POSSIBLE MECHANICAL FUNCTION OF SHELL PLICATION IN A TRIASSIC BRACHIOPOD

1964 ◽  
Vol 1 (2) ◽  
pp. 99-120 ◽  
Author(s):  
Gerd E. G. Westermann
Keyword(s):  
Membrane Surface ◽  
Half Width ◽  
Mechanical Function ◽  
Apical Angle ◽  
Sulcus Angle ◽  
Mean Size ◽  
The Subject ◽  
Shell Forming ◽  
Axial Growth ◽  
Maturity Parameters

A sample of 100 Spiriferina stracheyi (Salter) from a single chronodeme of the Anisian Whitehorse formation, Alberta Rocky Mountains, is the subject of covariation studies (individual allomorphosis) in the parameters half width + length mean ("size"), half width/length ratio, thickness, apical angle of fold and sulcus boundaries (fold–sulcus angle), plicae frequency, and apical angle between second right and left plicae from the median (plicae angle). Changes of growth rates for half width/length and plicae frequency at a mean "size" of 10 mm suggest the attainment of maturity; parameters vary nearly independently from "size" in the sample of mature specimens. The variation in the parameters is unusually great. Significant correlation of −0.36 exists between half width/length and plicae angle, i.e. the plicae are more widely spaced in long ("rounded") valves than in wide ("alate") valve variants. A corresponding correlation of +0.61 exists for plicae frequency, wide valves averaging double as many plicae as narrow valves. The same correlations are present in a Himalayan sample of this species.Although, usually, shell plication of bivalved filter-feeders with accretionary growth may simply result from ecologic–physiologic functions of a plicate commissure, in the species here studied the plicae themselves might have had a mechanical function, i.e. the shell forming a corrugated membrane surface in which the "wavelength" increases with the axial growth of the membrane.

scholarly journals Observations on the Fat Globules in Milk

1913 ◽  
Vol 5 (3) ◽  
pp. 331-356 ◽  
Author(s):  
W. F Cooper ◽  
W. H Nuttall ◽  
G. A Freak
Keyword(s):  
Annual Report ◽  
The Other ◽  
Optimum Temperature ◽  
Fat Globules ◽  
Chief Factors ◽  
Mean Size ◽  
The Subject ◽  
The Mean ◽  
Definite Result

Results of our previous work were published in the Journ. of Agric. Sri., IV, 1911. There, also, a brief summary of the chief papers published on the subject of the fat globules was given, to which it is unnecessary to refer in detail here.When the work was first commenced in 1909, the problem before us was the consideration of the variation in the size of the fat globules, with relation to churning, as regards the different breeds of cattle. The breed was considered because it was usually supposed that this was one of the chief factors which influenced churning. The most definite result of our work was that it was shown that consideration must be given to the character of the milk, irrespective of the breed. This conclusion is quite contrary to that of other workers, but an examination of their figures shows, undoubtedly, that this is actually the case: the results given by Woll (Digestion Expts., Seventh Annual Report, Agric. Expt. Stat, Wisconsin, 1890, 238; also Agric. Sci., 1892, vi, 445) emphasise this point particularly. It is also shown by this year's work, as may be seen from Tables V–XI.The comparative size of the globules has been worked out very thoroughly by Gutzeit, who measured the mean volume of the globule. Other workers give their results as “relative sizes.” In our work we attempted to ascertain the distribution of the fat in the globules, and to this end the number of globules of each size was determined, and curves were drawn. The result of this, however, was negative. At that time we were considering the breeds of the cows from which the milks were obtained; had we considered them solely as milks of a certain mean size of globule, much more might have been achieved.An apparatus was devised to give an absolute figure for the churnability of any cream, but, until the effect of the other factors has been determined, it is impossible to interpret the results. Some experiments to ascertain the optimum temperature were described also.

scholarly journals CSIG-14. COMBINING THE GLIOBLASTOMA CELL MEMBRANE-PERMEABILIZING EFFECT OF TUMOR TREATING FIELDS (TTFIELDS) WITH WITHAFERIN A (AND OTHER) CHEMOTHERAPY

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii30-ii30
Author(s):  
Edwin Chang ◽  
Chirag Patel ◽  
Caroline Young ◽  
Thomas Flores ◽  
Yi Zeng ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Bioluminescence Imaging ◽  
Membrane Surface ◽  
Firefly Luciferase ◽  
Field Of View ◽  
Cell Counting ◽  
Withaferin A ◽  
Primary Tumors ◽  
Tumor Treating Fields ◽  
Mean Size

Abstract BACKGROUND Efforts are underway to uncover novel, unorthodox therapies against glioblastoma (GBM). Tumor treating fields (TTFields) disrupt mitotic spindle formation and inhibits tumor growth. Combining TTFields with Withaferin A and other therapeutics, synergistically inhibited proliferation. We describe relevant mechanisms. METHODS Human and murine GBM cells (GBM2, GBM39, U87-MG, KR158B) were isolated from primary tumors. Cells were engineered to stably express firefly luciferase (fLuc). Proliferation was assessed by bioluminescence imaging (using D-Luciferin as a substrate for fLuc) or cell counting. Dextran-FITC binding and scanning electron microscopy (SEM) studies were used to probe effects on cellular membranes. RESULTS TTFields (200 kHz, 4 V/cm) significantly inhibited growth of cells (n=3/time point, p≤0.02; 2-way ANOVA, no TTFields vs. TTFields). Combination of Withaferin A or other chemotherapeutics with TTFields significantly inhibited growth of glioma cells synergistically beyond that of Withaferin A or TTFields alone (p< 0.01, at least n=3 experiments). Bioluminescence imaging suggested alterations in membrane configuration when cancer cells were exposed to TTFields. This was validated with observations of greater fluorescence of membrane-associating Dextran-FITC to U87-MG cells that were subjected to TTFields (p< 0.01, 2-way ANOVA, TTFields vs. no TTFields, n=3 experiments). SEM revealed significantly greater and larger number of holes on the membrane surface of TTFields-exposed U87-MG cancer cells (53.5±19.1 holes per field of view and mean size=240.6±91.7 nm2) compared to unexposed cells (23.9±11.0 holes per field of view and mean size=129.8±31.9 nm2, p< 0.005: TTFields exposed vs. non-exposed, n=3 samples, univariate Mann-Whitney test). CONCLUSION The findings suggest a novel combinatorial approach to treat GBM in a manner that is likely better than single treatment (drug or TTFields) alone and that is synergistic. Synergy is achieved through TTFields inducing increased permeability on membranes thus conferring greater accessibility to drug. Such a strategy is thus a promising candidate for future clinical translation in glioblastoma.

scholarly journals Engineered polyethersulfone membrane for well-dispersed silver nanoparticle impregnation at high loading: high water permeate flux and biofouling prevention

2021 ◽  
Author(s):  
Mohana Mukherjee ◽  
Rajdip Bandyopadhyaya
Keyword(s):  
Membrane Surface ◽  
Water Flux ◽  
High Water ◽  
High Loading ◽  
Permeate Flux ◽  
Ag Nps ◽  
Pore Blockage ◽  
Mean Size ◽  
Pes Membrane ◽  
20 Nm

Abstract We present a new method for impregnation of silver nanoparticles (Ag NPs) at high loading on PES membrane's external surface, simultaneously retaining native membrane's porosity – to achieve a high water permeate flux without biofouling. This was possible by PES membrane's surface modification with acrylic acid (AA), finally leading to AA-Ag-PES membrane. AA-Ag-PES had a high (9.04%) Ag-NP loading selectively on membrane surface, as discrete, smaller (mean size: 20 nm) NPs. In nonfunctionalized Ag-PES, aggregated (mean size: 70 nm) NPs, with lower Ag loading (0.73 wt.%) was obtained, with NP being present both on membrane surface and inside pores. Consequently, AA-Ag-PES could maintain similar water permeability and porosity (10,153.05 Lm−2 h−1bar−1 and 69.98%, respectively), as in native PES (11,368.74 Lm−2 h−1bar−1 and 68.86%, respectively); whereas both parameters dropped significantly for Ag-PES (4,869.66 Lm−2 h−1bar−1 and 49.02%, respectively). AA-Ag-PES also showed least flux reduction (7.7%) due to its anti-biofouling property and high flux recovery after usage and cleaning, compared to native PES and Ag-PES membrane's much higher flux reduction (54.29% and 36.7%, respectively). Hence, discrete NP impregnation, avoiding pore blockage, is key for achieving high water flux and anti-biofouling properties (in AA-Ag-PES), compared to non-functionalized Ag-PES, due to aggregated Ag-NPs inside its pores.

scholarly journals EXTH-53. TUMOR TREATING FIELDS LEADS TO CHANGES IN MEMBRANE PERMEABILITY AND INCREASED PENETRATION BY ANTI-GLIOMA DRUGS

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi93-vi93
Author(s):  
Edwin Chang ◽  
Chirag Patel ◽  
Corinne Beinat ◽  
Caroline Young ◽  
Thomas Flores ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Bioluminescence Imaging ◽  
Membrane Surface ◽  
Firefly Luciferase ◽  
Field Of View ◽  
Cell Counting ◽  
Withaferin A ◽  
Primary Tumors ◽  
Tumor Treating Fields ◽  
Mean Size

Abstract BACKGROUND Efforts are underway to uncover novel, unorthodox therapies against glioblastoma (GBM). Tumor treating fields (TTFields) disrupt mitotic spindle formation and stymie proliferation in tumor cells. Combining TTFields with Withaferin A, synergistically inhibited proliferation in GBM. We wished to uncover the relevant mechanism. METHODS Human and murine GBM cells (GBM2, GBM39, U87-MG, KR158B) were isolated from primary tumors. Cells were engineered to stably express firefly luciferase (fLuc). Proliferation was assessed by bioluminescence imaging (using D-Luciferin as a substrate for fLuc) or cell counting. Dextran-FITC binding and scanning electron microscopy (SEM) studies were used to probe effects on cellular membranes. RESULTS TTFields (200 kHz, 4 V/cm) significantly inhibited growth of cells (n=3/time point, p≤0.02; 2-way ANOVA, no TTFields vs. TTFields). Combination of Withaferin A with TTFields significantly inhibited growth of glioma cells synergistically beyond that of Withaferin A or TTFields alone (p< 0.01, at least n=3 experiments). Bioluminescence imaging suggested alterations in membrane configuration when cancer cells were exposed to TTFields. This was validated with observations of greater fluorescence of membrane-associating Dextran-FITC to U87-MG cells that were subjected to TTFields (p< 0.01, 2-way ANOVA, TTFields vs. no TTFields, n=3 experiments). SEM revealed significantly greater and larger number of holes on the membrane surface of TTFields-exposed U87-MG cancer cells (53.5±19.1 holes per field of view and mean size=240.6±91.7 nm2) compared to unexposed cells (23.9±11.0 holes per field of view and mean size=129.8±31.9 nm2, p< 0.005: TTFields exposed vs. non-exposed, n=3 samples, univariate Mann-Whitney test). CONCLUSION The findings suggest a novel combinatorial approach to treat GBM in a manner that is better than single treatment (drug or TTFields) alone and that is synergistic. Synergy is achieved through TTFields inducing increased permeability on membranes thus conferring greater accessibility to drug. Such a strategy is thus a promising candidate for future clinical translation in glioblastoma.

scholarly journals Report of Special Committee

1913 ◽  
Vol 1 (3) ◽  
pp. 326-332
Author(s):  
W. Allen Sturge ◽  
T. Reid Moir ◽  
W. H. Burrell ◽  
W. G. Clarke
Keyword(s):  
Vice President ◽  
Special Committee ◽  
The Subject ◽  
Shell Forming

At the suggestion of the President it was agreed to appoint a Special Committee to examine the shell forming the subject of Dr. Stopes' paper, and to report upon it. A Committee was accordingly formed consisting of the President of the Society (Dr. Allen Sturge), the Vice-President (Mr. J. Reid Moir, F.G.S.), the Secretary (Mr. W. G. Clarke), and Mr. W. H. Burrell, F.L.S.; the President to act as Chairman.By invitation of the President, the Committee met at Icklingham Hall from May 17th to 19th. Dr. Marie Stopes was also present, to be responsible for the safety of the specimen and to give such further information as the Committee might desire.

scholarly journals Mechanism investigation of virus removal in a membrane bioreactor

2006 ◽  
Vol 6 (6) ◽  
pp. 51-59 ◽  
Author(s):  
X. Zheng ◽  
J.X. Liu
Keyword(s):  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Membrane Pore ◽  
Virus Removal ◽  
Pore Sizes ◽  
Pathogenic Viruses ◽  
Mean Size ◽  
Membrane Modules ◽  
Membrane Pore Size ◽  
Model Virus

Virus removal in a membrane bioreactor (MBR) by gravity drain was studied. Coliphage f2 (mean size of 25 nm), which is similar in size to human enteric pathogenic viruses, was selected as a model virus. Two microfiltration membrane modules with pore sizes of 0.22 μm and 0.1 μm were applied to investigate the effects of membrane pore size on the virus rejection. The MBR with these modules could reject virus in a range of 2.6–5.1 logs. The experimental results showed that the mechanisms of virus removal in the MBR involved rejection and inactivation. The virus rejection depended mainly on the dynamic layer on the membrane surface (not membrane itself) because virus rejection by the membrane modules with pore sizes of 0.1 μm and 0.22 μm were similar. The microbial activity and the aeration oxidation were the two important factors for the virus inactivation. It was found that the inactivation of coliphage f2 was much more rapidly in activated sludge mixed liquor than in clean water, and the effect of aeration was significant.

Words

PMLA ◽  
1935 ◽  
Vol 50 (4) ◽  
pp. 1320-1327
Author(s):  
Colbert Searles
Keyword(s):  
Subject Matter ◽  
Assistant Professor ◽  
The Subject

THE germ of that which follows came into being many years ago in the days of my youth as a university instructor and assistant professor. It was generated by the then quite outspoken attitude of colleagues in the “exact sciences”; the sciences of which the subject-matter can be exactly weighed and measured and the force of its movements mathematically demonstrated. They assured us that the study of languages and literature had little or nothing scientific about it because: “It had no domain of concrete fact in which to work.” Ergo, the scientific spirit was theirs by a stroke of “efficacious grace” as it were. Ours was at best only a kind of “sufficient grace,” pleasant and even necessary to have, but which could, by no means ensure a reception among the elected.

Artificial satellite orbit computations

1966 ◽  
Vol 25 ◽  
pp. 363-371
Author(s):  
P. Sconzo
Keyword(s):  
Artificial Satellite ◽  
Satellite Orbit ◽  
Artificial Satellites ◽  
Orbital Elements ◽  
Differential Correction ◽  
Gravitational Effects ◽  
Short Intervals ◽  
The Subject ◽  
Introductory Discussion ◽  
Orbit Computation

In this paper an orbit computation program for artificial satellites is presented. This program is operational and it has already been used to compute the orbits of several satellites.After an introductory discussion on the subject of artificial satellite orbit computations, the features of this program are thoroughly explained. In order to achieve the representation of the orbital elements over short intervals of time a drag-free perturbation theory coupled with a differential correction procedure is used, while the long range behavior is obtained empirically. The empirical treatment of the non-gravitational effects upon the satellite motion seems to be very satisfactory. Numerical analysis procedures supporting this treatment and experience gained in using our program are also objects of discussion.

C. Wire Cabling for Telescope Systems

1966 ◽  
Vol 27 ◽  
pp. 159-161
Keyword(s):  
The Subject ◽  
Data Multiplexing

Rule: I'd like at this point to bring up the subject of cables and wireways around the telescope. We've touched upon this twice during previous sessions: the cable wrap up problem, the communications problem, and data multiplexing problem. I think we'll ask Bill Baustian if he will give us a brief run down on what the electrical run problems are, besides doubling the system every year.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

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