Orientadores Sylvio Luis Honório, Claudio Luiz Messias / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-27T23:01:54Z (GMT). No. of bitstreams: 1 Rocha_ArturBatistadeOliveira_D.pdf: 1714662 bytes, checksum: 577fdeb54b226ba61587e77781ac70cf (MD5) Previous issue date: 2015 / Resumo: O cultivo da batateira (Solanum tuberosum L.) apresenta problemas fitossanitários decorrentes do ataque de pragas e doenças, o que acarreta altos cultos de produção. As principais doenças pós-colheita em batata-semente são: podridão seca (agente causal: Fusarium solani), rhizoctoniose (agente causal: Rhizoctonia solani) e podridão mole (agente causal: Pectobacterium carotovorum subsp. carotovorum). Os principais glicoalcaloides presentes na batata são a ?-chaconina e ?-solanina, os quais possuem propriedades antimicrobianas e podem ser estimulados por diversos fatores, com destaque para a luz. O objetivo desta pesquisa foi investigar a aplicação da radiação ultravioleta UV-C e da luz fluorescente no controle dos patógenos Fusarium solani, Rhizoctonia solani e Pectobacterium carotovorum subsp. carotovorum nas cultivares Ágata, Atlantic e Monalisa de batata-semente após a colheita. A pesquisa foi realizada em duas etapas: (I) avaliou-se in vitro o efeito da radiação UV-C no desenvolvimento das colônias de F. solani e de R. solani e na germinação dos conídios de F. solani. In vivo avaliou-se o efeito da radiação UV-C e da luz fluorescente na severidade e na incidência de podridão seca e de rhizoctoniose na brotação, na perda de massa e no teor de sólidos solúveis em batata-semente 'Agata' e 'Atlantic'; (II): avaliou-se in vitro o efeito da radiação UV-C no desenvolvimento das colônias de P. carotovorum subsp. carotovorum. In vivo avaliou-se o efeito da radiação UV-C e da luz fluorescente na severidade e na incidência da podridão mole, na concentração de ?-chaconina e de ?-solanina, na brotação, na perda de massa e no teor de sólidos solúveis em batata-semente 'Agata' e 'Monalisa'. A exposição de F. solani e R. solani a uma densidade de energia de 105,6 kJ.m-2 de radiação UV-C diminui o desenvolvimento das colônias desses fungos para estudos in vitro. Para a germinação de conídios de F. solani foi exposta a uma densidade de energia de 52,8 kJ.m-2 de radiação UV-C. Além disso, a luz fluorescente foi mais eficaz do que a radiação UV-C para o controle da podridão seca e da rhizoctoniose, sem afetar a brotação. A exposição de P. carotovorum subsp. carotovorum na densidade de energia de 34,5 kJ.m-2 de radiação UV-C inibiu o desenvolvimento das colônias para estudos in vitro. A luz fluorescente foi mais eficaz do que a radiação UV-C para controle da podridão mole em tubérculos de batata, assim como, estimulou a síntese de glicoalcaloides. O controle da podridão mole em tubérculos de batata está relacionado a maior concentração de ?-chaconina e ?-solanina, especialmente na periderme. Os teores de ?-chaconina (11,6 a 26,0 mg.kg-1P.F.) e ?-solanina (11,4 a 25,1 mg.kg-1P.F.) mostraram-se eficazes para o controle da podridão mole. Além disso, a brotação não foi afetada de forma adversa / Abstract: The cultivation of potato (Solanum tuberosum L.) in the tropics suffers the attack of pests and diseases, burdening the cost of production. The main postharvest diseases in potato seeds are the dry rot (pathogen: Fusarium solani), black scab (pathogen: Rhizoctonia solani) and wet rot (pathogen: Pectobacterium carotovorum subsp. carotovorum. The efficiency of UV-C against a wide variety of microorganisms has been reported and there is interest in applying for seed disinfection. Potato plants contain glycoalkaloids being ?-chaconine and ?-solanine the main ones. The accumulation of these glycoalkaloids can be stimulated by several factors, especially light, having them important antimicrobial properties. The aim of this research was to evaluate the the postharvest application of ultraviolet (UV-C) radiation and the fluorescent light to control the pathogens: F. solani, R. solani, and P. carotovorum subsp. carotovorum on 'Agata', 'Atlantic', and 'Monalisa' potato seeds. The research was conducted in two stages: (I) the evaluation in vitro of the effect of UV-C radiation on the growth of F. solani and R. solani colonies and F. solani conidias germination and the in vivo effect of UV-C radiation and fluorescent light on dry rot and black scab severity and incidence, mass loss and soluble solids content on 'Agata' and 'Atlantic' and (II) the evaluation in vitro of the effect of UV-C radiation on P. carotovorum subsp. carotovorum colonies and was reported in vivo the effect of UV-C radiation and the fluorescent light on the severity and incidence of wet rot, ?-chaconine and ?-solanine, concentration, tuber sprouting, weight loss and soluble solids on 'Agata' and 'Monalisa'. Exposure of R. solani and F. solani at an energy density of 105,6 kJ.m-2 of UV-C radiation decreases the development of fungi colonies in vitro. Energy density of 52,8 kJ.m-2 inhibited the F. solani conidias germination. Moreover the fluorescent light was more effective than UV-C radiation to control dry root and black scab, without affecting the sprouting. The in vivo experiments showed that treated and untreated. UV-C tubers stored under fluorescent light were more effective to control soft rot than the UV-C treated tubers and stored under darkness. Control tubers under fluorescent light, UV-C treated under darkness, and UV-C treated under fluorescent light showed an increased concentration of ?-chaconine (11,6 to 26,0 mg.kg-1F.W.) and ?-solanine (11,4 a 25,1 mg.kg-1F.W.) for both cultivars / Doutorado / Tecnologia Pós-Colheita / Doutor em Engenharia Agrícola

A alga vermelha Gracilaria tenuistipitata tem sido utilizada como matéria prima para a produção de ágar e também como modelo para estudos fisiológicos e moleculares. Este trabalho analisou estratégias de fotoproteção contra a radiação UV dessa macroalga por meio de abordagens fisiológicas e moleculares, considerando a previsão de incremento de radiação UVB nas zonas tropicais do planeta nos próximos anos. Além disso, a interação entre a radiação UV e o suprimento de N foi também investigada. Essa interação estimulou a síntese de aminoácidos tipo micosporinas (MAAs) e outros compostos nitrogenados, o que proporciona proteção contra danos no aparato fotossintetizante. O envolvimento de um fotorreceptor para radiação UVA que regule a síntese de MAAs, com o efeito adicional de um segundo fotorreceptor, para radiação UVB é sugerido. Houve uma dependência da dose de radiação UV para aumento de MAAs. O aumento da intensidade da radiação UV causou efeitos negativos nos parâmetros da fotossíntese. Outra abordagem mostrou que a ausência de UVA causou danos ao DNA, com a presença de dímeros de ciclobutano pirimidina após 48 h de exposição à radiação PAR+UVB. Este estudo alerta para a importância da qualidade da radiação de UV e seu efeito biológico efetivo para danos no DNA e na fotoinibição. Fotoliases podem ter sido ativadas para evitar danos no DNA sob tratamentos com a presença de radiação UVA, tal como o sistema de enzimas antioxidantes, os quais desempenharam um papel secundário na fotoproteção da alga. A composição de carotenoides de G. tenuistipitata foi pouco afetada pelos tratamentos com N e UV. Este é o primeiro trabalho a mostrar a presença de anteraxantina em G. tenuistipitata, e se sugere a existência de um ciclo de xantofilas parcial composto por anteraxantina e zeaxantina. Um aspecto adicional foi o papel fotoprotetor de ficoeritrina, observado quando G. tenuistipitata foi tratada na presença de N, com PAR, UVA e UVB. Finalmente, a produtividade de MAAs por G. tenuistipitata foi estimulada sob tratamentos com radiação PAR+UV e suprimento de N, e se propõe que seja realizada uma aplicação em larga escala dessa alga vermelha para uso dessas substâncias como filtros de UV e antioxidantes. Desta forma, G. tenuistipitata foi capaz de lidar com a radiação UV, principalmente quando suprida com N e UVA, obtendo uma fotoproteção eficaz. Uma vez que se espera um aumento do índice de UV na superfície terrestre nos próximos anos, é possível que os organismos em ambientes oligotróficos sofram maiores impactos negativos causados por esta radiação / The red alga Gracilaria tenuistipitata has been used for the production of agar, as well as a model to physiological and molecular studies. This study analysed the photoprotective strategies of this macroalga against UV radiation through physiological and molecular approaches, considering the UV increase in tropical zones predicted by physical models. The interactive role of nitrogen supply and UV radiation was also investigated. The synthesis of mycosporine-like amino acids (MAAs) and other nitrogenous compounds was stimulated by both UVR and nitrogen, providing photoprotection against damages to photosynthetic apparatus. The involvement of a UVA-photoreceptor in the photocontrol of accumulation of MAAs and an additional effect with further activation of a second UVB-photoreceptor were suggested. There was a dependence of UV radiation dosis on MAAs accumulation. The increase of the UV irradiance caused a negative effect on the photosynthetic activity. The absence of UVA radiation caused DNA damage, with presence of cyclobutane-pirimidin dimmers after 48 h of exposure to PAR+UVB. This study shows the importance of light quality in the UV range and the biological effective irradiances to confer DNA damage and photoinhibition. Photolyases could be activated to avoid DNA damages under UVA treatments, as well as the antioxidant system, which had a possible secondary role on the photoprotection mechanisms. Carotenoid composition of G. tenuistipitata was slightly affected by UV and N treatments. This is the first study to show anteraxanthin in G. tenuistipitata, and the existence of a partial xanthophyll cycle is proposed, based on antheraxanthin and zeaxanthin. A further aspect observed was a photoprotective role of phycoerithrin in G. tenuistipitata, under the presence of UVA and UVB plus N supplement. Finally, MAAs productivity of G. tenuistipitata was stimulated under PAR+UV radiation and N supply, and we propose a large-scale application of this red alga for the use of these substances as photoprotector by both UV-screen and antioxidant capacities. Therefore, G. tenuistipitata was able to acclimate to UV radiation, under N-supply and UVA radiation i. e. efficient photoprotection and, considering the foreseen UV increment in the next years, its possible that oligotrophic organisms will suffer more with the negative effects of this radiation

The space environment possesses numerous unique and unusual attributes, creating challenges that must be considered in order to accomplish a successful space mission. Two of the detrimental aspects of the space environment include Atomic Oxygen, AO, and Ultraviolet, UV, radiation. UV radiation becomes more severe in space as there is no atmosphere to attenuate incoming photons, thereby exposing spacecraft to radiation that never reaches the surface of the Earth. Overall, space vehicles are exposed to a total of 107.4 Watts/m2 of light shorter than 400 nm. AO is created by the photo disassociation of molecular oxygen by UV radiation with wavelengths less than ~242.1 nm. AO is a major portion of the neutral atmosphere, and is the dominant species for altitudes between 180 and 675 km. Each of these environments can cause significant damage to spacecraft materials as they have sufficient energy to break molecular bonds: a generalization of AO energy is 4.5 +/- 1 eV while Vacuum Ultraviolet, VUV, radiation can break bonds as strong as 12.4 eV. Synergistic affects are observed when these two environments interact with materials simultaneously, resulting in an accelerated erosion rate. An apparatus has been developed in California Polytechnic State University’s, Cal Poly’s, space environments laboratory that can simulate the AO and VUV environments individually and simultaneously. This apparatus utilizes a radio frequency, RF, generator to produce a capacitively coupled plasma to create AO in conjunction with a deuterium lamp capable of emitting UV radiation as short as 115 nm. The system has been shown to produce an AO flux of 1.70 +/- 0.07•1016 atoms/cm2 while providing an equivalent sun power 4.5 times greater the solar output in the 120-200 nm region of UV light; all of this has been performed at a base pressure near 175 mTorr. Long duration tests of 24 hours, which would be analogous to durations used in a material interaction study, have shown an effective fluence of 1.47 +/- 0.06•1021 atoms/cm2, which would equate to an orbital exposure on the order of weeks to months. For the same duration a sample can be exposed to 108 equivalent sun hours of 120-200 nm radiation. Results from the simultaneous exposure also manifested an accelerated erosion rate, the expected synergetic reactions between the two environments.

Polyaromatic hydrocarbons (PAHs) are contaminants synthesized through incomplete combustion of carbon based substances. PAHs are known to be photodynamic and toxicity increases exponentially when in contact with ultraviolet radiation (UV). The effect of UV absent recovery periods and potential for latent toxicity during photo-induced toxicity are previously unknown and are not included within the toxicity model. Results of equal interval tests further support the current reciprocity model as a good indicator of PAH photo-induced toxicity. Interval test results also indicate a possible presence of time-dependent toxicity and recovery thresholds and should be included into toxicity risk assessments. Moreover, results of latent effects assays show that latent mortality is a significant response to PAH photo-induced toxicity and should be included into toxicity risk assessments. The present research demonstrates that UV exposure time rate is a significant driving force of PAH photo-induced toxicity.

The ionospheric response to solar EUV variability during 2011 - 2014 is shown by an EUV proxy based on primary ionization calculations using combined solar spectra from SDO/EVE and SolACES on board the ISS. The daily proxies are compared with global mean TEC analyses. At time scales of the solar rotation and longer, there is a time lag between EUV and TEC variability of about one to two days, indicating dynamical processes in the thermosphere/ionosphere systems. This lag is not seen at shorter time scales. When taking this delay into account the TEC variance at the seasonal and short-term time scale explained by EUV variations increases from 71% to 76%. / Die ionosphärische Antwort auf Variationen des solaren EUV im Zeitraum 2011-2014 wird anhand eines Proxys dargestellt, welcher die primäre Ionisation auf der Basis gemessener solare EUV-Spektren beinhaltet. Die täglichen Werte werden mit Analysen des global gemittelten Gesamtelektronengehalts verglichen. Auf Zeitskalen der solaren Rotation und länger findet sich eine Zeitverzögerung zwischen der EUV-Variation und des derjenigen des Gesamtelektronengehalts von ein bis 2 Tagen, welche auf dynamische Prozesse im System Thermosphäre/Ionosphäre hinweist. Die Verzögerung ist auf kurzen Zeitskalen nicht zu sehen. Wenn diese Verzögerung berücksichtigt wird, erhöht sich die durch EUV-Variationen erklärte Varianz des Elektronengehalts von 71% auf 76%.

Given the prevalence and risk associated with indoor tanning among college students, university campuses constitute a prime target for skin cancer prevention. This report identifies the successes and challenges faced in promoting a campus-wide tan-free policy through the National Council on Skin Cancer Prevention (NCSCP) Indoor Tan-Free Skin Smart Campus Initiative. Beginning in February 2016, we communicated with university faculty or staff members who have participated in skin cancer prevention via education, clinical care, or research at 20 universities regarding the steps to adopt the tan-free policy. One campus, East Tennessee State University (ETSU), successfully fulfilled all criteria and implemented the policy change to become the first US Indoor Tan-Free Skin Smart Campus. The greatest challenge faced in recruiting campuses was gaining administrative support. Reported reasons for not adopting the policy change included wanting to wait for other schools to join first and not seeing it as a top priority. Despite the importance of improving skin cancer awareness and decreasing tanning among university students, we faced several challenges in promoting campus-wide policy change. We identify a need for research on effective ways to disseminate university health policies and increased involvement of healthcare providers in policy-related work.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

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The effects of low doses of ionizing radiation on living things is a continually evolving area of research. Importantly, low dose effects were historically overlooked and not properly accounted for the assessment of risk to human health, as is the case with the contentious linear no-threshold model. These low dose effects are now known to be relevant to human health in both accidental and intentional exposures, including doses relevant to medical diagnostics and therapeutics. Furthermore, there is a relative dearth of information on low dose effects in non-human species, which necessitates further investigation and evaluation of radiosensitivity. Radiation-induced bystander effects occur in organisms due to the receipt of signals from directly irradiated cells, which act to communicate radiation damage to surrounding cells. Recent research has identified one type of bystander signal which is carried by photons of biological origin, however the effects produced in bystander cells receiving these photons has not been extensively investigated. It was suspected, based on previous research, that reactive oxygen species participate in the manifestation of this bystander effect. Three mammalian cell lines were assessed for their ability to produce bystander photons upon direct irradiation; subsequently, radiologically unexposed cells were exposed to the resulting photons and assayed for biological effects. The human cell lines used exhibited significant photon emissions and oxidative stress, clonogenic cell death, reduced cellular metabolism, and compromised mitochondrial oxidative phosphorylation following exposure to these photons. The use of a melanocyte cell line indicated that these effects are attenuated by melanin, and this is suspected to occur through photoabsorption or antioxidant mechanisms. Additionally, the same assays were conducted following cell exposure to hydrogen peroxide at low concentrations to assess responses to oxidative stress relevant to bystander responses, indicating less overall sensitivity in the examined melanocytes. These findings are significant because they contribute to our understanding of the mechanisms behind low dose biological effects, because they further challenge the linear no-threshold model and other models based on target theory, because they provide evidence for differential responses to the physical bystander signal in non-human species, and because secondary photon emissions are likely relevant to the medical radiation sciences. / Thesis / Master of Science (MSc) / Low doses of ionizing radiation interact with living things differently than high doses. Low dose effects are now known to be relevant to human health and protection of the environment. Radiation-induced bystander effects occur in cells due to the receipt of signals from irradiated cells which act to communicate radiation damage to surrounding cells. One type of bystander signal is carried by photons emitted from directly irradiated cells, however the effects produced in bystander cells receiving these photons has not been extensively investigated. This thesis investigates the cellular effects of these “biophotons”, including cell survival, oxidative stress, and metabolism.

<p dir="ltr">Prevention of the spread of diseases caused by airborne biological pathogens is of great concern. This was highlighted by the Covid-19 Pandemic, which was caused by the SARS-CoV-2 virus. One method for preventing the transmission of airborne pathogens is UV-C irradiation, which has been proven to effectively inactivate a wide range of airborne pathogens, including influenza viruses and coronaviruses. Disinfection of air using UV-C is usually employed through upper-room Ultraviolet Germicidal Irradiation (UVGI), UV-C based air cleaners in HVAC ducts, or stationary cabinets. In the research presented herein, near-field applications of UV-C disinfection are explored through implementation in personal protective equipment.</p><p dir="ltr">A series of personal protective devices were developed for real-time inactivation of airborne pathogens in military or civilian applications. The devices use UV-C radiation from low-pressure mercury lamps (254 nm) and UV-C LEDs (nominally 277 or 282 nm) to inactivate airborne pathogens that are inhaled or exhaled by users, thereby reducing the risk of disease transmission. The devices employ Porex PMR20, a material highly reflective of UV-C radiation, to promote photon recycling and improve the fluence rate fields inside the reactors. To quantify the efficacy of these UV-C devices, testing procedures were developed and applied. A two-part procedure was employed: (1) measurement of the fluence rate using the Micro Fluorescent Silica Device (MFSD) together with a positioning device and (2) biological experiments using T1 bacteriophage as an aerosolized challenge agent to quantify virus inactivation.</p><p dir="ltr">The fluence rate measurements were completed by fixing the location of the MFSD probe and moving the reactors to precise locations using the positioning device. The MFSD measurements were converted to fluence rate using measurements from an NIST-calibrated radiometer and collimated UV-C sources. When comparing the measurements with and without the PMR20, the local fluence rate for the LED reactors was found to be amplified by up to 10 times the value without the PMR20. A central peak was also found for both LED reactors, which was not present in measurements without the PMR20. Of the two LED reactors, the Nichia Reactor was found to have higher peaks in fluence rate, probably due to the higher output from the LEDs when compared to the JLED LEDs. The LP Hg Pod was found to have less significant amplification from the PMR20, with the maximum amplification being only 3 times the value without PMR20. The fluence rate near the walls lined with PMR20 was found to have the highest amplification for the Pod reactor, due to the lamp being located at the center of the reactor (unlike the LED reactors, where UV-C sources were positioned along the reactor walls).</p><p dir="ltr">The biological experiments were conducted using aerosolized T1 bacteriophage as a challenge agent. T1 was selected for these experiments because it has been shown to be more resistant to inactivation at the wavelengths of interest than most airborne pathogens; as such, T1 is a conservative surrogate for airborne pathogens in these applications. Experiments were conducted first at one flow rate and subsequently at a range of flow rates to quantify the effectiveness of the reactors and the impact the PMR20 on the inactivation response. When tested at the lowest flow rate of 2.5 L/min, all three reactors were found to provide inactivation at least as effective as the nominal removal provided by an N95 mask (95% or 1.3 log₁₀ units). The LP Hg Pod reactor was found to provide at least this level of inactivation (1.3 log₁₀ units) at flow rates up to 52.5 L/min when PMR20 lined the reactor. When tested without the PMR20, the loss in inactivation was substantial at 52.5 L/min but not at the lower flow rates.</p><p dir="ltr">The testing protocol developed and applied in this project could be applied to a range of other reactors intended for disinfection of air. A need exists to standardize testing and validation methods for UV-C based reactors and devices that are used to disinfect air. As such, the methods described herein may allow translation to other UV-C based devices.</p>