scholarly journals Studies on the nature of the amphibian organization centre. I—Chemical properties of the evocator

1935 ◽  
Vol 117 (804) ◽  
pp. 289-310 ◽  
Keyword(s):  
Active Substance ◽  
Chemical Properties ◽  
Egg Laying ◽  
Embryonic Induction ◽  
Soluble Substance ◽  
Animal Kingdom ◽  
Whole Process ◽  
Adult Tissues ◽  
Regional Character ◽  
Organization Centre

During the amphibian egg-laying season of 1933, Needham, Waddington, and Needham (1933, a , b ; 1934) obtained evidence that the activity of the organization centre of the newt gastrula is partly due to the presence of an ether-soluble substance. The active ether extracts were found to be capable of evoking the formation of a neural tube from the competent presumptive epidermis of the gastrula. It seems difficult, however, to suppose that they can determine the regional character of the evoked neural plate, as normal living organizers do, and the active substance is therefore spoken of as the evocator, to emphasize the fact that its functions represent only one part of the whole process of embryonic induction. The presence of the evocator could also be demonstrated in ether extracts of adult newt tissues; and in a research carried out at the same time Holtfreter (1933) showed that the evocator is present in a large number, if not in all, adult tissues from animals belonging to nearly all the groups of the animal kingdom. Holtfreter found that evocation occurred after the implantation of adult tissues which had been killed and treated with various solvents, but he showed that a prolonged extraction with ether tended to lessen, though it did not entirely destroy, the evocating power of the tissue. This result, which so far as it went was confirmatory of Needham, Waddington, and Needham’s work, was, however, denied by Fischer and Wehmeier (1934), who, on repeating the extraction experiments, could confirm the fact that the ether extracts were active, but claimed that the evocating ability of the tissues was not much lessened by the extraction. In a more recent communication (1934, a ) Holtfreter has repeated his extractions, and finds that the activity of the extracted tissue is only slightly lowered. It is very probable, however, that there will be difficulty in extracting the whole of the active ether-soluble substances from a given mass of tissue. There is general agreement that ether extracts contain an active substance.

scholarly journals Syngas Quality as a Key Factor in the Design of an Energy-Efficient Pyrolysis Plant for Scrap Tyres

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1455 ◽  
Author(s):  
Dina Czajczyńska ◽  
Renata Krzyżyńska ◽  
Hussam Jouhara
Keyword(s):  
Energy Demand ◽  
Chemical Properties ◽  
Industrial Emissions ◽  
Whole Process ◽  
Start Up ◽  
Key Factor ◽  
Industrial Emissions Directive ◽  
Pyrolytic Oil ◽  
Quality Of Products

In 2016 4.94 million tonnes of tyres were produced. Each tyre eventually become waste and pyrolysis has been considered an effective way of utilizing scrap tyres for several decades. However, pyrolysis has failed many times because the process has a great energy demand and the quality of products is unstable or insufficient for commercial use. Usually plants are focused on the production of pyrolytic oil or char and the gaseous phase is only a by-product. In this paper the importance of composition and quality of pyrolytic gas is emphasized. The main chemical properties make this gas a valuable biofuel that may satisfy energy requirements of the whole process (except for the start-up phase). Available data from literature concerning composition and other features of the pyrolytic gas from scrap tyres obtained at temperatures up to 1000 °C are compared with experimental results. The quality of evolved gases is discussed in the context of the Industrial Emissions Directive (IED), too. Finally, an analysis of the mass balances obtained allows a decision about the business profile and profitability.

scholarly journals A Strategy to Synthesize Multilayer Graphene in Arc-Discharge Plasma in a Semi-Opened Environment

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2279 ◽  
Author(s):  
Hai Tan ◽  
Deguo Wang ◽  
Yanbao Guo
Keyword(s):  
Discharge Plasma ◽  
Arc Discharge ◽  
Chemical Reduction ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Chemical Components ◽  
Multilayer Graphene ◽  
Whole Process ◽  
Hazardous Chemical ◽  
Physical And Chemical

Graphene, as the earliest discovered two-dimensional (2D) material, possesses excellently physical and chemical properties. Vast synthetic strategies, including chemical vapor deposition, mechanical exfoliation, and chemical reduction, are proposed. In this paper, a method to synthesize multilayer graphene in a semi-opened environment is presented by introducing arc-discharge plasma technology. Compared with previous technologies, the toxic gases and hazardous chemical components are not generated in the whole process. The synthesized carbon materials were characterized by transmission electron microscopy, atomic force microscopy, X-ray diffraction, and Raman spectra technologies. The paper offers an idea to synthesize multilayer graphene in a semi-opened environment, which is a development to produce graphene with arc-discharge plasma.

scholarly journals Modelling of Time-Dependent Wellbore Collapse in Hard Brittle Shale Formation under Underbalanced Drilling Condition

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-21
Author(s):  
Shanpo Jia ◽  
Zhiqiang Xiao ◽  
Bisheng Wu ◽  
Caoxuan Wen ◽  
Lufeng Jia
Keyword(s):  
Immersion Time ◽  
Progressive Failure ◽  
Drilling Fluid ◽  
Progressive Collapse ◽  
Failure Process ◽  
Chemical Properties ◽  
Whole Process ◽  
Drilling Condition ◽  
Shale Formation ◽  
Physical And Chemical

In recent years, the lithologic traps in a mid-depth formation are the focus of oil or gas exploration and development for eastern oilfields in China. The Shahejie Formation develops thick hard brittle shale, and the wellbore instability problem is prominent due to obvious hydration effect for long immersion time during drilling. Through the analysis of laboratory tests and field test results of physical and chemical properties and microstructure and mechanical properties of hard brittle shale, the instability mechanism is discussed for the wellbore in the shale formation. To simulate the whole process of progressive collapse of a wellbore in a hard brittle shale formation, a coupled hydraulic-mechanical-chemical (HMC) model is developed and this model is compiled with ABAQUS software as the solver. Then the coupled HMC model is applied to simulate the progressive evolution process of wellbore collapse in a hard brittle shale formation, and the influence of different parameters on the progressive failure of the wellbore is analysed. The results show that the wellbore enlargement rate increases with the drilling fluid immersion time and the influence of different parameters on the wellbore enlargement rate is different. The water absorption diffusion coefficient and the activity of the drilling fluid have the most obvious influence on the expansion of the wellbore, and the sensitivity is strong. The permeability of shale has little effect on the wellbore enlargement rate. The calculated progressive failure process of the wellbore is basically consistent with that of the actual drilling.

scholarly journals Experiments on Embryonic Induction

1934 ◽  
Vol 11 (3) ◽  
pp. 218-223
Author(s):  
C. H. WADDINGTON
Keyword(s):  
Recent Work ◽  
Primitive Streak ◽  
Chemical Substance ◽  
Boiling Water ◽  
Direct Result ◽  
Embryonic Induction ◽  
Embryonic Axes ◽  
Chick Blastoderm ◽  
Dead Material ◽  
Regional Character

1. Two cases of induction by coagulated organisers in the chick are described. The implants consisted of pieces of chick primitive streak, and previous to implantation they were killed and coagulated by immersion in boiling water. After this treatment they still retained the inducing capacity which they have been previously shown to possess in the live state. 2. Grafts of dead material into the chick blastoderm usually become enveloped in mesenchyme and thus isolated from the host ectoderm. 3. It is argued that, although there may in the normal egg be a gradient of inducing capacity, the inducing factor itself cannot be a gradient as such: and reference is made to the most recent work which shows that the factor is actually a chemical substance. 4. It is pointed out that there is as yet no evidence that dead organisers can determine the regional character of the embryonic axes which they induce, as live organisers can. 5. In one of the specimens described, the induced axis is accompanied by induced notochord. The question is raised as to whether this notochord is the direct result of the inducing stimulus acting on the host ectoderm, or whether the influence of the host's individuation field has played a part in its formation.

scholarly journals PERUBAHAN BEBERAPA SIFAT FISIS DAN KIMIA PASTA GAMBIR SELAMA PENYIMPANAN

2015 ◽  
Vol 1 (2) ◽  
pp. 102
Author(s):  
Anwar Kasim ◽  
Yoli Sub’han ◽  
Netty Sri Indeswari
Keyword(s):  
Physical Properties ◽  
Chemical Properties ◽  
Water Soluble ◽  
Soluble Substance ◽  
Initial Water ◽  
Randomized Design ◽  
Chemical Content ◽  
Water Soluble Substance ◽  
Physical And Chemical ◽  
Storage Change

ABSTRACT Studying about the change of physical and chemical properties Gambir paste during 28 days was conducted in order to know the change primarily the chemical content and physical properties as storage consequences. Experimental design was used completely randomized design for 4, 8, 12, 16, 20, 24, and 28 days storage periods. Replication was two and as a control was used paste non treatment. F-test and T-Dunnet test were applicated for statistical analysis. The result indicated that treatment can not change physical properties but change the chemical properties gambir paste. The initial water contents of gambir paste was 72.26% and after 28 days storage 71.68%. Color of gambir paste was still yellow during storage. The initial non water soluble substance was 6.96% and after 28 days storage 4.69%. The initial non alcohol soluble substance was 14.83% and after 28 days storage 13.15%. The initial chatechin contents was 72.22% and after 28 days storage 65.38%. The initial tannin contents 38.68% and after 28 days storage 35.12%. Total ash content of gambir paste was 2.72%.   Keywords : gambir, paste, storage, change, properties

Study of the kinetics of benzidamine hydrochloride release from topical sprays in an in vitro experiment

2020 ◽  
pp. 62-72
Author(s):  
E. F. Stepanova ◽  
V. V. Vernikovskiy ◽  
A. V. Morozov
Keyword(s):  
Active Substance ◽  
Dosage Form ◽  
Topical Therapy ◽  
Chemical Properties ◽  
Vitro Experiment ◽  
In Vitro Experiment ◽  
Analgesic Effects ◽  
Inflammatory Processes ◽  
Osmotic Activity

Inflammatory processes accompanied by a sore throat are a widespread symptom of both infectious and non-infectious genesis. In this case, topical therapy with medications that combine anti-inflammatory and analgesic effects, in the form of comfortable dosage forms — sprays, is the most effective. In this case, the used drug has a complex effect on contact tissues, due to both the actual pharmacological activity of the pharmaceutical substance and the physico-chemical properties of the excipients forming the dosage form. A study of the release of the active substance from sprays in the perspective of their topical application, as well as their osmotic activity in an in vitro experiment that simulates the process of application to the throat mucosa, was carried out. The real influence of the osmotic activity of the dosage form on the degree of release of the active substance due to the multidirectional nature of the resulting diffusion flows is shown.

scholarly journals THE FATE OF INJECTED PARTICULATE ANTIGENS IN RELATION TO THE FORMATION OF ANTIBODIES

1946 ◽  
Vol 84 (2) ◽  
pp. 157-165 ◽  
Author(s):  
T. N. Harris ◽  
W. E. Ehrich
Keyword(s):  
Lymph Node ◽  
Active Substance ◽  
Regional Lymph Node ◽  
Lymphatic Tissue ◽  
Soluble Substance ◽  
Antigenic Material ◽  
Soluble Material ◽  
In Cells

Earlier studies have shown that the injection of antigenic material into the pad of the rabbit's foot is followed by the appearance of antibodies in the regional lymph node, in lymph coming from that node, and especially in the lymphocytes present in such efferent lymph. In the present work the fate of particulate antigenic material has been investigated during the period between its injection into the foot of the rabbit and the appearance of antibodies in the regional lymphatic tissue. It has been found that soluble substance of the same immunologic specificity as the antigenic material injected can be identified in extracts of the injected tissue and of the regional lymph node, and in the efferent lymph from that node. The concentration of this soluble material falls off slowly in the injected tissue in the course of the few days following the injection. It falls off quickly in the extract of the lymph node and in the lymph itself, and its disappearance is succeeded by the appearance of antibody. Evidence is presented that the immunologically active substance is derived from the injected antigenic material by a physiologic process, and this process is discussed as the means by which antigens, originally comprised in cells, are made available to the lymphocyte.

Studies on Regional Specificity Within the Organization Centre of Urodeles

1950 ◽  
Vol 27 (2) ◽  
pp. 126-144
Author(s):  
C. H. WADDINGTON ◽  
T. YAO
Keyword(s):  
Spina Bifida ◽  
Anterior Part ◽  
Organizer Region ◽  
Neural Plate ◽  
Normal Embryo ◽  
Median Part ◽  
Regional Specificity ◽  
Spatio Temporal ◽  
Regional Character ◽  
Organization Centre

1. In young gastrulae of Triton alpestris the median part of the organization centre immediately in front of the blastopore was excised and replaced after reversal of its anterior-posterior axis. Completely normal embryos developed in many cases, but in others there was some degree of microcephaly or spina bifida. 2. Similar normal embryos can develop after exchange of the anterior and posterior regions of the organizer, either with normal or reversed orientation. 3. The spina bifida which frequently appears is a consequence of the impediment offered by the graft to the normal gastrulation movements. 4. Microcephaly may also result if the presence of the graft prevents the proper development of the anterior part of the archenteron roof. 5. It may also be caused when the posterior organizer region is brought into the anterior region, if the host fails to convert it into anterior material. This occurs the more frequently the older the grafted posterior material is. 6. Even at the end of gastrulation (slit yolk-plug stage) the regional character of the archenteron roof is not finally determined. A fairly normal embryo (with over-thick mesoderm) may develop if an extra archenteron roof is added with reversed orientation between the normal archenteron roof and the presumptive neural plate. 7. The determination of the regional structure of the archenteron roof and the neural plate is discussed. Attention is drawn to the spatio-temporal factors involved in the production and diffusion of the evocator with the dynamic system of the gastrulating egg.

The structure and function of the oviducal gland in octopods (Cephalopoda)

1975 ◽  
Vol 188 (1090) ◽  
pp. 95-101 ◽  
Keyword(s):  
Chemical Properties ◽  
Egg Laying ◽  
Octopus Vulgaris ◽  
Physical And Chemical Properties ◽  
Peripheral Part ◽  
Oviducal Gland ◽  
And Function ◽  
Physical And Chemical ◽  
And Chemical Properties

The oviducal gland of Octopus vulgaris is involved in the storage of spermatozoa and the production of an egg-laying cement. Spermatozoa are attached to the wall of spermathecae by means of their acrosome and retained there for several months before the maturity of the female. The cement (a mucoprotein) is synthesized in the peripheral part of the gland. In the central part a mucopolysaccharide is produced that acts as a polymerizer of the cement. This reaction was studied in vitro and some physical and chemical properties of the compounds are described. The cement serves finally to form an egg string for fixation to an appropriate substrate.

scholarly journals The transdermal penetration of novel amphiphilic MTC-Y carrier

2021 ◽  
Author(s):  
Piotr Kuropka ◽  
Maciej Janeczek ◽  
Dawid Bursy
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Histological Examination ◽  
Delivery System ◽  
Active Substance ◽  
Transdermal Drug Delivery ◽  
Chemical Properties ◽  
Fluorescence Microscope ◽  
Transdermal Drug Delivery System ◽  
Transdermal Penetration

Abstract A transdermal drug delivery system capable of transporting the active substance through skin is alternative path for drug delivery for different purposes. In an attempt to demonstrate the permeability of the active substance through the skin layers of the rats, the amphiphilic MTC-Y carrier was combined with fluorochromes of different chemical properties. After extraction, the skin material was subjected histological examination under fluorescence microscope Nikon Eclipse 80i UV-2A filter (EX330-380, DM-400, BA-420). Moreover, histological slides routinely stained with haematoxylin were analysed. Results indicate that use of the MTC-Y carrier seems to be very promising compound for drug delivery both locally and systematically

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