Smart windows—-dynamic control of building energy performance

This paper explores the potential of thermotropic (TT) windows as a means of improving overall building energy performance. Capitalising on their ability to dynamically alter solar and visible light transmittance and reflectance based on window temperature, they have the ability to reduce solar heat gains and subsequently reduce cooling loads when the external conditions exceed those required for occupant comfort. Conversely when the external conditions fall short of those required for comfort, they maintain a degree of optical transparency thus promoting opportunities afforded by passive solar gains. To test their overall effectiveness, thermotropic layers made of varying hydroxypropyl cellulose (HPC) concentrations (2 wt.%, 4 wt.% and 6 wt.%) were firstly synthesised and their optical properties measured. Building performance predictions were subsequently conducted in EnergyPlus for four window inclinations (90°, 60°, 30° and 0° to the horizontal) based on a small office test cell situated in the hot summer Mediterranean climate of Palermo, Italy. Results from annual predictions show that both incident solar radiation and outdoor ambient temperature play a significant role in the transmissivity and reflectivity of the glazing unit. If used as a roof light, a 6 wt.% HPC-based thermotropic window has a dynamic average Solar Heat Gain Coefficient (SHGC) between 0.44 and 0.56, this lower than that of 0.74 for double glazing. Predictions also show that in the specific case tested, the 6 wt.% HPC-based thermotropic window provides an overall annual energy saving of 22% over an equivalent double glazed unit. By maintaining the thermotropic window spectral properties but lowering the associated transition temperature ranges, it was found that the lowest temperature range provided the smallest solar heat gains. Although, this is beneficial during periods where cooling may be needed, in those periods where heating may be required, opportunities gained through passive solar heating are limited. In addition, with lower solar heat gain, there is a possibility that artificial lighting energy demand increases resulting in additional energy consumption

Repeated stimulation of the HPA axis alters white blood cell count without increasing oxidative stress or inflammatory cytokines in fasting elephant seal pups

The hypothalamic-pituitary-adrenal (HPA) axis controls the release of glucocorticoids, which regulate immune and inflammatory function by modulating cytokines, white blood cells and oxidative stress via glucocorticoid receptor (GR) signaling. Although the response to HPA activation is well characterized in many species, little is known about the impacts of HPA activation during extreme physiological conditions. Hence, we challenged 18 simultaneously fasting and developing elephant seal pups with daily intramuscular injections of adrenocorticotropin (ACTH), a GR antagonist (RU486), or a combination of the two (ACTH+RU486) for 4 days. We collected blood at baseline, 2 h and 4 days after the beginning of treatment. ACTH and ACTH+RU486 elevated serum aldosterone and cortisol at 2 h, with effects diminishing at 4 days. RU486 alone induced a compensatory increase in aldosterone, but not cortisol, at 4 days. ACTH decreased neutrophils at 2 h, while decreasing lymphocytes and increasing the neutrophil:lymphocyte ratio at 4 days. These effects were abolished by RU486. Despite alterations in white blood cells, there was no effect of ACTH or RU486 on transforming growth factor-β or interleukin-6 levels; however, both cytokines decreased with the 4 day fasting progression. Similarly, ACTH did not impact protein oxidation, lipid peroxidation or antioxidant enzymes, but plasma isoprostanes and catalase activity decreased while glutathione peroxidase increased with fasting progression. These data demonstrate differential acute (2 h) and chronic (4 days) modulatory effects of HPA activation on white blood cells and that the chronic effect is mediated, at least in part, by GR. These results also underscore elephant seals\u27 extraordinary resistance to oxidative stress derived from repeated HPA activation

Programmable probiotics for detection of cancer in urine

Rapid advances in the forward engineering of genetic circuitry in living cells has positioned synthetic biology as a potential means to solve numerous biomedical problems, including disease diagnosis and therapy. One challenge in exploiting synthetic biology for translational applications is to engineer microbes that are well tolerated by patients and seamlessly integrate with existing clinical methods. We use the safe and widely used probiotic Escherichia coli Nissle 1917 to develop an orally administered diagnostic that can noninvasively indicate the presence of liver metastasis by producing easily detectable signals in urine. Our microbial diagnostic generated a high-contrast urine signal through selective expansion in liver metastases (10[superscript 6]-fold enrichment) and high expression of a lacZ reporter maintained by engineering a stable plasmid system. The lacZ reporter cleaves a substrate to produce a small molecule that can be detected in urine. E. coli Nissle 1917 robustly colonized tumor tissue in rodent models of liver metastasis after oral delivery but did not colonize healthy organs or fibrotic liver tissue. We saw no deleterious health effects on the mice for more than 12 months after oral delivery. Our results demonstrate that probiotics can be programmed to safely and selectively deliver synthetic gene circuits to diseased tissue microenvironments in vivo.Ludwig Center for Molecular OncologyAmar G. Bose Research GrantSan Diego Center for Systems Biology (United States. National Institutes of Health Grant P50 GM085764)National Institute of General Medical Sciences (U.S.) (R01GM69811)National Cancer Institute (U.S.) (Koch Institute Support (Core) Grant P30-CA14051)National Institute of Environmental Health Sciences (Core Center Grant P30-ES002109)Misrock Foundation (Postdoctoral Fellowship)National Institutes of Health (U.S.) (Ruth L. Kirschstein National Research Service Award)Burroughs Wellcome Fund (Career Award at the Scientific Interface

Decreased soluble guanylate cyclase contributes to cardiac dysfunction induced by chronic doxorubicin treatment in mice

Aims: The use of doxorubicin, a potent chemotherapeutic agent, is limited by cardiotoxicity. We tested the hypothesis that decreased soluble guanylate cyclase (sGC) enzyme activity contributes to the development of doxorubicin-induced cardiotoxicity. Results: Doxorubicin administration (20 mg/kg, intraperitoneally [IP]) reduced cardiac sGC activity in wild-type (WT) mice. To investigate whether decreased sGC activity contributes to doxorubicin-induced cardiotoxicity, we studied mice with cardiomyocyte-specific deficiency of the sGC alpha 1-subunit (mice with cardiomyocyte-specific deletion of exon 6 of the sGC alpha 1 allele [sGC alpha 1(-/-CM)]). After 12 weeks of doxorubicin administration (2 mg/kg/week IP), left ventricular (LV) systolic dysfunction was greater in sGC alpha 1(-/-CM) than WT mice. To further assess whether reduced sGC activity plays a pathogenic role in doxorubicin-induced cardiotoxicity, we studied a mouse model in which decreased cardiac sGC activity was induced by cardiomyocyte-specific expression of a dominant negative sGC alpha 1 mutant (DNsGC alpha 1) upon doxycycline removal (Tet-off). After 8 weeks of doxorubicin administration, DNsGC alpha 1(tg/+), but not WT, mice displayed LV systolic dysfunction and dilatation. The difference in cardiac function and remodeling between DNsGC alpha 1(tg/+) and WT mice was even more pronounced after 12 weeks of treatment. Further impairment of cardiac function was attenuated when DNsGC alpha 1 gene expression was inhibited (beginning at 8 weeks of doxorubicin treatment) by administering doxycycline. Furthermore, doxorubicin-associated reactive oxygen species generation was higher in sGC alpha 1-deficient than WT hearts. Innovation and Conclusion: These data demonstrate that a reduction in cardiac sGC activity worsens doxorubicin-induced cardiotoxicity in mice and identify sGC as a potential therapeutic target. Various pharmacological sGC agonists are in clinical development or use and may represent a promising approach to limit doxorubicin-associated cardiotoxicity

Potentiation of Acetylcholine-Induced Relaxation of Aorta in Male UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) Rats: Sex-Specific Responses

Previous reports suggest that diabetes may differentially affect the vascular beds of females and males. The objectives of this study were to examine whether there were (1) sex differences in aortic function and (2) alterations in the relative contribution of endothelium-derived relaxing factors in modulating aortic reactivity in UC Davis Type 2 Diabetes Mellitus (UCD-T2DM) rats. Endothelium-dependent vasorelaxation (EDV) in response to acetylcholine (ACh) was measured in aortic rings before and after exposure to pharmacological inhibitors. Relaxation responses to sodium nitroprusside were assessed in endothelium-denuded rings. Moreover, contractile responses to phenylephrine (PE) were measured before and after incubation of aortic rings with a nitric oxide synthase (NOS) inhibitor in the presence of indomethacin. Metabolic parameters and expression of molecules associated with vascular and insulin signaling as well as reactive oxygen species generation were determined. Diabetes slightly but significantly impaired EDV in response to ACh in aortas from females but potentiated the relaxation response in males. The potentiation of EDV in diabetic male aortas was accompanied by a traces of nitric oxide (NO)- and prostanoid-independent relaxation and elevated aortic expression of small- and intermediate conductance Ca2+-activated K+ channels in this group. The smooth muscle sensitivity to NO was not altered, whereas the responsiveness to PE was significantly enhanced in aortas of diabetic groups in both sexes. Endothelium-derived NO during smooth muscle contraction, as assessed by the potentiation of the response to PE after NOS inhibition, was reduced in aortas of diabetic rats regardless of sex. Accordingly, decreases in pAkt and peNOS were observed in aortas from diabetic rats in both sexes compared with controls. Our data suggest that a decrease in insulin sensitivity via pAkt-peNOS-dependent signaling and an increase in oxidative stress may contribute to the elevated contractile responses observed in diabetic aortas in both sexes. This study demonstrates that aortic function in UCD-T2DM rats is altered in both sexes. Here, we provide the first evidence of sexual dimorphism in aortic relaxation in UCD-T2DM rats

Programmable probiotics for detection of cancer in urine

Rapid advances in the forward engineering of genetic circuitry in living cells has positioned synthetic biology as a potential means to solve numerous biomedical problems, including disease diagnosis and therapy. One challenge in exploiting synthetic biology for translational applications is to engineer microbes that are well tolerated by patients and seamlessly integrate with existing clinical methods. We use the safe and widely used probiotic Escherichia coli Nissle 1917 to develop an orally administered diagnostic that can noninvasively indicate the presence of liver metastasis by producing easily detectable signals in urine. Our microbial diagnostic generated a high-contrast urine signal through selective expansion in liver metastases (10 6 -fold enrichment) and high expression of a lacZ reporter maintained by engineering a stable plasmid system. The lacZ reporter cleaves a substrate to produce a small molecule that can be detected in urine. E. coli Nissle 1917 robustly colonized tumor tissue in rodent models of liver metastasis after oral delivery but did not colonize healthy organs or fibrotic liver tissue. We saw no deleterious health effects on the mice for more than 12 months after oral delivery. Our results demonstrate that probiotics can be programmed to safely and selectively deliver synthetic gene circuits to diseased tissue microenvironments in vivo

Muscular Apoptosis but Not Oxidative Stress Increases with Old Age in a Long-Lived Diver, the Weddell Seal

Seals experience repeated bouts of ischemia–reperfusion while diving, potentially exposing their tissues to increased oxidant generation and thus oxidative damage and accelerated aging. We contrasted markers of oxidative damage with antioxidant profiles across age and sex for propulsive (longissismus dorsi) and maneuvering (pectoralis) muscles of Weddell seals to determine whether previously observed morphological senescence is associated with oxidative stress. In longissismus dorsi, old (age 17–26 years) seals exhibited a nearly 2-fold increase in apoptosis over young (age 9–16 years) seals. There was no evidence of age-associated changes in lipid peroxidation or enzymatic antioxidant profiles. In pectoralis, 4-hydroxynonenal-Lys (4-HNE-Lys) levels increased 1.5-fold in old versus young seals, but lipid hydroperoxide levels and apoptotic index did not vary with age. Glutathione peroxidase activity was 1.5-fold higher in pectoralis of old versus young animals, but no other antioxidants changed with age in this muscle. With respect to sex, no differences in lipid hydroperoxides or apoptosis were observed in either muscle. Males had higher HSP70 expression (1.4-fold) and glutathione peroxidase activity (1.3-fold) than females in longissismus dorsi, although glutathione reductase activity was 1.4-fold higher in females. No antioxidants varied with sex in pectoralis. These results show that apoptosis is not associated with oxidative stress in aged Weddell seal muscles. Additionally, the data suggest that adult seals utilize sex-specific antioxidant strategies in longissismus dorsi but not pectoralis to protect skeletal muscles from oxidative damage

The lifetime of nitrogen oxides in an isoprene-dominated forest

The lifetime of nitrogen oxides (NO_x) affects the concentration and distribution of NO_x and the spatial patterns of nitrogen deposition. Despite its importance, the lifetime of NO_x is poorly constrained in rural and remote continental regions. We use measurements from a site in central Alabama during the Southern Oxidant and Aerosol Study (SOAS) in summer 2013 to provide new insights into the chemistry of NO_x and NO_x reservoirs. We find that the lifetime of NO_x during the daytime is controlled primarily by the production and loss of alkyl and multifunctional nitrates (ΣANs). During SOAS, ΣAN production was rapid, averaging 90 ppt h^(−1) during the day, and occurred predominantly during isoprene oxidation. Analysis of the ΣAN and HNO_3 budgets indicate that ΣANs have an average lifetime of under 2 h, and that approximately 45 % of the ΣANs produced at this site are rapidly hydrolyzed to produce nitric acid. We find that ΣAN hydrolysis is the largest source of HNO_3 and the primary pathway to permanent removal of NO_x from the boundary layer in this location. Using these new constraints on the fate of ΣANs, we find that the NO_x lifetime is 11 ± 5 h under typical midday conditions. The lifetime is extended by storage of NO_x in temporary reservoirs, including acyl peroxy nitrates and ΣANs

Synchronized cycles of bacterial lysis for in vivo delivery

The pervasive view of bacteria as strictly pathogenic has given way to an ppreciation of the widespread prevalence of beneficial microbes within the human body. Given this milieu, it is perhaps inevitable that some bacteria would evolve to preferentially grow in environments that harbor disease and thus provide a natural platform for the development of engineered therapies. Such therapies could benefit from bacteria that are programmed to limit bacterial growth while continually producing and releasing cytotoxic agents in situ. Here, we engineer a clinically relevant bacterium to lyse synchronously at a threshold population density and to release genetically encoded cargo. Following quorum lysis, a small number of surviving bacteria reseed the growing population, thus leading to pulsatile delivery cycles. We use microfluidic devices to characterize the engineered lysis strain and we demonstrate its potential as a drug deliver platform via co-culture with human cancer cells in vitro. As a proof of principle, we track the bacterial population dynamics in ectopic syngeneic colorectal tumors in mice. The lysis strain exhibits pulsatile population dynamics in vivo, with mean bacterial luminescence that remained two orders of magnitude lower than an unmodified strain. Finally, guided by previous findings that certain bacteria can enhance the efficacy of standard therapies, we orally administer the lysis strain, alone or in combination with a clinical chemotherapeutic, to a syngeneic transplantation model of hepatic colorectal metastases. We find that the combination of both circuit-engineered bacteria and chemotherapy leads to a notable reduction of tumor activity along with a marked survival benefit over either therapy alone. Our approach establishes a methodology for leveraging the tools of synthetic biology to exploit the natural propensity for certain bacteria to colonize disease sites.National Institute of General Medical Sciences (U.S.) (GM069811)San Diego Center for Systems Biology (P50 GM085764)National Cancer Institute (U.S.). Swanson Biotechnology Center (Koch Institute Support Grant (P30-CA14051))National Institute of Environmental Health Sciences (Core Center Grant (P30- ES002109))National Institutes of Health (U.S.) (NIH Pathway to Independence Award NIH (K99 CA197649-01))Misrock Postdoctoral fellowshipNational Defense Science and Engineering Graduate (NDSEG) Fellowshi

Importance of biogenic volatile organic compounds to acyl peroxy nitrates (APN) production in the southeastern US during SOAS 2013

Gas-phase atmospheric concentrations of peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), and peroxymethacryloyl nitrate (MPAN) were measured on the ground using a gas chromatograph electron capture detector (GC-ECD) during the Southern Oxidants and Aerosols Study (SOAS) 2013 campaign (1 June to 15 July 2013) in Centreville, Alabama, in order to study biosphere&ndash;atmosphere interactions. Average levels of PAN, PPN, and MPAN were 169, 5, and 9&thinsp;pptv, respectively, and the sum accounts for an average of 16&thinsp;% of NOy during the daytime (10:00 to 16:00 local time). Higher concentrations were seen on average in air that came to the site from the urban NOx sources to the north. PAN levels were the lowest observed in ground measurements over the past two decades in the southeastern US. A multiple regression analysis indicates that biogenic volatile organic compounds (VOCs) account for 66&thinsp;% of PAN formation during this study. Comparison of this value with a 0-D model simulation of peroxyacetyl radical production indicates that at least 50&thinsp;% of PAN formation is due to isoprene oxidation. MPAN has a statistical correlation with isoprene hydroxynitrates (IN). Organic aerosol mass increases with gas-phase MPAN and IN concentrations, but the mass of organic nitrates in particles is largely unrelated to MPAN.</p