740 research outputs found
Cavity-Enhanced Raman Spectroscopy in the Biosciences: In situ, Multicomponent and Isotope Selective Gas Measurements to Study Hydrogen Production and Consumption by Escherichia coli
Recently we introduced cavity-enhanced Raman spectroscopy
(CERS) with optical feedback cw-diode lasers as a sensitive analytical tool. Here
we report improvements made on the technique and its first application in the
biosciences for in situ, multicomponent, and isotope selective gas measurements
to study hydrogen production and consumption by Escherichia coli.
Under anaerobic conditions, cultures grown on rich media supplemented with
D-glucose or glycerol produce H2 and simultaneously consume some of it. By
introducing D2 in the headspace, hydrogen production and consumption could
be separated due to the distinct spectroscopic signatures of isotopomers.
Different phases with distinctly different kinetic regimes of H2 and CO2
production and D2 consumption were identified. Some of the D2 consumed
is converted back to H2 via H/D exchange with the solvent. HD was formed
only as a minor component. This reflects either that H/D exchange at
hydrogenase active sites is rapid compared to the rate of recombination, rapid recapture of HD occurs after the molecule is
formed, or that the active sites where D2 oxidation and proton reduction occur are physically separated. Whereas in glucose
supplemented cultures, addition of D2 led to an increase in H2 produced, while the yield of CO2 remained unchanged; with
glycerol, addition of D2 led not only to increased yields of H2, but also significantly increased CO2 production, reflecting an
impact on fermentation pathways. Addition of CO was found to completely inhibit H2 production and significantly reduce D2
oxidation, indicating at least some role for O2-tolerant Hyd-1 in D2 consumption
RELEVANSI PEMIKIRAN IRIGARAY TERHADAP ARSITEKTUR
Abstrak_ Teori arsitektur terlahir dari beberapa pemikiran filosof yang membahas tentang hubungan manusia dengan ruang. Pemikiran para filosof tersebut, menjelaskan bagaimana memahami manusia sebagai pengguna produk arsitektur. Berbagai pemikiran tersebut kemudian diterjemahkan oleh para praktisi dan mahasiswa arsitektur ke dalam konsep perancangan yang lebih humanis. Tulisan ini bertujuan mendiskripsikan pemikiran salah satu filosof yang berkontribusi pada perkembangan teori arsitektur, yaitu Luce Irigaray. Pemikiran Irigaray mengenai feminisme akan dijelaskan bagaimana relevansinya terhadap konsep desain arsitektur. Tulisan ini disusun dengan metode kajian literatur dengan mengkaji dua pemikiran Irigaray yaitu mengenai konsep fluiditas dan persepsi melalui sentuhan. Adapun hasil kajian dari kedua konsep hasil pemikiran Irigaray, yaitu fluiditas dan persepsi melalui sentuhan, keduanya menjelaskan bagaimana perbedaan gender dalam suatu ruang menentukan bentukan dari suatu produk arsitektur. Apabila arsitek telah dapat mewadahi perbedaan kebutuhan antar gender, maka karya tersebut telah mengakui kedua gender sebagai subyek yang diwadahi dalam suatu produk arsitektural, bukanlah lagi sebagai objek. Sehingga tercipta suatu karya arsitektur yang lebih humanis.Kata kunci: Irigaray; Feminisme; Teori Arsitektur. Abstract_ Architectural theory was born from several philosophical thoughts which discussed the relationship between humans and space. The thought of the philosophers explained how to understand humans as users of architectural products. These various thoughts were then translated by architectural practitioners and students into more humanistic design concepts. This paper aims to describe the thoughts of one of the philosophers who contributed to the development of architectural theory, Luce Irigaray. Irigaray thinking about feminism will explain how relevant it is to architectural design concepts. This paper is compiled with a literature review method by examining two irrational thoughts, the concept of fluidity and perception through touch. The results of the study of the two concepts of Irigaray's thinking, fluidity and perception through touch, both explain how gender differences in a space determine the formation of an architectural product. If the architect has been able to accommodate differences in needs between genders, then the work has recognized the two genders as subjects that are contained in an architectural product, no longer as objects. Thus creating a more humanistic architectural work.Keywords: Irigaray; Feminism; Architecture Theory
Total Syntheses of Amphidinolide H and G
Eureka! The first conquest of the exceptionally potent cytotoxic agent amphidinolide H, which exhibits activity in the picomolar range against human epidermoid cancer cells, was long overdue. The successful route critically hinges upon the scrupulous optimization of the fragment-coupling events (see picture; RCM=ring-closing metathesis) and on the careful adjustment of the peripheral protecting-group pattern
Total Syntheses of Amphidinolides B1, B4, G1, H1 and Structure Revision of Amphidinolide H2
Nature is a pretty unselective “chemist” when it comes to making the highly cytotoxic amphidinolide macrolides of the B/G/H series. To date, 16 different such compounds have been isolated, all of which could now be approached by a highly convergent and largely catalysis-based route (see figure). This notion is exemplified by the total synthesis of five prototype members of this family. Dinoflagellates of the genus Amphidinium produce a “library” of closely related secondary metabolites of mixed polyketide origin, which are extremely scarce but highly promising owing to the exceptional cytotoxicity against various cancer cell lines. Because of the dense array of sensitive functionalities on their largely conserved macrocyclic frame, however, these amphidinolides of the B, D, G and H types elapsed many previous attempts at their synthesis. Described herein is a robust, convergent and hence general blueprint which allowed not only to conquest five prototype members of these series, but also holds the promise of making “non-natural” analogues available by diverted total synthesis. This notion transpires for a synthesis-driven structure revision of amphidinolide H2. The successful route hinges upon a highly productive Stille–Migita cross-coupling reaction at the congested and chemically labile 1,3-diene site present in all such targets, which required the development of a modified chloride- and fluoride-free protocol. The macrocyclic ring could be formed with high efficiency and selectivity by ring-closing metathesis (RCM) engaging a vinyl epoxide unit as one of the reaction partners. Because of the sensitivity of the targets to oxidizing and reducing conditions as well as to pH changes, the proper adjustment of the protecting group pattern for the peripheral -OH functions also constitutes a critical aspect, which has to converge to silyl groups only once the diene is in place. Tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF) turned out to be a sufficiently mild fluoride source to allow for the final deprotection without damaging the precious macrolides
Te covered Si(001): a variable surface reconstruction
At a given temperature, clean and adatom covered silicon surfaces usually
exhibit well-defined reconstruction patterns. Our finite temperature ab-initio
molecular dynamics calculations show that the tellurium covered Si(001) surface
is an exception. Soft longitudinal modes of surface phonons due to the strongly
anharmonic potential of the bridged tellurium atoms prevent the reconstruction
structure from attaining any permanent, two dimensional periodic geometry. This
explains why experiments attempting to find a definite model for the
reconstruction have reached conflicting conclusions.Comment: 4 pages, 3 gif figure
Real-time In Situ Electron Spin Resonance Measurements on Fungal Spores of Penicillium digitatum during Exposure of Oxygen Plasmas
We report the kinetic analysis of free radicals on fungal spores of
Penicillium digitatum interacted with atomic oxygen generated plasma electric
discharge using real time in situ electron spin resonance (ESR) measurements.
We have obtained information that the ESR signal from the spores was observed
and preliminarily assignable to semiquinone radical with a g-value of around
2.004 and a line width of approximately 5G. The decay of the signal is possibly
linked to the inactivation of the fungal spore. The real-time in situ ESR has
proven to be a useful method to elucidate plasma-induced surface reactions on
biological specimens.Comment: 11 pages, 5 figure
Relationship between home care service use and changes in the care needs level of Japanese elderly
<p>Abstract</p> <p>Background</p> <p>With the introduction of long-term care insurance (LTCI) in Japan, more home care services are available for the community-dwelling elderly. To deliver effective home care services, it is important to know the effects of service use. In this study, as the first step to determine this, we sought to describe different home service use in the sustained/improved group and deteriorated group in their care needs levels, and to report the relationship between the use of home care services and changes in care needs levels.</p> <p>Methods</p> <p>The participants included 624 of a total of 1,474 users of LTCI services in one city in Japan. Home care service users were stratified into a 'lower care needs level subgroup' and a 'higher care needs level subgroup' based on the baseline care needs level. Simple statistical comparison and multiple logistic regression analyses in which the change in care needs level was set as a dependent variable were performed. Gender, age, and baseline care needs level were designated as control variables. Home based services were treated as independent variables. In this study, home care services consisted of home help, home bathing services, a visiting nurse, home rehabilitation, nursing home daycare, health daycare, loan of medical devices, respite stay in a nursing home, respite stay in a health care facility, respite stay in a sanatorium-type medical care facility, and medical management by a physician.</p> <p>Results</p> <p>In the lower care needs level subgroup, age (OR = 1.04, CI, 1.01-1.08), use of respite stay in a nursing home (OR = 2.55; CI, 1.43-4.56), and the number of types of long-term care services (OR = 1.33; CI, 1.02-1.74) used during an 11 month period were significantly related to a deterioration of the user's care needs level. In the higher care needs level subgroup, use of medical management by a physician (OR = 6.99; CI, 1.42-41.25) was significantly related to a deterioration of the user's care needs level. There were no home based services significantly related to sustaining or improving the user's care needs level.</p> <p>Conclusion</p> <p>There were different home service use in two groups (the sustained/improved group and the deteriorated group). Respite stay in a nursing home service use and more types of service use were related to experiencing a deterioration of care needs level in lower care needs level community-dwelling elderly persons in Japan. Further, medical management by a physician service was related to experiencing a deterioration of care needs level in higher care needs level community-dwelling elderly persons.</p
The HBZ gene, a key player in HTLV-1 pathogenesis
Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia/lymphoma (ATL) and is also associated with a variety of lymphocyte-mediated diseases. The HTLV-1 basic leucine zipper (HBZ) gene, found to be consistently expressed in ATL, has recently been the subject of intensive research efforts. In this review, we summarize recent findings about HBZ and discuss its roles and functions not only in the virus life cycle, but also in HTLV-1 disease pathogenesis
A structured review of long-term care demand modelling
Long-term care (LTC) represents a significant and substantial proportion of healthcare spends across the globe. Its main aim is to assist individuals suffering with more or more chronic illnesses, disabilities or cognitive impairments, to carry out activities associated with daily living. Shifts in several economic, demographic and social factors have raised concerns surrounding the sustainability of current systems of LTC. Substantial effort has been put into modelling the LTC demand process itself so as to increase understanding of the factors driving demand for LTC and its related services. Furthermore, such modeling efforts have also been used to plan the operation and future composition of the LTC system itself. The main aim of this paper is to provide a structured review of the literature surrounding LTC demand modeling and any such industrial application, whilst highlighting any potential direction for future researchers
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