Biosynthesis of medium-chain triacylglycerols and phospholipids by HepG-2 cells

In an attempt to understand the metabolism by the liver of fatty acids (FA) of different chain length, we have studied the incorporation of [1-¹⁴C]-labeled C₂, C₈, C₁₀, C₁₂, and C₁₆ into cellular lipids by HepG-2 cells. Over 90% of the radiolabeled FA were detected in phospholipids (PL) and triacylglycerols (TAG). The incorporation of C₁₂ and C₁₆ was three to four times higher than that of C₈ and C₁₀ (and reached 35 nmoles per mg protein after 1.5 h). The radioactivity of C₂, C₈, and C₁₀ was recovered mainly in PL. C₁₂ and C₁₆ were incorporated at approximately equal amounts into PL and TAG. The radioactivity of both C₂ and C₈ was recovered exclusively in long-chain FA, suggesting oxidation of C₈ into C₂ units prior to FA synthesis. C₁₀ likewise yielded mainly long-chain FA. However 10% of unchanged C₁₀ was found in PL and up to 30% in TAG. ¹⁴C–C₁₂ was largely incorporated unchanged. Under these conditions, the presence of C₁₀ and C₁₂ in PL and TAG was shown also by gas-liquid chromatography. In the presence of either C₂, C₈, or C₁₀, up to 30% of ¹⁴C-monounsaturated FA were detected in PL and TAG. With C₁₂ and C₁₆, the fraction of ¹⁴C-monounsaturated FA was much smaller suggesting that extensive desaturation occurred during de novo synthesis.     

Kinetic study on the hexacelsian-celsian phase transformation

The hexacelsian-celsian transformation from grains of 1/4 in. (0.635 cm) size is slow and erratic. This is because the rate of heterogeneous nucleation in such grains is low and is influenced by contamination present in the furnace. When the grain size is reduced to a –200 mesh powder, heterogeneous nucleation becomes a dominant factor and the transformation is accelerated. The transformation has three stages: the first is controlled by the rate of crystal growth, the second is controlled by the rates of nucleation and crystal growth, and the third is controlled by the rate of nucleation.The activation energy of crystal growth in the first stage of transformation is 20.1 kcal mole^–1 ±20%. This suggests that the hexacelsian-celsian transformation does not involve Si-0 and Al-O bond openings, since this would be expected to involve an activation energy of at least 60 kcal mole^–1.     

The apprehensive respondent: Failing to rate future life satisfaction in older adults.

Rating scales relating to the individual's past, present, and future were administered to Ss (aged 60–90 yrs); those who completed all ratings (N?=?589) were compared with others who specifically failed to rate the future (N?=?150). The groups were differentiated by age, gender, health, and marital status. Total subjective well-being did not differ, but specific subjective well-being factors concerning time and aging could serve as discriminators. These differences suggest that these older adults might be apprehensive about their future and that skipping future-related questions is a genuine reaction with both psychological and methodological implications. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Time-varying analogue constrained notch filter

The idea of discrete constrained notch filters is well known and widely described in the literature. Time-invariant as well as time-varying filters are considered. Because of the discrete nature of such filters, their application is limited to sampled signals, usually obtained as samples of low-frequency signals. the aim of this paper is to give some ideas on how to synthesize a time-varying analogue constrained notch filter which can be used directly for continuous signals.     

Optimal salting of macadamia (Macadamia integrifolia) nuts

Roasted macadamia (Macadamia integrifolia Storey) nuts were salted at various levels up to 19 g kg^?1 and presented to a taste panel. The results showed that the assessors could be divided into 'salt dislikers', to whom perceived quality decreased linearly with increase in salt content, and 'salt likers', to whom perceived quality increased as the salt content increased. It follows that the nuts can be produced to suit these two market segments separately, or else a single lightly salted compromise product can be offered to both groups.     

Why the old world cannot publish? Overcoming challenges in publishing high-impact IS research

We review the status of European publishing in high-impact Information System (IS) journals finding that the European publication record is disappointing. We consider popular explanations to this state of affairs and find them neither credible nor useful for improving the European record. We propose several constructive reasons for this including (1) the lack of appreciation of the article genre, (2) weak publishing cultures, (3) inadequate Ph.D. preparation for article publishing, (4) weak reviewing practices, (5) poorer command of research methods, (6) poorer understanding of the reviewing protocols, and (7) institutional shaping of research funding in Europe. We formulate several recommendations to affect these causes at the individual, institutional, journal, and European community level.     

Electrically controlled molecular recognition harnessed to activate a cellular response

Seamless embedment of electronic devices in biological systems is expected to add the outstanding computing power, memory, and speed of electronics to the biochemical toolbox of nature. Such amalgamation requires transduction of electronic signals into biochemical cues that affect cells. Inspired by biology, where pathways are directed by molecular recognition, we propose and demonstrate a generic electrical-to-biological transducer comprising a two-state electronic antigen and a chimeric cell receptor engineered to bind the antigen exclusively in its "on" state. T-cells expressing these receptors remain inactivated with the antigen in its "off" state. Switching the antigen to its "on" state by an electrical signal leads to its recognition by the T-cells and correspondingly to cell activation.     

Observation of nanosecond laser induced fluorescence of in vitro seawater phytoplankton

Seawater has been irradiated using a train of 70 ns flashes from a 440 nm laser source. This wavelength is on resonance with the blue absorption peak of Chlorophyll pigment associated with the photosystem of in vitro phytoplankton. The resulting fluorescence at 685 nm is instantaneously recorded during each laser pulse using a streak camera. Delayed fluorescence is observed, yielding clues about initiation of the photosynthetic process on a nanosecond time scale. Further data processing allows for determination of the functional absorption cross section, found to be 0.0095 A(2), which is the first reporting of this number for in vitro phytoplankton. Unlike other flash-pump studies of Chlorophyll, using a LED or flashlamp-based sources, the short laser pulse used here does not reveal any pulse-to-pulse hysteresis (i.e., variable fluorescence), indicating that the laser pulses used here are not able to drive the photosynthetic process to completion. This is attributed to competition from a back reaction between the photoexcited photosystem II and the intermediate electron acceptor. The significance of this work as a new type of deployable ocean fluorimeter is discussed, and it is believed the apparatus will have applications in thin-layer phytoplankton research.     

Determination of band offsets in heterostructured colloidal nanorods using scanning tunneling spectroscopy

The ability to tailor the properties of semiconductor nanocrystals through creating core/shell heterostructures is the cornerstone for their diverse application in nanotechnology. The band-offsets between the heterostructure components are determining parameters for their optoelectronic properties, dictating for example the degree of charge-carrier separation and localization. So far, however, no method was reported for direct measurement of these factors in colloidal nanocrystals and only indirect information could be derived from optical measurements. Here we demonstrate that scanning tunneling spectroscopy along with theoretical modeling can be used to determine band-offsets in such nanostructures. Applying this approach to CdSe/CdS quantum-dot/nanorod core/shell nanocrystals portrays its type I band structure where both the hole and electron ground state are localized in the CdSe core, in contrast to previous reports which predicted electron delocalization. The generality of the approach is further demonstrated in ZnSe/CdS nanocrystals where their type II band alignment, leading to electron-hole separation, is manifested.