Zeolitic imidazolate framework-coated acoustic sensors for room temperature detection of carbon dioxide and methane

The integration of nanoporous materials such as metal organic frameworks (MOFs) with sensitive transducers can result in robust sensing platforms for monitoring gases and chemical vapors for a range of applications. Here, we report on an integration of the zeolitic imidazolate framework-8 (ZIF-8) MOF with surface acoustic wave (SAW) and thickness shear mode quartz crystal microbalance (QCM) devices to monitor carbon dioxide (CO2) and methane (CH4) under ambient conditions. The MOF was directly coated on the Y-Z LiNbO3 SAW delay lines (operating frequency, f0 = 436 MHz) and AT-cut quartz TSM resonators (resonant frequency, f0 = 9 MHz) and the devices were tested for various gases in N2 under ambient conditions. The devices were able to detect the changes in CO2 or CH4 concentrations with relatively higher sensitivity to CO2, which was due to its higher adsorption potential and heavier molecular weight. The sensors showed full reversibility and repeatability which were attributed to the physisorption of the gases into the MOF and high stability of the devices. Both types of sensors showed linear responses relative to changes in the binary gas compositions thereby allowing to construct calibration curves which correlated well with the expected mass changes in the sorbent layer based on mixed-gas gravimetric adsorption isotherms measured on bulk samples. For 200 nm thick films, the SAW sensitivities to CO2 and CH4 were 1.44 × 10-6/vol% and 8 × 10-8/vol%, respectively, against the QCM sensitivities 0.24 × 10-6/vol% and 1 × 10-8/vol%, respectively, which were evaluated as the fractional change in the signal. The SAW sensors were also evaluated for 100 nm-300 nm thick films, the sensitivities of which were found to increase with the thickness due to the increased number of pores for the adsorption of a larger amount of gases. In addition, the MOF-coated SAW delay lines had a good response in wireless mode, demonstrating their potential to operate remotely for the detection of the gases at emission sites across the energy infrastructure

Numerical analysis and simulation of the dynamics of mountain glaciers

In this chapter, we analyze and approximate a nonlinear stationary Stokes problem that describes the motion of glacier ice. The existence and uniqueness of solutions are proved and an a priori error estimate for the finite element approximation is found. In a second time, we combine the Stokes problem with a transport equation for the volume fraction of ice, which describes the time evolution of a glacier. The accumulation due to snow precipitation and melting are accounted for in the source term of the transport equation. A decoupling algorithm allows the diffusion and the advection problems to be solved using a two-grids method. As an illustration, we simulate the evolution of Aletsch glacier, Switzerland, over the 21st century by using realistic climatic conditions

Preoperative biliary drainage for periampullary tumors causing obstructive jaundice; DRainage vs. (direct) OPeration (DROP-trial)

BACKGROUND: Surgery in patients with obstructive jaundice caused by a periampullary (pancreas, papilla, distal bile duct) tumor is associated with a higher risk of postoperative complications than in non-jaundiced patients. Preoperative biliary drainage was introduced in an attempt to improve the general condition and thus reduce postoperative morbidity and mortality. Early studies showed a reduction in morbidity. However, more recently the focus has shifted towards the negative effects of drainage, such as an increase of infectious complications. Whether biliary drainage should always be performed in jaundiced patients remains controversial. The randomized controlled multicenter DROP-trial (DRainage vs. Operation) was conceived to compare the outcome of a 'preoperative biliary drainage strategy' (standard strategy) with that of an 'early-surgery' strategy, with respect to the incidence of severe complications (primary-outcome measure), hospital stay, number of invasive diagnostic tests, costs, and quality of life. METHODS/DESIGN: Patients with obstructive jaundice due to a periampullary tumor, eligible for exploration after staging with CT scan, and scheduled to undergo a "curative" resection, will be randomized to either "early surgical treatment" (within one week) or "preoperative biliary drainage" (for 4 weeks) and subsequent surgical treatment (standard treatment). Primary outcome measure is the percentage of severe complications up to 90 days after surgery. The sample size calculation is based on the equivalence design for the primary outcome measure. If equivalence is found, the comparison of the secondary outcomes will be essential in selecting the preferred strategy. Based on a 40% complication rate for early surgical treatment and 48% for preoperative drainage, equivalence is taken to be demonstrated if the percentage of severe complications with early surgical treatment is not more than 10% higher compared to standard treatment: preoperative biliary drainage. Accounting for a 10% dropout, 105 patients are needed in each arm resulting in a study population of 210 (alpha = 0.95, beta = 0.8). DISCUSSION: The DROP-trial is a randomized controlled multicenter trial that will provide evidence whether or not preoperative biliary drainage is to be performed in patients with obstructive jaundice due to a periampullary tumor

The Value of Success: Acquiring Gains, Avoiding Losses, and Simply Being Successful

A large network of spatially contiguous, yet anatomically distinct regions in medial frontal cortex is involved in reward processing. Although it is clear these regions play a role in critical aspects of reward-related learning and decision-making, the individual contributions of each component remains unclear. We explored dissociations in reward processing throughout several key regions in the reward system and aimed to clarify the nature of previously observed outcome-related activity in a portion of anterior medial orbitofrontal cortex (mOFC). Specifically, we tested whether activity in anterior mOFC was related to processing successful actions, such that this region would respond similarly to rewards with and without tangible benefits, or whether this region instead encoded only quantifiable outcome values (e.g., money). Participants performed a task where they encountered monetary gains and losses (and non-gains and non-losses) during fMRI scanning. Critically, in addition to the outcomes with monetary consequences, the task included trials that provided outcomes without tangible benefits (participants were simply told that they were correct or incorrect). We found that anterior mOFC responded to all successful outcomes regardless of whether they carried tangible benefits (monetary gains and non-losses) or not (controls). These results support the hypothesis that anterior mOFC processes rewards in terms of a common currency and is capable of providing reward-based signals for everything we value, whether it be primary or secondary rewards or simply a successful experience without objectively quantifiable benefits

Plant-inducible virulence promoter of the Agrobacterium tumefaciens Ti plasmid

Agrobacterium tumefaciens is the causative agent of crown gall, a plant tumour that can arise on most species of dicotyledonous plants. The tumour-inducing capacity of the bacterium requires the presence of a large plasmid, designated the Ti plasmid, which itself contains two regions essential for tumour formation-the T(umour)-region and the Vir(ulence)-region. The T-region is transferred to plant cells by an unknown mechanism, and becomes stably integrated into the plant genome. The Vir-region has been identified by transposon mutagenesis, but the DNA of this region has never been detected in tumour lines. However, trans-complementation of Vir mutants indicates that genes of the Vir-region are functional in the bacterium. Moreover, the Vir- and T-regions can be physically separated in A. tumefaciens without loss of tumour-inducing capacity. Seven loci, designated virA-F and virO, have been identified in the Vir-region of the octopine Ti plasmid, but their functions are unknown. As virC mutants in the octopine-type plasmid pTiB6 are invariably avirulent in tests on various plant species, this gene seems to be essential for virulence and we are studying it in detail. We report here that the promoter of virC shows no detectable activity in A. tumefaciens and Escherichia coli K-12 grown in standard medium, but that its activity is induced by a plant product.

Laparoscopic adjustable banded roux-en-y gastric bypass as a primary procedure for the super-super-obese (body mass index > 60 kg/m2)

<p>Abstract</p> <p>Background</p> <p>Currently, there is no consensus opinion regarding the optimal procedure of choice in super-super-morbid obesity (Body mass index, BMI > 60 kg/m2). Roux-en-Y gastric bypass (RYGB) is associated with failure to achieve or maintain 50% excess weight loss (EWL) or BMI < 35 in approximately 15% of patients. Also, percent EWL is significantly less after 1-year in the super-super-obese group as compared with the less obese group and many patients are still technically considered to be obese (lowest post-surgical BMI > 35) following RYGB surgery in this group. The addition of adjustable gastric band (AGB) to RYGB has been reported as a revisional procedure but this combined bariatric procedure has not been explored as a primary operation.</p> <p>Methods</p> <p>In a primary laparoscopic RYGB, an AGB is drawn around the gastric pouch through a small opening between the blood vessels on the lesser curve and the gastric pouch. The band is then fixed by suturing the gastric remnant to the gastric pouch both above and below the band to prevent slippage.</p> <p>Results</p> <p>Between November 2009 and March 2010, 6 consecutive super-super-obese patients underwent a primary laparoscopic adjustable banded Roux-en-Y gastric bypass procedure at our institution. One male patient (21 years, BMI 70 kg/m²) developed a pneumonia postoperatively. No other postoperative complications were observed.</p> <p>Conclusion</p> <p>To the best of our knowledge, this is the first series of patients that underwent a laparoscopic adjustable banded RYGB as a primary operation for the super-super obese in the indexed literature. With the combined procedure, a sequential action mechanism for weight loss is to be expected. The restrictive, malabsorptive and hormonal working mechanism of the RYGB will induce weight loss from the start reaching a stabilised plateau of weight after 12 - 18 months. At that time, filling of the band can be started resulting in further gastric pouch restriction and increased weight loss. Moreover, besides improving the results of total weight loss, a gradual filling of the band can as well prevent the RYGB patient from weight regain if restriction would fade away with time.</p

Network centrality and organizational aspirations: A behavioral interaction in the context of international strategic alliances

Whereas social network analysis has been associated with organizational aspirations, little is known on how firm's structural positioning, and particularly network centrality, affects organizational aspirations to engage in international strategic alliances (ISA). This study examines the impact of network centrality on firm's internationalization behavior within the ISA domain in response to the performance-aspiration gap. We build on social and behavioral perspectives to predict that network centrality and performance-based aspirations will be associated with the number of ISA the firm engages in. Using a sample of 7760 alliance collaborations from the top 81 global pharmaceutical firms for the period of 1991-2012, we find supporting evidence for most of our arguments