432 research outputs found
Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers
[EN] The macromolecular dynamics of dendronized copolymer membranes (PECHs), obtained by chemical modification of poly(epichlorohydrin) with the dendron 3,4,5-tris[4-(n-dodecan-1-yloxy)benzyloxy] benzoate, was investigated. In response to a thermal treatment during membrane preparation, these copolymers show an ability to change their shape, achieve orientation, and slightly crystallize, which was also observed by CP-MAS NMR, XRD, and DSC. The phenomenon was deeply analyzed by dielectric thermal analysis. The dielectric spectra show the influence of several factors such as the number of dendritic side groups, the orientation, their self-assembling dendrons, and the molecular mobility. The dielectric spectra present a sub-Tg dielectric relaxation, labelled as gamma, associated with the mobility of the benzyloxy substituent of the dendritic group. This mobility is not related to the percentage of these lateral chains but is somewhat hindered by the orientation of the dendritic groups. Unlike other less complex polymers, the crystallization was dismantled before the appearance of the glass transition (alpha(Tg)). Only after that, clearing transition (alpha(Clear)) can be observed. The PECHs were flexible and offered a high free volume, despite presenting a high degree of modifications. However, the molecular mobility is not independent in each phase and the self-assembling dendrons can be eventually fine-tuned according to the percentage of grafted groups.This research was funded by the Spanish Ministry of Science, Innovation and Universities, grant POLYDECARBOCELL (ENE2017-86711-C3-1-R, ENE2017-86711-C3-3-R).Teruel Juanes, R.; Pascual-Jose, B.; Graf, R.; Reina, JA.; Giamberini, M.; Ribes-Greus, A. (2021). Effect of Dendritic Side Groups on the Mobility of Modified Poly(epichlorohydrin) Copolymers. Polymers. 13(12):1-19. https://doi.org/10.3390/polym13121961119131
Principles of crop modeling and simulation: I. uses of mathematical models in agricultural science
The Chub Mackerel (Scomber Colias) in the Atlantic Spanish Waters (ICES Divisions 8.c, 9.a North and 9.a South): Fishery data
Proximal and distal deep venous thrombosis in critically ill patients: incidence and prevalence
Participatory geographic information systems and land planning : life experiences for people empowerment and community transformation:[Systèmes dinformation géographique participatifs et aménagement du territoire : expériences philippines citoyennes de désenclavement]
Postharvest characterization of oranges 'Baianinha' stored under refrigeration and ambient conditions
The postharvest quality of fresh oranges (Citrus sinensis (L.) Osbeck, 'Baianinha') was evaluated in terms of chemical and physical properties, in May of 1998. An experiment was carried out in a completely randomized design, with two replications, submitting the fruits to two treatments: storage at ambient conditions (21 ± 0.4°C and RH = 60 ± 1.0%, and in cold room (1 ± 0,5°C and RH = 85 ± 2,5%). After 15 days of storage, a highly significant difference was observed (P=0,01) in the levels of ascorbic acid (decrease of 20% and 8%, at ambient condition and refrigerated fruits, respectively). Titratable acidity decrease approximately 14%, for fruits at ambient condition, and 8% for the refrigerated fruits. It was observed an increase of 30% (ambient condition) and 18% (refrigerated fruits), in the brix/titratable acidity ratio. The results demonstrated that there is a tendency of quality loss for fruits maintained at ambient condition. Therefore, the use of refrigeration is necessary for the maintenance of post harvest quality of fresh orange.A qualidade pós colheita de laranjas in natura (Citrus sinensis (L.) Osbeck, 'Baianinha'), foi avaliada em termos de suas propriedades quÃmicas e fÃsicas, em maio de 1998. Foi aplicado um delineamento inteiramente casualizado, com duas repetições, submetendo os frutos a dois tratamentos: armazenamento a temperatura ambiente (21 ± 0,4°C e UR= 60 ± 1,0%), e em uma câmara frigorÃfica (1 ± 0,5°C e UR = 85 ± 2,5%). Após 15 dias de armazenamento, foi observada uma diferença altamente significativa (P=0,01), nos nÃveis de ácido ascórbico (diminuição de 20% e 8%, nas laranjas expostas a temperatura ambiente e nos frutos refrigerados, respectivamente). A acidez titulável teve uma diminuição de aproximadamente 14%, para os frutos mantidos à temperatura ambiente, e de 8% para os frutos refrigerados. Comprovou-se um aumento de 30% (frutos em condições ambientais) e de 18% (frutos refrigerados), na relação sólidos solúveis e acidez titulável. Os resultados apontam uma tendência à perda da qualidade nos frutos mantidos em condições ambientais, o que reafirma a necessidade do uso de refrigeração para a conservação pós-colheita de laranja in natura.464
A selected ion flow tube study of the ion-molecule reactions of monochloroethene, trichloroethene and tetrachloroethene
Data for the rate coefficients and product cations of the reactions of a large number of atomic and small molecular cations with monochloroethene, trichloroethene and tetrachloroethene in a selected ion flow tube at 298 K are reported. The recombination energy of the ions range from 6.27 eV (HO) through to 21.56 eV (Ne). Collisional rate coefficients are calculated by modified average dipole orientation theory and compared with experimental values. Thermochemistry and mass balance predict the most feasible neutral products. Together with previously reported results for the three isomers of dichloroethene (J. Phys. Chem. A., 2006, 110, 5760), the fragment ion branching ratios have been compared with those from threshold photoelectron photoion coincidence spectroscopy over the photon energy range 9-22 eV to determine the importance or otherwise of long-range charge transfer. For ions with recombination energy in excess of the ionisation energy of the chloroethene, charge transfer is energetically allowed. The similarity of the branching ratios from the two experiments suggest that long-range charge transfer is dominant. For ions with recombination energy less than the ionisation energy, charge transfer is not allowed; chemical reaction can only occur following formation of an ion-molecule complex, where steric effects are more significant. The products that are now formed and their percentage yield is a complex interplay between the number and position of the chlorine atoms with respect to the C=C bond, where inductive and conjugation effects can be important
Impact of the COVID-19 Pandemic on a Cancer Fast-Track Programme
Introduction: The COVID-19 pandemic has disrupted many aspects of clinical practice in oncology, particularly regarding early cancer diagnosis, sparking public health concerns that possible delays could increase the proportion of patients diagnosed at advanced stages. In 2009, a cancer fast-track program (CFP) was implemented at the Clinico-Malvarrosa Health Department in Valencia, Spain with the aim of shortening waiting times between suspected cancer symptoms, diagnosis and therapy initiation. Objectives: The study aimed to explore the effects of the COVID-19 pandemic on our cancer diagnosis fast-track program. Methods: The program workflow (patients included and time periods) was analysed from the beginning of the state of alarm on March 16th, 2020 until March 15th, 2021. Data was compared with data from the same period of time from the year before (2019). Results: During the pandemic year, 975 suspected cancer cases were submitted to the CFP. The number of submissions only decreased during times of highest COVID-19 incidence and stricter lockdown, and overall, referrals were slightly higher than in the previous 2 years. Cancer diagnosis was confirmed in 197 (24.1%) cases, among which 33% were urological, 23% breast, 16% gastrointestinal and 9% lung cancer. The median time from referral to specialist appointment was 13 days and diagnosis was reached at a median of 18 days. In confirmed cancer cases, treatment was started at around 30 days from time of diagnosis. In total, 61% of cancer disease was detected at early stage, 20% at locally advanced stage, and 19% at advanced stage, displaying time frames and case proportions similar to pre-pandemic years. Conclusions: Our program has been able to maintain normal flow and efficacy despite the challenges of the current pandemic, and has proven a reliable tool to help primary care physicians referring suspected cancer patients.S
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