First Phase Of Activity Research Articles

MANFAAT AKTIVASI FLY ASH BATU BARA DENGAN VARIASI KONSENTRASI NAOH SEBAGAI ADSORBEN

Water is one of the most important natural resources for human life. However, there are some problems that cause water to get polluted and not be used properly, one of which is the liquid waste of the hydrocarbon industry. Fly ash is a residue from coal combustion. Fly ash can be used as an adsorbent to reduce the content of hazardous fluid waste that could threaten human life. The study aims to find out the best NaOH concentration ratio between 1 M and 3 M added to activate fly ash against COD decrease, BOD, TSS, pH, and color change in Kutawaru Cilacap battery waste. The study passes through several stages, namely the first phase of activation of fly ash with NaOH at concentration ratios of 1M and 3M with a ratio of 1:5 for 3 hours. Then, in the adsorption process, the activated fly ash is mixed with battery liquid waste. The final phase is the testing of batik waste at the DLH Cilacap. The results obtained are at the concentration of 1M NaOH because it can reduce COD, BOD, and TSS up to 76%. With the result of COD of 3286 mg/L, BOD of 4921 mg/L, and TSS of 115 mg/L, whereas the results of concentration 3M, with COD of 3615 mg/L, COD 5397 mg/L, and TSS of 36 mg/L, PH for both these concentrations of 8 and the change in color of waste batik that remains black concentrated.

RadioTransNet, Radiotherapy Translational and Preclinical Research Network: Results from the dedicated French cancer institute (INCa) call for projects

PurposeThe RadioTransNet project is a French initiative structuring preclinical and translational research in radiation therapy for cancer at national level. The network's activities are organized around four chosen priorities, which are: target definition, normal tissue, combined treatments and dose modelling. The subtargets linked to these four major priorities are unlimited. They include all aspects associated with fundamental radiobiology, preclinical studies, imaging, medical physics research and transversal components clearly related to these scientific areas, such as medical oncology, radio-diagnostics, nuclear medicine and cost-effectiveness considerations. MethodDuring its first phase of activity, four workshops following the consensus conference model and based on scientific and medical state of the art in radiotherapy and radiobiology were organized on the four above-mentioned objectives to identify key points. Then a road map has been defined and served as the basis for the opening in 2022 of a dedicated call, SEQ-RTH22, proposed by the French cancer national institute (INCa). ResultsFour research projects submitted by RadioTransNet partners have been selected to be supported by INCa: the first by Professor Anne Laprie from Oncopole Claudius-Regaud and Inserm ToNic in Toulouse on neurocognition and health after pediatric irradiation, the second submitted by Fabien Milliat from IRSN aims to study decryption and targeting of endothelial cell–immune cells interactions to limit radiation-induced intestinal toxicity, the third project, submitted by Yolanda Prezado from institut Curie–CNRS on proton minibeam radiotherapy as a new approach to reduce toxicity, and the latest project proposed by R. de Crevoisier from centre Eugène-Marquis in Rennes on predictive multiscale models of head and neck radiotoxicity induced for optimized personalized radiation therapy. Topics of each of these projects are presented here. ConclusionRadioTransNet project has been launched in 2018, supported by INCa, in order to structure and promote preclinical research in oncology radiotherapy and to favor collaboration between the actors of this research. INCa relied on RadioTransNet initiatives and activities, resulting in the opening of dedicated call for projects. Beyond its first main goals, RadioTransNet network is able to help to fund the human and technical resources necessary to conduct optimal translational and preclinical research in radiation oncology.

PENGARUH PIJAT AROMA TERAPI TERHADAP NYERI PERSALINAN DI BPS ZAHRA PUTRI PRATAMA, SST

Background: Labor pain as an unpleasant feeling that is an individual response that accompanies in the process of labor due to changes in physiological function of the birth canal and uterus. Pain is felt very subjective and individual. Objective: To determine the effect of aromatherapy massage using lavender oil to labor pain during the first phase of activation in primigravida mother at midwife Private Practice Zahra Putri Pratama, SST, midwives Private Practice Sudilah, Amd.Keb Metro City 2018. Method: Quantitative research type, This research design is pre experiment with One Group Pre-test approach - Post-test Design. The population in this study is the total of pregnant women aterem in April at BPS Zahra and Sudilah as many as 30 pregnant women. The sample in this study amounted to 24 people. Sampling in this research by accidental sampling. Data collection using observation sheets. The analysis used t-test dependent test statistic. Known average labor pain before given with average score value of labor pain frequency 6.62 With Severe Pain. Known Average Pain of labor after being given with an average score score of the frequency of labor pain 3.62 With Moderate Pain. There was an effect of lavender aromatherapy massage on the active stage I labor phase with P-Value 0.000 value. It is expected that midwives can apply to every patient who will give birth so that the labor pain that the mother can feel is reduced by massage using lavender aromatherapy.

Pelatihan Model Pembelajaran Menggunakan Microsoft Teams di SD Muhammadiyah 2 Denpasar

SD Muhammadiyah 2 Denpasar is a partner of this service activity. The number of teachers who teach at this school is 42 people. SD Muhammadiyah 2 Denpasar seeks to provide services in an innovative, creative and fun learning process, and refers to the student center, which is expected to increase and develop the potential of students. During the Covid-19 Pandemic, schools held online learning. Learning is done by the teacher giving assignments by asking students to study the material in the book through Whatsapp media. Discussion of learning materials is also carried out via whatsapp. The school also uses the zoom app which is not paid for. This causes problems because of the time limit for using zoom and the number of participants. There is limited time to use zoom so that the learning process is not complete in completing one learning topic. Likewise, the limitation of 100 participants also creates obstacles in the learning process because there are subjects that are attended by more than 100 students. To overcome these problems, Microsoft Teams will be used as a learning media in this school. The first phase of activity, namely providing training on Microsoft Teams learning media, has been carried out for two days by the proposing team. The training was attended by homeroom teachers for grades 4, 5 and 6. The training participants were very enthusiastic about participating in the training activities. Participants are able to practice directly the training material provided. The second phase of service activities was continued by evaluating and monitoring the use of MsTeams by participants who had received training in previous service activities. The results of the evaluation showed that this training activity gave satisfaction to the participants because the training topics provided provided an alternative to the use of digital media for learning for students at SD Muhammadiyah 2 Denpasar.

Caltech-NRAO Stripe 82 Survey (CNSS). V. AGNs That Transitioned to Radio-loud State

Abstract A recent multiyear Caltech-NRAO Stripe 82 Survey revealed a group of objects that appeared as new radio sources after >5–20 yr of absence. They are transient phenomena with respect to the Faint Images of the Radio Sky at Twenty Centimeters survey and constitute the first unbiased sample of renewed radio activity. Here we present a follow-up, radio, optical, and X-ray study of them. The group consists of 12 sources, both quasars and galaxies with wide redshift (0.04 < z < 1.7) and luminosity ( ) distributions. Their radio properties in the first phase of activity, namely the convex spectra and compact morphology, allow them all to be classified as gigahertz-peaked spectrum (GPS) sources. We conclude that the spectral changes are a consequence of the evolution of newly born radio jets. Our observations show that over the next few years of activity the GPS galaxies keep the convex shape of the spectrum, while GPS quasars rapidly transform into flat-spectrum sources, which may result in them not being recognized as young sources. The wide range of bolometric luminosities, black hole masses, and jet powers among the transient sources indicates even greater population diversity in the group of young radio objects. We also suggest that small changes of the accretion disk luminosity (accretion rate) may be sufficient to ignite low-power radio activity that evolves on the scale of decades.

Large-scale gravity-driven phenomena in the Crotone Basin, southern Italy

The aim of this study is to better define the scale, timing and driving mechanisms of a seaward-gliding landmass currently affecting the Crotone Basin, a forearc basin on the Ionian side of Calabria (southern Italy). An integrated approach of seismic, well and field data, together with literature information, have revealed that the slide includes an onshore updip extensional domain compatible with the presence of a curved seaward-dipping fault system to the NW, which is connected southward to an offshore downdip compressional domain through a buried detachment surface lying at a Messinian halite layer. The landmass, which involves Messinian-Pleistocene deposits, has started to slide since the Zanclean, and experienced a paroxysmal episode between late Zanclean and early Piacenzian linked to transpressional tectonics. After a phase of inactivity during the Calabrian, the gravitational collapse underwent a second reactivation since middle Pleistocene due to regional uplift, which seems to be restricted to the offshore sector, the Crotone peninsula and probably the eastern coastal area. • A better definition of the scale, timing and driving mechanisms of the Crotone Megalandslide is provided. • A first phase of activity started during the Zanclean and ended during the Gelasian, and involved the whole basin. • A second phase of activity persists since the middle Pleistocene and involved only the Crotone peninsula and the offshore area.

Peculiarities of Athletes’ Adaptation and Preparation for 24th World University Games in Bangkok

Travelling across several time zones exposes the sportsman to a shift of his internal biological clock and the result is a transient desynchronization of the circadian rhythm lasting for several days until the body adapts to new environmental conditions. The subjects of this study were 12 Lithuanian Track and Field athletes participating in the 24th University Games in Bangkok. We used the model of integral evaluation of the body functioning during exercise which integrates changes of three functional elements: P — periphery system (muscles), R — regulatory system (brain), S — supplying system (heart, blood-vessel system). A Finger Taping Test, where the time intervals were recorded in milliseconds between separate motions, and a nonlinear dimensional reduction by grouping them to various components were used for analysis. We observed a lot of changes in various indices but the main attention was paid to the assessment of indices providing information about the mobilization and recovery of the cardiovascular system and the complexity of body functioning. After the arrival the characteristic feature was a slower mobilization of the body functions at the onset of exercise for the first 4—5 days, though the level of mobilization during the exercise remained the same. Another characteristic feature was the slower recovery of cardiovascular indices after exercise for the first 6—7 days. There were some phases in the process of adaptation after sudden change of geographical and environmental conditions before competition. The first phase of activation of regulatory systems occurred, and the phase of increased energy demands appeared after 48 hours and lasted for the next five days. A wide range of individual variations characteristic of adaptive changes in the body depended on training and competitive experience of athletes, their personality, sleep and behavior habits and training loads performed before departure to the venue of competitions as well. The behaviour of athletes and training strategies during the first days were important and could help accelerate the adaptation. And on the contrary, heavy training loads could decrease the speed of adaptive changes.Keywords: cardiovascular system, complexity, recovery, adaptation

Reknit Revolution: Knitwear Design for the Domestic Circular Economy

An ongoing initiative seeks to encourage hand knitters to expand their practices to encompass reknitting: the reworking of existing knitted items using knit-based skills, techniques and knowledge. Reknitting offers potential benefits in terms of promoting repair and re-use by individual users within the domestic sphere, thereby contributing to the “domestic circular economy”. Although reknitting was a common element of hand knitting practice in the past, the knowledge of how to open, alter, unravel and reknit has largely been lost. This gap in practice presents a fertile challenge for contemporary knitted textile design. A first phase of activity saw the initial development and testing of reknitting techniques suitable for the garments in our wardrobes today. This project demonstrated that it is possible to engage knitters with reknitting, but that support is needed to overcome barriers to participation and shift perceptions of what is both possible and desirable. Three interconnected elements of support are discussed: inspiration, information and confirmation. A second phase of activity, centered around an exhibition in a public gallery, aimed to communicate the techniques to a wider knitting community. Exhibits included physical garments, a large-scale infographic and a film; adaptable instructions were developed and published on a companion website. Through analysis of these exhibits and instructions, categories within each of the three elements of support were identified to create a more detailed taxonomy of support for domestic reknitting practice. Reflection on the progress of this initiative indicates the direction for future activity: raising broader awareness of reknitting, primarily via online channels, and structuring opportunities for participation to build a mutually supportive community of practice. It is anticipated that the taxonomy of support could be applied to other initiatives seeking to promote domestic circular economy activity.

Environmental context of a Neolithic site at Beifudi, north-west Hebei Province, China

The earliest evidence of prehistoric religious practice in China found so far comes from excavations at Beifudi, about 120 km south of Beijing, in the form of votive offerings and porcelain sorcery masks dated to the period 8000–7000 yr BP. These finds are part of a rich Neolithic site located on the second river terrace on the north shore of the Yi River. This paper presents results of pollen analysis of part of a sediment profile from a depression at the edge of first terrace towards second terrace, a few hundred metres away from the main archaeological finds. A sequence of marked changes in environment occurred between 9000 cal yr BP and 6000 cal yr BP, and dating evidence suggests strong associations with the ebb and flow of human activity in the area. The first phase of activity on the site begins at around 8000 cal yr BP, towards the end of a period of relatively dry, cold environmental conditions. Between 7800 cal yr BP and 7400 cal yr BP, the first clear evidence of cereal cultivation appears in the pollen record. Rich archaeological finds occur during the same time period, suggesting local prosperity. This first phase of the Beifudi culture ends at 7300 cal yr BP, when warmer and wetter conditions are inferred and wetland areas expand, reducing the area available for crop cultivation near the site. A return to drier and cooler conditions from 6900 cal yr BP corresponds with the second phase of apparent prosperity in the archaeological record from Beifudi. This phase ends at around 6500 cal yr BP, at the start of another shift towards wetter conditions in the flood plain environment. The pollen record suggests that environmental conditions in the flood plain were a major determinant of human activity at Beifudi in the early-mid Holocene.

Thermo-mechanical fatigue tests on uniaxial and component-like 1CrMoV rotor steel specimens

An extensive project has been undertaken to characterize the thermal fatigue behaviour of 1CrMoV rotor steel under service-like loading conditions. In the first phase of activity, thermo-mechanical fatigue (TMF) tests were performed on plain uniaxial tensile specimens subject to service-like loading conditions characterized by low strain rates, thermal transients to 565 °C and long hold times at the peak temperature. These were followed by thermo-mechanical fatigue tests performed on circumferentially notched bars in order to study creep–fatigue crack initiation and short crack growth behaviour at stress concentrations. In the final phase of the project a new thermal fatigue experiment was implemented, applying severe thermal cycles to a large 3D feature specimen with a complex 10 mm deep groove. The experiment aimed to reproduce at specific notch locations loading conditions representative of turbine rotor features in service in terms of multiaxial stress state and thermal strain gradients. The results of these TMF and thermal fatigue studies are summarized in this paper.

Functional role of JNK in neuritogenesis of PC12-N1 cells

JNKs, also known as SAPKs, are activated in response to a wide variety of factors including growth factors, cytokines, UV radiation, and heat shock. In the rat pheochromocytoma PC12 cells, the JNK signaling pathway mediates diverse functions such as differentiation and apoptosis. We have previously shown that activated JNK is required for later stages of neuritogeneis induced by NGF in a variant PC12 cell line (N1). Here, the functional role of JNK in N1 cells is further investigated. We show that NGF treatment, which induces extensive neurite branching and cell soma enlargement in the N1 cells, stimulates a biphasic activation of JNK. The first phase of activation is rapid and transient, beginning at 15 min after NGF exposure and lasting approximately 45 min. The second phase of activation is sustained, beginning at 9–12 h of NGF treatment and lasting for at least 24 h. Similar biphasic pattern of JNK activation is also observed in the parental PC12 cells. Using the specific JNK inhibitor SP600125, we show that the biphasic activation is necessary for neurite outgrowth and branching, and that inhibition of either phase suppresses neuritogenesis in the N1 cells. These results suggest that dynamic JNK activation may play a key role in neurite outgrowth during neuronal development.

Response of bacterial community during bioremediation of an oil-polluted soil.

To study the response of the bacterial community to bioremediation of a soil with an aged contamination of crude oil. The bacterial community in laboratory soil columns during a 72-day biostimulation treatment was followed by analysing the number of total cultivable hydrocarbon-degrading bacteria, soil respiratory activity and the 16S-23S rDNA internal transcribed spacer homoduplex heteroduplex polymorphisms (ITS-HHP) of total soil bacterial DNA. ITS-HHP permits an estimate of both length and sequence polymorphism in a 16S-23S rDNA spacer population, using to advantage the homoduplex and heteroduplex fragments that are generated during PCR. The treatment, made by air sparging and biostimulation with a mineral nutrient and surfactant solution, resulted in a 39.5% decrease of the total hydrocarbon content. Within 4 days of treatment onset the bacterial community underwent a first phase of activation that led to a substantial increase in the observable diversity. Subsequently, after a 12-day period of stability, another activation phase was observed with further shifts of the community structure and an increase in the abundance and diversity of catechol-2,3-dioxygenase (C23O) genes. The overall data suggest an important contribution of uncultivable bacteria to the soil bioremediation, since, during the second activation phase, the increases of the respiratory activity, bacterial diversity and C23O gene abundance and diversity were not accompanied by a corresponding increase of the cultivable bacteria number. This study shows that successive phases of activation of bacterial populations occur during a bioremediation treatment of oil-polluted soil.

Seismicity and Velocity Structure of Loihi Seamount from the 1996 Earthquake Swarm

The largest earthquake swarm yet recorded on Loihi submarine volcano took place in July and August of 1996. The swarm consisted of two phases of seismic activity and was associated with the formation of a pit crater and additional faulting of Loihi's summit platform. The first phase of activity was comprised of predomi- nantly high-frequency events scattered over the southern flanks of the volcano. Fol- lowing a day of seismic quiescence, the second phase of activity began, consisting of lower-frequency earthquakes with strong T-phases. The phase 2 events took place beneath Loihi's summit, presumably marking the formation of the pit crater, Pele's Pit. Data obtained by an ocean-bottom seismometer (OBS) on Loihi during the swarm help constrain a new velocity model for Loihi. The relocated earthquakes, combined with other characteristics of the swarm, enabled us to develop a model for the events leading up to the formation of Pele's Pit that includes (1) a prolonged eruption, (2) a tectonic event beneath Loihi's south flank, and (3) the drainage of a shallow magma chamber.

Petrogenesis of the Toba Tuffs, Sumatra, Indonesia

During the past 1.2 my, at least 3400 km3 of magma have been erupted in four ash flow tuff units from the Toba Caldera Complex. This activity culminated at 74 ka with the fourth eruption, which produced 2800 km3 of magma and formed the 100 km × 30 km caldera visible today. A relatively homogeneous two-pyroxene dacite was erupted during the first phase of activity. Magma erupted during each successive eruption was compositionally zoned, generally ranging from rhyodacite to rhyolite. The youngest three tuff deposits contain up to 40 wt % crystals of quartz, sanidine, plagioclase, biotite, and amphibole. Minor minerals are magnetite, ilmenite, allanite, zircon, fayalite, and orthopyroxene; inclusions of apatite and pyrrhotite are common. Extensive fractional crystallization in double-diffusive convecting magma bodies is suggested for creation of the compositional variation. Although similar in composition and mineralogy, the tuffs can be distinguished by subtle variations in their mineral, whole-rock, and glass compositions. Intensive parameter determinations suggest that much of the crystallization of the quartz-bearing tuffs occurred between 700 and 760°C at depths of 10 km. Water pressure estimates indicate that Ptot > PH2O; thus volatile oversaturation probably did not initiate the eruptions. Individual pumice blocks and fiamme collected from the youngest three units record simultaneous eruption across compositional boundaries. Low-energy ring fracture eruptions resulted in dense welding of all units except for the top of the youngest unit, and thick accumulations of rhyodacitic magma in the collapsing calderas.

Retrovirus-induced target cell activation in the early phases of infection: the mouse mammary tumor virus model.

Mouse mammary tumor virus (MMTV) infects B lymphocytes and expresses a superantigen on the cell surface after integration of its reverse-transcribed genome. Superantigen-dependent B- and T-cell activation becomes detectable 2 to 3 days after infection. We show here that before this event, B cells undergo a polyclonal activation which does not involve massive proliferation. This first phase of B-cell activation is T cell independent. Moreover, during the first phase of activation, when only a small fraction of B cells is infected by MMTV(SW), viral DNA is detected only in activated B cells. Such a B-cell activation is also seen after injection of murine leukemia virus but not after injection of vaccinia virus, despite the very similar kinetics and intensity of the immune response. Since retroviruses require activated target cells to induce efficient infection, these data suggest that the early polyclonal retrovirus-induced target cell activation might play an important role in the establishment of retroviral infections.

Pyrogenic stimulation of vascular resistance in conscious sheep

Increased arterial blood pressure following a pyrogenic reaction has been reported in previous studies, however the mechanism of this hypertension has not been examined in detail. The present study investigated the effects of both intravenous (IV) and intracerebroventricular (ICV) injection of lipopolysaccharide (LPS) from E.coli on body temperature (Tb), mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), calculated total peripheral resistance (CTPR), stroke volume (SV) and plasma levels of adrenocorticotropin (ACTH) and arginine vasopressin (AVP) in conscious, chronically instrumented sheep. IV injection of LPS (1 μg) increased Tb in a biphasic manner from 38.7 ± 0.1 to 39.5 ± 0.2 °C after 50 min and to 39.9 ± 0.2 °C after 130 min and MAP increased biphasically from 64 ± 1 to 70 ± 4 mmHg after 40 min and to 78 ± 3 mmHg after 130 min. CO initially decreased from 4.4 ± 0.1 to 3.5 ± 0.1 after 40 min followed by a secondary rise to 4.8 ± 0.1 l/min after 100 min. This occurred together with a large, biphasic increase in CTPR from 14.5 ± 1.0 to 22.0 ± 2.0 mmHg/l/min at 40 min and to 18.1 ± 0.1 mmHg/l/min at 120 min. HR increased from 68 ± 4 to 97 ± 4 b/min and SV decreased from 65 ± 2 to 41 ± 4 ml/beat during the first phase of activation. Plasma ACTH increased from 22 ± 9 to 1043 ± 175 pg/ml after 80 min and plasma AVP increased from [ if0.7 ± 0.2 to 12 ± 4.0 pg/ml after 60 min. ICV injection of LPS produced a long-lasting increase in Tb and MAP, but had no effect on HR or plasma AVP. Plasma ACTH increased from 30 ± 12 to 427 ± 110 pg/ml. These changes suggest that intravenous pyrogenic infection produces a potent vasoconstrictor action in sheep to increase blood pressure, possibly mediated by the actions of AVP within the CNS, or other pyrogenically released vasoconstrictor factors. Furthermore, the duration of activation of the cardiovascular system following peripheral and central LPS administration is different, which together with the contrasting effects on ACTH and AVP, indicate the involvement of several hypertensive mechanisms.

Responses of trigeminal subnucleus oralis nociceptive neurones to subcutaneous formalin in the rat

Extracellular recordings of 33 single nociceptive neurones of the trigeminal subnucleus oralis (SNO) were made in rats under halothane nitrous oxide anaesthesia. These neurones were tested for their responses to a s.c. injection of formalin in their receptive field. Such a chemical noxious stimulation is known to induce a biphasic response of nociceptive dorsal horn neurones, the second period of which would be due to inflammation. Twenty-three neurones were characterized as nociceptive non-specific (NnS) and 10 as nociceptive specific neurones (NS). Formalin activated both SNO NS and NnS neurones, but, when they responded, NS neurones ( n = 5) showed only the first phase of activity while NnS neurones showed either one ( n = 13) or two phases ( n = 6). Biphasic responses were most often observed for NnS neurones with Aδ- and C-fibre inputs. These results indicate that the time-course similarity between the behavioural and the neuronal responses to formalin exists only for some SNO convergent neurones and that therefore the SNO does not seem to be very involved in the inflammatory component of the pain caused by formalin.

Nitrate reductase activity changes during a culture cycle of tobacco cells: the participation of a membrane-bound form enzyme

The in vivo and vitro nitrate reductase (NR; EC 1.6.6.1) activities of suspension cell cultures were investigated in two strains of Nicotiana tabacum: a photomixotrophic green wild type (WT) and non-photosynthetic green type RubisCo − (SP25). During a batch culture cycle of 21 days, two peaks of in vivo NR activity (NRA) were observed: an early peak at 7 h and a second peak which reached a maximum at 6–8 days. At the beginning of the culture, in vitro activity was detected early for the WT cells compared to SP25 cells for which the activity was very low or absent. During the second peak, in vitro activity was present in the two strains and correlated very well with in vivo activity. Immunoblot experiment suggested that NR 120 kDa polypeptide did not accumulate in the cytosol at the beginning of the first phase of activity and the NR protein seemed to be labile. In contrast, the NR protein was stable during the second peak. On the other hand, it was observed that the dividing cells at 5–8 days seemed to accumulate nitrate, while the non-dividing cells, at the beginning of the culture, are unable to do that. This feature might be related to a change of cell permeability for nitrate because NR activity causing nitrate reduction is better in the second peak than in the first one. In correlation with this likely permeability change, external nitrate concentration modulated the first peak NRA and not the second one. The differential sensitivity of NRA of the two peaks to nitrate, led us to rediscuss the localization site of NR and to focus our experiments on a membrane-bound form of this enzyme.

Platelet desensitization by arachidonic acid is associated with the suppression of endoperoxide/thromboxane A 2 binding to the membrane receptor

The inhibitory mechanism of high levels of exogenously added arachidonic acid on activation of washed human platelets was investigated. While low levels of arachidonic acid (5–10 μM) induced aggregation, ATP secretion and increase in cytoplasmic free Ca 2+ concentration (first phase of activation), these platelet responses did not occur significantly at high concentrations (30–50 μM). However, much higher concentrations than 80 μM again elicited these responses (second phase). The first phase of platelet activation was inhibited by cyclooxygenase inhibitor, indomethacin, whereas the second one was independent of such treatment. Thromboxane B 2 was produced dose-dependently until reaching a plateau at arachidonic acid concentrations higher than 20 μM, irrespective of the lack of aggregation and secretion at high concentrations. After that the amount of free arachidonic acid which remained unmetabolized in platelets gradually increased. High concentrations of arachidonic acid as well as other polyunsaturated fatty acids caused desensitization of platelets in response to U46619, and also depressed the specific [ 3H]U46619-binding to the receptor as well as other polyunsaturated fatty acids. The amount free arachidonic acid needed in platelets to suppress [ 3H]U46619 binding corresponded to that needed to inhibit platelet aggregation. Furthermore, arachidonic acid dose-dependently induced fluidization of lipid phase of platelet membranes as detected by 1,6-diphenyl-1,3,5-hexatriene. These results suggest that the inhibition of platelet response by high levels of arachidonic acid can be attributed to interference with endoperoxide /thromboxane A 2 binding to the receptor, probably due to perturbation of the membrane lipid phase due to excess amounts of free arachidonic acid remaining in the membranes.

The Black Stockarton Moor subvolcanic complex, Galloway

The Black Stockarton Moor subvolcanic complex is a composite of intersecting porphyrite dyke swarms, granodioritic sheet intrusions, small granodiorite stocks and breccia pipes of late Caledonian age, emplaced within the Lower Palaeozoic turbidite sequence of the Southern Uplands of Scotland. Evolution from the subvolcanic to the plutonic igneous regimes can be traced in a first phase of activity with the successive intrusion of dykes, sheets, stocks and the adjacent Bengairn and Criffel plutonic complexes. The minor intrusions were partially preserved from obliteration by the subsequent plutonism, as the centre of igneous activity shifted progressively from W to E. A second phase of intrusion, post-dating most, if not all, of the plutonic activity, took place within an entirely different stress field producing en echelon sigmoidal porphyrite dykes with maximum dilation roughly at right angles to that of the earlier intrusions. Deep crustal shear is postulated as the source of the tension fractures, which were subsequently filled by the second phase dykes, and also of 2 of the 3 sets of wrench faults which cut the area.