Effects of player-video game interaction on the mental effort of older adults with the use of electroencephalography and NASA-TLX.

While player-video game interaction appears to affect older adults in gaming, there is limited knowledge regarding the cognitive demands associated with the anticipation of performing a button press, specifically focusing on the input and game elements relation (I/E relation) in game environments. The study aims to investigate the effects of lateral and rotational displacement amplitudes of game elements, triggered by a single button-press, on the cognitive effort of older adults. Both subjective and objective measurement methods were employed to assess these effects. A total of 48 older adults participated in three casual video game tasks encompassing lateral and rotational displacements at varying I/E relations (low, medium, and high). Results obtained from the NASA Task Load Index and electroencephalography (EEG) measurements revealed significant differences between the I/E relations. Specifically, the subjective rating of cognitive demand among older players was significantly impacted by a small rotation angle associated with a button press, leading to increased mental, physical, and temporal demands, along with decreased performance. Surprisingly, the analysis of EEG data, particularly the theta-alpha ratio, revealed significant interaction effects of I/E relations, button press type, and game type on the cognitive demand required during gameplay. These findings offer practical implications and point towards future avenues for developing player-video game interactions that are more cognitively friendly for older players in gaming environments.

Effects of photopic and cirtopic illumination on steady state pupil sizes.

The conventional view was that cones are responsible for pupil constriction in photopic lighting conditions. With the discovery of intrinsically photosensitive retinal ganglion cells (ipRGC), it was found that signals from ipRGCs along with cones mediated the pupil light reflex in photopic lighting conditions. Although both signals contributed, it was unclear how these signals were summed. In the work reported here, steady-state pupil size was measured with an infrared camera under LED lighting conditions with different color temperatures and luminance. A formula was then derived for pupil size according to the linear summation of cirtopic and photopic luminance. This formula allowed direct calculations to predict pupil size well when LED photopic luminance ranged from about 50cd/m2 to 300cd/m2, which is the general luminance level range for computer and smartphone screens.

An interpenetrating network composite for a regenerative spinal disc application.

Severe degeneration of the intervertebral disc has an immensely debilitating effect on quality of life that has become a serious health and economic burden throughout the world. The disc plays an integral role in biomechanical movement and support within the spine. The emergence of tissue engineering endeavours to restore the structural characteristics and functionality of the native tissue. Hydrogels have been widely investigated as a candidate for regeneration of the gelatinous nucleus pulposus due to its architectural resemblance and fluid retention characteristics. However, hydrogels are often limited due to small compressive stiffness and tear resistance, leading to extrusion complications. Reinforcement of the hydrogel network using polymeric scaffolds may address these issues of inadequate mechanical properties and implant instability. This study investigates the potential of a carrageenan gel-infused polycaprolactone scaffold for nucleus pulposus tissue engineering. Mechanical properties were characterised using viscoelastic and poroelastic frameworks via microindentation. The incorporation of polymeric reinforcement within the gels increased material stiffness to that comparable to the native nucleus pulposus, however permeability was significantly greater than native values. A preliminary cell evaluation culturing NIH 3T3s over 21 days suggested the incorporation of polymeric networks also enhanced cellular proliferation compared to gels alone.

Majorana transport in superconducting nanowire with Rashba and Dresselhaus spin-orbit couplings.

The tunneling experiment is a key technique for detecting Majorana fermion (MF) in solid state systems. We use Keldysh non-equilibrium Green function method to study two-lead tunneling in superconducting nanowire with Rashba and Dresselhaus spin-orbit couplings. A zero-bias dc conductance peak appears in our setup which signifies the existence of MF and is in accordance with previous experimental results on InSb nanowire. Interestingly, due to the exotic property of MF, there exists a hole transmission channel which makes the currents asymmetric at the left and right leads. The ac current response mediated by MF is also studied here. To discuss the impacts of Coulomb interaction and disorder on the transport property of Majorana nanowire, we use the renormalization group method to study the phase diagram of the wire. It is found that there is a topological phase transition under the interplay of superconductivity and disorder. We find that the Majorana transport is preserved in the superconducting-dominated topological phase and destroyed in the disorder-dominated non-topological insulator phase.

Task factor usability ratings for different age groups writing Chinese.

This study evaluated how different task factors affect performance and user subjective preferences for three different age groups of Chinese subjects (6-11, 20-23, 65-70 years) when hand writing Chinese characters. The subjects copied Chinese character sentences with different settings for the task factors of writing plane angle (horizontal 0 degrees , slanted 15 degrees ), writing direction (horizontal, vertical), and line spacing (5 mm, 7 mm and no lines). Writing speed was measured and subjective preferences (effectiveness and satisfaction) were assessed for each of the task factor settings. The result showed that there was a conflict between writing speed and personal preference for the line spacing factor; 5 mm line spacing increased writing speed but it was the least preferred. It was also found that: vertical and horizontal writing directions and a slanted work surface suited school-aged children; a horizontal work surface and horizontal writing direction suited university students; and a horizontal writing direction with either a horizontal or slanted work surface suited the older adults.

The use of antibodies in the treatment of infectious diseases.

There is a long history of the use of antibodies in the treatment and prophylaxis of infectious diseases, because these molecules play a critical role in directing the effector mechanisms of the immune system against the pathogens they recognise. However, the widespread application of this therapy has been hampered by allergic reactions, production costs and the availability of alternative drugs such as antibiotics. Some of these obstacles can now be overcome with advances in biotechnology, which has enabled the development of antibody-based drugs for use first in treating cancer, and recently, for treating infectious diseases. The efficacy of such antibodies has been demonstrated in various in vitro studies, animal models and clinical trials for a variety of both viral and bacterial pathogens. Antibodies appear to hold great promise as a new class of drugs against infectious diseases.

A study of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in the livestock waste compost of Hong Kong, PR China.

Composting is one of the waste disposal methods adopted for disposal of livestock waste in Hong Kong. The composting livestock waste normally undergoes 6-8 weeks fermentation, followed by 16-20 weeks maturation. The matured compost is sold as soil conditioner in the local market. In 2006, feedstock material and a time-series of compost samples were collected throughout the fermentation and maturation process from the Sha Ling Composting Plant in the New Territories. The feedstock material and compost samples were analyzed for contents of three unintentional persistent organic pollutants (POPs), i.e. dioxins/furans, dioxin-like PCBs and total PCBs. These POPs are unintentionally produced by-products of chemical industrial processes and combustion processes. Selected heavy metals were also analyzed, which served as conservative tracers to determine potential mass loss during the composting process. Levels of contamination by these POPs were found to be low in the matured compost for sale. The mean concentrations (lower-upper bound) of total dioxins/furans, total dioxin-like PCBs and total PCBs were 2.01-2.05 ng I-TEQ/kg dw, 0.04-0.05 ng WHO-TEQ/kg dw and 1.55-1.55 microg/kg dw, respectively. Progressively elevated levels of these POPs were observed in the compost samples during the fermentation process. Analysis of the congener profiles revealed that the heptaCDD and octaCDD were the main contributors to the observed increase in dioxin/furan content. The possible sources of dioxins/furans in the compost were discussed. The study results established a local dioxins/furans emission factor specific to the trade and provided a better estimate of the annual dioxins/furans emission for the livestock waste composting activity in Hong Kong.

PRG4 exchange between the articular cartilage surface and synovial fluid.

The boundary lubrication function of articular cartilage is mediated in part by proteoglycan 4 (PRG4) molecules, found both in synovial fluid (SF) and bound to the articular cartilage surface. Currently the mechanism by which PRG4 binds to the articular surface is not well understood. The objectives of this study were to determine (1) the effect of bathing fluid contents on PRG4 concentration at the articular surface ([PRG4](cart)), and (2) whether native PRG4 can be removed from the surface and subsequently repleted with PRG4 from synovial fluid. In one experiment, cylindrical cartilage disks were stored in solutions of various PRG4 concentrations, either in phosphate-buffered saline (PBS) or SF as the carrier fluid. In a separate experiment, cartilage disks were stored in solutions expected to remove native PRG4 from the articular surface and allow subsequent repletion with PRG4 from SF. [PRG4](cart) was independent of PRG4 concentration of the bathing fluid, and was similar for both carrier fluids. PRG4 was removed from cartilage by treatment with hyaluronidase, reduction/alkylation, and sodium dodecyl sulphate, and was repleted fully by subsequent bathing in SF. These results suggest that the articular surface is normally saturated with tightly bound PRG4, but this PRG4 can exchange with the PRG4 in SF under certain conditions. This finding suggests that all tissues surrounding the joint cavity that secrete PRG4 into the SF may help to maintain lubrication function at the articular surface.

Effects of different task factors on speed and preferences in Chinese handwriting.

This study was conducted to determine the speed of Chinese handwriting and explore the effects of the task factors, tool type, paper texture, writing plane angle, and line spacing on writing speed and subjective preferences. The results showed that the average duration of writing a 9-stroke character was 1487 ms. Paper texture and line spacing had a significant effect on production speed. Uncoated paper and 3 mm-line spacing enhanced writing speed. Subjects had clear preferences for writing with a pen, on uncoated paper, in a horizontal plane, and with relatively wide line spacing (5 mm/7 mm/lineless). There was a conflict between writing speed and personal preference on the line spacing factor. Although narrow line spacing (3 mm) increased writing speed, it was not preferred by the subjects over wider spacing on the evaluation attributes of comfort, ease, fatigue, and overall preference. To take a balance between writing speed and personal preference, a line spacing of at least 5 mm is recommended.

Photocatalytic thin film cascade reactor for treatment of organic compounds in wastewater.

The photocatalytic oxidation of benzoic acid was investigated in a pilot scale-cascade photoreactor. The photoreactor consists of an array of UV lamps (40 W, 365 nm) illuminating a cascade of three inclined 316 stainless steel plates, on which titanium dioxide (TiO2) was immobilized by electrophoretic deposition. The percentage removal of total organic carbon (TOC) of liquid samples was determined. The photocatalytic process was affected by several operating parameters. Increasing the solution temperature was found to reduce the dissolved oxygen (DO) level and to decrease the rate of the degradation process. The Langmuir-Hinshelwood equation was found to be accurate for modeling the degradation of benzoic acid with initial concentrations of 50 ppm, 75 ppm and 100 ppm. The rate of removal of TOC was positively affected by UV light intensity, but appeared to be independent of solution flowrate in the range examined. Control experiments confirmed that the effects of adsorption of the solute onto the TiO2 catalysts and photolytic degradation were negligible.

Molecular cloning and characterization of a RING-H2 finger protein, ANAPC11, the human homolog of yeast Apc11p.

Yeast Apc11p together with Rbx1 and Roc2/SAG define a new class of RING-H2 fingers in a superfamily of E3 ubiquitin ligases. The human homolog of Apc11p, ANAPC11 was identified during a large-scale partial sequencing of a human liver cancer cDNA library and partial characterization was performed. This 514 bp full-length cDNA has a predicted open reading frame (ORF) encoding 84 amino acids. The ORF codes for ANAPC11, the human anaphase promoting complex subunit 11 (yeast APC11 homolog), which possesses a RING-H2 finger motif and exhibits sequence similarity to subunits of E3 ubiquitin ligase complexes. In Northern blot hybridization with poly(A) RNA of various human tissues using radio-labelled ANAPC11 cDNA probe, we found strong signals detected in skeletal muscle and heart; moderate signals detected in brain, kidney, and liver; and detectable but low signals in colon, thymus, spleen, small intestine, placenta, lung, and peripheral blood leukocyte. The ANAPC11 gene is located at the human chromosome 17q25. ANAPC11 is distributed diffusely in the cytoplasm and nucleus with discrete accumulation in granular structures in all the cell lines (AML 12, HepG2, and C2C12) transfected. Expression level of ANAPC11 is found higher in certain types of cancer determined in the RNA dot blot experiment.

Safety and ergonomics evaluation of hybrid systems in Hong Kong.

This study is aimed at understanding common safety and ergonomics problems with robot installation in Hong Kong. Information was collected through direct observations and personal interviews with robot users from advanced hybrid manufacturing systems. The application areas of robots and types of safety devices employed were investigated. The ages, types of jobs, daily working hours and working conditions of personnel were examined. Fire precaution measures, types and varieties of training programs for users were analyzed. The results showed that although investments were made for installation of robots for improving production activity, limited attention was paid to the health, safety, and ergonomics aspects in the hybrid systems. There were also cases reported where no formal guidelines for robot manipulation and operation were provided. It seems that management and users paid attention to robot function and capability more than robot safety during robotization process. Conclusions were made by the authors that efforts should immediately be made to adopt recommendations on the safety devices and facilities and training requirements for improving users' health and safety before fatal accidents occur.

Influence of photodynamic therapy on immunological aspects of disease - an update.

Photodynamic therapy (PDT) utilises light-absorbing compounds combined with directed photo-irradiation to produce clinical effects. This review updates advances in the understanding of the biochemical pathways triggered by PDT within cells, its influence upon different immune parameters and progress in the use of PDT against human immune-mediated disease. Several works have further defined the notable capacity of PDT to foster anticancer immunity.

Cardiopulmonary exercise testing in heart transplant candidates.

INTRODUCTION: We evaluated the results of patients with congestive heart failure (CHF) who underwent cardiopulmonary exercise testing (CPET) as part of their assessment for heart transplantation in order to examine the relationship between exercise capacity and resting indices of left ventricular function in these patients. MATERIALS AND METHODS: Twenty-seven ambulatory heart transplant candidates underwent CPET using a cycle ergometer and an incremental work-rate protocol till symptom-limitation. These patients included 24 men and 3 women with a mean age of 42.3 years. The aetiology of CHF was coronary artery disease in 14 patients, dilated cardiomyopathy in 11 patients, and congenital heart disease in 2 patients. Mean resting left ventricular ejection fraction (LVEF) was 19% (range 7% to 36%). RESULTS: Thirteen of the 27 tests performed were maximal studies and all except 2 subjects attained a measurable anaerobic threshold during CPET. Of the 13 maximal tests, the causes of exercise limitation were cardiomyopathy in 3 patients, ischaemic heart disease in 2 patients, significant oxygen desaturation in 2 patients, ventilatory limitation due to obstructive lung disease in 1 patient, ventilatory limitation secondary to a restrictive lung disease in 3 patients, and combined obstructive ventilatory and cardiovascular limitation in 2 patients. There was no significant correlation between resting LVEF and peak VO2 percent predicted (r = 0.14, P = 0.49). CONCLUSIONS: Exercise intolerance in patients with CHF may not be related to limited cardiac reserve and non-cardiac causes of exertional symptoms should also be considered. CPET is useful for the evaluation of functional capacity and mechanisms of exercise intolerance in patients with CHF.

Consequences of the photodynamic treatment of resting and activated peripheral T lymphocytes.

The impact of the immunomodulatory photosensitizer benzoporphyrin derivative monoacid ring A (BPD-MA, verteporfin) and visible light on the survival and surface receptor pattern of resting and activated murine T cells was evaluated. T cells treated for 48 h with immobilized anti-CD3 monoclonal antibody upregulated expression of the interleukin-2 receptor alpha-chain (CD25), transferrin receptor (CD71), the apoptosis-regulating Fas receptor (CD95), contained a greater level of the anti-apoptotic protein Bcl-2 and accumulated significantly more BPD-MA than their unactivated counterparts. Activated T cells displayed a modestly greater susceptibility to the photodynamic induction of DNA fragmentation than resting T cells. Resting T cells treated with sub-lethal levels of BPD-MA and light did not exhibit changes in surface levels of CD3, CD4, CD8, CD28, CD45 or T cell receptor (TCR) beta-chain structures. However, levels of major histocompatibility complex (MHC) class I antigens were decreased while the density of Thy-1.2 (CD90) increased on these cells. Photodynamically treated T cells failed to express optimal CD25 levels when exposed to the mitogenic anti-CD3 antibody. Activated T cells treated with sub-lethal levels of BPD-MA and light exhibited lower CD25 levels, a temporary block in cell cycle transition, but unaltered expression of MHC Class I, CD3, CD4, CD8, CD45, CD54, CD71, CD122 (IL-2R beta-chain) or TCR beta-chain antigens 24 h afterward. Resting and activated T lymphocytes differ in susceptibility to PDT-mediated apoptosis but both types are sensitive to anti-proliferative effects the treatment exerts at sub-lethal photosensitizer levels. The marked sensitivity of activated T cells to photodynamic inactivation likely contributes to the immunomodulatory action of BPD-MA.

Photodynamic therapy and immunity.

Photodynamic therapy (PDT) is widely recognized as a technique with which to treat malignant tumors that are accessible to an activating light source. PDT utilizes light absorbing compounds that catalyse the formation of cytotoxic oxygen species to produce the antitumor effect subsequent to direct light irradiation. PDT also exhibits immunomodulatory attributes. The photodynamic treatment of solid tumors triggers a large influx of granulocytes and macrophages into the region, leading to T-cell mediated anti tumor immunity against residual cancer. In apparent contrast, the application of levels of light less than those required for tumor ablation and over a larger body surface lessened disease severity when applied in murine autoimmune models. Furthermore, PDT is inhibitory for immunologically-mediated reactions to topically applied chemical haptens. The capacity of PDT to influence immune responses appears related to its capacity to target activated T lymphocytes as well as influence the immunostimulatory attributes of antigen presenting cells.

Revising and validating the random search model for competitive search.

A random search model was fit to a total of 2592 visual search times on a single-target detection task. By using a competing homogeneous background and uniform stimulus material, specifying viewing distance, controlling the presentation of search task material, and eliminating some options for extreme search strategies, very high correlation coefficients were found when a random search model was fit to both the individual data and to pooled data. A response time parameter was incorporated into the traditional random-search model and very good predictions of search performance were obtained.

Inhibition of contact hypersensitivity with different analogs of benzoporphyrin derivative.

Four structural analogs of benzoporphyrin derivative (BPD), a potent anti-tumor photosensitizer, were evaluated for their capacity to influence the immunologically-mediated contact hypersensitivity (CHS) response against the hapten 2,4-dinitrofluorobenzene (DNFB). Immunocompetent hairless strain mice received BPD monoacid ring A (BPD-MA, verteporfin) and returned to normal housing conditions or treated with 690 nm red light (transcutaneous photodynamic therapy, PDT). Unexpectedly, we found that mice given BPD-MA exhibited significantly reduced CHS ear swelling responses to DNFB upon antigenic challenge, whether or not they had been treated with PDT. A significant reduction in the CHS response to DNFB was observed when BPD-MA or PDT was given 48 or 24 h prior to, on the same day, or 24 or 72 h after DNFB sensitization. However, the magnitude of the CHS response was unaffected if these treatments were given 96 h after DNFB sensitization, 24 h before challenge with DNFB. Significantly reduced CHS responses also occurred in Balb/c mice given BPD-MA with or without PDT. Mice given BPD-MA but retained in total darkness throughout the experimental period generated full-fledged ear swelling responses to DNFB indicating that CHS suppression with BPD-MA was light dependent. BPD monoacid ring B (BPD-MB) strongly reduced the CHS response of Balb/c mice kept under ambient light while BPD diacid ring A (BPD-DA) and BPD diacid ring B (BPD-DB) also lowered the CHS response but were less effective than the monoacid forms. Other photosensitizers including Photofrin, tin etiopurpurin, and zinc phthalocyanine did not alter the CHS response of Balb/c mice maintained under ambient light. The ability of different BPD analogs to inhibit the CHS response in mice held under ambient light conditions appears related to the potent photosensitizing activity of these compounds.

Expression of an abnormal sized c-kit transcript in Hong Kong Chinese acute lymphoblastic leukaemia patients.

Blast cells from a majority of acute myelogenous leukaemia (AML) patients express c-kit mRNA. However, c-kit expression has not been observed in patients with acute lymphoblastic leukaemia (ALL) and lymphoproliferative disease. We report here the detection of an abnormal sized c-kit mRNA in two Hong Kong Chinese patients with pre-B ALL and common ALL.

Transcutaneous photodynamic therapy alters the development of an adoptively transferred form of murine experimental autoimmune encephalomyelitis.

Transcutaneous photodynamic therapy (PDT), utilizing benzoporphyrin derivative monoacid ring A (BPD, verteporfin) and whole-body light exposure, was assessed for its capacity to modify the course of adoptively transferred experimental autoimmune encephalomyelitis (EAE) in PL mice. Using a novel cell culture technique to facilitate the induction of this neurodegenerative condition, disease signs commenced 3-4 weeks after the transfer of myelin basic protein (MBP)-reactive lymph node or spleen cells to naive syngeneic recipients. Mice administered MBP-sensitized lymph node cells preincubated with BPD followed by whole-body 690 nm light irradiation (15 J/cm2) did not display symptoms of EAE. Although almost all animals given MBP-sensitized spleen cells developed EAE, mice given BPD (1 mg/kg) and the light treatment 24, 48 or 120 h after spleen cell transfer exhibited significantly less severe disease symptoms than control animals. Mice given the photodynamic treatment 24 h after spleen cell transfer also exhibited a significantly later disease onset than the control animals. Treatment of mice with PDT 24 h prior to spleen cell transfer did not influence subsequent disease severity but modestly delayed its onset. In the absence of directed light, BPD did not influence the development of EAE. Spinal cord tissues were evaluated for the presence of T cell receptor (TCR) V alpha 4 mRNA transcripts that specifically encode for the TCR alpha-chain of MBP-reactive T cells of PL mice. Using the polymerase chain reaction, V alpha 4 TCR mRNA transcripts were present in spinal cord samples prepared from almost all control mice but in only about one-half of spinal cord samples prepared from mice treated with PDT 24 h after spleen cell transfer. These observations indicated that PDT had limited the expansion of MBP-specific V alpha 4+ T cells within the central nervous system. Transcutaneous PDT represents a new technique with which to approach the treatment of autoimmune disease.