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Preparing the mixture in the Otto engine
No full textOvisnost razvoja motora s unutarnjim izgaranjem o kvaliteti goriva postojala je sve od pojave prvog motora. Svojstva goriva i njihova kakvoća imali su dominantnu ulogu u razvoju motora s unutarnjim izgaranjem. Proces pripreme smjese za izgaranje a u konačnici i izgaranja goriva je vrlo složeni kemijski i termodinamički proces. Tijekom izgaranja oslobađa se toplina koja zbog vremenske ovisnosti postaje dinamika oslobađanja topline s određenim utjecajem na ciklus. Trajanje procesa pripreme smjese i izgaranje ima svoje vremensko trajanje, a razvoj sustava usmjeren je na optimiranje trajanja procesa i povećanje kvalitete izgaranja. U radu je analiziran proces pripreme gorive smjese u Ottovu motoru, razvoj sustava za pripremu smjese te utjecaj načina pripreme smjese na sam proces izgaranja.Internal combustion engine's dependency on fuel quality existed ever since the development of the first engine. Fuel properties and their quality have played a dominant role in internal combustion engine development. The preparation process of the combustion mixture and it's final combustion is a very complicated chemical and thermodynamical process. During combustion, heat is released which, because of the time dependency, becomes a heat releasing dynamic with a defined influence on the combustion cycle. The duration and the combustion of the mixture has it's defined time period and
the development of this system is directed on optimizing the time and the strength of combustion. The preparation of the combustion mixture in Otto's engine, development of combustion preparation systems analyzed in this work and the effect the preparationof the mixture has the very combustion process is analyzed in this work
EFFECT OF PENTADECAPEPTIDE BPC 157 ON INJURED TENDONS OF SUPRASPINATUS AND INFRASPINATUS MUSCLE IN RAT
No full textUvod: Puknuće (ruptura) tetiva nadgrebnog (supraspinatus) i podgrebnog (infraspinatus)
mišića predstavlja, po incidenciji, najučestaliju skupinu masivnih ruptura rotatorne manšete
ramena. Masivna ruptura, potpuni prekid dviju ili više tetiva rotatorne manšete, ne cijeli
spontano. Konzervativno liječenje usmjereno je na održavanje funkcije i sprečavanje napretka
patoanatomskih promjena kao čimbenika odgovornih za visok postotak neuspjeha kirurškog
popravka masivnih ruptura rotatorne manšete.
Pretpostavljamo da oštećene tetive nadgrebnog i podgrebnog mišića mogu cijeliti primjenom
pentadekapeptida BPC 157, u skladu s već pokazanim pozitivnim učincima na hipovaskularna
i hipocelularna meka tkiva kao što su tetive i ligamenti, a napose intrasinovijalne tetive, kao
što su to tetive rotatorne manšete.
Materijal i metode: Devedeset ženskih albino štakora Wistar učinjena je transekcija tetiva
nadgrebnog i podgrebnog mišića i potom su, po slučaju, raspoređene u pokusne skupine.
Trećina je dobivala BPC 157 u dozi 10 µg/kg, trećina u dozi 10 ng/kg, a trećina je služila kao
kontrola. Prema putu primjene svaka skupina je razdijeljena na intraartikularnu i peroralnu
skupinu. Time su formirane 4 terapijske i 2 kontrolne skupine. Funkcionalna mjerenja
provođena su 4., 7., 10., 14., 21., 28., 42. i 56. dana nakon operacije. Životinje su žrtvovane,
po trećina iz svake skupine, 2., 4. i 8. tjedna nakon operacije. Nakon žrtvovanja provedena je
makroskopska procjena te priprema preparata za histološku obradu. Statistička analiza
provedena je metodom faktorijalne analize varijance popraćena post – hoc testom učinaka i
interakcija varijabli tijekom vremena praćenja.
Rezultati: Rezultati analize hoda pokazali su značajan gubitak funkcije neposredno nakon
operacije. Većina parametara pokazala je tendenciju oporavka kod svih pokusnih skupina
tijekom trajanja studije. Nasuprot kontrolnim skupinama sve tretirane skupine pokazale su
znatno brži, a prema određenim pokazateljima, i gotovo potpun funkcijski oporavak.pojavljuje se tijekom vremena praćenja. Nije bilo razlike u funkcionalnim rezultatima s obzirom na dozu BPC 157 ili prema putu primjene. Morfološki (makroskopski i
mikroskopski) jasno je vidljiva razlika između kontrolnih i tretiranih skupina životinja.
Značajna mišićna atrofija prati se od drugog tjedna u kontrolnoj skupini, a do kraja studije
dolazi do umnažanje fibroblasta u perimiziju. Tretirane skupine od početka studije imaju
promjere mišićnih vlakana usporedive s promjerima vlakana kontralateralne neoperirane
strane, a kod kontrolnih životinja kontralateralno javlja se hipertrofija mišićnih vlakana.
Zaključak: Pentadekapeptid BPC 157 ima značajan ljekovit učinak na ozlijeđene tetive
podgrebnog i nadgrebnog mišića, na štakorskom modelu masivne rupture rotatorne manšete,
neovisno o putu primjene i primjenjenoj dozi.
Kontraktura praktički potpuno nestaje odmah po primjeni pentadekapeptida BPC 157 i ne pojavljuje se tijekom vremena praćenja. Nije bilo razlike u funkcionalnim rezultatima s
obzirom na dozu BPC 157 ili prema putu primjene. Morfološki (makroskopski i
mikroskopski) jasno je vidljiva razlika između kontrolnih i tretiranih skupina životinja.
Značajna mišićna atrofija prati se od drugog tjedna u kontrolnoj skupini, a do kraja studije
dolazi do umnažanje fibroblasta u perimiziju. Tretirane skupine od početka studije imaju
promjere mišićnih vlakana usporedive s promjerima vlakana kontralateralne neoperirane
strane, a kod kontrolnih životinja kontralateralno javlja se hipertrofija mišićnih vlakana.
Zaključak: Pentadekapeptid BPC 157 ima značajan ljekovit učinak na ozlijeđene tetive
podgrebnog i nadgrebnog mišića, na štakorskom modelu masivne rupture rotatorne manšete,
neovisno o putu primjene i primjenjenoj dozi.Background and Objectives: Ruptured tendons of supraspinatus (SSP) and infraspinatus
(ISP) muscles, by current concepts, are part of rotator cuff pathology, and representh the most
common sub group in the massive rotator cuff tears. Massive tears are defined as a complete
ruptures of two or more rotator cuff tendons. Rotator cuff tear (RCT) is the most common
tendon injury seen in orthopedic patients and the leading cause of shoulder pain and
dysfunction in adults.
The progress of symptoms and functional impairment are often directly correlated with
anatomical deterioration. Recovery, to normal levels of function, could be achieved, trough a
standardised, non-operative treatment programmes as an effective alternative to surgery for
many patients. However, follow-ups are necessary to avoid an irreparable stage.
Pain and decreasing shoulder strength and function should alert the physician to promptly
recognize promptly the onset or aggravation of existing rotator cuff tears. Partial-thickness
tears (PTT), over the time, enlarge and propagate, trough full-thickness tears (FTT), into
massive rotator cuff tears (MRCT). Eventually, the glenohumeral joint experiences series of
degenerative alterations, which is known as cuff tear arthropathy (RTCA). Massive RCT does
not heal spontaneously and, due to muscle inactivity and retraction, develops distinct chronic
pathological changes. Reduction in tendon elasticity and viability and histological changes
such as fatty infiltration and muscle atrophy, are thought to be the key factors responsible for
the failure of surgically attempted massive RCT repair and poor clinical outcomes.
Considerable progress in understanding rotator cuff pathology and the treatment has been
made over the last two decades. Nevertheless, there is still wide potential to improve the
outcome of cuff tears further.
Also, in-depth studies regarding stable gastric pentadecapeptide BPC 157, apparently
demonstrated consistently positive and prompt healing effects for various, both traumatic and
systemic injury types, have been caried out over the past two decades.
We assume that injured tendons of supraspinatus and infraspinatus muscle could be healed by
therapy with stable gastric pentadecapeptide BPC 157. This approach would be in line with its
effect on plethora of soft tissues, especially hypovascular and hypocellular soft tissues such as
tendons and ligaments, and, more specifically, intrasynovial tendons - such as rotator cuff
tendons.
Material and Methods: To test our hypothesis, we conducted a study using a surgical rat
model with a massive rotator cuff tear, SSP and ISP. We carried out functional measurements
and both macroscopic and microscopic assessment.
All ninety experimental animals - female Wistar albino rats weighing an average approx 200
grams and aged betweet 8 to 10 weeks, underwent supraspinatus and infraspinatus tendon
transection under general anesthesia. After the surgery they were randomly assigned to
different experimental groups. These were formed according to the planned time of sacrifice
and sampling, in three equal groups ie 2 weeks, 4 weeks and 8 weeks. In addition, according
to the method of medication into two groups ie intra-articular (ia) and peroral (po). Each of
these groups in further divided in three equal subgroups, taking into account the dose of the
active substance – BPC 157 (10 mcg/kg or 10 ng/kg - for both ia and po group,) or neutral
substance (saline ia or water po). In total, four treatment groups were formed with respect to
the route of administration and dose of pentadecapeptide BPC 157 and two control groups
with respect to the route of administration.
Throughout whole duration of experiment, functional measurements (gait analysis and
shoulder contracture assessment test) were conducted on day 4, 7, 10, 14, 28, 42 and 56 after
the surgery. The rats were sacrificed 2, 4 and 8 weeks after the surgery. Immediately after
sacrificing the observed animals, the shoulder joints were opened, examined macroscopically
and scored. Supraspinatus and infraspinatus muscles were harvested, both from operated and
uninjured side, for comparision. Muscle samples were subsequently prepared for histological
interpretation.
Statistical analysis was carried out using the method of factorial analysis of variance for each
dependent variable as measure of the evaluation of the function. Independent variables were 3
types of therapy x 2 methods of administration of the treatment. In addition, in order to
analyze the time effect, number of days after the lesion was used as an independent variable in
the analysis.
Results: The functional parameters of walking and range of motion, which are indicators of
shoulder's function, significantly changed immediately after the supraspinatus and
infraspinatus transsection. Some changes remained during the entire study, while others were
temporary or showed a tendency to recover. Some parameters were even better comparing to
preoperative ones. In particular, this was observed with the speed and length of the paw. The
recovery trend was observed in the width of the paw and the distance between the middle
fingers.
Adjusting the right paws and reducing the stride width suggests that the right front paw moves
medially to compensate for the injury and to stabilize the animal, simmilar to tripod.
Obviously, the animal was carrying as little weight as possible on the injured limb after the
surgery. Over the time, as observed towards the end of the study, the animal was gaining
strength in the injured leg which no longer required protection due to the injury, the right front
paw returned to its former place. Also, the normalization of the gap between the middle
fingers and the width of the paw indicates the cessation of cracking of the damaged limb.
These functional parameters, which which tend to improve with time, are consistent within
the treated groups, had not changed significantly. Even they change initially, they'd normalize
by the fourth week.
Contracture almost completely disappears aftter the use of pentadecapeptide BPC 157,
regardless of the method of administration or dose application.
There was no difference in the functional results with respect to the dose of BPC 157 or due
to the method of administration.
Morphological (macroscopic and microscopic) clearly show the difference between the
control and treated groups of animals. Significant muscular atrophy is observed from the
second week in the control group and also, by the end of the experiment the multiplication of
fibroblasts in the perimysium. We found no signs of fat infiltration. The treated groups from
the beginning of the study have the diameters of muscle fibers comparable to the diameters of
the fibers of the contralateral uninjured side, while the contralateral side of the control animals
shows signs of hypertrophy of muscle fibers.
Altrough there are limitations of this study, since the general histological and biomechanical
estimates of the rotator cuff rupture model of animals are poorly comparable with clinical
estimates. The tendons in this study model were separated by an acute surgical procedure, andnot by the gradual progression of degeneration associated with chronic tendon ruptures. Thus,
many functional changes occurred immediately after the operation, rather than gradual, small
functional and structural changes over time. Therefore, the functional assessment of the
shoulder is an important component of any preclinical study for assessing the degree of, what
results can be transferred to the clinic. In addition, especially when interpreting the functional
results and, histologicaly the absence of fat infiltration, it should be taken into account that the
8 to 10 weeks old Wistar rats are still in the growth and development stage.
Conclusion: The results of the study confirmed our hypothesis and has shown that the
pentadecapeptide BPC 157, used either in microgram or nanogramm dose, has significant
positive effects on the damaged SSP and ISP tendons in a rat model of a rotator cuff rupture,
at the functional and structural levels results. No difference was noticed due to the method of
administration and the dose of BPC 157, which is in line with numerous previous studies of
the effects of BPC 157 pentadecapeptide.
Pentadecapeptide BPC 157, with its well-known properties, the absence of toxic and side
effects as well as the fact that the lethal dose has not been reached, is certainly suitable for
both local and systemic use.
Due to its ability to facilitate almost complete functional and histological restitution of organs
and tissues, the potential of pentadecapeptide BPC 157 is very positive and clear. In
accordance with the results of this study and evidence of the positive effect of BPC 157 on
damaged tendons in rats, it can be concluded that BPC 157 can be an effective
pharmacotherapeutic agent in the treatment of rupture of the tendons of the supraspinatus and
infraspinatus muscles. The demonstrated effectiveness in microgram and nanogram dosage is
a clear indicator of the exceptional endogenous effect of the introduction of pentadecapeptide
BPC 157 and the basis for further studies at even lower doses
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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