Physiological comfort evaluation under different airflow directions in a heating environment.

BACKGROUND: Indoor airflow and thermal comfort are difficult to assess through subjective evaluations because airflow sensations can differ based on various factors, such as personal characteristics, interests, preferences, and the current state of mind. Thus, subjective evaluations should be combined with objective assessments, such as physiological measurements. This study evaluated airflow and thermal comfort through physiological measurements, including skin temperature, electroencephalography, respiration, and electrocardiography, in addition to subjective evaluations. METHODS: Twenty participants entered a test room at 30 °C after staying in an acclimation room at 18 °C for 20 min. They were exposed to indirect and direct airflow toward their faces and performed four tasks under each condition: resting, counting to 10 s following time alerts, counting to 10 s in the mind, and mental calculation. The mean speed of the air directed to the participants' faces was 0.123 m/s and 0.225 m/s in the indirect and direct conditions, respectively. RESULTS: The gamma and beta bands of electroencephalograms taken at the left-temporal (T3) and left-parietal (P7) sites showed significantly lower amplitudes under the indirect condition (gamma, T3: p = 0.034, P7: p = 0.030; beta, T3: p = 0.051, P7: p = 0.028). Similarly, the variability of respiration was lower under the indirect condition (p < 0.010). The amplitudes of gamma and beta waves showed significant correlations with anxiousness levels (gamma, T3: r = 0.41; beta, T3: r = 0.35). CONCLUSIONS: Our results suggest that indirect heating airflow causes lower mental stress and fatigue than those induced by direct flow, which is equivalent to more comfort. The results of this study suggest that physiological measurements can be used for the evaluation of unconscious indoor comfort, which cannot be detected by subjective evaluations alone.

Physiological and subjective comfort evaluation under different airflow directions in a cooling environment.

Indoor comfort is influenced by airflow direction, but subjective evaluations can differ. This study evaluates the airflow comfort with subjective assessments and physiological measurements, including skin temperature, electroencephalograms, and electrocardiograms. Nineteen participants entered a test room at 20°C after staying in a room at 32°C for acclimation. They were exposed to indirect and direct airflow conditions to their faces and performed four tasks under each condition: resting, counting to 10 s following time alerts, counting to 10 s in mind, and mental calculation. Subjective assessments showed relatively higher thermal sensation and pleasantness under indirect airflow. The psychological time calculated from counting behaviors was longer under indirect airflow, indicating suppression of negative emotions. The face temperatures significantly declined during experiments under direct airflow. The beta and gamma bands of electroencephalograms were inhibited under the indirect condition, and these amplitudes were negatively correlated with pleasant feelings. Electrocardiogram parameters indicated that sympathetic nervous activity was predominant during counting, following alerts and mental calculation in indirect airflow. This study supports the comfort of indirect airflow based on reliable evidence.

Continuous microfluidic DNA extraction using phase-transfer magnetophoresis.

This paper reports a novel microfluidic-chip based platform using "phase-transfer magnetophoresis" enabling continuous biomolecule processing. As an example we demonstrate for the first time continuous DNA extraction from cell lysate on a microfluidic chip. After mixing bacterial Escherichia coli culture with superparamagnetic bead suspension, lysis and binding buffers, DNA is released from cells and captured by the beads. These DNA carrying beads are continuously transported across the interfaces between co-flowing laminar streams of sample mixture, washing and elution buffer. Bead actuation is achieved by applying a time-varying magnetic field generated by a rotating permanent magnet. Flagella-like chains of magnetic beads are formed and transported along the microfluidic channels by an interplay of fluid drag and periodic magnetic entrapment. The turnover time for DNA extraction was approximately 2 minutes with a sample flow rate of 0.75 µl s(-1) and an eluate flow rate of 0.35 µl s(-1). DNA recovery was 147% (on average) compared to bead based batch-wise extraction in reference tubes within a dilution series experiment over 7 orders of magnitude. The novel platform is suggested for automation of various magnetic bead based applications that require continuous sample processing, e.g. continuous DNA extraction for flow-through PCR, capture and analysis of cells and continuous immunoassays. Potential applications are seen in the field of biological safety monitoring, bioprocess control, environmental monitoring, or epidemiological studies such as monitoring the load of antibiotic resistant bacteria in waste water from hospitals.

Efficient synthesis of 2,4,5-trisubstituted 2,5-chiral tetrahydropyridines using a one-pot asymmetric azaelectrocyclization protocol.

The stereocontrolled synthetic procedure for the preparation of 2,4,5-trisubstituted 2,5-chiral 1,2,5,6-tetrahydropyridines was established using a one-pot asymmetric azaelectrocyclization protocol; the generality of this protocol was demonstrated by synthesizing the title compounds with various aryl and alkenyl substituents at the C-2 position.

DNA molecule manipulation by motor proteins for analysis at the single-molecule level.

Massively parallel and individual DNA manipulation for analysis has been demonstrated by designing a fully self-assembled molecular system using motor proteins. DNA molecules were immobilized by trapping in a polyacrylamide gel replica, and were digested by a restriction enzyme, XhoI, for DNA analysis. One end of the lambdaDNA was modified with biotin and the other end was modified with digoxin molecules by fragment labeling and ligation methods. The digoxin-functionalized end was immobilized on a glass surface coated with anti-digoxigenin antibody. The biotinylated end was freely suspended and experienced Brownian motion in a buffer solution. The free end was attached to a biotinylated microtubule via avidin-biotin biding and the DNA was stretched by a kinesin-based gliding assay. A stretched DNA molecule was fixed between the gel and coverslip to observe the cleavage of the DNA by the enzyme, which was supplied through the gel network structure. This simple process flow from DNA manipulation to analysis offers a new method of performing molecular surgery at the single-molecule scale.