Time Series Analysis and Model of Heart-Beat Rate,Oxygen Consumption,and Locomotor Activity from the Sand-crab Portunus pelagicus (Linnaeus)

Auto-correlation, cross-correlation, and Fourier transform decomposition were applied to data on parameters of perfusion, respiration, and behaviour in P. pelagicus. Cardiac activity, although discontinuous in buried crabs, formed a regular alternating time-series with a stable periodicity. Cross-correlation showed a close temporal linking between cardiac activity and oxygen consumption over 24 hours. Similar temporal patterns were observed in locomotor activity. Pausing (bradycardia) and pulsing (tachycardia) were investigated by “power spectrum” analysis and summarised in the form of a Fourier transform model.     

Detectability and criterion measures in temporal generalization

Computer simulation of performance on “normal” and “episodic” temporal generalization tasks was used to examine the relations between the theoretical parameters of models which fit temporal generalization data (“timing sensitivity” and “threshold”), and the d′ (detectability) and beta (decision criterion) measures of signal-detection theory. In general, changes in timing sensitivity altered d′, whereas threshold changes affected beta, supporting the assertion that the two sorts of variables (“sensitivity/detectability” and “threshold/criterion”) were psychologically equivalent. Cases where temporal generalization gradients were apparently contaminated by “random responding” could be treated by changes in beta, but cases in which temporal generalization gradients were not peaked at the standard posed severe problems for a simple signal-detection account, although existing models of temporal generalization performance could deal with them.     

Baseline gamma activity EEG and induced responses to facial stimuli of the visual cognitive set

Power spectra of cortical potentials of baseline activity during interstimuli intervals (4 s; Fourier transform in the frequency band of 1-60 Hz) and short-term (0.8 s) induced responses to facial stimuli (wavelet transform in the 15-60 Hz band) were assessed in the study of the visual cognitive set to facial expression. Significant differences between groups of subjects with different set rigidity were observed only at the set-testing stage. Estimation of the short-term (0.8 s) induced responses of the wavelet spectra in the group with plastic set revealed an increase in the power (in comparison with the power of background activity) of the gamma2 band (41-60 Hz) in the left hemisphere of the temporal, central and occipital areas, whereas in the group with rigid set these power spectra decreased. At the same time the power in the gamma1 band (21-40 Hz) was significantly lower (at the same level with the rigid form), indicating a discrete nature and functional selectivity in the gamma frequency band.     

Baseline EEG gamma activity and induced responses to facial stimuli during the formation of a visual cognitive set

The power spectra of cortical potentials of baseline activity during interstimulus intervals (4 s; Fourier transform in the frequency band of 1–60 Hz) and short-term (0.8 s) induced responses to facial stimuli (wavelet transform in the 15–60 Hz band) were assessed during the study of the visual cognitive set to facial expression. Significant differences between groups of subjects with different set plasticities were observed only at the set-testing stage. Estimation of short-term (0.8 s) induced responses of wavelet spectra in the group with the plastic set revealed an increase in the power (compared to the power of background activity) of the γ₂ band (41–60 Hz) in the temporal, central and occipital areas of the left hemisphere, whereas in the group with the rigid set these power spectra decreased. At the same time, the power in the γ₁ band (21–40 Hz) was significantly lower (at the same level with the rigid form), indicating the discrete nature and functional selectivity in the γ frequency band.     

The diversity of temporal niches in mammals

The division of animals into those that are diurnal (day-active) and those that are nocturnal (night-active) is widely recognized. However, closer examination of the selection of temporal niches by mammalian species reveals the existence of a gradient of diurnality between and within species, wherein “diurnal” and “nocturnal” are merely the opposite ends of a continuum. Evidence against a simple diurnal - nocturnal dichotomy includes the existence of species without any preference for time of day, species with a crepuscular pattern of activity, species containing both diurnal and nocturnal individuals, species containing individuals that spontaneously shift from a nocturnal to a diurnal activity pattern, species showing degrees of diurnality greater or smaller than those of other species, organismal variables exhibiting degrees of diurnality greater or smaller than those of other variables, and species having different temporal patterns under the effects of different environmental variables. Research on the neural processes responsible for temporal niche selection has revealed no fundamental difference between the circadian clocks of diurnal and nocturnal animals, but recent findings suggest that different output pathways from the clock in a given species may operate with different circadian phases, thus providing an explanation for why different body functions in the same individual are subjected to different temporal niche selections.     

Temporal analysis of tone pulses within the courtship songs of two siblingDrosophila species,their interspecific hybrid,and behavioral mutants ofD. melanogaster (Diptera: Drosophilidae)

Temporal analyses were applied to the tone pulses within the courtship songs of Drosophila melanogaster, D. simulans,their interspecific hybrid, and behavioral mutants of D. melanogaster.Linear regression was performed on various parameters of the song pulses (cycles per pulse, absolute peak amplitude, intrapulse frequency, number of peaks in fast Fourier transform, width of the primary frequency peak, and interpulse interval), as a function of their positions within pulse trains. Significant differences in the slope values of these two species and of the mutant genotypes allowed for discriminative quantification of temporal changes within trains. These results are discussed in relation to previous kinds of temporal analyses of Drosophilacourtship songs and also with regard to the mechanisms of song production.     

In vitro antidiabetic,antioxidant, antimicrobial,and cytotoxic activity of Murraya koenigii leaf extract intercedes ZnO nanoparticles

Nanotechnology is an emerging field with tremendous potential and usage of medicinal plants and green preparation of nanoparticles (NPs) is one of the widely explored areas. These have been shown to be effective against different biological activities such as diabetes mellitus, cancer, antioxidant, antimicrobial, etc. The current studies focus on the green synthesis of zinc NPs (ZnO NPs) from aqueous leaf extract of Murraya koenigii (MK). The synthesized Murraya koeingii zinc oxide NPs (MK ZnO NPs) were characterized using UV–visible spectroscopy, dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive spectrum (EDS) and cyclic voltammetry (CV). The synthesized MK ZnO NPs were evaluated for their in vitro antidiabetic, antioxidant, antimicrobial, and cytotoxic activity. They demonstrated significant antidiabetic and cytotoxic activity, as well as moderate free-radical scavenging and antibacterial activity.     

Temperature profiles, and the effect of sleep on them, in relation to morningness-eveningness in healthy female subjects

There were 15 healthy female subjects, differing in their position on the “morningness-eveningness” scale, studied for 7 consecutive days, first while living a sedentary lifestyle and sleeping between midnight and 08:00 and then while undergoing a “constant routine.” Rectal temperature was measured at regular intervals throughout this time, and the results were subjected to cosinor analysis both before and after “purification” for the effects of physical activity. Results showed that there was a phase difference in the circadian rhythm of core temperature that was associated with the morningness score, with calculations that “morning types” would be phased earlier than “evening types” by up to about 3h. This difference in phase (which was also statistically significant when the group was divided by a median split into a “morning group” and an “evening group”) could not be attributed to effects of waking activity and existed in spite of the subjects keeping the same sleep-wake schedule. Moreover, it persisted when the subjects' data had been purified and when the data were obtained from the constant routine. That is, there was an endogenous component to this difference in phase of the core temperature. The morning group also showed a greater fall of core temperature during sleep; this was assessed in two ways, the main one being a comparison of constant routine and nychthemeral data sets after correction for any effects of activity. Even though the morning group was sleeping at a later phase of their circadian temperature rhythm than was the evening group, neither group showed a fall of temperature due to sleep that varied with time elapsed since the temperature acrophase. It is concluded that another factor that differs between morning and evening types is responsible for this difference. (Chronobiology International, 18(2), 227-247, 2001)     

Effects of Ca crosslinking on structure and properties of waterborne polyurethane-carboxymethylated guar gum films

Films from waterborne polyurethane (WPU) and carboxymethylated guar gum (CMGG) with different contents (20–80 wt%) were prepared through solution casting method, and then were crosslinked with calcium chloride. The effect of CMGG content on the miscibility, morphology and physical properties of the blend films is investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, density measurements, differential scanning calorimetry, dynamic mechanical thermal analysis, thermogravimetric analysis, water sensitivity measurements, solvent-swelling and tensile tests. The results reveal that the uncrosslinked films exhibit good miscibility when CMGG content is lower than 60 wt%, whereas typical “sea-island” structure occurs when the CMGG content further increases. After crosslinking with calcium ion, the blend films form a relatively dense architecture, which leads to better miscibility, higher storage modulus and thermal stability. The crosslinked films also exhibit better tensile strength (11.6–56.5 MPa) and solvent-resistance than that of the uncrosslinked films over the entire composition range. A model describing the configuration of Ca²⁺-chelating structure was proposed to illustrate the different structures of the two series of the blend films.     

Circadian control of migratory restlessness and the effects of exogenous melatonin in the brambling, Fringilla montifringilla

Circadian pacemakers control both “daytime” activity and nocturnal restlessness of migratory birds, and the daily rhythm of melatonin release from the pineal has been suggested to be involved in the control of migratory activity. To study the phase relations between the two activity components during entrainment and when free running, locomotor activity of bramblings (Fringilla montifringilla) was recorded continuously under a 12:12 “cool light” to “warm light” cycle (CL:WL, ca. 5000 K and ca. 2500 K, respectively) or blue light to red light cycle (BL:RL, maxima at 440 and 650 nm, respectively) at different irradiance ratios. Migratory activity was expressed primarily during the WL or RL phase of the light cycles. Under free-running conditions, the circadian periods τ correlated with the phase relations between day and night (migratory) activity components during preceding entrainment. Bramblings with migratory activity had significantly longer τ at constant light intensity than the same individuals without migratory activity. Birds with migratory activity reentrained faster after a 6h phase shift of the CL:WL cycle than birds without migratory activity. When exogenous melatonin was given in the drinking water (200 μg/mL 1% ethanol or 0.86 mM) to bramblings exposed to 12:12 CL:WL cycles with constant irradiance, the amounts of activity, which were initially higher during the WL phase of the light cycle, were suppressed to similar low levels during both light phases. The systematic changes in the amounts of activity during melatonin treatment were not correlated with consistent changes in entrainment status. The data support the hypothesis that changes in the amplitude and level of the daily melatonin cycle are involved in regulating migratory restlessness, by either allowing or inhibiting nocturnal activity. (Chronobiology International, 17(4), 471-488, 2000)     

Altered Oscillation and Synchronization of Default-Mode Network Activity in Mild Alzheimer’s Disease Compared to Mild Cognitive Impairment: An Electrophysiological Study

Some researchers have suggested that the default mode network (DMN) plays an important role in the pathological mechanisms of Alzheimer’s disease (AD). To examine whether the cortical activities in DMN regions show significant difference between mild AD from mild cognitive impairment (MCI), electrophysiological responses were analyzed from 21 mild Alzheimer’s disease (AD) and 21 mild cognitive impairment (MCI) patients during an eyes closed, resting-state condition. The spectral power and functional connectivity of the DMN were estimated using a minimum norm estimate (MNE) combined with fast Fourier transform and imaginary coherence analysis. Our results indicated that source-based EEG maps of resting-state activity showed alterations of cortical spectral power in mild AD when compared to MCI. These alterations are characteristic of attenuated alpha or beta activities in the DMN, as are enhanced delta or theta activities in the medial temporal, inferior parietal, posterior cingulate cortex and precuneus. With regard to altered synchronization in AD, altered functional interconnections were observed as specific connectivity patterns of connection hubs in the precuneus, posterior cingulate cortex, anterior cingulate cortex and medial temporal regions. Moreover, posterior theta and alpha power and altered connectivity in the medial temporal lobe correlated significantly with scores obtained on the Mini-Mental State Examination (MMSE). In conclusion, EEG is a useful tool for investigating the DMN in the brain and differentiating early stage AD and MCI patients. This is a promising finding; however, further large-scale studies are needed.     

Conformation,orientation, and adsorption kinetics of dermaseptin B2 onto synthetic supports at aqueous/solid interface

The antimicrobial activity of cationic amphipathic peptides is due mainly to the adsorption of peptides onto target membranes, which can be modulated by such physicochemical parameters as charge and hydrophobicity. We investigated the structure of dermaseptin B2 (Drs B2) at the aqueous/synthetic solid support interface and its adsorption kinetics using attenuated total reflection Fourier transform infrared spectroscopy and surface plasmon resonance. We determined the conformation and affinity of Drs B2 adsorbed onto negatively charged (silica or dextran) and hydrophobic supports. Synthetic supports of differing hydrophobicity were obtained by modifying silica or gold with omega-functionalized alkylsilanes (bromo, vinyl, phenyl, methyl) or alkylthiols. The peptide molecules adsorbed onto negatively charged supports mostly had a beta-type conformation. In contrast, a monolayer of Drs B2, mainly in the alpha-helical conformation, was adsorbed irreversibly onto the hydrophobic synthetic supports. The conformational changes during formation of the adsorbed monolayer were monitored by two-dimensional Fourier transform infrared spectroscopy correlation; they showed the influence of peptide-peptide interactions on alpha-helix folding on the most hydrophobic support. The orientation of the alpha-helical Drs B2 with respect to the hydrophobic support was determined by polarized attenuated total reflection; it was around 15 +/- 5 degrees. This orientation was confirmed and illustrated by a molecular dynamics study. These combined data demonstrate that specific chemical environments influence the structure of Drs B2, which could explain the many functions of antimicrobial peptides.     

Plasma Concentration of Nine Hormones and Neurotransmitters During Usual Activities or Constant Bed Rest for 34 H

Thyroid-stimulating hormone (TSH), Cortisol, melatonin, prolactin, luteinizing hormone (LH), delta-sleep-inducing peptide (DSIP), its phosphorylated form (P-DSIP), heart rate, and body temperature were measured every half hour during two 24-h periods in five normal men. τ-Amino-butyric acid (GABA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were measured less frequently. The first period, the “activity” condition, included usual daily activities. The second period, or “rest” condition, consisted of fasting, constant bed rest during 34 h, and partial light deprivation. Compared with the “rest” condition, the “activity” condition increased heart rate, temperature, LH, and TSH in most subjects, and Cortisol in two of five subjects. It retarded the onset of nocturnal Cortisol and melatonin secretion. The temporal pattern and the absolute values of the concentrations of DSIP, P-DSIP, MHPG, GABA, and prolactin showed no or minimal changes during the two conditions. In spite of the influence of the “activity” versus “rest” condition on several hormones, the mean concentrations as well as the temporal organization of their secretion into plasma were quite stable within each subject, whereas they varied much more between individuals. TSH, Cortisol, and melatonin values were also stable within an 8-month period in one subject who was studied on four occasions. The results illustrate that the patterns of hormones rhythms and their reactivity to changes in the environment are, to a large extent, specific to each subject.     

Detection of insect infestation in museum objects by carbon dioxide measurement using FTIR

Detecting the presence of active insects in various stages of their lifecycle within an art object is often difficult in the absence of direct visualization of the insect. It usually relies on one's ability to assess the evidence of their activity around, on, or in the object. To augment this “eyeball” method, a Fourier transform infrared spectroscopy system was used to determine the presence of the insect through its respired gas, carbon dioxide. The application of the procedure to assist in control of insect infestation within art objects is described. Two instruments are discussed in this paper. The prototype instrument could detect a change in carbon dioxide that was 0.3–0.4 ppm/h and required days to reliably determine this level. The second instrument could detect changes as low as 0.09 ppm/h and could provide results in only 4 h. Carbon dioxide measurements were collected from representative insect groups that have caused problems in art objects; these were worker termites (Reticulitermes sp.), carpet beetle adult and larvae (Anthrenus sp.), an odd beetle larva (Thylodrias sp.) and a mature silverfish (Lepisma sp.), as well as selected museum art objects composed of wood, fabric, and/or feathers suspected of harboring insects.     

Metabonomic alterations in hippocampus, temporal and prefrontal cortex with age in rats

The metabolic changes in hippocampus, temporal cortex and prefrontal cortex in SD rats along with aging were explored using a metabonomic approach, which based on high resolution “magic angle spinning” ¹H NMR spectroscopy. The metabolite profiles were analyzed by partial least squares-discriminant analysis, and the results showed that the metabolites of the above three brain regions in old rats were dramatically different from that in the adult and young rats. The old rats showed increased myo-inositol and lactate in all of the three brain regions, and decreased N-acetylaspartate in temporal and frontal cortex, Glutamate–GABA level became imbalance in temporal cortex of old rats. In addition, compared with the adult female rats, male rats had higher levels of N-acetylaspartate, taurine, and creatine in temporal or frontal cortex. The age-related metabolic changes may indicate the early functional alterations of neural cells in these brain regions, especially the temporal cortex. The gender-related metabolic changes suggest the significance of the hormonal regulation in brain metabolism. Our work highlights the potential of metabolic profiling to enhance our understanding of biological mechanisms of brain aging.     

Twenty-four-hour pattern of angina pectoris, acute myocardial infarction and sudden cardiac death: Role of blood pressure, heart rate and rate-pressure product circadian rhythms

Population-based epidemiology and clinical case studies document a prominent 24-hour pattern in the occurrence of silent and non-silent angina pectoris (AP), acute myocardial infarction (AMI), and sudden cardiac death (SCD). When the data are summarized per 3 - 6 hour intervals of the 24 hours, the temporal pattern of these ischemic heart disease (IHD) events shows a single morning peak between 06:00 and 12:00 h in incidence. However, when the occurrence of such events is examined according to the hour of their occurrence, several studies reveal a second late-afternoon/early-evening minor peak. The true day - night pattern in AP, AMI, and SCD is unknown because the data represent nothing more than the recorded “time of day” of the events. It has been postulated that the day - night pattern in IHD events is at least in part dependent on endogenous circadian rhythms, which are synchronized by the daily routine of sleep in darkness/activity in light. Approximately 20% of the working population is involved in night and rotating shift employment; thus, “time of day” studies are not likely to accurately represent the actual “chronorisk” of vulnerable individuals to IHD events. Moreover, it is likely that the events in the persons comprising the population and clinical case studies were influenced by ongoing treatment with antihypertensive, anticoagulant, and antianginal medications. Details regarding the class, dose, and schedule of such medications are rarely if ever reported in accounts of IHD events. Many of the investigations were conducted decades ago, when short-acting antihypertensive and cardiovascular medications required twice or thrice-a-day dosing, and thus the observed day - night variations could be significantly affected by such multiple treatment timings each day. Thus, the magnitude and nature (single versus multiple peaks) of the reported day - night patterns in AP, AMI, and SCD are suspect, as are their geneses. Presently, it is hypothesized that multiple cyclic exogenous triggers (e.g. posture, physical exertion, emotional stress, and medication scheduling) superimposed upon an endogenous 24-hour susceptibility-resistance pattern that arises from circadian rhythms in heart rate, blood pressure, rate-pressure product, and haemostasis, are major contributory factors.     

Preparation, characterization, and antibacterial activity of oleic acid-grafted chitosan oligosaccharide nanoparticles

An oleic acid-grafted chitosan oligosaccharide (CSO-OA) with different degrees of amino substitution (DSs) was synthesized by the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling reaction. Fourier transform infrared spectroscopy (FT-IR) suggested the formation of an amide linkage between amino groups of chitosan oligosaccharide and carboxyl groups of oleic acid. The critical aggregation concentrations (CACs) of CSO-OA with 6%, 11%, and 21% DSs were 0.056, 0.042, and 0.028 mg·mL⁻¹, respectively. Nanoparticles prepared with the sonication method were characterized by means of transmission electron microscopy (TEM) and Zetasizer, and the antibacterial activity against Escherichia coli and Staphylococcus aureus was investigated. The results showed that the CSO-OA nanoparticles were in the range of 60–200 nm with satisfactory structural integrity. The particle size slightly decreased with the increase of DS of CSO-OA. The antibacterial trial showed that the nanoparticles had good antibacterial activity against E. coli and S. aureus.     

Synthesis and characterization of cysteine functionalized silver nanoparticles for biomolecule immobilization

A facile method for the aqueous phase synthesis of cysteine-functionalized silver nanoparticles by potato extract has been reported in the present work. These functionalized nanoparticles were then used for the covalent immobilization of a biomolecule, alkaline phosphatase, on its surface through carbodiimide coupling. Different reaction parameters such as cysteine concentration, reducing agent concentration, temperature, pH and reaction time were varied during the nanoparticles’ formation, and their effects on plasmon resonance were studied using Ultraviolet–visible spectroscopy. Fourier transform infrared spectroscopy was used to confirm the surface modification of silver nanoparticles by cysteine and the particle size analysis was done using particle size analyzer, which showed the average nanoparticles’ size of 61 nm for bare silver nanoparticles and 201 nm for the enzyme-immobilized nanoparticles. The synthesized nanoparticles were found to be highly efficient for the covalent immobilization of alkaline phosphatase on its surface and retained 67 % of its initial enzyme activity (9.44 U/mg), with 75 % binding efficiency. The shelf life of the enzyme-nanoparticle bioconjugates was found to be 60 days, with a 12 % loss in the initial enzyme activity. With a simple synthesis strategy, high immobilization efficiency and enhanced stability, these enzyme-coated nanoparticles have the potential for further integration into the biosensor technology.     

Synthesis, characterization, and antifungal activity of novel quaternary chitosan derivatives

Three novel quaternary chitosan derivatives were successfully synthesized by reaction of chloracetyl chitosan (CACS) with pyridine (PACS), 4-(5-chloro-2-hydroxybenzylideneamino)-pyridine (CHPACS), and 4-(5-bromo-2-hydroxybenzylideneamino)-pyridine (BHPACS). The chemical structure of the prepared chitosan derivatives was confirmed by Fourier transform infrared (FT-IR) and ¹³C nuclear magnetic resonance (¹³C NMR) and their antifungal activity against Cladosporium cucumerinum, Monilinia fructicola, Colletotrichum lagenarium, and Fusarium oxysporum was assessed. Comparing with the antifungal activity of chitosan, CACS, and PACS, CHPACS and BHPACS exhibited obviously better inhibitory effects, which should be related to the synergistic reaction of chitosan itself with the grafted 2-[4-(5-chloro-2-hydroxybenzylideneamino)-pyridyl]acetyl and 2-[4-(5-bromo-2-hydroxybenzylideneamino)-pyridyl]acetyl.     

Penicillin G acylase-fatty lipid biocomposite films show excellent catalytic activity and long term stability/reusability

The formation of biocomposite films of the pharmaceutically important enzyme penicillin G acylase (PGA) and fatty lipids under enzyme-friendly conditions is described. The approach involves a simple beaker-based diffusion protocol wherein the enzyme diffuses into the lipid film during immersion in the enzyme solution, thereby leading to the formation of a biocomposite film. The incorporation of the enzyme in both cationic as well as anionic lipids suggests the important role of secondary interactions such as hydrophobic and hydrogen bonding in the enzyme immobilization process. The kinetics of formation of the enzyme-lipid biocomposites has been studied by quartz crystal microgravimentry (QCM) measurements. The stability of the enzyme in the lipid matrix was confirmed by Fourier transform infrared spectroscopy (FTIR) and biocatalytic activity measurements. Whereas the biological activity of the lipid-immobilized enzyme was marginally higher than that of the free enzyme, the biocomposite film exhibited increased thermal/temporal stability. Particularly exciting was the observation that the biocomposite films could be reused in biocatalysis reactions without significant loss in activity, which indicates potentially exciting biomedical/industrial application of these films.