Offshore pelagic subsidies dominate carbon inputs to coral reef predators.

Coral reefs were traditionally perceived as productive hot spots in oligotrophic waters. While modern evidence indicates that many coral reef food webs are heavily subsidized by planktonic production, the pathways through which this occurs remain unresolved. We used the analytical power of carbon isotope analysis of essential amino acids to distinguish between alternative carbon pathways supporting four key reef predators across an oceanic atoll. This technique separates benthic versus planktonic inputs, further identifying two distinct planktonic pathways (nearshore reef-associated plankton and offshore pelagic plankton), and revealing that these reef predators are overwhelmingly sustained by offshore pelagic sources rather than by reef sources (including reef-associated plankton). Notably, pelagic reliance did not vary between species or reef habitats, emphasizing that allochthonous energetic subsidies may have system-wide importance. These results help explain how coral reefs maintain exceptional productivity in apparently nutrient-poor tropical settings, but also emphasize their susceptibility to future ocean productivity fluctuations.

Multifocal tDCS targeting the resting state motor network increases cortical excitability beyond traditional tDCS targeting unilateral motor cortex.

Scientists and clinicians have traditionally targeted single brain regions with stimulation to modulate brain function and disease. However, brain regions do not operate in isolation, but interact with other regions through networks. As such, stimulation of one region may impact and be impacted by other regions in its network. Here we test whether the effects of brain stimulation can be enhanced by simultaneously targeting a region and its network, identified with resting state functional connectivity MRI. Fifteen healthy participants received two types of transcranial direct current stimulation (tDCS): a traditional two-electrode montage targeting a single brain region (left primary motor cortex [M1]) and a novel eight-electrode montage targeting this region and its associated resting state network. As a control, 8 participants also received multifocal tDCS mismatched to this network. Network-targeted tDCS more than doubled the increase in left M1 excitability over time compared to traditional tDCS and the multifocal control. Modeling studies suggest these results are unlikely to be due to tDCS effects on left M1 itself, however it is impossible to completely exclude this possibility. It also remains unclear whether multifocal tDCS targeting a network selectively modulates this network and which regions within the network are most responsible for observed effects. Despite these limitations, network-targeted tDCS appears to be a promising approach for enhancing tDCS effects beyond traditional stimulation targeting a single brain region. Future work is needed to test whether these results extend to other resting state networks and enhance behavioral or therapeutic effects.

Intrinsic functional architecture in the anaesthetized monkey brain.

The traditional approach to studying brain function is to measure physiological responses to controlled sensory, motor and cognitive paradigms. However, most of the brain's energy consumption is devoted to ongoing metabolic activity not clearly associated with any particular stimulus or behaviour. Functional magnetic resonance imaging studies in humans aimed at understanding this ongoing activity have shown that spontaneous fluctuations of the blood-oxygen-level-dependent signal occur continuously in the resting state. In humans, these fluctuations are temporally coherent within widely distributed cortical systems that recapitulate the functional architecture of responses evoked by experimentally administered tasks. Here, we show that the same phenomenon is present in anaesthetized monkeys even at anaesthetic levels known to induce profound loss of consciousness. We specifically demonstrate coherent spontaneous fluctuations within three well known systems (oculomotor, somatomotor and visual) and the 'default' system, a set of brain regions thought by some to support uniquely human capabilities. Our results indicate that coherent system fluctuations probably reflect an evolutionarily conserved aspect of brain functional organization that transcends levels of consciousness.

Real-time, nonintrusive oxidation detection system for the welding of reactive aerospace materials.

We describe the development of a real-time nonintrusive monitor to detect degradation of a gas shield condition during laser welding by use of on-axis spectrally resolved detection of light emitted from the workpiece. Failure of gas shielding to the point at which there is a risk of contamination from the air is revealed by the marked increase in the intensity of a spectral feature around 426 nm. To avoid unwanted sensitivity to the overall intensity of the radiation, the intensity at 426 nm is normalized by that at 835 nm, where the spectrum is insensitive to gas shielding. We collected the radiation by using the same optics as are used to deliver the processing beam, and thus the detection process is entirely nonintrusive. We demonstrate successful operation for welding stainless steel and titanium under both helium and argon gas shielding.

Accumulation of fibrinogen-coated microparticles at a fibrin(ogen)-rich inflammatory site.

We have developed methods for coating with fibrinogen both liposomes and microscopic droplets of olive oil. Because the fibrinogen bound to them is functional in the classic sense of fibrin gelation, the coated microparticles may have potential as vehicles for the targeted delivery of various molecules to sites of fibrin(ogen) deposition in vivo. So that we could assess directly this potential, we first established a method for eliciting reproducibly a focal, fibrin(ogen)-rich, inflammatory lesion in a hind footpad of mice. We then monitored the tissue distribution of fibrinogen-coated microparticles following their injection into the tail vein of mice bearing this well-defined lesion. As happens with most microparticles following their intravenous administration, liposomes and oil droplets, whether coated with fibrinogen or not, accumulate rapidly in the liver and spleen of treated animals. Indeed, in the case of oil droplets, accumulation of fibrinogen-coated microparticles in those organs and in the lungs is even greater than that of fibrinogen-free microparticles. However, as distinct from fibrinogen-free liposomes and oil droplets, fibrinogen-coated microparticles also accumulate in the inflamed hind footpad. We conclude that fibrinogen-coated liposomes and oil droplets do have potential as vehicles for delivering molecules to sites of fibrin(ogen) deposition in vivo.

Practical spread spectrum pulse compression for ultrasonic tissue imaging.

Spread spectrum pulse compression is a signal processing algorithm that enhances critical system performance parameters such as signal-to-noise ratio, peak power requirements, minimum detectable signal, and total dynamic range. For this research, a digital, real-time, Barker coded, bi-phase modulator was designed and constructed, as well as a simple ultrasonic test tank containing both synthetic targets and excised goat's liver. Upon reception and demodulation of the spread spectrum ultrasonic echo, cross-correlation with a sidelobe suppression filter was performed. Due to limitations such as narrow bandwidth, and very short minimum ranges, a practical ultrasonic pulse compression system must be restricted to short code lengths. For 13 bit Barker code compression, the expected increase in signal-to-noise ratio of 11 dB was realized; at the same time greater than 30 dB of instantaneous dynamic range was maintained.

Optical sensor to monitor and control temperature and build height of the laser direct-casting process.

A nonintrusive optical sensor system is applied to real-time process control of the recently developed laser direct-casting process, in which a stream of metal powder is introduced into the beam of a high-power (500-W) cw laser to fabricate complex three-dimensional structures. The sensor system allows two critical parameters, temperature and build height, associated with this process to be monitored and controlled continuously. We achieved a height-sensing resolution of ?0.25 mm and temperature control with a resolution of ?10 degrees C at a typical working temperature of 1500 degrees C with an evident improvement in process quality, especially for complex workpieces comprising relatively high, thin walls at which the conductive heat transfer varies substantially as the process proceeds.

The feasibility of HLA matching for lung transplantation.

The benefits of HLA matching have been clearly demonstrated in renal and cardiac transplantation. Recent studies suggest that HLA matching may be associated with improved survival rates for transplantation as well. However, the effect of HLA matching for lung transplantation has not been clearly demonstrated. Despite the possible benefits of HLA compatibility, matching for lung transplantation is based solely on ABO compatibility and lung size. Several factors limit the feasibility of utilizing HLA matching for lung transplantation. Among these factors is the time required to perform HLA typing, to identify appropriate recipients, and to allocate lungs; an additional constraint is the urgent need for transplantation in patients experiencing rapid clinical decline. The obstacles to using prospective HLA matching for lung allocation are significant, and matching lung donors and recipients according to histocompatibility status would require considerable effort. However, with supra-regional cooperation among transplant centers and procurement agencies, it appears feasible to consider HLA matching for lung transplantation. Given the potential for improved survival, a project should be undertaken to determine the impact of HLA matching on the outcome of lung transplantation.

Risk of preterm delivery from preterm labor in high-risk patients.

This study aimed to determine the incidence of preterm labor and birth (< 37 weeks' gestation) in patients at high risk for early delivery. In this retrospective, descriptive study, 17,186 women with high-risk factors for early delivery were studied over a five-year period (1986-1990). Study groups included women with prior preterm delivery, multifetal gestations, uterine abnormalities and cervical factors. The rate of preterm labor for all patients averaged 40% (range, 30-46%). The rate of preterm delivery in the four groups ranged from 14% to 30% and averaged 19.7%. In those who experienced preterm delivery, only 32% of cases were due to preterm labor with advanced cervical dilatation, failed tocolysis or preterm premature rupture of membranes. The majority of early deliveries were due to medical or obstetric disorders as well as to patient/physician factors. The incidence of preterm labor remains significant when women have high-risk factors for preterm delivery. However, the incidence of preterm delivery, particularly that due to avoidable factors, such as failed tocolysis and preterm rupture of the membranes, is considerably lower than that quoted in the literature.

Magnetic backprojection imaging of the vascular lumen.

Current injected into a phantom model generated a magnetic field which was distorted above a simulated atherosclerotic lesion. The output of a Hall effect magnetic sensor was used in a backprojection to reconstruct the centroid of the simulated blood flow and thus localize the modeled atherosclerotic plaque region.

Laparoscopic Pomeroy tubal ligation as a teaching model for residents.

We reviewed our preliminary experience with laparoscopically directed bilateral midtubal resection for tubal ligation (endoscopic Pomeroy) as a potential teaching tool for the acquisition of endoscopic skills during residency training. Thirty-five laparoscopic Pomeroy and 206 banding procedures were reviewed. Age, parity and weight were similar in the two groups. The operative time for banding was reduced slightly after experience with > 10 procedures. In contrast, the operative time for laparoscopic Pomeroy procedures decreased dramatically after individual experience with only a few (< or = 5) procedures. The mean operative time for the Pomeroy group approached that of the more traditional banding technique at five procedures. Our data indicate that laparoscopic Pomeroy sterilization can be an effective teaching tool for operative laparoscopy, allowing residents to repeatedly perform an easy and safe procedure that incorporates basic techniques. Advanced operative endoscopic procedures could then be taught more efficiently after the acquisition of basic skills.

PIP: 25 gynecology residents performed laparoscopic banding (tubal rings) sterilization on 206 women and laparoscopic Pomeroy sterilization on 35 women, all of whom underwent tubal sterilization at the University of Mississippi Medical Center between September 1988 and October 1990. Three faculty members and a fourth year resident retrospectively analyzed the data of both groups to determine the effect of the Pomeroy method on operative laparoscopic skills acquired by the residents during training. Both groups were similar in age, parity, and weight. Each of the 23 residents performed 1-22 laparoscopic banding procedures. As residents gained experience, the time to perform both banding and Pomeroy methods decreased significantly (p = 0.026). After a resident had conducted 5 Pomeroy procedures, the surgery time had approached that of laparoscopic banding. These findings show that gynecology faculty can use laparoscopic Pomeroy tubal ligation as an effective teaching tool for laparoscopy by providing residents an opportunity to repeatedly perform an easy and safe procedure that includes basic techniques. After developing the basic skills, the residents can then learn more efficiently advanced operative endoscopic techniques.

No touch pulse measurement by optical interferometry.

Arterial pulsatility was measured using an optical interferometer. As opposed to laser Doppler flow meters, the prototype system we evaluated can detect pulsation profiles of major arteries with potentially useful information including pulse wave velocity, profile of pulse pressure, etc.

Galanin: a novel intraovarian regulatory peptide.

Galanin is a 29-amino acid peptide that acts as a neuropeptide in many tissues. To date, galanin action and the hormonal regulation of galanin gene expression have not been described in the ovary of any species. To study possible ovarian expression and regulation of galanin, immature gonadotropin-primed rats were given hCG (10 IU), and their ovaries were collected 0, 4, 8, 12, and 20 h after hCG treatment for determination of galanin messenger RNA (mRNA) concentration by solution hybridization. Galanin mRNA levels progressively increased after hCG administration, peaking at 12 h (2.4-fold increase vs. 0 h), with a subsequent return to 0 h levels at 20 h. To determine a possible ovarian role for galanin, rats were killed 48 h after gonadotropin administration, their ovaries were removed, and granulosa cells were harvested. These cells and the ovarian tissue remaining after granulosa cell collection (i.e. "shells") were each cultured for 24 h with increasing concentrations of galanin (0, 10, 100, and 1000 nM) in the presence or absence of LH. The medium was examined for steroid production and metalloproteinase inhibitor activity. In granulosa cell cultures, galanin increased the levels of estradiol by 26% and had no effect on progesterone, but decreased metalloproteinase inhibitor activity by 61% in the conditioned medium. In the shell cultures, galanin increased estradiol, progesterone, and androstenedione in the medium, suggesting that galanin acts on cells other than granulosa cells or that galanin action requires a paracrine interaction between granulosa and thecal cells. Our data demonstrate that galanin message is increased by hCG, and that galanin acts to amplify ovarian steroidogenesis while decreasing metalloproteinase inhibitor activity. These findings establish that ovarian galanin mRNA is hormonally stimulated and that galanin acts as an intraovarian regulatory peptide.