The present study investigated whether exposure to aromas during recess periods affects work performance. Subjects comprised 36 healthy male students (mean age, 24.2 +/- 2.2 years) who were randomly divided into three groups: (1) control group, not exposed to aroma during recesses; (2) jasmine group, exposed to jasmine aroma during recesses; and (3) lavender group, exposed to lavender aroma during recesses. All participants completed five work sessions performing a task requiring concentration on a computer monitor, with each session lasting 60 min. Recess periods of 30 min were provided between each session. To clarify the time at which work concentration was lowest, work performance for the control group was analyzed. Concentration was lowest in the afternoon period, where afternoon drowsiness is strongest. Comparison of the three groups for this time period indicated significantly higher concentration levels for the lavender group than for the control group. No such effect was noted for the jasmine group. Although lavender is a sedative-type aroma, use during recess periods after accumulation of fatigue seems to prevent deterioration of performance in subsequent work sessions.

No abstract

Plasmodium falciparum, a human malaria parasite, invades an erythrocyte during one stage of its life cycle. In an infected erythrocyte, the P. falciparum organism develops a membrane structure called the parasitophorus vacuolar membrane. The parasitophorus vacuolar membrane extends into the host cell cytoplasm and forms a complex membrane structure, thus called the tubovesicular membrane network (reviewed in Refs. 1-3). These membrane systems outside the P. falciparum cell are important for the transport of various nutrients such as glucose, phospholipids, and amino acids and for extrusion of antimalarial agents so as to maintain suitable circumstances for them (3-6). In addition to the formation of such intraerythrocytic membrane systems, P. falciparum cells also transport some proteins such as erythrocyte membrane protein-1 of P. falciparum (PfEMP1) 1 and PfEMP3 to the erythrocyte plasma membrane, which results in the formation of a knob-like structure on the surfaces of the infected erythrocytes. These proteins are responsible for protection against immunological attack and attachment of infected erythrocyte to endothelial cells, one of the crucial steps for cerebral malaria (1-3, 7-11). Importantly, the extraparasite protein transport process can not rely upon the endogenous transport machinery in the host cells, because mature erythrocytes are completely devoid of machinery for protein trafficking. Thus, the malaria parasite must transport proteins through the plasma membrane and the membrane structure in the cytoplasm of the host cells by means of their own mechanism, although the molecular pathway for the transport of proteins through the parasite plasma membrane is less understood.It has been shown that the transport of some proteins from malaria parasites is sensitive to BFA (12-16), which is a well known macrolide antibiotic produced by fungi that blocks eukaryotic protein trafficking processes, especially transport from the endoplasmic reticulum to the Golgi apparatus by inhibiting the activities of ADP-ribosylation factors and guanine nucleotide exchange factors (17). These results suggest that the transport pathway from the endoplasmic reticulum to the Golgi apparatus is involved in the targeting of parasite

The expansion of protein sequence databases has enabled us to design artificial proteins by sequence-based design methods, such as full-consensus design (FCD) and ancestral-sequence reconstruction (ASR). Artificial proteins with enhanced activity levels compared with native ones can potentially be generated by such methods, but successful design is rare because preparing a sequence library by curating the database and selecting a method is difficult. Utilizing a curated library prepared by reducing conservation energies, we successfully designed two artificial l-threonine 3-dehydrogenases (SDR-TDH) with higher activity levels than native SDR-TDH, FcTDH-N1, and AncTDH, using FCD and ASR, respectively. The artificial SDR-TDHs had excellent thermal stability and NAD recognition compared to native SDR-TDH from Cupriavidus necator (CnTDH); the melting temperatures of FcTDH-N1 and AncTDH were about 10 and 5 °C higher than that of CnTDH, respectively, and the dissociation constants toward NAD of FcTDH-N1 and AncTDH were 2- and 7-fold lower than that of CnTDH, respectively. Enzymatic efficiency of the artificial SDR-TDHs were comparable to that of CnTDH. Crystal structures of FcTDH-N1 and AncTDH were determined at 2.8 and 2.1 Å resolution, respectively. Structural and MD simulation analysis of the SDR-TDHs indicated that only the flexibility at specific regions was changed, suggesting that multiple mutations introduced in the artificial SDR-TDHs altered their flexibility and thereby affected their enzymatic properties. Benchmark analysis of the SDR-TDHs indicated that both FCD and ASR can generate highly functional proteins if a curated library is prepared appropriately.

No abstract

Five healthy adult women aged 20 to 28 had 12-15 polysomnographic recordings, as well as daily basal body temperature and multiple LH, FSH, estrogen and progesterone measurements taken during a single menstrual cycle. Sleep stages were scored both visually and with a spindle and delta-wave, real-time, automatic analysing system. A cubic growth-curve model showed that the frequency of sleep spindles changed markedly over the menstrual cycle: spindle frequency was lowest about 18 days before onset of menses and highest 3 days before onset of menses. Slow waves did not change. The percentages of Stage 1 and REM sleep showed small changes during the menstrual cycle, and other parameters of visually scored sleep showed no tendency to change. Spindle frequency may reflect the effects of sex hormones on the reticular thalamic nucleus and may be a quantitative marker of premenstrual sleep disturbances.

The active form of vitamin B12 (methylcobalamin) has been reported to be effective on sleep‐wake rhythm disorders. Previous studies, however, were performed under open trial, and the effect of vitamin B12 has not been properly evaluated. The aim of this double‐blind study was to investigate the efficacy of methylcobalamin on delayed sleep phase syndrome (DSPS). Methylcobalamin (3 mg/day) or placebo was administered for 4 weeks. The subjects were 50 patients with DSPS aged 13–55 years (26.8 ± 1.3), 27 of whom received the active drug while 23 received the placebo. No significant differences were observed between the 2 groups in subjective evaluations of mood or drowsiness during the daytime or in night sleep by sleep‐log evaluation. These results indicate that 3 mg methylcobalamin administered over 4 weeks is not an effective treatment for DSPS.

Twenty-five young people (Y group), three elderly people and seven people with various sleep disorders (SD group) kept a sleep log for 2-7 days, and their wrist-activity was monitored simultaneously. The sensitivity and specificity of the sleep log, and the ratio of agreement between the sleep log and actigraphic sleep-wake state were calculated. The sensitivity and specificity in Y group were 87.93 ± 6.49% and 96.51 ± 2.37%, respectively. The sensitivity in SD group was significantly lower than in Y group. Even in Y group one-hour agreement ratios dropped during the sleep onset period.