with loess (16.7 mSv y(-1)). These calculations are based on summer measurements only. It is expected that the true effective dose rates will be significantly higher.

Light-induced dynamic changes of NADPH fluorescence in Synechocystis PCC 6803 and its ndhB-defective mutant M55.

Blue-green fluorescence emission of intact cells of Synechocystis PCC6803 and of its ndhB-defective mutant M55 was measured with a standard pulse-amplitude-modulation chlorophyll fluorometer equipped with a new type of emitter-detector unit featuring pulse-modulated UV-A measuring light and a photomultiplier detector. A special illumination program of repetitive saturating light pulses with intermittent dark periods (10 s light, 40 s dark) was applied to elicit dynamic fluorescence changes under conditions of quasi-stationary illumination. The observed effects of artificial electron acceptors and inhibitors on the responses of wild-type and mutant M55 cells lead to the conclusion that changes of NAD(P)H fluorescence are measured. In control samples, a rapid phase of light-driven NADP reduction is overlapped by a somewhat slower phase of NADPH oxidation which is suppressed by iodoacetic acid and, hence, appears to reflect NADPH oxidation by the Calvin cycle. Mercury chloride transforms the light-driven positive response into a negative one, suggesting that inhibition of NADP reduction at the acceptor side of PSI leads to reduction of molecular oxygen, with the hydrogen peroxide formed (via superoxide) causing rapid oxidation of NADPH. The new fluorescence approach opens the way for new insights into the complex interactions between photosynthetic and respiratory pathways in cyanobacteria.

Design and operation of a very large ring laser gyroscope.

The design and initial operation of a vertical square He-Ne ring laser G0 with a perimeter of 14 m is discussed. This builds on earlier demonstrations of the feasibility of large ring lasers (perimeter approximately 4 m) for single-mode gyroscope operation and with lesser pulling than navigation gyroscopes. With servoing of the rf excitation to yield single-mode operation, G0 gave a quality factor 1 x 10(12) and a Sagnac line with a frequency of 287.8 +/- 1.0 Hz induced by Earth rotation Omega(E). This has confirmed some vital questions over the feasibility of very large gyroscopes for geodetic measurements at the level of 10(-9) Omega(E).