A new approach is presented to estimate the amounts and spatial distribution of groundwater recharge based on the groundwater dating tracers super(3)H, super(3)He and CFC-11. The method was applied ...in a groundwater project in southwest Niger (Africa). The model developed to simulate observed tracer concentrations is composed of a model to account for the water transported through the unsaturated zone followed by a dispersion box model to determine the age distribution of the sampled groundwater volume. For the unsaturated zone transport, a one- dimensional approach was used considering tracer transport in the water and the gas phase. The calculated tracer concentrations at the groundwater table are then used as input functions for the subsequent dispersion box model. Using a dispersion box model it is possible to outline regions where recharge preferably occurs. To account for the high variance of soil properties in space, a Monte Carlo simulation was performed. The results show estimated recharge rates of 50- 300 mm year super(-1) (+/-50%). The large error bars are mainly due to high uncertainties of the soil parameters. Therefore, a better estimation of the average soil moisture would lead to more accurate results. The resulting spatial distribution of dispersion parameters indicates that recharge mainly occurs in the ancient riverbeds where surface runoff from the laterite plateaux is gathered and leads to spatially limited high recharge events. Where the soil is not permeable enough, these events lead to the observed temporary or permanent lakes. This new conceptual view of major recharge mechanisms contradicts the former picture of recharge occurring in this region, but it coincides better with other independent measurements, such as the stable isotope ratios of water.
Here, we present a case of a tracheal fistula due to an anastomotic insufficiency following abdominothoracic esophageal resection. Despite immediate discontinuity resection, the tracheal fistula ...could not be surgically closed, resulting in incomplete control of the source of infection and an alternative treatment concept in the form of interventional fistula closure using a Y-tracheal stent. However, owing to existing severe acute respiratory distress syndrome (ARDS), which is associated with a considerable risk of peri-interventional hypoxia, a temporary bridging concept using venovenous extracorporeal membrane oxygenation (ECMO) was implemented successfully.
A total of 9600 swab samples from 900 carcasses originating from ten different abattoirs were subjected to-bacteriological examination. Two sampling sites, brisket and forearm, consistently showed ...the highest contamination rates. The following sites are recommended for sampling: on the lateral side of the carcass neck, forearm, shoulder, brisket and abdomen. The neck is recommended for the medial side. Compared to the large variance of contamination either on individual carcasses or between different carcasses, the differences in the variance of results between double swab and incision sampling techniques should be of minor importance. Considering this big variance of colony counts, it is suggested to take five to six swab samples from each of at least ten to 15 carcasses once a month. With a view to a more differentiated and evident evaluation the results should be recorded in ‘box plots’ and not in the form of mean values and standard deviations. The data confirms bacteriological monitoring of beef carcasses as a useful tool for the verification of slaughter hygiene.
We investigated the role of nitric oxide (NO) in the vascular response to high extraluminal K
+-concentrations in the in vitro model of isolated rat middle cerebral arteries (MCA). Under control ...conditions, rat MCA dilated at 20, 30, 40 and 60 mM K
+. At 80 mM K
+, a slight vasoconstriction occurred. The unspecific NO synthase (NOS)-inhibitor L
ω-nitro-L-arginine (L-NNA) increased the resting tone at 3 mM K
+ by 31±5% (
P<0.01). While the vasodilatative effect of 20 mM K
+ was unaffected by L-NNA, NOS-inhibition resulted in vasoconstriction at ≥ 40 mM K
+ (
P<0.01). In presence of L-NNA, the basal vessel diameter was restored by either the NO-donor
S-nitroso-
N-acetylpenicillamine (SNAP) or the cell-permeable guanosine-3′,5′-cyclic monophosphate (cGMP) analogue 8-Br-cGMP. Co-application of L-NNA with either SNAP or 8-Br-cGMP resulted in partial restitution of the vasodilatative effect of 40 mM K
+, respectively. In presence of the soluble guanylyl cyclase inhibitor 1
H-l,2,4oxadiazolo4,3-aquinoxalin-1-one (ODQ), the vascular response to 40 mM K
+ was abolished. Our findings together with findings from the literature indicate a modulator role of NO at K
+ ≥ 40 mM K
+, involving a cGMP-dependent mechanism.
The intention of the present work was to investigate the influence of the grain size on the electrical properties of Mn decorated SrTiO
3 ceramics. To obtain different average grain sizes the samples ...were prepared by variation of the following sintering conditions: form of the green bodies, heating/cooling ramps, sintering atmosphere, sintering time, and sintering temperature. The grain boundaries of the ceramics were decorated with Mn by diffusion from the ceramics surfaces. Impedance analysis techniques in the scope of time and frequency dependence were used for electrical characterization and accelerated life testing (ALT) measurements were performed to characterize the ageing behaviour.
The C-C bond-cleaving acetylacetone dioxygenase Dke1 (EC 1.13.11.50) is a Fe2 + -dependent enzyme from Acinetobacter johnsonii that activates oxygen to convert a range of -dicarbonyl substrates into ...-oxo-aldehyde and acid products. Previous methods of downstream processing yielded Dke1 with substoichiometric Fe2 + content. This paper reports the integration of enzyme production in E. coli and affinity chromatography to prepare recombinant Dke1 that is completely loaded with its metal cofactor. The specific activity of Dke1 in E. coli cell extracts could be increased up to 20-fold, compared to optimized enzyme production with the natural host. Introduction of an affinity-tag allowed the isolation of fully active Dke1 in a single purification step with high yield (70%). Mass spectrometric analysis revealed at the level of >80% sequence coverage that the isolated enzyme corresponded exactly to the predicted gene product. Tagged Dke1 is shown to have retained the functional properties of native Dke1.
Recently, lung volume reduction LVR removal of about 20% of lung volume), has been performed to treat severe emphysema. Little is known, however, about the mechanism and time course of functional ...improvement, and the reasons that such patients can be tracheally extubated very early. Therefore, we studied changes in ventilatory mechanics in 12 patients after LVR. Measurements of work of breathing (WOB), intrinsic positive end-expiratory pressure (PEEPi), dynamic compliance (Cdyn), and mean airway resistance (Rawm) were performed the day before surgery, early postoperatively, and 1 and 3 mo after surgery. All measurements were performed on tracheally extubated patients, simultaneously assessing esophageal pressure via esophageal balloon catheter and air flow via tightly adjusted mask. Standard spirometry was assessed pre-operatively and 1 and 3 mo postoperatively. The patients presented with forced expiratory volume in 1 s (FEV1), of 670 +/- 50 mL and pathological values of WOB and PEEPi. All patients were successfully tracheally extubated within 5 h postoperatively. Immediately thereafter, a marked and sustained decrease in WOB, PEEPi, and Rawm was noted, as well as an increase in Cdyn. Ventilatory mechanics improved immediately after LVR, probably due to decompression of lung tissue, thereby enabling successful tracheal extubation.
: Some misprints appeared on page 640, in Table II and in the last paragraph of Section 2.2 (line 9). One should read: "3.075 × 10-2", "-4.900 × 10-4", "1.440 × 10-5", "2.500 × 10-9" and "1.0 × ...10-8", respectively (there are not exponential functions).
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