Bioelectronic nose and its application to smell visualization

There have been many trials to visualize smell using various techniques in order to objectively express the smell because information obtained from the sense of smell in human is very subjective. So far, well-trained experts such as a perfumer, complex and large-scale equipment such as GC-MS, and an electronic nose have played major roles in objectively detecting and recognizing odors. Recently, an optoelectronic nose was developed to achieve this purpose, but some limitations regarding the sensitivity and the number of smells that can be visualized still persist. Since the elucidation of the olfactory mechanism, numerous researches have been accomplished for the development of a sensing device by mimicking human olfactory system. Engineered olfactory cells were constructed to mimic the human olfactory system, and the use of engineered olfactory cells for smell visualization has been attempted with the use of various methods such as calcium imaging, CRE reporter assay, BRET, and membrane potential assay; however, it is not easy to consistently control the condition of cells and it is impossible to detect low odorant concentration. Recently, the bioelectronic nose was developed, and much improved along with the improvement of nano-biotechnology. The bioelectronic nose consists of the following two parts: primary transducer and secondary transducer. Biological materials as a primary transducer improved the selectivity of the sensor, and nanomaterials as a secondary transducer increased the sensitivity. Especially, the bioelectronic noses using various nanomaterials combined with human olfactory receptors or nanovesicles derived from engineered olfactory cells have a potential which can detect almost all of the smells recognized by human because an engineered olfactory cell might be able to express any human olfactory receptor as well as can mimic human olfactory system. Therefore, bioelectronic nose will be a potent tool for smell visualization, but only if two technologies are completed. First, a multi-channel array-sensing system has to be applied for the integration of all of the olfactory receptors into a single chip for mimicking the performance of human nose. Second, the processing technique of the multi-channel system signals should be simultaneously established with the conversion of the signals to visual images. With the use of this latest sensing technology, the realization of a proper smell-visualization technology is expected in the near future.     

Fuzzy logic feedback control for fed-batch enzymatic hydrolysis of lignocellulosic biomass

A fuzzy logic feedback control system was developed for process monitoring and feeding control in fed-batch enzymatic hydrolysis of a lignocellulosic biomass, dilute acid-pretreated corn stover. Digested glucose from hydrolysis reaction was assigned as input while doser feeding time and speed of pretreated biomass were responses from fuzzy logic control system. Membership functions for these three variables and rule-base were created based on batch hydrolysis data. The system response was first tested in LabVIEW environment then the performance was evaluated through real-time hydrolysis reaction. The feeding operations were determined timely by fuzzy logic control system and efficient responses were shown to plateau phases during hydrolysis. Feeding of proper amount of cellulose and maintaining solids content was well balanced. Fuzzy logic proved to be a robust and effective online feeding control tool for fed-batch enzymatic hydrolysis.     

Ca2+ Signaling and Cell Death Induced by Protriptyline in HepG2 Human Hepatoma Cells

The effect of protriptyline on Ca²⁺ physiology in human hepatoma is unclear. This study explored the effect of protriptyline on [Ca²⁺]_i and cytotoxicity in HepG2 human hepatoma cells. Protriptyline (50–150 μM) evoked [Ca²⁺]_i rises. The Ca²⁺ entry was inhibited by removal of Ca²⁺. Protriptyline‐induced Ca²⁺ entry was confirmed by Mn²⁺‐induced quench of fura‐2 fluorescence. Except nifedipine, econazole, SKF96365, GF109203X, and phorbol 12‐myristate 13 acetate did not inhibit Ca²⁺ entry. Treatment with the endoplasmic reticulum Ca²⁺ pump inhibitor 2,5‐di‐tert‐butylhydroquinone (BHQ) inhibited 40% of protriptyline‐induced response. Treatment with protriptyline abolished BHQ‐induced response. Inhibition of phospholipase C (PLC) suppressed protriptyline‐evoked response by 70%. At 20–40 μM, protriptyline killed cells which was not reversed by the Ca²⁺ chelator 1,2‐bis(2‐aminophenoxy)ethane‐N,N,N′,N′‐tetraacetic acid‐acetoxymethyl ester (BAPTA/AM). Together, in HepG2 cells, protriptyline induced [Ca²⁺]_i rises that involved Ca²⁺ entry through nifedipine‐sensitive Ca²⁺ channels and PLC‐dependent Ca²⁺ release from endoplasmic reticulum. Protriptyline induced Ca²⁺‐independent cell death.     

Comparative proteomic analysis of mesenchymal stem cells derived from human bone marrow,umbilical cord,and placenta: Implication in the migration

Umbilical cord (UC) and placenta (P) have been suggested as alternatives to bone marrow (BM) as sources of mesenchymal stem cells (MSC) for cell therapy, with both UC‐ and P‐MSC possess immunophenotypic and functional characteristics similar to BM‐MSC. However, their migration capacity, which is indispensable during tissue regeneration process, is unclear. Under defined conditions, the migration capacity of BM‐ and P‐MSC was found 5.9‐ and 3.2‐folds higher than that of UC‐MSC, respectively. By the use of 2‐DE and combined MS and MS/MS analysis, six differentially expressed proteins were identified among these MSC samples, with five of them known to be involved in cell migration as migration enhancing or inhibiting proteins. Consistent with their migration capacity, the levels of migration enhancing proteins including cathepsin B, cathepsin D and prohibitin,were significantly lower in UC‐MSC when compared with those in BM‐ and P‐MSC. For the migration inhibiting proteins such as plasminogen activator inhibitor‐1 (PAI‐1) and manganese superoxide dismutase, higher expression was found in the UC‐MSC. We also showed that the overexpression of the PAI‐1 impaired the migration capacity of BM‐ and P‐MSC while silencing of PAI‐1 enhanced the migration capacity of UC‐MSC. Our study indicates that PAI‐1 and other migration‐related proteins are pivotal in governing the migration capacity of MSC.     

Segregation for somatic embryogenesis on stem-internode explants from potato seedlings

Differences in productivity for somatic embryos (SEs) in vitro among 18 potato cultivars and three wild Solanum species in an earlier study led to the hypothesis that regeneration of SEs may be under genetic control. To examine this possibility, three test crosses were initiated; Coastal Russet×AF 186-2; Costal Russet×Lenape; AF 186-2×Lenape. True potato seedlings from these crosses were germinated in vitro. Five stem internode explants from each seedling were excised and cultured on two successive media to promote the formation of SEs. Seedling explants Costal Russet×AF 186-2 cross produced more SE than the other two crosses, and explants from the AF 186-2×Lenape cross generally only produced <10 SEs per explant. SEs were produced on the stem-internode explants from the three crosses at different rates. Data for the number of explants producing SEs and numbers of SEs per explant were highly significant. Regeneration of SEs is probably under nuclear control and the inheritance for regeneration may be quite straightforward. This revised version was published online in June 2006 with corrections to the Cover Date.     

Lack of chemokine receptor CCR5 promotes murine fulminant liver failure by preventing the apoptosis of activated CD1d-restricted NKT cells

Fulminant liver failure (FLF) consists of a cascade of events beginning with a presumed uncontrolled systemic activation of the immune system. The etiology of FLF remains undefined. In this study, we demonstrate that CCR5 deficiency promotes the development of acute FLF in mice following Con A administration by preventing activated hepatic CD1d-restricted NKT cells (but not conventional T cells) from dying from activation-induced apoptosis. The resistance of CCR5-deficient NKT cells from activation-induced apoptosis following Con A administration is not due to a defective Fas-driven death pathway. Moreover, FLF in CCR5-deficient mice also correlated with hepatic CCR5-deficient NKT cells, producing more IL-4, but not IFN-gamma, relative to wild-type NKT cells. Furthermore, FLF in these mice was abolished by IL-4 mAb or NK1.1 mAb treatment. We propose that CCR5 deficiency may predispose individuals to the development of FLF by preventing hepatic NKT cell apoptosis and by regulating NKT cell function, establishing a novel role for CCR5 in the development of this catastrophic liver disease that is independent of leukocyte recruitment.     

Release of arachidonate from diglyceride in human platelets requires the sequential action of a diglyceride lipase and a monoglyceride lipase

Release of arachidonate from 2-arachidonyl diglyceride by human platelet microsomes was investigated. Diglycerides labeled with ¹⁴C-stearate at sn-1 and with ³H-arachidonate at sn-2 were used as a substrate for microsomal diglyceride lipase. Diglyceride was deacylated first at sn-1 as evidenced by the accumulation of 2-arachidonyl monoglyceride but not of 1-stearoyl monoglyceride. Subsequent release of arachidonate from monoglyceride required the action of a monoglyceride lipase. Studies on substrate specificity indicated that diglyceride lipase utilized 2-arachidonyl diglyceride as the best substrate.     

Primary structure of streptococcal proteinase. III. Isolation of cyanogen bromide peptides: complete covalent structure of the polypeptide chain.

The following sequence has been derived for streptococcal proteinase. (See article). The sequence permits the assignment of the single cysteine residue essential for catalytic action at position 47 from the NH2 terminus of the protein. The tryptophan residue at the binding site of the enzyme is at position 214. A histidine residue at position 195 has been assigned as the catalytically important entity in the molecule. Streptococcal proteinase and papain, an enzyme with similar properties, are compared with respect to structure and function.     

Relaxation kinetics of Helix pomatia alpha-hemocyanin. Whole-half molecule reaction at pH 5.7 in 0.4 M NaCl.

Two independent relaxation kinetics methods were used to study samples of α-hemocyanin kindly furnished to us by members of the Biochemical Laboratory of the University of Groningen. A Durrum-Gibson stopped-flow apparatus was used to obtain concentration-jump data in the light-scattering mode. A recently developed pressurejump light-scattering apparatus was used to obtain completely independent data. The studies were made in 0.1 m acetate buffer at pH 5.7 containing 0.4 m NaCl, conditions under which equilibrium light-scattering studies had been reported by Engelborghs and Lontie (1973, J. Mol. Biol., 77, 577–587). In the companion paper (Kegeles, 1977, Arch. Biochem. Biophys., 180, 530–536), a model is proposed, consisting of a system containing a mixture of reactive and unreactive whole molecules, from which data are derived for the formation constant of whole molecules from halves and the fraction of material which is capable of undergoing reaction. The present study uses this estimate of this fraction of reactive material to permit the evaluation of overall rate constants and equilibrium constants. When the estimate of 65% of reactive material derived without making nonideality corrections is applied to the kinetics data, very satisfactory agreement is obtained between the equilibrium constant acquired from equilibrium data and the equilibrium constants derived from the kinetics data.     

Fill Factor Losses in Cu2ZnSn(SxSe1−x)4 Solar Cells: Insights from Physical and Electrical Characterization of Devices and Exfoliated Films

Besides the open circuit voltage (V_OC) deficit, fill factor (FF) is the second most significant parameter deficit for earth‐abundant kesterite solar cell technology. Here, various pathways for FF loss are discussed, with focus on the series resistance issue and its various contributing factors. Electrical and physical characterizations of the full range of bandgap (E_g = 1.0–1.5 eV) Cu₂ZnSn(S_xSe_1?x)₄ (CZTSSe) devices, as well as bare and exfoliated films with various S/(S + Se) ratios, are performed. High intensity Suns‐V_OC measurement indicates a nonohmic junction developing in high bandgap CZTSSe. Grazing incidence X‐ray diffraction, Raman mapping, field emission scanning electron microscopy, and X‐ray photoelectron spectroscopy indicate the formation of Sn(S,Se)₂, Mo(S,Se)₂, and Zn(S,Se) at the high bandgap CZTSSe/Mo interface, contributing to the increased series resistance (R_S) and nonohmic back contact characteristics. This study offers some clues as to why the record‐CZTSSe solar cells occur within a bandgap range centered around 1.15 eV and offers some direction for further optimization.