Coordination of the movements of the appendages in the Tasmanian mountain shrimp Anaspides tasmaniae (Crustacea; Malacostraca; Syncarida)

1981 ◽  
Vol 212 (1187) ◽  
pp. 213-231 ◽  
Keyword(s):  
Functional Condition ◽  
Structural Condition ◽  
Main Line ◽  
Ongoing Activity ◽  
Linear Sequence ◽  
Oscillator Function ◽  
Abdominal Appendages ◽  
Thoracic Appendage

The syncarid Anaspides has changed very little in structure since the Palaeozoic and is considered to represent a very early branch from the main line of crustacean evolution. An examination of locomotory co-ordination in Anaspides is made on the assumption that a primitive functional condition will be found where a primitive structural condition exists. The animal uses its thoracic endopodites and its abdominal appendages for locomotion and its thoracic exopodites for respiration. The locomotory appendages are coordinated in a linear sequence, with the exception of the large thoracic appendage at the junction of the abdomen and the thorax. Ipsilateral coupling is weak and gliding coordination is common. The respiratory appendages show considerable independence from the locomotory appendages even though the thoracic exopodites and endo-podites share common basal segments. The exception to this is that, where there is ongoing activity in the respiratory appendages while the animal is stationary, the rhythm of the respiratory appendages determines the rhythm of the locomotory appendages at the commencement of movement. The implications of these findings for an understanding of locomotory oscillator function are discussed.

Ultrastructural aspects of gymnosperms reproductive organs tissues due to their functional condition

1978 ◽  
Vol 36 (2) ◽  
pp. 440-441
Author(s):  
G. M. Kozubov
Keyword(s):  
Metabolic Activity ◽  
Functional Condition ◽  
Reproductive Organs ◽  
Considerable Change ◽  
Complicated Structure ◽  
Tetrad Stage ◽  
Ubisch Bodies ◽  
Similar Organization ◽  
Female Reproductive Organs ◽  
High Metabolic Activity

The ultrastructure of reproductive organs of pine, spruce, larch and ginkgo was investigated. It was found that the male reproductive organs possess similar organization. The most considerable change in the ultrastructure of the microsporocytes occur in meiosis. Sporoderm is being laid at the late tetrad stage. The cells of the male gameto-phyte are distinguished according to the metabolic activity of the or- ganells. They are most weakly developed in the spermiogenic cell. Ta-petum of the gymnosperms is of the periplasmodic - secretorial type. The Ubisch bodies which possess similar structure in the types investigated but are specific in details in different species are produced in tapetum.Parietal and subepidermal layers are distinguished for their high metabolic activity and are capable of the autonomous photosynthesis. Female reproductive organs differ more greatly in their struture and have the most complicated structure in primitive groups. On the first stages of their formation the inner cells of nucellus are transformed into the nucellar tapetum in which the structures similar to the Ubisch bodies taking part in the formation of the sporoderm of female gametophyte have been found.

The Total Synthesis of Rhabdastrellic Acid A

2018 ◽  
Author(s):  
Yaroslav Boyko ◽  
Christopher Huck ◽  
David Sarlah
Keyword(s):  
Total Synthesis ◽  
Late Stage ◽  
Cross Coupling ◽  
Side Chains ◽  
General Strategy ◽  
Modular Approach ◽  
Linear Sequence ◽  
Generating Sequence ◽  
First Time

<div>The first total synthesis of rhabdastrellic acid A, a highly cytotoxic isomalabaricane triterpenoid, has been accomplished in a linear sequence of 14 steps from commercial geranylacetone. The prominently strained <i>trans-syn-trans</i>-perhydrobenz[<i>e</i>]indene core characteristic of the isomalabaricanes is efficiently accessed in a selective manner for the first time through a rapid, complexity-generating sequence incorporating a reductive radical polyene cyclization, an unprecedented oxidative Rautenstrauch cycloisomerization, and umpolung 𝛼-substitution of a <i>p</i>-toluenesulfonylhydrazone with in situ reductive transposition. A late-stage cross-coupling in concert with a modular approach to polyunsaturated side chains renders this a general strategy for the synthesis of numerous family members of these synthetically challenging and hitherto inaccessible marine triterpenoids.</div>

Te inf uence of ergonomic factors on the formation of occupational risk of health disorders of agricultural machine operators

2019 ◽  
Vol 1 (7) ◽  
pp. 400-405
Author(s):  
Tamara A. Novikova ◽  
Aleksey N. Danilov ◽  
Vladimir F. Spirin
Keyword(s):  
Physical Activity ◽  
Functional Condition ◽  
Anthropometric Data ◽  
Agricultural Machine ◽  
Machine Operators ◽  
Health Disorders ◽  
Space Layout ◽  
Combine Harvesters ◽  
High Degree ◽  
The Impact

Introduction. T e leading place in the structure of occupational morbidity of agricultural machine operators is occupied by vertebroneurological diseases, the development of which can be associated with the impact of ergonomic factors of labor activity. T e aim of the study is to assess the ergonomic factors of working conditions on mobile agricultural machinery and to identify their impact on the formation of health disorders of agricultural machine operators. Materials and methods. Complex physiological and ergonomic researches at operation of tractors and combine harvesters of old samples of domestic production including an assessment of the organization of workplaces on compliance to requirements of ergonomics and anthropometric data of workers, temporary, statodynamic, biomechanical characteristics of working poses and movements, a functional condition of machine operators (130 people aged 20–45 years with professional experience of work not less than three years) in dynamics of a work shift are carried out. Anthropometric studies were conducted among male machine operators (663 people) aged 18–59 years and with experience in the profession for more than three years. Results. The discrepancy between the size and space-layout parameters of workplaces ergonomic requirements and anthropometric data of machine operators, causing the formation of uncomfortable working positions, increasing physical activity and the severity of the labor process. A high degree of correlation between changes in the parameters of the neuromuscular system and the severity of the discrepancy between the ergonomic parameters of anthropometric characteristics of machine operators (r=0,7). T e results of the research allowed to determine the priority measures for the prevention of vertebroneurological diseases in agricultural machine operators. Conclusions. T e organization of workplaces on domestic tractors and combine harvesters of old samples does not meet the ergonomic requirements and anthropometric data of machine operators, which is the reason for the formation of an uncomfortable working posture, increased statodynamic physical activity, early development of fatigue and fatigue in the process, which can cause the development of pathological conditions of the spine and ligamentous apparatus. Ergonomic improvement of workplaces is one of the priority measures to preserve the health of agricultural machine operators.

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