Mechanical behavior in living cells consistent with the tensegrity model

Alternative models of cell mechanics depict the living cell as a simple mechanical continuum, porous filament gel, tensed cortical membrane, or tensegrity network that maintains a stabilizing prestress through incorporation of discrete structural elements that bear compression. Real-time microscopic analysis of cells containing GFP-labeled microtubules and associated mitochondria revealed that living cells behave like discrete structures composed of an interconnected network of actin microfilaments and microtubules when mechanical stresses are applied to cell surface integrin receptors. Quantitation of cell tractional forces and cellular prestress by using traction force microscopy confirmed that microtubules bear compression and are responsible for a significant portion of the cytoskeletal prestress that determines cell shape stability under conditions in which myosin light chain phosphorylation and intracellular calcium remained unchanged. Quantitative measurements of both static and dynamic mechanical behaviors in cells also were consistent with specific a priori predictions of the tensegrity model. These findings suggest that tensegrity represents a unified model of cell mechanics that may help to explain how mechanical behaviors emerge through collective interactions among different cytoskeletal filaments and extracellular adhesions in living cells.

Mechanical maintenance manual. Road locomotives with model 244 engines.

Mode of access: Internet.

Operator's, organizational, direct support, and general support maintenance manual : refrigeration unit, mechanical, panel type, 5000 Btu/hr, gasoline engine driven (GED), model ERU-5G (NSN 4110-01-076-1991).

"1 May 1981."

Operator, organizational, direct support, and general support maintenance manual : refrigeration unit, mechanical, panel type, field portable, 5000 Btu capacity, Dixie-Narco, Inc. model DN-5000-IV, FSN 4110-933-6114 ....

"October 1972."

Operator's, organizational, direct support, and general support maintenance manual : refrigeration unit, mechanical panel mounted for refrigerator prefabricated : electric motor driven, Keco model F 10000 R-6 (4110-01-077-8253) : gasoline engine driven ....

Includes index.

Operator, organizational, direct support and general support maintenance manual : refrigeration unit, mechanical, panel type; 10,000 BTU/hr, gasoline engine driven (GED), (R & H Metal Products Corp. model RMP-J/1-10G), NSN 4110-01-010-5970, (R & H Metal Products Corp. model RMP-J/11-10E electric motor driven), NSN 4110-01-015-9003.

Includes index.

Operator and organizational maintenance manual : refrigeration unit, mechanical, panel type, gasoline engine driven, 9000 Btu, type I, for semitrailer, refrigerator, 7 1/2 ton (Redmanson model RGP-9000), FSN 4110-935-1512 ... FSN 4110-935-5483.

"November 1974."

Organizational maintenance repair parts and special tools list : refrigeration unit, mechanical, panel type, gasoline engine driven, 9000 Btu, type I, for semitrailer, refrigerator, 7 1/2 ton (Redmanson model RGP-9000), NSN 4110-00-935-1512 ....

"March 1976."

Organizational, direct support, and general support maintenance repair parts and special tools lists ... for refrigeration unit, mechanical, panel type, 10,000 Btu/hr, electric motor driven, model-REMD-K/II-10LS, NSN 4110-01-163-2140.

"3 March 1987."

Identification of Mechanical Parameters in Mathematical Model of Human Abdominal Fascia

Миглена Г. Кирилова-Донева - Едномерен експеримент на релаксация беше извършен с 14 образци от човешка пъпна фасция. Механичното поведение на фасцията по време на релаксация беше моделирано прилагайки нелинейната теория на Максвел-Гуревич-Рабинович. Параметрите на модела за изследваните образци бяха определени и стойностите им бяха сравнени в зависимост от посоката на натоварване на образците по време на експеримента. Установено бе, че стойностите на началния вискозитет ∗η0 и на параметъра ∗m, който се влияе от скоростта на деформация на материала се изменят в много широки граници не само за образци от различни донори, но и за образци от един донор. В резултат от прилагането на модела бе изчислено изменението на вискозитета и вискозната деформация на материала по време на релаксацията. Бе показано, че изменението на вискозитета и вискозната деформация зависи от посоката на натоварване на образците.

Assessing the effectiveness of five-year mechanical engineering technology programs of junior colleges in Taiwan, R.O.C.: An application of the CIPP evaluation model

The purpose of this study was to evaluate the mechanical engineering technology curriculum effectiveness at the junior college in Taiwan by using the CIPP evaluation model. The study concerned the areas of the curriculum, curriculum materials, individualized instruction, support services, teaching effectiveness, student achievement, and job performance. A descriptive survey method was used with questionnaires for data collection from faculty, students, graduates, and employers.^ All categories of respondents tended to agree that the curriculum provides appropriate occupational knowledge and skills. Students, graduates, and faculty tended to be satisfied with the curriculum; faculty tended to be satisfied with student achievement; graduates tended to be satisfied with their job preparation; and employers were most satisfied with graduates' job performance.^ Conclusions were drawn in the context, input, process, and product of the CIPP model. In Context area: Students were dissatisfied with curriculum flexibility in students characteristics. Graduates were dissatisfied with curriculum design for student's adaptability in new economic and industrial conditions; practicum flexibility in student characteristics; and course overlap. Both students and graduates were dissatisfied with practicum credit hours. Both faculty and students were dissatisfied with the number of required courses.^ In Input area: Students, faculty, and graduates perceived audiovisuals and manipulative aids positively. Faculty and students perceive CAI implementation positively. Students perceived textbooks negatively.^ In Process area: Faculty, students, and graduates perceived all support service negatively. Faculty tended to perceive the ratios of graduates who enter advanced study and related occupation, and who passed the professional skills certification, negatively. Students tended to perceive teaching effectiveness in terms of instructional strategies, the quality of instruction, overall suitability, and receivable, negatively. Graduates also tended to identify the instructional strategies as a negative perception. Faculty and students perceived curriculum objectives and practicum negatively. Both faculty and students felt that instructors should be more interested in making the courses a useful learning experience.^ In Product area: Employers were satisfied with graduates' academic preparation and job performance, adaptability, punctuality, and their ability to communicate, cooperate, and meet organization needs. Graduates were weak in terms of equipment familiarity and supervisory ability.^ In sum, the curriculum of the five-year mechanical engineering technology programs of junior college in Taiwan has served adequately up to this time in preparing a work force to enter industry. It is now time to look toward the future and adapt the curriculum and instruction for the future needs of this high-tech society. ^