Photochemical colour change for traditional watercolour pigments in low oxygen levels

An investigation for light exposure on pigments in low-oxygen environments (in the range 0–5% oxygen) was conducted using a purpose-built automated microfadometer for a large sample set including multiple samples of traditional watercolour pigments from nineteenth-century and twentieth-century sources, selected for concerns over their stability in anoxia. The pigments were prepared for usage in watercolour painting: ground and mixed in gum Arabic and applied to historically accurate gelatine glue-sized cotton and linen-based papers. Anoxia benefited many colorants and no colorant fared worse in anoxia than in air, with the exception of Prussian blue and Prussian green (which contains Prussian blue). A Prussian blue sampled from the studio materials of J.M.W. Turner (1775 − 1851) was microfaded in different environments (normal air (20.9% oxygen) 0, 1, 2, 3.5, or 5% oxygen in nitrogen) and the subsequent dark behaviour was measured. The behaviour of the sample (in normal air, anoxia, and 5% oxygen in nitrogen) proved to be consistent with the 55 separately sourced Prussian blue samples. When exposed to light in 5% oxygen in nitrogen, Prussian blue demonstrated the same light stability as in air (at approximately 21°C and 1 atmosphere). Storage in 5% oxygen is proposed for ‘anoxic’ display of paper-based artworks that might contain Prussian blue, to protect this material while reducing light-induced damage to other components of a watercolour, including organic colorants and the paper support

Wechselbeziehungen zwischen endogenem veränderlichen Testosteronspiegel und fettfreiem Körpergehalt bei Jungen und Älteren Sportlern

The purpose of this study was to examine the endogenous circulating testosterone levels and lean body mass (LBM) in young to middle-aged physically active - sportsmen to determine, whether there any relationships between these parameters in normal circumstances (i.e., no medical problems or pharmacolo- gical manipulations). Healthy, drug-free men (n=127) were recruited for testing (mean±SD, age 25.0±4.8 yr). Morning blood samples were obtained and underwater weighing was performed to determine the body composition (the measures were: LBM, fat weight [FW], body fat percentage [%fat]). Testosterone (T) was analyzed via RIA. Correlation analysis was performed to determine if thee were any significant relationships between the measures. Coefficients between T and LBM (r = 0.266), FW (r = -0.255), and %fat (r = -0.280) were significant (p<0.005). These findings show that endogenous testosterone and LBM are significantly related to one another in physically active men; however, the magnitude of the relationship is moderate at best. This suggests that the LBM component of men (which is comprised primarily of muscle mass) is related to circulating testosterone levels; but it is also strongly influenced by other factors.UVOD Testosteron je anabolički androgeni spolni steroidni hormon povezan sa sintezom proteina. Mnogi veličinu tijela i mišićni razvoj povezuju s razinom testosterona u odraslih muškaraca. Takovo se poimanje razvilo zbog anaboličkih svojstava toga hormona. No, u stvarnosti, stupanj razvoja mišićne mase u pojedinca ovisi i o mnogim drugim faktorima; od kojih su neki fiziološke naravi, neki su vezani za ponašanje pojedinca, dok su drugi nasljedne prirode (Florini, 1987). Ipak, postoje dokazi koji podupiru pretpostavku kako opća razina cirkulirajućeg testosterona može biti, u određenoj mjeri, faktor koji doprinosi količini mišićne mase muškaraca in vivo. Ongphiphadhanakul i suradnici (1999) ustanovili su na uzorku fizički neaktivnih odraslih muškaraca (sedentarni stil života) da je mišićna tjelesna masa značajno povezana s endogenom razinom testosterona. U dvodijelnom modelu konstitucije ljudskog tijela, ono se dijeli na masnu komponentu (udio masnoga tkiva) i na nemasnu tjelesnu masu (LBM – engl. lean body mass). I sama sastavnica nemasne tjelesne mase sastoji se od nekoliko faktora, među kojima je nedvojbeno najvažniji onaj koji se odnosi na masu skeletnih mišića (Behnke, Wilmore, 1974; Brozek i sur. 1963). Neka druga istraživanja pokazala su kako unos testosterona (egzogeni testosteron) povećava nemasnu tjelesnu masu (LBM). Arslanian i suradnici (1997) izvijestili su kako je četveromjesečni tretman testosteronom u adolescenata koji su kasnili u biološkom razvoju (retardanti - zakašnjeli pubertet) rezultiraom povećanjem LBM za 7,6 kg. Bhasin i suradnici (1996) su otkrili da primjena testosterona u odraslih muškaraca povesava LBM, a kada se taj unos kombinira s vježbanjem, tada je povećanje količine nemasne tjelesne mase još veće. Griggs i suradnici (1989) dobili su slične rezultate na temelju jednomjesečne primjene testosterona, kombinirane s trenažnim programom za razvoj snage, što je razultiralo 12%-tnim povećanjem nemasne tjelesne mase te 27%-tnim ubrzanjem i povećanjem sinteze mišićnih proteina. Sveukupno, rezultati navedenih istraživanja potvrduju tvrdnju kako ukupna razina cirkulirajućeg testosterona pozitivno utječe na nemasnu tjelesnu masu (LBM) i, posebice, na mišićnu masu. Taj problem, međutim, nije do sada bio predmetom iscrpnih znanstvenih istraživanja, a osobito se previše pozornosti nije posvećivalo bazalnom statusu uzorka fizički aktivnih muškaraca. Ovo je istraživanje stoga usmjerenjo na ispitivanje razine cirkulirajućeg endogenog testosterona i nemasne tjelesne mase na uzorku zdravih muškaraca kako bi se utvrdilo postoje li relacije među navedenim parametrima i u uvjetima fizički aktivnog svakodnevnog života. ISPITANICI I METODE Uzorak ispitanika činila su 142 zdrava muškarca, koja su dala pismeni pristanak za sudjelovanje u ovom istraživanju. Tjelesne karakteristike uzorka (aritmetička sredina ± standardna devijacija): dob – 25,1±1,4.6 godina (raspon od 18 do 45 godina), tjelesna masa – 77,9±10,8 kg, visina – 176,9±8,8 cm. Ispitanici su odgovorili na jednostavan upitnik o stupnju njihove fizičke aktivnosti. Svaki je ispitanik bio redovito fizički aktivan (3,9±1,3 dana/tjedno; 44±19 min/dan), tj. bio je uključen u neki od mnogobrojnih oblika redovitog tjelesnog vježbanja, od rekreativnog vježbanja do sudjelovanja u natjecateljskim sportskim disciplinama. Mnogi ispitanici bili su sportaši - natjecatelji iz 9 različitih sportova (lacrosse – kanadski nacionalni sport, sličan hokeju na travi, ali se igra specijalnim reketima, op. prev., američki nogomet, atletika – trkači, bacači i skakači, hrvanje, košarka, bejzbol, nogomet, biciklizam i plivanje). Svaki sport bio je zastupljen relativno malim, k tome i nejednakim brojem ispitanika. Zato nisu provedene usporedne analize rezultate ispitanika iz pojedinih sportskih disciplina. Naime, mali uzorci ispitanika iz pojedinačnih sportskih disciplina ugrozili bi statistička načela (Linton i Gallo, 1975). Ispitanici bi se u našemu laboratoriju pojavili približno oko osam sati ujutro, 12 sati nakon posljednjeg obroka. Prvo su se 15 minuta odmarali ležeći na leđima. Nakon toga su im uzeti uzorci krvi iz vene na ruci. Iz krvnih se uzoraka ispitivala opća razina cirkulirajuseg testosterona standardnim radioimunološkim mjernim postupkom (DPC Inc, Los Angeles, CA). Nakon vađenja krvi, ispitanicima je izmjerena tjelesna masa baždarenom medicinskom vagomi (preciznost mjerenja ±0,10 kg). Velikim kliznim antropometrom izmjerena je visina ispitanika (preciznost mjerenja ±0,10 cm). Tijekom mjerenja ispitanici su bili odjeveni samo u kratke sportske hlačice. Provedeno je funkcionalno dijagnosticko testiranje dišnoga sustava kako bi se odredio rezidualni plusni volumen. Podvodno vaganje korišteno je za utvrđivanje građe tijela (Sinning i Hackney, 1984). Na temelju podvodnog vaganja odredena je gustoća tijela koja je uvrštena u formulu Brozeka i suradnika (1963) za izračunavanje postotka tjelesne masnose (% masti). Nemasna tjelesna masa (LBM) i težina masnog tkiva (FW – fat weight) izračunata je na temelju postotnih vrijednosti masnog tkiva. Podaci su obrađeni bivarijatnom linearnom regresijskom korelacijskom analizom. Vrijednosti testosterona su u svim slučajevima predstavljale nezavisnu varijablu, dok su izračunate varijable korištene kao zavisna varijabla (p<0.05). REZULTATI I RASPRAVA Srednja vrijednost koncentracije testosterona u ispitanika iznosila je 26,64 nmol/l (±SD = 12,57), što je vrijednost unutar klinički prihvatljivog raspona za muškarce te dobi (Tietz, 1990). Rezultati dobiveni analizom tjelesne konstitucije bili su LBM = 67,21±9,16 kg, FW =9,18±5,48 kg i postotak masnoga tkiva = 11,75±5,66%). Rezultati regresijske korelacijske analize pokazali su značajnu povezanost između razine testosterona i LBM (slika 1). Neke od ostalih tjelesnih mjera također su pozitivno korelirale s razinom testosterona. Ti su rezultati prikazani u tablici 1. Premda su utvrdene statistički značajne povezanosti između varijabli, dobiven je ralativno nizak stupanj zajedničkog varijabiliteta za udio testosterona u varijanci pojedinih varijabli (< 9.0 %). Primarni zaključak proistekao iz ovog rada ukazuje na značajnu povezanost ukupne količine cirkulirajućeg endogenog testoserona i nemasne tjelesne mase u fizički aktivnih muškaraca. Međutim, veličina povezanosti je, u najboljem slučaju, umjerena. Dobiveni se rezultati uvelike slažu s nalazima Ongphadhanakula i suradnika (1995) koji su isti problem proucavali na uzorku sedentarnih, neaktivnih muškaraca. Hako je navedeno istraživanje obuhvaćalo, na neki način, komparabilnu grupu fizički neaktivnih, sedentarnih muškaraca, smatrali smo kako u našem istraživanju kontrolna grupa nije nužno potrebna. Prema modelu prosječnog muškarca (15 % masnog tkiva, 70 kg tjelesne mase), ukupna masa skeletnih mišića iznosi približno 52 % nemasne tjelesne mase (LBM) (Behnke i Wilmore, 1974). U fizički aktivnih muškaraca taj je postotak u pravilu nešto veći, s mogusnošću da dosegne 60% ili čak i više postotaka (Behnke i Wilmore, 1974). Na temelju takvog odnosa zaključli smo da je sastavnica nemasne tjelesne mase (LBM), a onda i mišisna masa u fizicki aktivnih muškaraca povezana s razinama cirkulirajućeg testosterona. Ipak, i ovdje se također pokazalo da na odnos testosterona i mišićne mase znatno utječu i ostali faktori, poput prehrambenih navika, genetskih, naslijedenih osobina te ostalih endogenih hormona (Florini, 1978). ZAKLJUČAK Mnogi sportaši misle kako postoji snažna izravna veza između razine testosterona i mišićne mase. Zbog toga se neki sportaši poduzimati i krajnje, čak i opasne mjere ne bi li povećali razinu testosterona u svome tijelu (dodaci u prehrani i/ili čak i uzimanje nedopuštenih sredstva, preparata ili dopinga). Autori ovog istraživanja vjeruju kako se dobiveni rezultati poslužiti i pomosi trenerima i kineziolozima da uvjere sportaše u to da je razina testosterona samo jedna od sastavnica u procesu razvoja mišićne mase, kao i da je korištenje doping-sredstava, poput, primjerice, anaboličkih steroida, nepotrebno.Das Ziel dieser Untersuchung war endogenen, veränderlichen Testosteronspiegel und fettfreies Körpergehalt (LBM) bei jungen und ältern Sportler zu messen, um die gegebenfalls vorhandenen Relationen unter den Parametern selbst im durchschnittlichen alltäglichen Umständen (d. h. wenn die Testpersonen einen guten Allgemeinbefund aufweisen ohne jegliche Medikamenteneinnahme) fest zu stellen. An der Untersuchung nahmen freiwillig 142 gesunde Testpersonen teil, die im Alter von 25.1±4.6 keine Medikamente einnahmen. Am Morgen wurden Blutproben genommen und danach wurde unter dem Wasserspiegel das Körpergewicht gemessen, womit der Körperbau (Maßstäbe: fettfreies Körpergehalt(LBM), Fettansatz im Fettgewebe (FW)) und der Fettspiegel (Fett-%) festgesatzt wurden. Testosteronspiegel (IT) wurde über RIA-Methode fest gestellt. Die Angaben wurden über lineare regressive Korrelationsanalyse mit zwei Varianzen bearbeitet, damit fest gestellt wurde, ob es bedeutende Wechselbeziehungen zwischen den Maßstäbe gäbe. Korrelationskoeffizienten zwischen T und LBM (r = 0.299) bzw. FW (r = -0.246) und Fett-% (r = -0.271) waren von einer Bedeutung nur bei P-Wert <0.005). Die Ergebnisse weisen darauf hin, dass der endogene, veränderliche Testosteronspiegel und fettfreise Körpergehalt bei körperlich aktiven Männern eine wechselseitige Beziehung aufweist, obwohl die Beziehung von keiner besonderen Bedeutung ist. Die Ergebnisse zeigen, dass das fettfreie Körpergehalt bei Männern (vowiegend aus Muskelgewebe) mit Schwenkungen imveränderlichen Testosteronspiegel zu tan hätte, dass es aber von anderen Faktoren - Essgewohnheiten, Erbgut und andere endogene Hormone - auch stark beeinflusst wird

Psychophysiology in microgravity and the role of exercise

The Space Transportation-Shuttle (STS) Program has greatly expanded our capabilities in space by allowing for missions to be flown more frequently, less expensively, and to encompass a greater range of goals than ever before. However, the scope of the United State's role and involvement in space is currently at the edge of a new and exciting era. The National Aeronautics and Space Administration (NASA) has plans for placing an orbiting space station (Space Station Freedom) into operation before the year 2000. Space Station Freedom promises to redefine the extent of our involvement in space even further than the STS program. Space Station crewmembers will be expected to spend extended periods of time (approximately 30 to 180 days) in space exposed to an extremely diverse and adverse environment (e.g., the major adversity being the chronic microgravity condition). Consequently, the detrimental effects of exposure to the microgravity environment is of primary importance to the biomedical community responsible for the health and well-being of the crewmembers. Space flight and microgravity exposure present a unique set of stressors for the crewmember; weightlessness, danger, isolation/confinement, irregular work-rest cycles, separation from family/friends, and mission/ground crew interrelationships. A great deal is beginning to be known about the physiological changes associated with microgravity exposure, however, limited objective psychological findings exist. Examination of this latter area will become of critical concern as NASA prepares to place crewmembers on the longer space missions that will be required on Space Station Freedom. Psychological factors, such as interpersonal relations will become increasingly important issues, especially as crews become more heterogeneous in the way of experience, professional background, and assigned duties. In an attempt to minimize the detrimental physiological effects of prolonged space flight and microgravity exposure, the United States and Russian space agencies have taken steps to implement various countermeasure programs. One of the principle countermeasures used by both nations is exercise during space flight. The purpose is to present a brief overview of the major research findings examining the psychophysiological changes associated with microgravity exposure, and to address the potential role of exercise as a countermeasure in affecting these psychophysiological changes

The homotopy theory of simplicial props

The category of (colored) props is an enhancement of the category of colored operads, and thus of the category of small categories. In this paper, the second in a series on "higher props," we show that the category of all small colored simplicial props admits a cofibrantly generated model category structure. With this model structure, the forgetful functor from props to operads is a right Quillen functor.Comment: Final version, to appear in Israel J. Mat

Effect of short term caffeine supplementation and intermittent exercise on muscle damage markerseffect of short term caffeine supplementation and intermittent exercise on muscle damage markers

Aim: To evaluate the effect of oral caffeine supplementation and strenuous intermittent exercise on muscle damage markers in soccer players. Materials and Methods: 15 male professional soccer players completed a placebo controlled double blind test protocol. At 45 min before exercise, participants ingested 5.5 mg•kg-1 body mass of caffeine (CAF, n=8) or cellulose (CEL, n=7). The exercise was 2 trials of 6 sets of 10 sprints (20 m each) with 10 s recovery time between sprints, 2 min between sets and 15 min between trials. Blood samples were collected before (PRE), 24, 48 and 72 h after exercise. Serum activity of creatine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransaminase (AST), and alanine aminotrasaminase (ALT) were quantified. Results: Serum enzyme activity was enhanced by exercise in both groups, without a synergistic effect of caffeine. Conclusion: Our results suggest muscle damage markers increases after physical activities, but caffeine supplementation (5.5 mg•kg-1 body mass) has no influence upon serum enzymes reflective of muscle integrity and damage

Feminae: an international multi-site innovative project for female athletes.

Sufficient high-quality studies in sport science using women as participants are lacking, meaning that our knowledge and understanding of female athletes in relation to their ovarian hormone profiles is limited. Consortia can be used to pool talent, expertise, and data, thus accelerating our learning on a given topic and reducing research waste through collaboration. To this end, we have assembled an international multi-site team, described herein, to investigate the effects of the menstrual cycle and oral contraceptive pill phase on aspects of exercise physiology and sports performance in female athletes. We intend to produce an adequately powered, high-quality dataset which can be used to inform the practices of female athletes. Our approach will also employ research transparency – through the inclusion of a process evaluation - and reproducibility – through a standardised study protocol

Mutations in protocadherin 15 and cadherin 23 affect tip links and mechanotransduction in mammalian sensory hair cells

Immunocytochemical studies have shown that protocadherin-15 (PCDH15) and cadherin-23 (CDH23) are associated with tip links, structures thought to gate the mechanotransducer channels of hair cells in the sensory epithelia of the inner ear. The present report describes functional and structural analyses of hair cells from Pcdh15av3J (av3J), Pcdh15av6J (av6J) and Cdh23v2J (v2J) mice. The av3J and v2J mice carry point mutations that are predicted to introduce premature stop codons in the transcripts for Pcdh15 and Cdh23, respectively, and av6J mice have an in-frame deletion predicted to remove most of the 9th cadherin ectodomain from PCDH15. Severe disruption of hair-bundle morphology is observed throughout the early-postnatal cochlea in av3J/av3J and v2J/v2J mice. In contrast, only mild-to-moderate bundle disruption is evident in the av6J/av6J mice. Hair cells from av3J/av3J mice are unaffected by aminoglycosides and fail to load with [3H]-gentamicin or FM1-43, compounds that permeate the hair cell's mechanotransducer channels. In contrast, hair cells from av6J/av6J mice load with both FM1-43 and [3H]-gentamicin, and are aminoglycoside sensitive. Transducer currents can be recorded from hair cells of all three mutants but are reduced in amplitude in all mutants and have abnormal directional sensitivity in the av3J/av3J and v2J/v2J mutants. Scanning electron microscopy of early postnatal cochlear hair cells reveals tip-link like links in av6J/av6J mice, substantially reduced numbers of links in the av3J/av3J mice and virtually none in the v2J/v2J mice. Analysis of mature vestibular hair bundles reveals an absence of tip links in the av3J/av3J and v2J/v2J mice and a reduction in av6J/av6J mice. These results therefore provide genetic evidence consistent with PCDH15 and CDH23 being part of the tip-link complex and necessary for normal mechanotransduction

Effects of Intensive Training on Prolactin Responses to Submaximal Exercise in Males

The purpose of this study was to determine if serum prolactin responses to submaximal exercise were affected by 8 weeks of intensive training (5 cl/wk, 90 min/d 65-200% V02max). Nine males performed 90 minute continuous exercise bouts (cycle ergometry; 65% V02 max) at the end of 1, 4, and 8 weeks of training. Blood samples were obtained pre-training, and pre-, post-exercise. Significant differences were not seen in pre- and post-exercise prolactin levels at weeks 1 and 4. However, at week 8 the post-exercise prolatin was significantly greater than the pre-exercise levels (6.8 ± 0.9 vs 3.8 ± 1.0 ng·ml-1; P-1, respectively). The findings suggest intensive training results in a relative augmentation of the post-exercise prolactin response; however, this effect seems to be due primarily to the training induced lowered resting prolactin levels

Relationship between Cardiovascular Risk Factors and Adipokines in Adolescents

This study evaluated the associations of adipokines with cardiovascular risk factors

Effects of Exercise Training on Bone Health Parameters in Individuals With Obesity:A Systematic Review and Meta-Analysis

International audienceBackground: Osteoporosis causes bone fragility, increasing the risk of fractures. Evidence suggests a strong correlation between obesity and fracture risk. Physical training is known to enhance bone resistance and protect from fracture; however, its osteogenic effect in the presence of obesity remains unknown.and nbsp;Objective: We sought to evaluate the influence of exercise training on bone health indices in individuals with obesity.and nbsp;Methods: This systematic literature search was conducted using common electronic databases from inception - December 2019. The following key terms (and synonyms searched for by the MeSH database) were included and combined using the operators &quot;AND, &quot; &quot;OR, &quot; &quot;NOT &quot;: [( &quot;body mass index &quot; OR obesity OR obese OR overweight OR fat mass) AND ( &quot;bone mineral density &quot; OR &quot;bone mineral content &quot; OR &quot;peak bone mass &quot; OR &quot;mechanical loading &quot; OR &quot;Osteoporosis &quot; OR &quot;bone geometry &quot; OR &quot;bone resistance &quot;) AND ( &quot;exercise training &quot; OR &quot;physical training &quot; OR &quot;strength training, &quot; OR &quot;resistance training &quot; OR &quot;aerobic training &quot; OR &quot;combined training &quot;)].and nbsp;Results: After screening, 10 studies (889 initial records) were included in the final analysis (8 different countries, 263 participants). Two studies investigated males, six females, and two, both sexes. The training duration was at least eight weeks with 2-3 sessions/week. Physical training displayed a significant trivial impact on the whole body (WB) BMD (0.13 SMD; 95% CI [0.00, 0.26], p = 0.046). Subgroup analyses indicated a significant small increase in the WB BMD (0.27 SMD; 95% CI [0.00, 0.53], p = 0.048) in the endurance training group, a non-significant trivial increase in the WB BMD (0.11 SMD; 95% CI [-0.06, 0.29], p = 0.203) in the resistance group, and a non-significant trivial increase in the WB BMD (0.03 SMD; 95% CI [-0.26, 0.32], p = 0.86) in the combined training group. In addition, a significant small decrease was found in the weight of trained subjects (-0.24 SMD; 95% CI [-0.42, -0.05], p = 0.011).and nbsp;Conclusion: Physical training has little to no effect on the WB BMD in subjects with overweight/obesity. Currently, insufficient evidence to advocate for any specific type of exercise for enhancing bone health exists for overweight/obese individuals. Investigations examining the impact of varying types of physical exercise on WB BMD of obese individuals are needed