Non-constraining sleep/wake monitoring system using bed actigraphy

This paper introduces a new method, bed actigraphy (BACT) for user-friendly sleep-wake monitoring. BACT provides a non-intrusive acquisition of activity data, and in particular does not require that sensors be attached to the subject’s body. The system consists of four load-sensing cells supporting the bed, an A/D converter, and a microcontroller with appropriate software. The performance of BACT was compared to that of standard polysomnography (PSG) recordings and wrist-worn actigraphy (ACT). Ten normal volunteers underwent overnight PSG recordings and were examined simultaneously with BACT and ACT. An automatic scoring algorithm scored each 30-s epoch of the BACT recordings for either ‘Wake’ or ‘Sleep.’ A sleep specialist manually scored the PSG recordings, and the results were divided into ‘Wake’ and ‘Sleep’ categories. The three methods showed a significant correlation when compared with in the contingency test. The mean epoch-by-epoch agreements between the BACT and PSG, ACT and PSG, and BACT and ACT recordings were 95.2, 92.9, and 94.3%, respectively. The mean absolute differences in sleep percentage (SP) between them were 1.8 ± 0.82, 3.4 ± 1.45, and 1.9 ± 1.16 %, respectively. BACT differentiation of the ‘Wake’ and ‘Sleep’ stages proved to be sufficiently robust, and its results were comparable to PSG analysis. This finding supports the experimental and clinical value of bed-activity monitoring during sleep.     

Characterisation of the dynamic vertical force distribution under the foot

Measurement of force distribution under the sole of the foot during walking can provide enormous quantities of data with modern recording techniques. Methods are described for presenting such data in pictorial, in parametric and in graphical form. Parametric characterisations include magnitude, timing and location of peak forces and ‘impulses’ (the force-time integrals), parameters describing the local concentration of force and the distribution of the ‘impulse’ over areas of the foot sole. Pictorial displays include force-time graphs for selected areas of the foot, display of movement of the centre of pressure on specific areas and cross-sections through the pressure distribution profile at a specified recorded instant. Such characterisations were considered useful if they provided information on pathological conditions of the feet. A ‘normal’ group was studied to give a baseline for comparisons. An example of abnormality, compared with the normal group, in a patient with rheumatoid arthritis is given. This demonstrates an abnormal distribution of force on the forefoot, and abnormal movement of the centre of pressure consistent with the patient favouring a painful region for weight-bearing.     

The use of a ‘phantom scalp’ to assess the possible direct pickup of mobile phone handset emissions by electroencephalogram electrode leads

A ‘Phantom Scalp’ was constructed from a conducting foam mat to form a layer under a 62-electrode electroencephalogram cap closely approximating the electrical properties of a human scalp. The mat was placed over a polystyrene manikin head to preserve a correct anatomical arrangement. Electrical signals were recorded with a Global System for Mobile (GSM) communications mobile phone handset in place against the side of the ‘head’. Amplitude spectra were compared for three phone conditions: ‘off’, ‘standby’ and ‘transmit’. At 217 Hz, significant differences were obtained between ‘transmit’ and the other two conditions, but no significant differences were noted for the physiologically important range 0.5–30 Hz. An anomalous difference was noted for one electrode in the range 30–45 Hz.     

Fractal dynamics of polarized bioelectrodes

This study is concerned with mathematical modelling of the fundamental relationship which exists between the current density and the overpotential across the metalsolution interface in the linear range using methods of system theory enhanced by ‘fractal’ concepts. A primer for both 1/f-type scaling and ‘anomalous’ relaxation/dispersion concepts is provided, followed by a brief review of the research history pertinent to the metal electrode polarization dynamics. Next, the ‘fractal relaxation systems’ approach is introduced to characterize, systems which attenuate with a fractional power-low dependence on frequency through a ‘scaling exponent’. The ‘singularity structure’ which is a scaling, rational system function is proposed to expand fractal systems in terms of basic subsystems individually representing elementary exponential relaxations and collectively exhibiting scaling properties. We stress that the ‘singularity structure’ carries scaling information identical to the conventional ‘distribution of relaxation times’ function. ‘Structure scale’ and ‘view scale’ concepts are presented in the due course to streamline the analysis of scaling phenomena in general and the polarization impedance in particular. System theory-wise, the notable result is that the fractional power function attenuation, or equivalently, the logarithmic nature of the distribution function translates into the ‘self-similar’ pattern replication of the system singularities in the s-plane. The singularity arrangement is governed by a recursive rule solely based on the knowledge of the fractional power factor or the scaling exponent.     

Finger interaction during maximal radial and ulnar deviation efforts: experimental data and linear neural network modeling

The purpose of this study was to characterize finger interactions during radial/ulnar deviation, including interactions with flexion movements. Subjects performed single-finger and multi-finger maximal voluntary contraction (MVC), and maximal forces and various indices of interaction among the fingers were quantified. MVCs in radial/ulnar deviation were 50–80% as strong as in flexion. Along with the ‘master’ fingers (i.e., those explicitly instructed to produce force), substantial force production was also observed in ‘slave’ fingers (i.e., those not explicitly instructed to produce force), a phenomenon termed: force ‘enslaving’. In addition, a drop in MVC during multi-finger tasks as compared to single finger tasks (force ‘deficit’) was also observed. A previously unreported phenomenon that we term: ‘preferred direction enslaving’ was also apparent; both master and slave fingers produced force in the instructed direction with a non-zero perpendicular component. Due to the architectural separation of the involved muscles, preferred direction enslaving provides strong evidence that enslaving results from neural rather than biomechanical factors. A final new phenomenon: ‘negative deficit’, or force ‘facilitation’ was observed in 46.4% of the trials in 21 out of 23 subjects during multi-finger lateral efforts and was further demonstrative of extensive interconnection among neurons serving hand muscles. The data were modeled with high accuracy (∼4% mean square error) using a linear neural network with motor ‘commands’ as inputs and finger forces as outputs. The proposed network, equivalent to linear regression, can be used to determine the extent to which finger forces are influenced by peripheral constraints during functional prehensile activities.     

Object-based three-dimensional X-ray imaging

A form of three-dimensional X-ray imaging, called Object 3-D, is introduced, where the relevant subject material is represented as discrete ‘objects’. The surface of each such object is derived accurately from the projections of its outline, and of its other discontinuities, in about ten conventional X-ray views, distributed in solid angle. This technique is suitable for many applications, and permits dramatic savings in radiation exposure and in data acquisition and manipulation. It is well matched to user-friendly interactive displays.     

Bioenergetics and biomechanics of cycling: the role of ‘internal work’

The ‘dissection’ of energy expenditure of cycling into the metabolic equivalent of the different forms of mechanical work done, inaugurated 30 years ago by di Prampero and collaborators, has been much debated in the last few decades. The mechanical internal work, particularly, which is currently associated to the movement of the lower limbs, has been approached, estimated and discussed in several different ways and there is no agreed consensus on its role in cycling. This paper, through re-processing previously published data of oxygen consumption during pedalling at different frequency, external load and limb mass, proposes a model equation and a multiple non-linear regression as the method to assess the internal work of cycling. With that tool a very consistent metabolic equivalent of the internal work is obtained. However, a software simulation of pedalling limbs showed, as suggested in the literature, that the link with the chain ring allows the system to passively revolve forever, after an initial push. This result challenges the very existence of the ‘kinematic internal work’ of cycling. We conclude and suggest that the ‘viscous internal work’, an often neglected and almost unmeasurable portion of the internal work that could be proportional to the ‘kinematic’ form, is responsible for the extra metabolic expenditure as measured when the pedalling frequency of cycling increases.     

Auditory temporal modulation of the visual Ternus effect: the influence of time interval

Research on multisensory interactions has shown that the perceived timing of a visual event can be captured by a temporally proximal sound. This effect has been termed ‘temporal ventriloquism effect.’ Using the Ternus display, we systematically investigated how auditory configurations modulate the visual apparent-motion percepts. The Ternus display involves a multielement stimulus that can induce either of two different percepts of apparent motion: ‘element motion’ or ‘group motion’. We found that two sounds presented in temporal proximity to, or synchronously with, the two visual frames, respectively, can shift the transitional threshold for visual apparent motion (Experiments 1 and 3). However, such effects were not evident with single-sound configurations (Experiment 2). A further experiment (Experiment 4) provided evidence that time interval information is an important factor for crossmodal interaction of audiovisual Ternus effect. The auditory interval was perceived as longer than the same physical visual interval in the sub-second range. Furthermore, the perceived audiovisual interval could be predicted by optimal integration of the visual and auditory intervals.     

Karyotype diversity and the origin of grapefruit

Grapefruit is a group of citrus of recent origin, probably resulting from a cross between pummelo and sweet-orange. Aiming to investigate this putative origin and the genetic variability among grapefruit cultivars, the karyotype of six grapefruits, two pummelos, and one tangelo cultivar (grapefruit × tangerine) were analyzed using sequential CMA/DAPI double staining and FISH with rDNA probes. The karyotypes of grapefruit ‘Duncan’ and ‘Foster’ differ from those of ‘Flame’, ‘Henderson’, ‘Marsh’ and ‘Rio Red’. The former have two chromosomes with a single CMA⁺ band in both terminal regions (C type chromosome) and six chromosomes with only one CMA⁺ terminal band (D type), whereas the latter have three C and five D type chromosomes. All accessions investigated exhibited two chromosomes with 5S rDNA but a variable number of 45S rDNA. The two former grapefruits displayed four 45S rDNA sites, whereas the remaining grapefruit cultivars had five. The two pummelos showed identical karyotypes, homozygous for CMA⁺ bands and their four rDNA sites. From each pummelo chromosome pair one chromosome seems to be present in grapefruit karyotypes. The different grapefruit karyotypes might result from independent crosses between pummelos of different karyotypic constitution and sweet-oranges. The chromosome markers found in the tangelo ‘Orlando’ and the position of their two 45S rDNA confirm the grapefruit ‘Duncan’ and the tangerine ‘Dancy’ as their parents.     

Artefact cancellation in motor-sensory evoked potentials: two approaches using adaptive filtration and exponential approximation

Adaptive filtering for artefact cancellation in motor-sensory evoked potentials using signals obtained by subtraction methods (double-stimulus, off-nerve and subthreshold) is proposed. This is advantageous as inherent non-linear distortions can be overcome in an easier way by adaptive filtering. Efficiency is assessed with reference signals synthesised by varying the shape and reducing the amplitude of a ‘pure’ evoked potential in the range from 10% to 50%. The experiments show virtually identical shapes of the ‘pure’ and the filtered signal. The time shift between them is insignificant if a causal filter and small number of Widrow coefficients, e.g. N=8, are used. Further, two-exponential artefact approximation is applied with subsequent direct subtraction from the contaminated signal by a specially designed PC-controlled system for data acquisition and processing. For a fast procedure convergence, one-parametric optimisation of the time-constant τ is used, starting with τ=0.5 ms. The results obtained with artefact-corrupted evoked potentials from several subjects prove the efficiency of the approach. It has the substantial advantage of avoiding the need for reference signals. Both methods have advantages compared with other known software techniques.     

Identification,detection and transmission of a new vitivirus from <Emphasis Type="Italic">Mentha</Emphasis>

Summary Mentha × gracilis ‘Variegata’ is an ornamental clone with a phenotype caused by virus infection. Several clones were ordered from mail-order nurseries in an attempt to identify a virus consistently associated with symptoms. One of these clones did not exhibit typical ‘Variegata’ symptoms, and steps were taken to identify any agents causing the ‘off-type’ symptoms. One of the viruses identified in the atypical ‘Variegata’ clone is a previously unknown virus, a member of the family Flexiviridae. Sequence and phylogenetic analysis indicate that the virus, designated as mint virus-2, is related to members of the species Grapevine virus A, Grapevine virus B and Heracleum latent virus, placing it in the genus Vitivirus. A detection protocol for the virus has been developed, and the mint aphid (Ovatus crataegarius) was able to transmit the virus in the presence of a helper virus but not from single infected plants.     

Noninvasive automatic measurement of arterial elasticity in human fingers and rabbit forelegs using photoelectric plethysmography

A new instrument for the noninvasive measurement of arterial elastic properties such as ‘pressure-volume relationship’ and ‘volume elastic modulus’ in human fingers or in rabbit forelegs has been designed using a transmittance infra-red photoelectric plethysmography technique. The measurement and display of the results by this system is carried out automatically by use of a conventional personal computer. Using this instrument, the progressive and regressive changes in arterial elastic properties have been clearly demonstrated in the forelegs of hyperlipoedemic rabbits with experimental atherosclerosis. The effect of vasodilation by isosorbide dinitrate on the finger arteries of patients with congestive heart failure was also successfully studied. This instrument is capable of a rapid and reliable measurement of arterial elasticity and appears to be useful not only in basic cardiovascular research laboratories but also in clinics.     

Sources of common computer-cardiologist discord in e.c.g. interpretations in ambulatory population

Based on clinical experience in performing mass computerised interpretations of e.c.g.s, some common sources of computer-cardiologist disagreements are presented. Examples are given along with a discussion of the technological or logical bases for discord. It is concluded that computer interpretations are generally reliable and accurate; however, disagreements sometimes occur in borderline cases, in tracings with much electrical ‘noise’ or in those where the transitions between different segments of the QRS complex are not well demarcated. A computerised e.c.g. interpretation system can help the cardiologist by providing all required measurements and most of the diagnostic statements. Thus, only review and validation of the processed tracings are needed. By continuously refining the program criteria based on the accumulated experience of many cardiologists, the reliability and acceptability of computer e.c.g. interpretations could be enhanced and expanded to screen large populations.     

Characteristics of fasting and fed myoelectric activity in rat small intestine: evaluation by computer analysis

Evaluation of gastrointestinal myoelectric activity has been limited by the assessment techniques and the complexity of the recorded myoelectric signal. Commonly, myoelectric activity is evaluated as motor patterns, which only gives a semiquantitative measure of myoelectric events within the bowel wall. Using myoelectric recordings from the proximal small intestine in rats, a computerized system for acquisition, storage, display and calculation of characteristics for the myoelectric activity was developed. The software was tested in myoelectric recordings from nine rats in fasting and fed states. All migrating myoelectric complexes (MMCs) during fasting and fed myoelectric patterns were recognized in both digital and analog recordings. Reproduction of myoelectric recordings by the computerized system was indistinguishable from that of the analog system. Employing an appropriate cut-off trigger level and a high sampling frequency, spike potentials were recorded in the proximal jejunum with 0.4 (0.3–0.5) spikes 10 s^-1 during phase 1 of MMC, 19.5 (15.1–23.9) (P<0.001) during phase 2, and 103.8 (97.2–110.5) (P<0.001) during phase 3. In fasted state, MMCs were most frequent in the proximal jejunum whereas fewer were found in the duodenum and distal jejunum. To achieve stable values for MMC cycle length at least four MMCs had to be calculated. After feeding in phase 1, the myoelectric activity increased to 23.8 (13.6–33.9) spikes 10 s^-1 (P< 0.001), whereafter the spiking activity decreased over a period of 2 h until a fasting motor pattern was resumed. It is concluded that computerized technology enables evaluation not only of myoelectric patterns, but also of spiking activity per time unit, i.e. the intensity of myoelectric activity in the gut.     

Nasal airflow measurement using a compensated thermistor anemometer

A nasal anemometer is a useful tool for speech therapists in their assessment of treatment effectiveness. This work is the second part of a research scheme which describes how the system is compatible with the use of an IBM PC-AT microcomputer using a suitable analogue-to-digital convertor. This enables the system to perform signal processing and to display, draw, and calculate a numerical ‘figure of merit’ using Kendall's tau nonparametric correlation.     

Reasons women give for abortion: a review of the literature

The aim was to identify from empirical research that used quantitative or qualitative methods the reasons women give for having an abortion. A search was conducted of peer-reviewed, English language publications indexed in eight computerized databases with publication date 1996–2008, using keywords ‘abortion’ and ‘reason’ (Medline: ‘induced abortion’ OR ‘termination of pregnancy’ OR ‘elective abortion’ and ‘reason’). Inclusion criteria were empirical research on humans that identified women’s reasons for undergoing an abortion, conducted in ‘high-income’ countries. 19 eligible papers were found. Despite variation in methods of generating, collecting, and analysing reasons, and the inadequacy of methodological detail in some papers, all contributed to a consistent picture of the reasons women give for having an abortion, with three main categories (‘Woman-focused’, ‘Other-focused’, and ‘Material’) identified. Ambivalence was often evident in women’s awareness of reasons for continuing the pregnancy, but abortion was chosen because continuing with the pregnancy was assessed as having adverse effects on the life of the woman and significant others. Women’s reasons were complex and contingent, taking into account their own needs, a sense of responsibility to existing children and the potential child, and the contribution of significant others, including the genetic father.     

Wearable unrestraining footprint analysis system. Applications to human gait study

The paper describes an original wearable plantar dynamics analysis system, which puts subjects under particularly unrestraining walking conditions. It is based on foot-pressure distribution measurement in soft, thin, but reliable multisensor soles composed of 2×127 barosensitive cells. The system was applied to gait and posture studies of ten nonpathologic subjects. Specific computing and graphic programs were developed for gait analysis and clinical applications. Online visualisation of footprints allowed the operator to monitor the experiments. Because of human gait variability, data were collected over a prolonged sequence, and a ‘mean step’ was statistically computed, which is more representative of individual walking. Initial graphic and numerical results confirm the value of the method and offer encouragement for further studies intended to define normal or pathologic gait patterns. The system included additional signal inputs for correlative studies with kinematic or physiological parameters.     

Mindful pregnancy and childbirth: effects of a mindfulness-based intervention on women’s psychological distress and well-being in the perinatal period

This pilot study explored the effects of an 8-week mindfulness-based cognitive therapy group on pregnant women. Participants reported a decline in measures of depression, stress and anxiety; with these improvements continuing into the postnatal period. Increases in mindfulness and self-compassion scores were also observed over time. Themes identified from interviews describing the experience of participants were: ‘stop and think’, ‘prior experience or expectations’, ‘embracing the present’, ‘acceptance’ and ‘shared experience’. Childbirth preparation classes might benefit from incorporating training in mindfulness.     

Evolutionarily conserved cytogenetic changes in hematological malignancies of dogs and humans – man and his best friend share more than companionship

The pathophysiological similarities shared by many forms of human and canine disease, combined with the sophisticated genomic resources now available for the dog, have placed ‘man’s best friend’ in a position of high visibility as a model system for a variety of biomedical concerns, including cancer. The importance of nonrandom cytogenetic abnormalities in human leukemia and lymphoma was recognized over 40 years ago, but the mechanisms of genome reorganization remain incompletely understood. The development of molecular cytogenetics, using fluorescence in situ hybridization (FISH) technology, has played a significant role in our understanding of cancer biology by providing a means for ‘interrogating’ tumor cells for a variety of gross genetic changes in the form of either numerical or structural chromosome aberrations. Here, we have identified cytogenetic abnormalities in naturally occurring canine hematopoietic tumors that are evolutionarily conserved compared with those that are considered characteristic of the corresponding human condition. These data suggest that humans and dogs share an ancestrally retained pathogenetic basis for cancer and that cytogenetic evaluation of canine tumors may provide greater insight into the biology of tumorigenesis.     

Haemostatic investigations: The impact of new technologies

Blood loss following trauma is controlled by a complex series of interactions involving the vascular surface, blood platelets and ‘activated’ coagulation factors. Activation of the coagulation cascade involves a series of zymogen to enzyme transformations with each enzyme associating with a co-factor on a ‘surface’ such as negatively charged platelet membrane phospholipid to form reaction complexes. In physiological terms it is possible that this system is continuously switched on producing low levels of activated serine proteases which are continuously being neutralised by protease inhibitors and co-factor neutralising reactions which down-regulate blood clotting processes, thus maintaining patency of the vascular tree. It is in this context that the concept of identifying molecular markers of haemostatic activation is well recognised. The haemostatic investigations now include biochemical and immunological investigations in order to detect small concentrations of products from intravascular thrombin generation, platelet-specific proteins released as a consequence of platelet release reaction, circulating activated clotting factors, activation peptides and ‘activated clotting factor-inhibitor’ complexes. This review will concentrate on new markers of haemostasis which are currently being used in the investigation of thrombosis.