Chromosome map of the Siamese cobra: did partial synteny of sex chromosomes in the amniote represent “a hypothetical ancestral super-sex chromosome” or random distribution?

Background Unlike the chromosome constitution of most snakes (2n=36), the cobra karyotype shows a diploid chromosome number of 38 with a highly heterochromatic W chromosome and a large morphologically different chromosome 2. To investigate the process of sex chromosome differentiation and evolution between cobras, most snakes, and other amniotes, we constructed a chromosome map of the Siamese cobra (Naja kaouthia) with 43 bacterial artificial chromosomes (BACs) derived from the chicken and zebra finch libraries using the fluorescence in situ hybridization (FISH) technique, and compared it with those of the chicken, the zebra finch, and other amniotes. Results We produced a detailed chromosome map of the Siamese cobra genome, focusing on chromosome 2 and sex chromosomes. Synteny of the Siamese cobra chromosome 2 (NKA2) and NKAZ were highly conserved among snakes and other squamate reptiles, except for intrachromosomal rearrangements occurring in NKA2. Interestingly, twelve BACs that had partial homology with sex chromosomes of several amniotes were mapped on the heterochromatic NKAW as hybridization signals such as repeat sequences. Sequence analysis showed that most of these BACs contained high proportions of transposable elements. In addition, hybridization signals of telomeric repeat (TTAGGG)n and six microsatellite repeat motifs ((AAGG)8, (AGAT)8, (AAAC)8, (ACAG)8, (AATC)8, and (AAAAT)6) were observed on NKAW, and most of these were also found on other amniote sex chromosomes. Conclusions The frequent amplification of repeats might involve heterochromatinization and promote sex chromosome differentiation in the Siamese cobra W sex chromosome. Repeat sequences are also shared among amniote sex chromosomes, which supports the hypothesis of an ancestral super-sex chromosome with overlaps of partial syntenies. Alternatively, amplification of microsatellite repeat motifs could have occurred independently in each lineage, representing convergent sex chromosomal differentiation among amniote sex chromosomes

Quantitative assessment of walking time and postural change in patients with COPD using a new triaxial accelerometer system

Atsuyoshi Kawagoshi,1,2 Noritaka Kiyokawa,2 Keiyu Sugawara,2 Hitomi Takahashi,2 Shunichi Sakata,3 Saori Miura,4 Sachie Sawamura,5 Masahiro Satake,1 Takanobu Shioya1 1Department of Physical Therapy, Akita University Graduate School of Health Sciences, Akita, 2Department of Rehabilitation, Akita City Hospital, Akita, 3Kumamoto Technology and Industry Foundations, Kumamoto, 4Department of Rehabilitation, Saitama Medical University, Saitama, 5Department of Rehabilitation, Research Institute for Brain and Blood Vessels-Akita, Akita Prefecture Hospital Organization, Akita, Japan Background: The purpose of this study was to quantify the walking time and frequency of postural changes in daily life in patients with chronic obstructive pulmonary disease (COPD) using a new triaxial accelerometer system. Methods: Twenty-six elderly patients with stable COPD (age 76.8 &plusmn; 6.2 years; percent forced expiratory volume in one second [%FEV1] 52.9% &plusmn; 26.3%) and 20 age-matched elderly subjects (age 73.0 &plusmn; 4.2 years; %FEV1 124.0% &plusmn; 22.3%) participated in the study. The subjects&rsquo; time spent walking (slow, fast), standing, sitting, and lying down and the frequency of their postural changes (getting up, standing up) were assessed for 7 consecutive days using an Activity Monitoring And Evaluation System (A-MES&trade;). We analyzed the relationships among walking times, frequency of postural changes, and physiologic factors in both COPD patients and controls. Results: The COPD patients&rsquo; total walking time, including slow (<2 km/hour) and fast (&ge;2 km/hour) walking, and their frequency of standing up were significantly lower than those of the age-matched controls (P < 0.01). The fast walking time in daily life was significantly correlated with the 6-minute walking distance, quadriceps femoris muscle force, and dyspnea (P < 0.01). Conclusion: These results suggest that both slow (<2 km/hour) and fast (&ge;2 km/hour) walking time and frequency of postural changes is significantly decreased in COPD patients compared with healthy elderly subjects. The data also suggest that the COPD patients&rsquo; different walking times in daily life are significantly correlated with exercise capacity and dyspnea. The 6-minute walking distance had the strongest correlation with fast walking time. Keywords: slow walking, fast walking, frequency of postural changes, chronic obstructive pulmonary disease, triaxial acceleromete

Energy dissipation in hydraulic jumps on horizontal rough beds

Hydraulic jump is an important phenomenon for hydraulic engineers. It has received a significant attention since last century, as it usually occurs in correspondence with hydraulic structures. In river restoration projects, it is quite usual to protect the stilling basin bed with coarse materials. Therefore, a correct assessment of the hydraulic jump properties on rough beds assumes a fundamental importance in the perspective of a correct management of rivers rehabilitation. In particular, hydraulic jump can be used as an efficient and economic energy dissipater. Nevertheless, there is still a lack of knowledge on the energy dissipation process in the presence of rough beds in different relative roughness conditions. Therefore, the present paper aims to analyze the effects of both relative roughness and inflow Froude number on the energy dissipation in a large range of bed configurations. Four different bed materials were tested and a useful relationship was derived to predict the dissipative phenomenon

Dynamic hyperinflation and dyspnea during the 6-minute walk test in stable chronic obstructive pulmonary disease patients

Masahiro Satake,1 Takanobu Shioya,1 Sachiko Uemura,1 Hitomi Takahashi,2 Keiyu Sugawara,2 Chikage Kasai,2 Noritaka Kiyokawa,2 Toru Watanabe,2 Sayaka Sato,2 Atsuyoshi Kawagoshi2 1Department of Physical Therapy, Akita University Graduate School of Health Sciences, Akita, Japan; 2Department of Rehabilitation, Akita City Hospital, Akita, Japan Abstract: The purpose of this study was to investigate the relationship between dynamic hyperinflation and dyspnea and to clarify the characteristics of dyspnea during the 6-minute walk test (6MWT) in chronic obstructive pulmonary disease patients. Twenty-three subjects with stable moderate chronic obstructive pulmonary disease (age 73.8&plusmn;5.8 years, all male) took part in this study. During the 6MWT, ventilatory and gas exchange parameters were measured using a portable respiratory gas analysis system. Dyspnea and oxygen saturation were recorded at the end of every 2 minute period during the test. There was a significant decrease in inspiratory capacity during the 6MWT. This suggested that dynamic hyperinflation had occurred. Dyspnea showed a significant linear increase, and there was a significant negative correlation with inspiratory capacity. It was suggested that one of the reasons that dyspnea developed during the 6MWT was the dynamic hyperinflation. Even though the tidal volume increased little after 2 minutes, dyspnea increased linearly to the end of the 6MWT. These results suggest that the mechanisms generating dyspnea during the 6MWT were the sense of respiratory effort at an early stage and then the mismatch between central motor command output and respiratory system movement. Keywords: field walking test, chronic respiratory diseases, respiratory gas analysis, inspiratory capacity, IC, inspiratory reserve volume, IRV, Borg CR-10 scale, COP