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Kaolin and diatomite are abundant and widely available geological materials that may immobilize or stabilize functional chemical species on their surfaces for various applications. Acid-treated kaolin and diatomite were intercalated with photocatalyst Ag-TiO2 nanoparticles using the sol–gel technique to prepare nanocomposite ceramic materials. The nanocomposites were sintered between 900°C and 1000°C to induce thermal reactions and to enhance nanoparticle–substrate attachment. Chemical and thermal characterizations of the acid-treated materials and intercalated nanocomposites were performed with energy-dispersive X-ray (EDX) analysis and differential scanning calorimetry (DSC), respectively. The Brunauer–Emmett–Teller (BET)-specific surface area and scanning electron microscopy (SEM) were employed for physical and microstructural characterization of the nanocomposites, respectively. Morphological studies revealed a uniform distribution of Ag-TiO2 nanocrystallites in pores and on mineral particle surfaces. The BET analysis showed remarkable surface and grain modification by sintering. Decreases in the BET-specific surface area were observed for the sintered ceramic nanocomposite, Ag-TiO2-kaolin (20.244 to 5.446 m2/g) and Ag-TiO2-diatomite (19.582 to 10.148 m2/g).
The goal of most rice improvement programs is the enhancement of farmers’ yield using less land and limited water. This study evaluated 77 upland rice genotypes under optimal upland growing conditions in the field and ranked the genotypes using base indices. Subsequently, eighteen cultivars selected from the field trial were screened under drought in rainout-shelter conditions. The traits evaluated for index selection were yield, days to flowering, plant height, number of panicles and filled grains. Under field conditions, based on the sum of economic weight assigned to five traits used to compute the selection index, IR 68704-145-1-1-B and IR 63380-16 were the best genotypes. In the rainout-shelter experiment, Ofada 2 (508 gm−2) had the highest grain yield under non-stress conditions while ITA 117 (152.38 gm−2) had the highest grain yield under drought stress. The base index was efficient for selecting superior genotypes with the best combination for all the traits considered. Susceptibility to drought stress of the landraces leads to poor grain yield.
To identify the frequency of and risk factors associated with complications necessitating removal of the peripherally inserted central catheters (PICCs) in patients receiving outpatient parenteral antibiotic therapy (OPAT) and to determine the appropriateness of OPAT in children with OPAT-related complications.
A retrospective cohort of children who had a PICC inserted at the Johns Hopkins Children’s Center between January 1, 2003, and December 31, 2013, and were discharged from the hospital on OPAT was assembled.
A total of 1,465 PICCs were used to provide antibiotic therapy for 955 children after hospital discharge. Among these, 117 PICCs (8%) required removal due to a complication (4.6 of 1,000 catheter days). Children discharged to a long-term care facility were at increased risk of adverse PICC events (incidence risk ratio [IRR], 3.32; 95% confidence interval [CI], 1.79–6.17). For children receiving OPAT, age of the child (adjusted IRR [aIRR], 0.95; 95% CI, 0.92–0.98), noncentral PICC tip location (aIRR, 2.82; 95% CI, 1.66–4.82), and public insurance (aIRR, 1.63; 95% CI, 1.10–2.40) were associated with adverse PICC events. In addition, 34 patients (32%) with adverse events may not have required intravenous antibiotics at the time of hospital discharge.
Of children discharged with PICCs on OPAT during the study period, 8% developed a complication necessitating PICC removal. Children discharged to a long-term care facility had an increased rate of complication compared with children who were discharged home. With improved education regarding appropriate duration of antibiotic therapy and situations in which early conversion to enteral therapy should be considered, PICC-related complications may have been avoided in 32% of children.
Infect. Control Hosp. Epidemiol. 2016;37(4):420–424
Staphylococcus aureus is a common cause of healthcare-associated infections in neonates.
To examine the impact of methicillin-susceptible S. aureus (MSSA) decolonization on the incidence of MSSA infection and to measure the prevalence of mupirocin resistance.
We retrospectively identified neonates admitted to a tertiary care neonatal intensive care unit (NICU) from April 1, 2011, through September 30, 2014. We compared rates of MSSA-positive cultures and infections before and after implementation of an active surveillance culture and decolonization intervention for MSSA-colonized neonates. We used 2 measurements to identify the primary outcome, NICU-attributable MSSA: (1) any culture sent during routine clinical care that grew MSSA and (2) any culture that grew MSSA and met criteria of the National Healthcare Safety Network’s healthcare-associated infection surveillance definitions. S. aureus isolates were tested for mupirocin susceptibility. We estimated incidence rate ratios using interrupted time-series models.
Before and after the intervention, 1,523 neonates (29,220 patient-days) and 1,195 neonates (22,045 patient-days) were admitted to the NICU, respectively. There was an immediate reduction in the mean quarterly incidence rate of NICU-attributable MSSA-positive clinical cultures of 64% (incidence rate ratio, 0.36 [95% CI, 0.19–0.70]) after implementation of the intervention, and MSSA-positive culture rates continued to decrease by 21% per quarter (incidence rate ratio, 0.79 [95% CI, 0.74–0.84]). MSSA infections also decreased by 73% immediately following the intervention implementation (incidence rate ratio, 0.27 [95% CI, 0.10–0.79]). No mupirocin resistance was detected.
Active surveillance cultures and decolonization may be effective in decreasing S. aureus infections in NICUs.
Infect. Control Hosp. Epidemiol. 2016;37(4):381–387
To characterize the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) transmission and infections in a level IIIC neonatal intensive care unit (NICU) and identify barriers to MRSA control.
Setting and Design.
Retrospective cohort study in a university-affiliated NICU with an MRSA control program including weekly nares cultures of all neonates and admission nares cultures for neonates transferred from other hospitals or admitted from home.
Medical records were reviewed to identify neonates with NICU-acquired MRSA colonization or infection between April 2007 and December 2011. Compliance with hand hygiene and an MRSA decolonization protocol were monitored. Relatedness of MRSA strains were assessed using pulsed-field gel electrophoresis (PFGE).
Of 3,536 neonates, 74 (2.0%) had a culture grow MRSA, including 62 neonates with NICU-acquired MRSA. Nineteen of 74 neonates (26%) had an MRSA infection, including 8 who became infected before they were identified as MRSA colonized, and 11 of 66 colonized neonates (17%) developed a subsequent infection. Of the 37 neonates that underwent decolonization, 6 (16%) developed a subsequent infection, and 7 of 14 (50%) that remained in the NICU for 21 days or more became recolonized with MRSA. Using PFGE, there were 14 different strain types identified, with USA300 being the most common (31%).
Current strategies to prevent infections—including active identification and decolonization of MRSA-colonized neonates—are inadequate because infants develop infections before being identified as colonized or after attempted decolonization. Future prevention efforts would benefit from improving detection of MRSA colonization, optimizing decolonization regimens, and identifying and interrupting reservoirs of transmission.
We studied methicillin-resistant Staphylococcus aureus (MRSA)-colonized children with multiple intensive care unit (ICU) admissions to assess the persistence of MRSA colonization. Our data found that children with more than 1 year between ICU admissions had a higher prevalence of MRSA colonization than the overall ICU population, which supports empirical contact precautions for children with previous MRSA colonization.
Anodic spark deposition (ASD) is an advanced plasma-electrochemical coating process to prepare polycrystalline, ceramic-like conversion coatings on metal surfaces. As an example, polycrystalline barium titanate (BaTiO3) phases have been prepared by the anodic conversion of metal substrate and the metal ions in the electrolyte. By a combination of various characterization techniques, the configuration of the coating was elucidated. On the metal substrate a thin (~50 nm) passivating amorphous film of titania (TiO2) first forms, which subsequently changes to anatase and rutile structures. With increasing anodic potentials, a plasma-chemical conversion reaction starts, leading to the heterogeneous formation of BaTiO3 layers of 2–10 μm thickness. The results of this study lead to the formulation of a model describing a polycrystalline and inhomogeneous layer configuration.
Chemical interactions between polyvinyl alcohol (PVA) and triethanol amine titanate chelate were studied using x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The titanate chelate cross coupled the PVA solution and produced a viscous gel. The gel had a three-dimensional network structure containing -CPVA-O-Ti-O-CPVA- organic complexes. A new C(ls) signature at 285.7 eV and an O(ls) signature at 531.25 eV were associated with the formation of these complexes. The water of the PVA solution was physically retained in the gelled structure and was readily available for chemical reactions. The removal of this entrapped water was irreversible and led to a collapsed film of Ti-cross-linked PVA.
The microstructure and microchemistry of ceramic/polymer interfaces in a calcium aluminate/polyvinyl alcohol composite material have been studied using transmission electron microscopy (TEM), high resolution electron microscopy (HREM), x-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDS). Interfaces consisted of an amorphous interphase layer, inside of which were dispersed metastably retained CaAl2O5 · 8H2O crystallites. The amorphous phase was a mixture of the hydration products of calcium aluminate and aluminum–crosslinked, polyvinyl alcohol. The crystalline hydration product CaAl2O5 · 8H2O was metastably retained due to polymer poisoning of nucleation sites and significant reduction of conversion kinetics.
Fracture mechanisms in calcium aluminate macro-defect-free-cement were studied by in situ deformation in the TEM. Fracture occurred predominantly at the cement / polymer interface. The toughening mechanism involved crack bridging at the interphase / polymer interface. XPS studies of the chemistry of the interphase revealed it to be made up of an AlOC complex in addition to the amorphous hydration product phase.
Single phase, pure monocalcium aluminate (CaAl2O4) powders are chemically synthesized at temperatures as low as 900°C. The powders have a specific surface area of approximately 10 m2/g. The hydration kinetics of CaAl2O4 and the morphology of the hydrates are analyzed using electron microscopy techniques
Ultramicrotomy has been used to prepare TEM specimens from nickel sulfide inclusions in plate glass and from calcium aluminate / polyvinyl alcohol composite materials. Microstructural studies showed that the inclusion probably contained at least two different phases, namely Ni7S6 and Ni3S2. Although microtomy-induced cracking and chatter were observed, important microstructural features such as twins and Moire patterns were preserved. The microchemistry of the polymer phase in the ceramic / polymer composite was precisely determined.
Let E be a separated locally convex barrelled space with continuous dual E′ and algebraic dual E* and let M be a subspace of E* with and dim Robertson, Tweddle and Yeomans have recently considered the question of barrelledness under the Mackey topology τ(E,E' + M) when E is given to be barrelled under its original topology τ(E,E') , , .
In (12) we introduced the concept of essential separability and used it to define two classes of locally convex spaces, δ-barrelled spaces and infra-δ-spaces, which serve as domain and range spaces respectively in certain closed graph theorems (12, Theorems 3 and 7). In this note we continue the study of these ideas. The relevant definitions are reproduced below.
The purpose of this note is to prove a result which is known to hold for Fréchet spaces [1, Chapitre II, §5, Exercise 24]. M. M. Day [2, p. 37] attributes the Banach space case to H. Löwig, although the earliest version that we have been able to find is that given by G. W. Mackey in [7, Theorem 1-1]. Recently H. E. Lacey has given an elegant proof for Banach spaces . It is perhaps interesting to note that the non-locally convex case can be deduced from these known results which are established by duality arguments.
Our main purpose is to describe those separated locally convex spaces which can serve as domain spaces for a closed graph theorem in which the range space is an arbitrary Banach space of (linear) dimension at most c, the cardinal number of the real line R. These are the δ-barrelled spaces which are considered in §4. Many of the standard elementary Banach spaces, including in particular all separable ones, have dimension at most c. Also it is known that an infinite dimensional Banach space has dimension at least c (see e.g. ). Thus if we classify Banach spaces by dimension we are dealing, in a natural sense, with the first class which contains infinite dimensional spaces.
In the usual definition of an inductive limit of locally convex spaces, one is given a linear space E, a family (Eα) of locally convex spaces and a set (iα) of linear maps from Eα into E. Garling in  studies an extension of this, looking at absolutely convex subsets Sα of Eα and restrictions jα of iα to such sets. If, in the definition of Garling [2, p. 3], each Sα is instead a balanced semiconvex set, then the finest linear (not necessarily locally convex) topology on E for which the maps ja are continuous, will be referred to as the generalized *-inductive limit topology of the semiconvex sets. This topology is our object of study in the present paper; we find applications in the closed graph theorem.
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