Porous coordination cages have garnered considerable interest as a distinct class of permanently porous materials due to their unique molecular nature, setting them apart from more traditional ...metal–organic materials, including metal–organic frameworks. Postsynthetic modification (PSM) of cages offers a promising avenue for tailoring their properties, but challenges remain, including maintaining solubility, functional group compatibility and stability, and potential changes in porosity. Here, we explore novel approaches to address these challenges and enhance the versatility of coordination cages. We initially targeted alkylation and acylation reactions, where anhydrides were ultimately employed as relatively mild reagents. To expand the toolkit of PSM reactions, we explored Pd-catalyzed cross-coupling reactions, where high-throughput methodologies were used to optimize reaction conditions. In this regard, we identify Pd(OAc)2 with a 1,1′-bis(di-tert-butylphosphino)ferrocene ligand as an efficient reagent for the PSM of aryl-bromide functionalized cages with arylboronic acids. Overall, this work broadens the scope of the PSM of cages and highlights its potential as an avenue to tailor cages for specific applications in gas adsorption, separation, and catalysis.
To determine whether the endothelin-1 or endothelin-3 genes are genetically linked with blood pressure and relative heart weight in segregating rat populations, in the context of an elevated dietary ...sodium chloride intake.
Endothelin-1 and endothelin-3 genotypes of rats in segregating populations, derived from crosses of Dahl salt-sensitive (SS/Jr) rats with contrasting inbred strains, including Lewis rats, spontaneously hypertensive rats and Dahl salt-resistant (SR/Jr) rats, were determined using restriction fragment length polymorphisms. Segregating populations were fed a high (8%)-sodium chloride diet. Linkage of genotype with blood pressure or relative heart weight was determined by analysis of variance. Chromosomal location of the rat endothelin-3 gene was determined by genotyping a panel of recombinant inbred strains.
Two alleles for the endothelin-1 gene and three alleles for the endothelin-3 gene were identified. The endothelin-1 locus did not cosegregate with blood pressure or relative heart weight. The endothelin-3 locus cosegregated with blood pressure and relative heart weight in an SS/Jr x F1 (SS/Jr x SR/Jr) population, but not in populations containing a higher percentage of genes from the SR/Jr strain. The endothelin-3 and seminal vesicle protein-1 loci were linked and located on rat chromosome 3.
The endothelin-3 gene is, or is linked to, a locus on chromosome 3 that regulates blood pressure and relative heart weight in inbred Dahl rats, and these effects were strongly dependent on the genetic background.
Improvements in drought tolerance of crop plants require research focused on physiological processes. In 2002 and 2003 pot experiments with sugar beet were conducted in a greenhouse. Two (2002) or ...three (2003) different genotypes were subjected to three watering regimes (100, 50 and 20% of water holding capacity). Gas exchange, chlorophyll fluorescence and water-use efficiency (WUE) as parameters of possible relevance for drought stress tolerance in sugar beet were investigated. It was studied whether
13C discrimination (Δ) is suitable as an indirect measure for WUE of sugar beet.
DM yield, photosynthesis rate, transpiration rate and stomatal conductance decreased with increasing severity of drought stress. In contrast, internal CO
2 partial pressure remained relatively stable and effective quantum yield of photosynthesis was reduced only under severe drought, which points at non-stomatal inhibition of photosynthesis. Different sugar beet genotypes showed significant differences in DM yield, but interactions between genotype and water supply did not occur, indicating that genotypic differences in drought tolerance did not exist. In accordance with that, drought-sensitivity of gas exchange and chlorophyll fluorescence was the same in different genotypes. Δ was higher in the leaves than in the taproot. Reductions in Δ in drought-stressed plants corresponded to about 24% higher WUE. Differentiating between plant organs, only leaf Δ was negatively correlated with WUE
L whereas taproot Δ and WUE
T were unrelated. Δ was therefore proven to be a sensitive indicator for water availability during the growing period. However, similar as other parameters relevant for drought stress tolerance it requires investigations in broader genetic material of sugar beet to detect genotypic differences.
In this report, we present the commissioning and validation results for a commercial proton pencil beam scanning RayStation treatment planning system.
The commissioning data requirements are (1) ...integrated depth dose curves, (2) spot profiles, (3) absolute dose/monitor unit calibration, and (4) virtual source position. An 8-cm parallel plate chamber was used to measure the integrated depth dose curves by scanning a beam composed of a single spot in a water phantom. The spot profiles were measured at 5 different planes using a 2-dimensional scintillation detector. The absolute dose/monitor unit calibration was based on dose measurements in single-layer fields of size 10 × 10 cm
. The virtual-source position was calculated from the change in spot spacing with the distance from the isocenter. The beam model validation consisted of a comparison against commissioning data as well as a new set of verification measurements. For end-to-end testing, a series of phantom plans were created. These plans were measured at 1 to 3 depths using a 2-dimensional ion chamber array and evaluated for gamma index using the 3% and 3 mm criteria.
The maximum deviation for spot sigma measured versus calculated was -0.2 mm. The point-dose measurements for single-layer beams were within ± 3%, except for the largest field size (29 × 29 cm
) and the highest energy (226 MeV). The point doses in the spread-out Bragg peak plans showed a trend in which differences > 3% were seen for ranges > 30 cm, field sizes > 15 × 15 cm
, and depths > 25 cm. For end-to-end testing, 34 planes corresponding to 13 beams were analyzed for gamma index with a minimum pass rate of 92.8%.
The acceptable verification results and successful end-to-end testing ensured that all components of the treatment planning system were functional and the system was ready for clinical use.
Gas Storage in Porous Molecular Materials Deegan, Meaghan M.; Dworzak, Michael R.; Gosselin, Aeri J. ...
Chemistry : a European journal,
01/2021, Letnik:
27, Številka:
14
Journal Article
Aging is accompanied by an alteration in myocardial contractility. However, its noninvasive detection is difficult. The effect of chronic exercise on this decrease is unknown. Murine models of ...senescence are increasingly used to test therapies in aging. We tested whether strain rate imaging detected left ventricular (LV) systolic dysfunction in aging mice and was able to assess a potential improvement after exercise.
Young (3 weeks), adult (2 to 3 months), and old (6 to 18 months) C57BL6 male mice underwent echocardiograms with strain rate imaging, either in sedentary conditions or before, 2 weeks and 4 weeks after chronic swimming. Hemodynamic parameters of LV function including maximal and end-systolic elastance were obtained before euthanizing. LV fibrosis was measured using Sirius red staining. Conventional echocardiography was unable to detect LV systolic dysfunction in old mice, whereas both systolic strain rate and load-independent hemodynamic parameters such as preload recruitable stroke work and end-systolic elastance were significantly decreased. Both strain rate and load-independent hemodynamic parameters normalized after 4 weeks of exercise. Both endocardial and epicardial fibrosis were increased in the LV of aging mice. Endocardial fibrosis decreased in exercised aged mice.
Strain rate noninvasively detects LV systolic dysfunction associated with aging in mice, whereas conventional echocardiography does not. Chronic exercise normalizes LV systolic function and decreases fibrosis in old mice. Strain rate imaging in mice may be a useful tool to monitor the effect of new therapeutic strategies preventing the myocardial dysfunction associated with aging.
It is proved that every discrete Morse function in the sense of Forman on a finite regular CW complex can be represented by a polyhedral Morse function in the sense of Banchoff on an appropriate ...embedding in Euclidean space of the barycentric subdivision of the CW complex; such a representation preserves critical points. The proof is stated in terms of discrete Morse functions on posets.
The Challenger spacecraft explosion of Jan. 28, 1986, offered an opportunity to study the memories of normal latency and adolescent children of different emotional involvements following one sudden ...and distant disaster. How would children of various levels of concern express their memories? And if studied over time, how would these narratives change? Would there be developmental differences? And would there be false details of memory?
The authors set out to compare the memories of 153 children from Concord, N.H. (who watched the explosion on television), and Porterville, Calif. (who heard about it). The structured-interview responses of involved and less involved children; latency-age versus adolescent children; and those seen initially (5-7 weeks after the explosion) versus those same children seen later (at 14 months) were statistically compared.
The vast majority of children's memories of Challenger were clear, consistent, and detailed, with highlighting of personal placement, who else was there, and personal occurrences linked to the event. Those children who were less emotionally involved demonstrated significantly less clarity, consistency, and correct ordering of sequences and were less likely to remember personal placement, other people who were there, and related personal incidents. About 30% of all children in this study misunderstood something about Challenger and incorporated these misunderstandings into their memories as false details. Latency-age children continued to harbor false details for 14 months, as opposed to the adolescents.
Childhood memories of the Challenger space shuttle explosion appeared predictable, were related to patterns of memory that have been observed following single, unrepeated traumas, and reflected age and stage differences.
As the size of breast tumors continues to decrease, it has become more difficult to obtain adequate tumor tissue for molecular studies. We have used the estrogen receptor (ER) gene as a model to ...study the ability to perform a quantitative analysis of ER mRNA extracted from archival breast carcinoma specimens using reverse transcriptase polymerase chain reaction. Based upon ER mRNA abundance, tumors were characterized as having low, medium, or high ER mRNA expression. These data were compared with ER and progesterone receptor (PR) status determined by enzyme immunoassay, tumor histology, and Bloom-Richardson grade. Comparing the low and high ER mRNA groups, there were statistically significant differences in ER-positive status (10% versus 95%; P = 0.0001), PR-positive status (10% versus 90%; P = 0.0001), and tumor grade (2.67 +/- 0.12 versus 2.09 +/- 0.14; P = 0.0025). Of the 28 tumors in the high ER mRNA group, 5 (18%) were invasive lobular carcinomas whereas all 24 tumors with low ER mRNA were invasive ductal carcinomas. These data demonstrate that archival breast tumor specimens can be characterized for ER mRNA abundance. In addition, we conclude that the mechanisms regulating ER gene transcription influence the phenotype of breast carcinomas. These results also suggest that this technique can be designed to provide a quantitative analysis of gene expression for any gene of interest utilizing archival tumor specimens.
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