Thermodynamic Modeling of Aqueous Piperazine/N-(2-Aminoethyl) Piperazine for CO2 Capture

AbstractAqueous piperazine (PZ) blended with N-(2-aminoethyl) piperazine (AEP) is an attractive solvent for CO2 capture from coal-fired power plants. A rigorous thermodynamic model was developed in Aspen Plus® to predict properties of PZ/AEP/H2O/CO2, using the electrolyte-Nonrandom Two-Liquid (eNRTL) activity coefficient model. A sequential regression was performed to represent CO2 solubility, speciation, and amine volatility data over operationally significant loading and temperature ranges. The model predicts a CO2 cyclic capacity of 0.86mol/kg (PZ + AEP + water) for 5 m PZ/2 m AEP, compared to 0.50mol/kg for 7 m MEA and 0.86mol/kg for 8 m PZ. The predicted heat of absorption is 75 to 85kJ/mol CO2 in the operating loading range (0.288–0.380mol CO2/mol alkalinity). Speciation for PZ/AEP/H2O at various CO2 loading and temperature was also predicted, from which behavior of CO2 in the amine system was proposed

Development of an extended chemical mechanism for global–through–urban applications

AbstractThe interactions between climate and air quality are receiving increasing attention due to their high relevancy to climate change. Coupled climate and air quality models are being developed to study these interactions. These models need to address the transport and chemistry of atmospheric species over a large range of scales and atmospheric conditions. In particular, the chemistry mechanism is a key component of such models because it needs to include the relevant reactions to simulate the chemistry of the lower troposphere, the upper troposphere, and the lower stratosphere, as well as the chemistry of polluted, rural, clean, and marine environments. This paper describes the extension of an existing chemistry mechanism for urban/regional applications, the 2005 version of the Carbon Bond Mechanism (CB05), to include the relevant atmospheric chemistry for global and global–through–urban applications. Updates to the mechanism include the most important gas–phase reactions needed for the lower stratosphere as well as reactions involving mercury species, and a number of heterogeneous reactions on aerosol particles, cloud droplets, and Polar Stratospheric Clouds (PSCs). The extended mechanism, referred to as CB05 for Global Extension (CB05_GE), is tested for a range of atmospheric conditions using a zero–dimensional box–model. A comparison of results from the extended mechanism with those from the original starting mechanism for both clean and polluted conditions in the lower troposphere shows that the extended mechanism preserves the fidelity of the original mechanism under those conditions. Simulations of marine Arctic conditions, upper tropospheric conditions, and lower stratospheric conditions with the box model illustrate the importance of halogen chemistry and heterogeneous reactions (on aerosol surfaces as well as PSCs for stratospheric conditions) for predicting ozone and elemental mercury depletion events that are often observed during these conditions. Depletions that are comparable to observed depletions are predicted by the box model for very clean conditions (extremely low or zero concentrations of aldehydes and other VOCs) because, in the absence of continuous sources of active halogens, these conditions result in less conversion of active chlorine and bromine to more stable products, such as HCl and HBr

Blends of amines with piperazine for CO2 capture

Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a blend of piperazine and at least one diamine or triamine.Board of Regents, University of Texas Syste

Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate-Scale Hydrodynamic Model

The Washington State Department of Ecology contracted with Pacific Northwest National Laboratory to develop an intermediate-scale hydrodynamic and water quality model to study dissolved oxygen and nutrient dynamics in Puget Sound and to help define potential Puget Sound-wide nutrient management strategies and decisions. Specifically, the project is expected to help determine 1) if current and potential future nitrogen loadings from point and non-point sources are significantly impairing water quality at a large scale and 2) what level of nutrient reductions are necessary to reduce or dominate human impacts to dissolved oxygen levels in the sensitive areas. In this study, an intermediate-scale hydrodynamic model of Puget Sound was developed to simulate the hydrodynamics of Puget Sound and the Northwest Straits for the year 2006. The model was constructed using the unstructured Finite Volume Coastal Ocean Model. The overall model grid resolution within Puget Sound in its present configuration is about 880 m. The model was driven by tides, river inflows, and meteorological forcing (wind and net heat flux) and simulated tidal circulations, temperature, and salinity distributions in Puget Sound. The model was validated against observed data of water surface elevation, velocity, temperature, and salinity at various stations within the study domain. Model validation indicated that the model simulates tidal elevations and currents in Puget Sound well and reproduces the general patterns of the temperature and salinity distributions

Lymphatic trafficking kinetics and near-infrared imaging using star polymer architectures with controlled anionic character

Targeted lymphatic delivery of nanoparticles for drug delivery and imaging is primarily dependent on size and charge. Prior studies have observed increased lymphatic uptake and retentions of over 48 hrs for negatively charged particles compared to neutral and positively charged particles. We have developed new polymeric materials that extend retention over a more pharmaceutically relevant 7-day period. We used whole body fluorescence imaging to observe in mice the lymphatic trafficking of a series of anionic star poly-(6-O-methacryloyl-D-galactose) polymer-NIR dye (IR820) conjugates. The anionic charge of polymers was increased by modifying galactose moieties in the star polymers with succinic anhydride. Increasing anionic nature was associated with enhanced lymphatic uptake up to a zeta potential of ca. -40 mV; further negative charge did not affect lymphatic uptake. Compared to the 20% acid-conjugate, the 40 to 90% acid-star-polymer conjugates exhibited a 2.5- to 3.5-fold increase in lymphatic uptake in both the popliteal and iliac nodes. The polymer conjugates exhibited node half-lives of 2 to 20 hrs in the popliteal nodes and 19 to 114 hrs in the deeper iliac nodes. These polymer conjugates can deliver drugs or imaging agents with rapid lymphatic uptake and prolonged deep-nodal retention; thus they may provide a useful vehicle for sustained intralymphatic drug delivery with low toxicity

Lymphatic trafficking kinetics and near-infrared imaging using star polymer architectures with controlled anionic character

This is the published version. Copyright ElsevierTargeted lymphatic delivery of nanoparticles for drug delivery and imaging is primarily dependent on size and charge. Prior studies have observed increased lymphatic uptake and retentions of over 48 hrs for negatively charged particles compared to neutral and positively charged particles. We have developed new polymeric materials that extend retention over a more pharmaceutically relevant 7-day period. We used whole body fluorescence imaging to observe in mice the lymphatic trafficking of a series of anionic star poly-(6-O-methacryloyl-D-galactose) polymer-NIR dye (IR820) conjugates. The anionic charge of polymers was increased by modifying galactose moieties in the star polymers with succinic anhydride. Increasing anionic nature was associated with enhanced lymphatic uptake up to a zeta potential of ca. -40 mV; further negative charge did not affect lymphatic uptake. Compared to the 20% acid-conjugate, the 40 to 90% acid-star-polymer conjugates exhibited a 2.5- to 3.5-fold increase in lymphatic uptake in both the popliteal and iliac nodes. The polymer conjugates exhibited node half-lives of 2 to 20 hrs in the popliteal nodes and 19 to 114 hrs in the deeper iliac nodes. These polymer conjugates can deliver drugs or imaging agents with rapid lymphatic uptake and prolonged deep-nodal retention; thus they may provide a useful vehicle for sustained intralymphatic drug delivery with low toxicity.This work was supported by awards from the American Cancer Society (RSG-08-133-01-CDD), the Susan G. Komen Foundation (KG090481), a Pfizer Predoctoral Scholarship to TRB, and a PhRMA Foundation Predoctoral Fellowship to TRB. Also, the authors would like to thank Dr. Sarah Kieweg and Thora Whitmore for the use of the Advanced Rheometer 2000. TRB performed imaging studies and SD characterized and synthesized the materials; their contributions and authorship were equal in this study

RNA Sequencing Reveals Differential Expression of Mitochondrial and Oxidation Reduction Genes in the Long-Lived Naked Mole-Rat When Compared to Mice

The naked mole-rat (Heterocephalus glaber) is a long-lived, cancer resistant rodent and there is a great interest in identifying the adaptations responsible for these and other of its unique traits. We employed RNA sequencing to compare liver gene expression profiles between naked mole-rats and wild-derived mice. Our results indicate that genes associated with oxidoreduction and mitochondria were expressed at higher relative levels in naked mole-rats. The largest effect is nearly 300-fold higher expression of epithelial cell adhesion molecule (Epcam), a tumour-associated protein. Also of interest are the protease inhibitor, alpha2-macroglobulin (A2m), and the mitochondrial complex II subunit Sdhc, both ageing-related genes found strongly over-expressed in the naked mole-rat. These results hint at possible candidates for specifying species differences in ageing and cancer, and in particular suggest complex alterations in mitochondrial and oxidation reduction pathways in the naked mole-rat. Our differential gene expression analysis obviated the need for a reference naked mole-rat genome by employing a combination of Illumina/Solexa and 454 platforms for transcriptome sequencing and assembling transcriptome contigs of the non-sequenced species. Overall, our work provides new research foci and methods for studying the naked mole-rat's fascinating characteristics

Expanding provider-initiated HIV testing at STI clinics in China

Despite expanding sexually transmitted epidemics in South China, the majority of patients presenting to sexually transmitted infection (STI) clinics are not routinely screened for HIV infection. Identifying barriers to offering HIV testing among STI care providers is an important public health priority. The aim of this study was to investigate the frequency of offering HIV testing among STI care providers in South China and reported physician barriers to offering HIV testing. More detailed operational data regarding HIV test offer frequency and barriers to testing may enhance routine HIV testing at STI clinics. A sample of 62 STI care providers within the Pearl River Delta Region of South China completed a survey including socio-demographic and training background information (including sex, age, medical education, year of terminal medical degree, HIV-specific training), reasons for not offering HIV testing routinely, and physical examination and sexual history taking practices. Frequency of offering HIV testing was calculated based on reports from research assistants and operational data. STI care providers offered HIV testing to 3011/10592 (28.4%) of their patients. There was substantial variability across providers in the frequency of offering testing, ranging from 3% to 100%. None of the identified physician factors were associated with offering HIV testing 100% of the time in the multivariate model. The most commonly physician reported barriers to HIV testing included: 1) low perceived prevalence of disease; and 2) not recommended by current guidelines. Forty-seven providers (76%) reported asking about same sex behaviors rarely or never. Further research on HIV screening practices of STI care providers may help scale up HIV provider-initiated testing and counseling programs

‘How people from Chinese backgrounds make sense of and respond to experiences of mental distress: Thematic analysis

This is the peer reviewed version of the following article: E. Y. W. Yeung, F. Irvine, and K. M. S. Tsang, ‘How people from Chinese backgrounds make sense of and respond to the experiences of mental distress: Thematic analysis’, Journal of Psychiatric and Mental Health Nursing, Vol. 24 (8): 589-599, October 2017, which has been published in final form at https://doi.org/10.1111/jpm.12406. Under embargo. Embargo end date: 3 August 2018. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.Introduction: Late presentation and low utilisation of mental health services are common among Chinese populations. An understanding of their journey towards mental health care helps to identify timely and appropriate intervention. Aim: We aimed to examine how Chinese populations make sense of the experiences of mental distress, and how this understanding influences their pathways to mental health care. Method: We undertook in-depth interviews with fourteen people with mental health problems and sixteen family members. Thematic analysis was used to analyse data. Results / Discussions: Different conceptualisation of mental distress and the stigma attached to mental health problems explained why most participants accessed services at crisis points. Because of mental illness stigma, they were reluctant to seek help outside of the family. Participants used a pragmatic pluralistic approach to incorporate ritual healing and western interventions to manage mental distress as they travelled further on the pathway journey. Families play a key role in the journey and are prepared to visit different parts of the world to seek traditional healers. Implications for practice: Mental health nurses need to adopt a transcultural working approach to address mental health issues so that family will get the support needed to continue their caring role.Peer reviewe