Hydrate composite particles for ocean carbon sequestration: field verification

This paper reports on the formation and dissolution of CO2/seawater/CO2 hydrate composite particles produced during field experiments in Monterey Bay, CA using a CO2 injector system previously developed in the laboratory. The injector consisted of a coflow reactor wherein water was introduced as a jet into liquid CO2, causing vigorous mixing of the two immiscible fluids to promote the formation of CO2 hydrate that is stable at ambient pressures and temperatures typical of ocean depths greater than approximately 500 m. Using flow rate ratios of water and CO2 of 1:1 and 5:1, particulate composites of CO2 hydrate/liquid CO2/seawater phases were produced in seawater at depths between 1100 and 1300 m. The resultant composite particles were tracked by a remotely operated vehicle system as they freely traveled in an imaging box that had no bottom or top walls. Results from the field experiments were consistent with laboratory experiments, which were conducted in a 70 L high-pressure vessel to simulate the conditions in the ocean at intermediate depths. The particle velocity and volume histories were monitored and used to calculate the conversion of CO2 into hydrate and its subsequent dissolution rate after release into the ocean. The dissolution rate of the composite particles was found to be higher than that reported for pure CO2 droplets. However, when the rate was corrected to correspond to pure CO2, the difference was very small. Results indicate that a higher conversion of liquid CO2 to CO2 hydrate is needed to form negatively buoyant particles in seawater when compared to freshwater, due primarily to the increased density of the liquid phase but also due to processes involving brine rejection during hydrate formation.     

A pilot study of the association of tumor necrosis factor alpha polymorphisms with psoriatic arthritis in the romanian population

Tumor necrosis factor alpha (TNF-alpha) is an important pro-inflammatory cytokine implicated in the pathogenesis of psoriatic arthritis. We have performed a case-control association study of three TNF-alpha gene polymorphisms in a group of Romanian psoriatic arthritis patients versus ethnically matched controls. A second group of patients with undifferentiated spondyloarthritis was used in order to look for similarities in the genetic background of the two rheumatic disorders. The -857C/T polymorphism was associated with susceptibility to psoriatic arthritis in our population at the individual level (p = 0.03, OR 1.65, 95% CI 1.05-2.57) and in combined haplotypes with the -238G/A and -308G/A SNPs. Regarding the investigated polymorphisms and derived haplotypes, no potential association was found with the susceptibility to undifferentiated spondyloarthritis in Romanian patients.     

Infrared Assisted Production of 3,4-Dihydro-2(1H)-pyridones in Solvent-Free Conditions

A green approach for the synthesis of a set of ten 4-aryl substituted-5-alcoxy carbonyl-6-methyl-3,4-dihydro-2(1H)-pyridones using Meldrum's acid has been devised, the absence of solvent and the activation with infrared irradiation in addition to a multicomponent protocol are the main reaction conditions. The transformations proceeded with moderated yields (50-75%) with a reasonable reaction rate (3 h). It is worth noting that two novel molecules of the new class of the bis-3,4-dihydropyridones were also obtained. In addition, a comparison without the use of infrared irradiation was performed.     

Aryloxy Triester Phosphoramidates as Phosphoserine Prodrugs: A Proof of Concept Study

The specific targeting of protein-protein interactions by phosphoserine-containing small molecules has been scarce due to the dephosphorylation of phosphoserine and its charged nature at physiological pH, which hinder its uptake into cells. To address these issues, we herein report the synthesis of phosphoserine aryloxy triester phosphoramidates as phosphoserine prodrugs that are enzymatically metabolized to release phosphoserine. This phosphoserine-masking approach was applied to a phosphoserine-containing inhibitor of 14-3-3 dimerization, and the generated prodrugs exhibited improved pharmacological activity. Collectively, this provided a proof of concept that the masking of phosphoserine with biocleavable aryloxy triester phosphoramidate masking groups is a viable intracellular delivery system for phosphoserine-containing molecules. Ultimately, this will facilitate the discovery of phosphoserine-containing small-molecule therapeutics.     

Thermodynamic and thermophysical effects enabling high-forced convection heat transfer coefficients in supercritical fluids

Abstract

The strong variation of thermophysical properties of working fluids operating in the vicinity of the critical point makes this thermodynamic domain attractive to several energy applications. Therefore, herein a two-dimensional numerical method is used to investigate the effect of local thermophysical property variations on the local and overall thermal performance of internal convective heat transfer in a pipe in 324 operational conditions. Focusing on carbon dioxide and water as heat transfer fluids, an association of the variation of key thermophysical properties with thermohydraulic performance metrics is proposed, namely: (a) the local and (b) mean convective heat transfer coefficient and (c) the maximal temperature obtained at the tube wall. It is shown that there is an optimal combination of parameters such as mass flow rate, operating pressure, wall heat flux, and inlet temperature that, when properly selected, allow for a minimal maximal wall temperature. As expected, optimality is strongly associated with the Widom—or pseudo critical—line that extends from the critical point. Interestingly, however, contrary to what is observed in constant-property fluids, high heat transfer coefficient or minimal maximum temperature lead to different sets of optimal operating conditions. This difference is explained by how thermophysical properties vary locally along heat exchangers, which significantly affects overall heat transfer.     

A survey of ocular sports trauma and the role of eye protection

PurposeThe incidence of sports associated ocular injuries presenting to emergency departments is rising. Despite this, eye protection is not widely used in the general population. This survey was conducted to determine the spectrum of ocular sports injuries that presented to the emergency department of an ophthalmic hospital, which serves a large sector of inner city London. The role of eye protection in preventing ocular sports injuries was also investigated.MethodsAll patients who attended the emergency department with sports associated ocular injuries between May and July 2008 were identified. Medical records of these patients were examined.ResultsThere were a total of 16 999 ophthalmic emergency attendances. 48 (0.28%) patients presented with sports related ocular injuries. The outcomes of the consultations were: 13 (27.1%) patients discharged from the emergency department, 17 (35.4%) had reviews arranged in the emergency department, 18 (37.5%) referred to subspecialties. The mean presenting LogMAR visual acuities of patients that were discharged, reviewed in the emergency department, and referred to subspecialties were 0.01 (±0.33), 0.48 (±0.75), and 0.31 (±0.61) respectively. Visual acuities were better by 0.39 (95% CI 0.01–0.77, p = 0.042) in patients who were discharged compared to patients who were reviewed in the emergency department or referred to subspecialties. Evaluation of records revealed that no patients wore eye protection and none were given advice regarding prevention of future injuries.ConclusionResults from this survey show that ocular sports injuries account for a proportion of ophthalmic emergency attendances with a potential impact on service provision. It is essential that ophthalmologists, optometrists and other healthcare professionals are aware of the potential ocular morbidity from sports trauma and the importance of providing advice on the prevention of such injuries.     

Symposium review: Genomic investigations of flavor formation by dairy microbiota

Flavor is one of the most important attributes of any fermented dairy product. Dairy consumers are known to be willing to experiment with different flavors; thus, many companies producing fermented dairy products have looked at culture manipulation as a tool for flavor diversification. The development of flavor is a complex process, originating from a combination of microbiological, biochemical, and technological aspects. A key driver of flavor is the enzymatic activities of the deliberately inoculated starter cultures, in addition to the environmental or “nonstarter” microbiota. The contribution of microbial metabolism to flavor development in fermented dairy products has been exploited for thousands of years, but the availability of the whole genome sequences of the bacteria and yeasts involved in the fermentation process and the possibilities now offered by next-generation sequencing and downstream “omics” technologies is stimulating a more knowledge-based approach to the selection of desirable cultures for flavor development. By linking genomic traits to phenotypic outputs, it is now possible to mine the metabolic diversity of starter cultures, analyze the metabolic routes to flavor compound formation, identify those strains with flavor-forming potential, and select them for possible commercial application. This approach also allows for the identification of species and strains not previously considered as potential flavor-formers, the blending of strains with complementary metabolic pathways, and the potential improvement of key technological characteristics in existing strains, strains that are at the core of the dairy industry. An in-depth knowledge of the metabolic pathways of individual strains and their interactions in mixed culture fermentations can allow starter blends to be custom-made to suit industry needs. Applying this knowledge to starter culture research programs is enabling research and development scientists to develop superior starters, expand flavor profiles, and potentially develop new products for future market expansion.     

Suppressing η-phase development in steel-cemented tungsten carbide: A spark plasma sintering study

We describe the phase stability of a cemented tungsten carbide prepared using a high-vanadium tool steel as the cementing/binder phase and confirm suppression of (Fe, W)₆C η-phase formation, attributed to the preferential formation of a V_0.78W_0.22C_1−x phase that exists as islands within the Fe-rich binder matrix. The samples were prepared using spark plasma sintering (SPS), starting from commercially available WC and A11-LVC tool steel powders. The starting powders were ball milled adding 10, 15, and 20 vol.% steel. An A11-LVC tool steel was chosen as a low-cost hard steel (49 HRC) that does not contain Ni or Co but has a high vanadium (~9 wt.%) and carbon (~1.75 wt.%) content. Our results show that sintering by SPS can produce high-density (>98%) WC-steel specimens in which the matrix wets the WC grain surfaces and formation of the brittle η-phase is avoided. The η phase is often regarded as embrittling and undesirable, and its presence can result in degradation of mechanical properties. Microhardness values for the WC-10 and WC-15 vol.% steel samples were 12.3 ± 1.2 and 13.0 ± 0.9 GPa, respectively, whereas the fracture toughness values were 8.83 ± 0.48 and 8.81 ± 0.61 MPa·m^1/2, respectively.