Kinetic properties of DM-nitrophen and calcium indicators: rapid transient response to flash photolysis

We describe a high temporal resolution confocal spot microfluorimetry setup which makes possible the detection of fluorescence transients elicited by Ca2+ indicators in response to large (50-200 microM), short duration (< 100 ns), free [Ca2+] transients generated by laser flash photolysis of DM-nitrophen (DM-n; caged Ca2+). The equilibrium and kinetic properties of the commercially available indicators Fluo-3, Rhod-2, CalciumOrange-5N (COr-5N) and CalciumGreen-2 (CGr-2) were determined experimentally. The data reveal that COr-5N displays simple, fast response kinetics while, in contrast, Fluo-3, Rhod-2 and CGr-2 are characterized by significantly slower kinetic properties. These latter indicators may be unsuitable for tracking Ca2+ signaling events lasting only a few milliseconds. A model which accurately predicts the time course of fluorescence transients in response to rapid free [Ca2+] changes was developed. Experimental data and model predictions concur only when the association rate constant of DM-n is approximately 20 times faster than previously reported. This work establishes a quantitative theoretical framework for the study of fast Ca2+ signaling events and the use of flash photolysis in cells and model systems.     

Highlighting the ‘Multiple’ in MSPs: The Case of Cerro Chapelco,Patagonia, Argentina

Mainstream opinions put forward the idea that changes in water policies should be moving toward Integrated Water Resources Management at the level of the river basin (or watersheds). For its implementation, participation by river basin organizations (river basin authorities, river basin committees, communities of users, multi-stakeholder platforms, etc.) and by stakeholders is promoted. Multi-Stakeholder Platforms (MSPs) are presented as neutral spaces for negotiations in order to solve water conflicts among different (multiple) actors, who are all invited to participate in the discussion. Evidence from this case study suggests that even where water is put forward as the main issue to be tackled, in the background there may be far more sensitive issues at stake that shape the arenas of negotiation of policy design and implementation. MSPs can be used to bring to the fore issues that are easy to address, but can also be the background for wider social and political complexities. This is pursued using technical language to justify political definitions of boundaries, stakeholders and processes of participation. The ‘Watershed as a unit of planning’ approach is also presented as a neutral way of using a technical definition to set the boundaries for resource management. However, this study shows that the definition of boundaries is not necessarily as natural as it appears but is much more of a political decision that defines which resources are involved and which actors are considered or left out. The ‘multiple’ in MSPs is not only about ‘stakeholders’, but the different constructions of boundaries, scales and political interests, which include and exclude stakeholders. In the implementation of an MSP, the Multiple is rhetorical and not a representation of realties.     

Monitoring of degradation of porous silicon photonic crystals using digital photography

We report the monitoring of porous silicon (pSi) degradation in aqueous solutions using a consumer-grade digital camera. To facilitate optical monitoring, the pSi samples were prepared as one-dimensional photonic crystals (rugate filters) by electrochemical etching of highly doped p-type Si wafers using a periodic etch waveform. Two pSi formulations, representing chemistries relevant for self-reporting drug delivery applications, were tested: freshly etched pSi (fpSi) and fpSi coated with the biodegradable polymer chitosan (pSi-ch). Accelerated degradation of the samples in an ethanol-containing pH 10 aqueous basic buffer was monitored in situ by digital imaging with a consumer-grade digital camera with simultaneous optical reflectance spectrophotometric point measurements. As the nanostructured porous silicon matrix dissolved, a hypsochromic shift in the wavelength of the rugate reflectance peak resulted in visible color changes from red to green. While the H coordinate in the hue, saturation, and value (HSV) color space calculated using the as-acquired photographs was a good monitor of degradation at short times (t < 100 min), it was not a useful monitor of sample degradation at longer times since it was influenced by reflections of the broad spectral output of the lamp as well as from the narrow rugate reflectance band. A monotonic relationship was observed between the wavelength of the rugate reflectance peak and an H parameter value calculated from the average red-green-blue (RGB) values of each image by first independently normalizing each channel (R, G, and B) using their maximum and minimum value over the time course of the degradation process. Spectrophotometric measurements and digital image analysis using this H parameter gave consistent relative stabilities of the samples as fpSi > pSi-ch.     

On the training and testing of entry-level commercial motor vehicle drivers

This study examined the effectiveness of 3 different training types on commercial motor vehicle (CMV) drivers’ skill levels. The training types included a conventional 8-week certified course, a conventional 8-week certified course with approximately 60% of driving time spent in a CMV driving simulator, and a Commercial Driver's License (CDL) test focused short course. Participants’ scores on the Division of Motor Vehicles (DMV) road and range tests were assessed. In addition to their DMV scores, participants replicated DMV road and range driving tests in an instrumented vehicle and the CMV driving simulator. Results indicated no training group differences in DMV road tests. There were differences between training groups on DMV range tests and real truck and simulator versions of the DMV road and range tests; on these tests conventional- and simulator-trained participants generally scored higher than CDL-focused participants. However, all groups performed higher in the real truck than in the simulator for both road and range tests. These findings indicate the need for a minimum standard of entry-level CMV driver training as well as support of the use of a driving simulator for training entry-level drivers; however, testing using a simulator does not appear to be feasible with current technology.     

Acute pancreatitis as a triggering factor for thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) constitutes a poorly understood multisystemic disease of vascular origin that may involve any organ by thrombotic occlusions of the small vessels. Treatment with plasmapheresis is the best therapeutic option at this present moment. Involvement of the pancreas is a well established feature of this disease, which has generally been interpreted as a consequence of pancreatic vascular compromise. However, there are a few cases in the literature in which the clinical signs of TTP developed well after the clinical and laboratory demonstration of acute pancreatitis (AP). Therefore, the possibility of pancreatic inflammation as a triggering factor of TTP may need to be considered. This cause-effect relationship between AP and TTP remains unclear. We report a patient with chronic pancreatitis presenting with two episodes of TTP, triggered by acute relapses of pancreatitis. TTP may, thus, constitute a hematological complication of AP. We discuss the pathophysiological aspects of this association, along with therapeutical options.     

Removal and processing inner ear specimens for morphological research on guinea pig ear

Seventy (70) dissections of temporal bones of grown-up guinea pigs were done by the AA. in order to get a suitable approach to obtain inner ear studies, aiming at a morphological investigation.     

Influence of the smoking habit in the surgery of inflammatory bowel disease

The smoking habit is a key factor in the development of inflammatory bowel disease (IBD), but little information exists as to the relationship between smoking habit, the need of surgery and its complications. OBJECTIVES: To investigate the relationship between smoking habit, the need of surgery, their complications and clinical recurrence after surgery in Crohn's disease (CD) and ulcerative colitis (UC). METHODS: We studied a group of 62 patients (22 with UC and 40 with CD) with previous surgery. We analyzed the clinical and surgical characteristics of the disease. Smoking habit was established by a personal interview. This group of patients was compared with another control group of 202 patients (133 with UC and 69 with CD) with IBD without previous surgery. RESULTS: Smoking habit was similar between operated and non-operated patients for both UC (73% and 80% non-smokers) and CD (67% and 63% smokers) The number and type of complications after surgery were not related with smoking habit. In CD patients, although the recurrences did not depend on the smoking habit, they did occur earlier in smokers than in non smokers (83.6 +/- 21 vs 155 +/- 50 weeks, p = ns). CONCLUSIONS: The smoking habit does not seem to influence significantly the need of surgery and post surgical development of IBD, although in CD the smokers seems to present recurrence before non smokers.     

The reception of Kurt Lewin in Spanish psychology: A study through specialized journal publications.

Analyzed 75 references to K. Lewin's work in 20 psychological journals, as a measure of Lewin's impact on Spanish psychology from 1920 to 1989. Results show a growing impact of his work, solidly asserting itself from the 1970s onwards in the Spanish psychological scene. Knowledge of Lewin's writings in Spain is quite wide and representative of his production as a whole. Lewin's presence is most visible in social psychological journals, works, and authors, although it may also be found in other areas, notably experimental psychology, educational psychology, and the history of psychology. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optimizing offset times in Optical Burst Switching networks with variable Burst Control Packets sojourn times

In this paper, we consider the case of an Optical Burst Switching (OBS) network where the Switch Control Units (SCU) do not work at the peak rate. As a consequence, some Burst Control Packets (BCPs) will have to wait in queue to be processed, and then the BCP sojourn time will be variable. On the contrary, the optical burst does not leave the optical domain and the delay suffered is close to the propagation delay. Hence, chances are that the BCP arrives late to a given switch and, in that case, the optical burst will be dropped. We propose a Load-adaptive Offset Time algorithm (LOT) that takes into account the BCP variable sojourn time for the offset time calculation. The algorithm performs on-line calculation of the Discrete Fourier Transform (DFT) of the BCPs waiting time pdf. Our findings show that this procedure is very efficient both in terms of bandwidth usage and processing load. For example, considering a Gaussian service time for the BCPs, it turns out than less than 45 coefficients are necessary to calculate the offset time for a SCU utilization factor larger than 0.1.