Search results for "Oxide"

Poly(ethylene oxide)-block-poly(n-butyl acrylate)-block-poly(acrylic acid) triblock terpolymers with highly asymmetric hydrophilic blocks: synthesis …

2013

The synthesis and aggregation behaviour in aqueous media of novel amphiphilic poly(ethylene oxide)-block-poly(n-butyl acrylate)-block-poly(acrylic acid) (PEO–PnBA–PAA) triblock terpolymers were studied. Terpolymers composed of two highly asymmetric hydrophilic PEO (113 monomer units) and PAA (10–17 units) blocks, and a longer soft hydrophobic PnBA block (163 or 223 units) were synthesized by atom transfer radical polymerisation (ATRP) of n-butyl acrylate and tert-butyl acrylate (tBA), followed by selective hydrolysis of the PtBA blocks. These terpolymers are not directly soluble in water but form defined spherical micelles by employing the dialysis method as confirmed by dynamic light scatt…

Chemical initiation for butyl and lauryl acrylate monolithic columns for CEC.

2009

Butyl acrylate (BA)- and lauryl acrylate (LA)-based monolithic stationary phases for CEC were synthesized, using a redox system as initiator of polymerization. BA monoliths were initiated with ammonium peroxodisulfate, whereas LA columns were obtained with lauroyl peroxide as initiator. In both cases, TEMED was used to activate the process. The influence of porogenic solvent composition on both morphological and electrochromatographic properties of the resulting monoliths was investigated. Excellent efficiencies (minimum plate heights of 4.2-6.3 microm for BA columns and 2.6-5.3 microm for LA stationary phases, for a PAHs mixture) were achieved. The capability of separation of both types of…

Design of nonionic surfactants for supercritical carbon dioxide

1996

Interfacially active block copolymer amphiphiles have been synthesized and their self-assembly into micelles in supercritical carbon dioxide (CO 2 ) has been demonstrated with small-angle neutron scattering (SANS). These materials establish the design criteria for molecularly engineered surfactants that can stabilize and disperse otherwise insoluble matter into a CO 2 continuous phase. Polystyrene- b -poly(1,1-dihydroperfluorooctyl acrylate) copolymers self-assembled into polydisperse core-shell-type micelles as a result of the disparate solubility characteristics of the different block segments in CO 2 . These nonionic surfactants for CO 2 were shown by SANS to be capable of emulsifying u…

1993

The influence of lithium tert-butoxide (tBuOLi) and of lithium chloride on the oligomerization of tert-butyl acrylate (tBuA) initiated by tert-butyl α-lithioisobutyrate (tBiB-Li) was investigated. These additives affect both the kinetics and the product distribution. Whereas the addition of LiCl leads to a narrower molecular-weight distribution (MWD) the presence of tBuOLi induces broader MWD's, characterized by a very high fraction of the dimer. Both additives decrease the rates of propagation to different degrees. These effects are discussed on the basis of the formation of aggregates and adducts, the lithiated dimer having a higher tendency to form aggregates than the other oligomers. Th…

Nitrous oxide emission from a moving bed membrane biofilm reactor: the effect of the sludge retention time

2016

The aim of the present study was to investigate the nitrous oxide (N2O) emissions from a University of Cape Town (UCT) moving bed membrane bioreactor pilot plant. An experimental campaign was carried out during 60 days with three different sludge retention time (SRT). The pilot plant reactor was provided of funnel shape covers that guaranteed gas accumulation in the headspace. The results highlighted that N2O concentrations significantly increased when the biofilm concentrations increased within the aerobic and anoxic compartments. Furthermore, results have shown an increase of N2O with the decrease of SRT. Moreover, the MBR tank resulted the key emission source (up to 70% of the total N2O …

Aequorin-expressing yeast emits light under electric control

2011

In this study, we show the use of direct external electrical stimulation of a jellyfish luminescent calcium-activated protein, aequorin, expressed in a transgenic yeast strain. Yeast cultures were electrically stimulated through two electrodes coupled to a standard power generator. Even low (1.5. V) electric pulses triggered a rapid light peak and serial light pulses were obtained after electric pulses were applied periodically, suggesting that the system is re-enacted after a short refraction time. These results open up a new scenario, in the very interphase between synthetic biology and cybernetics, in which complex cellular behavior might be subjected to electrical control.

Targeted-lung delivery of dexamethasone using gated mesoporous silica nanoparticles. A new therapeutic approach for acute lung injury treatment

2021

Acute lung injury (ALI) is a critical inflammatory syndrome, characterized by increased diffuse inflammation and severe lung damage, which represents a clinical concern due to the high morbidity and mortality in critical patients. In last years, there has been a need to develop more effective treatments for ALI, and targeted drug delivery to inflamed lungs has become an attractive research field. Here, we present a nanodevice based on mesoporous silica nanoparticles loaded with dexamethasone (a glucocorticoid extensively used for ALI treatment) and capped with a peptide that targets the TNFR1 receptor expressed in pro-inflammatory macrophages (TNFR-Dex-MSNs) and avoids cargo leakage. TNFR-D…

Biology and management of therapy-related acute promyelocytic leukemia.

2013

Therapy-related acute promyelocytic leukemia (t-APL) has been increasingly reported after exposure to cytotoxic and/or immunosuppressive agents given for prior malignancies or autoimmune diseases. t-APL represents both a model for better understanding human leukemogenesis and an interesting therapeutic subset which requires specific adaptations for optimal management.We discuss here potential risk factors for t-APL development and the main biologic and clinical characteristics of t-APL as compared to de-novo APL.In addition, we review therapeutic results obtained in patients with t-APL receiving conventional retinoic acid and chemotherapy and discuss new treatment opportunities with minimal…

Acute Promyelocytic Leukemia during Pregnancy: A Systematic Review of the Literature

2020

The management of pregnant women with acute promyelocytic leukemia (APL) is a challenging situation where limited evidence-based information is available. We performed a systematic literature review to analyze the outcomes reported for both mother and fetus when APL is diagnosed during pregnancy. PubMed, Scopus and Web of Science databases were systematically searched to identify studies reporting cases of APL during pregnancy. Sixty-six articles met the eligibility criteria (53 single case reports). Ninety-two patients were eligible for induction therapy, with most them being treated with all-trans retinoic acid alone (32%) or combined with chemotherapy (43%), while the remaining patients …

Real Life Experience with ATRA-Arsenic Trioxide Based Regimen in Acute Promyelocytic Leukemia - Updated Results of the Prospective German Intergroup …

2016

Abstract Background: Standard therapy of acute promyelocytic leukemia has long relied on the combination of All-trans-retinoic acid (ATRA) and chemotherapy. The introduction of arsenic trioxide (ATO) in APL treatment has allowed achievement of similarly high remission and survival rates coupled with significantly reduced myelosuppression. Recent results of the APL0406 trial by the GIMEMA-AMLSG-SAL study groups showed that the combination of ATRA and arsenic trioxide (ATO) is superior to standard ATRA and chemotherapy (CHT) in front-line therapy of low/intermediate risk acute promyelocytic leukemia (APL). The implications of these results for the clinical practice of APL patients in Germany …