258 research outputs found
Ergosterol Effect on the Desaturation of 14C-Cis-Vaccenate in Tetrahymena
Supplement of ergosterol to the growth medium of the ciliated protozoan Tetrahymena pyriformis W leads to incorporation of the foreign sterol within cell membranes and suppression of synthesis of the native sterol-like compound tetrahymanol, as well as to changes in the fatty acid compositions of several major classes of membrane lipid. Alteration of fatty acid composition is thought to represent a regulatory mechanism whereby optimum membrane fluidity is maintained when the slightly dissimilar foreign sterol is added into the phospholipid bilayer of the membranes.
The present study, using several different conditions of growth temperature, substrate concentrations and incubation time, and ergosterol concentrations and exposure time, is an attempt to provide evidence supporting a hypothetical regulatory mechanism. This mechanism proposes that there is a feedback regulation by membrane-bound sterol on an enzyme or enzymes involved in synthesis of the long chain fatty acids contained in membrane phospholipid. Such a mechanism could account for the balance between sterol and fatty acid content of membrane. The data presented here show that a statistically significant increase in desaturation of 14C-cis-vaccenate can be demonstrated in Tetrahymena cell cultures whose membranes contain the foreign sterol, when growth temperature is maintained at 20° or 29.5°.
Tetrahymena desaturated 14C-cis-vaccenate substrate in both ergosterol supplemented and normal cultures. The 14C labeled product, 6,11-18:2 was recovered and separated by silver nitrate-Unisil column chromatography
Multiple species comparative analysis of human chromosome 22 between markers D22S1687 and D22S419 and gene expression profiling in zebrafish.
Major large scale insertions or deletions that resulted in gene number differences between human and chimpanzee were discovered in the IGLL and LCR22s within this region, with four human insertions from 6 Kb to 75 Kb and three chimpanzee insertions from 12 Kb to 74 Kb observed in the IGLL region, two human insertions of 59 Kb and 36 Kb in LCR22-6, and a 67 Kb chimpanzee insertion in LCR22-8. Small scale insertions and deletions, in addition to exon shuffling, elevated nucleotide divergence rate and positive selection were also observed in the putative genes, partially duplicated genes and pseudogenes in the IGLL and LCR22s. Thus, the second major conclusion of this study is the major differences between human and chimpanzee in this region lies in the highly repetitive regions of the IGLL and the LCR22s.Comparison of a 4.5 Mb region of human chromosome 22 between markers D22s1687 and D22s419, with the syntenic region in chimpanzee had revealed overall DNA sequence identity of approximately 97.6%, Ka/Ks ratio of known protein coding genes at approximately 0.25, with the majority of amino acid changes between hydrophilic amino acids, followed by changes between hydrophobic amino acids, and the least changes between hydrophobic to hydrophilic amino acids or vise versa. Thus, the first major conclusion of this study is that overall, this chromosomal region is highly conserved between human and chimpanzee, and the known protein coding genes are undergoing purifying selections, in which 75% of nucleotide substitutions that led to amino acid changes were eliminated by adaptive evolution.Through whole mount in situ hybridization studies, a total of 12 human orthologs in zebrafish, including 4 newly predicted putative genes with no previously known expression profile and function, showed specific expression in the developing zebrafish embryonic central nervous system, optic system, the neural crest cells, ottic vesicle, liver, and notochord. Thus, the third major conclusion from this present study is that many predicted genes which currently lack expression data and functional information likely are time and tissue specific during developmental processes
Minimally invasive esophageal surgery-standard of care-our experience
Background: Surgery is the most effective treatment for the resectable esophageal cancer of the middle & lower third and gastro-esophageal junction (GEJ) tumors. We hereby scrutinise our experience in minimally invasive esophageal surgery (MIES) to evaluate its safety and efficacy as an oncosurgical procedure.Methods: The study included99consecutive patients. Depending on the location of the tumor, either thoracoscopic transthoracic esophagectomy (TTE) in prone position or laparoscopic transhiatal esophagectomy (THE) was planned. 2 field comprehensive nodal dissection were part of both the surgical procedures.Results: 05 patients were excluded, 18 were inoperable and 12 had open surgery.64 underwent MIES (THE-37, TTE-27), Male: Female-31:33. Nodal Harvest (nodes): THE-14.27, TTE-14.77. Margins (cm): THE-proximal (P) - 6.70, distal (D) -2.51, TTE: (P)-5.41, (D)-5.11.30 days Morbidity (26): cervical leak-05, left vocal cord palsy-05, tracheostomy-03, respiratory insufficiency-03, aspiration-01, chyle leak-01, exploratory laparotomy-01, cardiac-02, stroke-01, surgical emphysema -01, abdominal wound Infection -0330 days Mortality (1) –pulmonary embolus. Operative time (minutes): THE-234, TTE-322. Blood loss (ml/patient): THE-265, TTE-380. Hospital stays (days): THE-7.3, TTE-10.Conclusions: 79% of properly selected & evaluated cases underwent MIES, with one Mortality and 26 events of morbidity. 6% required conversion. The procedure detected inoperability in 16% cases. The nodal yield, status of margins, operative time, blood loss and hospital stay indicates that MIES has a future to become a standard of care in the treatment of esophageal cancers.
An Adaptive Controller Design for Flexible-joint Electrically-driven Robots With Consideration of Time-Varying Uncertainties
Almost all present control strategies for electrically-driven robots are under the rigid robot assumption. Few results can be found for the control of electrically driven robots with joint flexibility. This is because the presence of the joint flexibility greatly increases the complexity of the system dynamics. What is worse is when some system dynamics are not available and a good performance controller is required. In this paper, an adaptive design is proposed to this challenging problem. A backstepping-like procedure incorporating the model reference adaptive control is employed to circumvent the difficulty introduced by its cascade structure and various uncertainties. A Lyapunov-like analysis is used to justify the closed-loop stability and boundedness of internal signals. Moreover, the upper bounds of tracking errors in the transient state are also derived. Computer simulation results are presented to demonstrate the usefulness of the proposed scheme. Keywords: Adaptive control; Flexible-joint electrically-driven robot; FAT
2. Introduction
Control of rigid robots has been well understood in recent years, but most of the schemes ignore the dynamics coming from electric motors and harmonic drivers that are widely implemented in the industrial robots. However, actuator dynamics constitute an important part of the complete robot dynamics, especially in the cases of high-velocity movement and highly varying loads[1],[2]. The main reason for using a reduced model is to simplify complexity of controller design. For each joint, consideration of the flexibility from the
M. C. Chien was with the Department of Mechanical Engineering, National Taiwan University of Science and Technology. He is now with the Mechanical and Systems Research Laboratories, Industrial Technology Research Institute, No. 195, Sec. 4, Chung-Hsing Rd., Chutung, Hsinchu, 310, Taiwan, R.O.C. (e-mail: [email protected]). 2 A. C. Huang is with the Department of Mechanical Engineering, National Taiwan University of Science and Technology. No. 43, Keelung Rd., Sec. 4, Taipei, Taiwan, ROC. (Tel:+886-2-27376490, Fax: +886-2-37376460, E-mail: [email protected]). (A. C. Huang provides phone number because he is the corresponding author.
A Regressor-free Adaptive Control for Flexible-joint Robots based on Function Approximation Technique
The essential oil of Glossogyne tenuifolia
[[abstract]]Glossogyne tenuifolia (Labill) Cass. (Compositae) is a traditional anti-pyretic and hepatoprotective herb in The Pescadores Islands. The essential oil of the dried herb, from four seasons, was isolated using a simultaneous steam-distillation and solvent-extraction (SDE) apparatus. The essential oil contents were in the range of 0.48–0.77 mg g?1, with an average of 0.66 mg g?1, and declined with the seasons. Generally, the essential oils from four seasons exhibited similar volatile profiles. A total of 62 different compounds were isolated by the SDE method and, among them, 30 compounds were identified, including 13 terpenes, 16 oxygen-containing compounds (eight alcohols, five aldehydes, one ester and two ketones) and one other compound. Terpenes were predominantly present in the essential oil and accounted for 61.3–76.0% of the essential oil with an average of 69.1%. The second most abundant class was alcohols, accounting for 12.4–15.9% of the essential oil, with an average of 14.1%. Consistently for four seasons, the most abundant eight compounds were in the descending order: p-cymene > β-pinene > β-phellandrene > limonene > cryptone > α-pinene > 4-terpineol + γ-muurolene. However, these eight compounds accounted for 71.5% of the average of the essential oil and, in combination, might give rise to the overall citrus-like aroma of the G. tenuifolia
Sixteen years post radiotherapy of nasopharyngeal carcinoma elicited multi-dysfunction along PTX and chronic kidney disease with microcytic anemia
BACKGROUND: The hypothalamic–pituitary (h-p) unit is a particularly radiosensitive region in the central nervous system. As a consequence, radiation-induced irreversible, progressively chronic onset hypopituitarism (RIH) commonly develops after radiation treatments and can result in variably impaired pituitary function, which is frequently associated with increased morbidity and mortality. CASE PRESENTATION: A 38-year-old male subject, previously having received radiotherapy for treatment of nasopharygeal carcinoma (NPCA) 16 years ago, appeared at OPD complaining about his failure in penile erection, loss of pubic hair, atrophy of external genitalia: testicles reduced to 2×1.5 cm; penile size shrunk to only 4 cm long. Characteristically, he showed extremely lowered human growth hormone, (HGH, 0.115 ng/mL), testosterone (<0.1 ng/mL), total thyroxine (tT4: 4.740 g/mL), free T4 (fT4, 0.410 ng/mL), cortisol (2.34 g/dL); lowered LH (1.37 mIU/mL) and estradiol (22 pg/mL); highly elevated TSH (7.12 IU/mL). As contrast, he had low end normal ACTH, FSH, total T3, free T3, and estriol; high end normal prolactin (11.71 ng/mL), distinctly implicating hypopituitarism-induced hypothyroidism and hypogonadism. serologically, he showed severely lowered Hb (10.6 g/dL), HCT (32.7%), MCV (77.6 fL), MCH (25.3 pg), MCHC (32.6 g/dL), and platelet count (139×103/L) with extraordinarily elevated RDW (18.2%), together with severely lowered ferritin (23.6 ng/mL) and serum iron levels; highly elevated total iron binding capacity (TIBC, 509 g/dL) and transferrin (363.4 mg/dL), suggesting microcytic anemia. Severely reduced estimated glomerular filtration rate (e-GFR) (89 mL/mim/1.73 m2) pointed to CKD2. Hypocortisolemia with hyponatremia indicated secondary adrenal insufficiency. Replacement therapy using androgen, cortisol, and Ringer’s solution has shown beneficial in improving life quality. CONCLUSIONS: To our believe, we are the first group who report such complicate PTX dysfunction with adrenal cortisol insufficiency concomitantly occurring in a single patient
Perspectives of vector management in the control and elimination of vector-borne zoonoses
The complex transmission profiles of vector-borne zoonoses (VZB) and vector-borne infections with animal reservoirs (VBIAR) complicate efforts to break the transmission circuit of these infections. To control and eliminate VZB and VBIAR, insecticide application may not be conducted easily in all circumstances, particularly for infections with sylvatic transmission cycle. As a result, alternative approaches have been considered in the vector management against these infections. In this review, we highlighted differences among the environmental, chemical, and biological control approaches in vector management, from the perspectives of VZB and VBIAR. Concerns and knowledge gaps pertaining to the available control approaches were discussed to better understand the prospects of integrating these vector control approaches to synergistically break the transmission of VZB and VBIAR in humans, in line with the integrated vector management (IVM) developed by the World Health Organization (WHO) since 2004
Scope of Real Time Fluorescence Imaging in Esophagectomy
Esophagectomy is a challenging surgery that is known to be associated with high rates of morbidity. Anastomotic leaks, pneumonia, conduit necrosis and chyle leaks are the commonly reported complications. Perfusion assessment and tissue injection based fluorescence guided surgery (FGS) are the newer clinical applications of fluorescent dyes. With the advent and integration of real time fluorescence imaging with the existing minimal access platforms, the esophageal surgeon can employ these techniques to potentially improve outcomes. During thoracic dissection, thoracic duct lymphography, fluorescence guided airway visualization, tracheal perfusion assessment and sentinel lymph node biopsy/dissection are the reported clinical applications. In the abdominal dissection, gastroepiploic arcade identification, gastric conduit perfusion assessment and proximal esophagus perfusion assessment have been described. Using the different routes of administration, the same dye can be used for different uses at separate points in a single esophagectomy surgery. The principles and evidence pertaining to these applications have been outlined
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