1,463 research outputs found
Biodeterioramento e conservazione chimica del tempio Bhimkichak, Malhar, Chhatisgarh, India
Stone cultural heritage materials are at risk of bio-deterioration caused by diverse populations of microorganisms living in biofilms. The microbial metabolites of these biofilms are responsible for the deterioration of the underlying substratum and may lead to physical weakening and discoloration of stone [1,18]. Fungal ability in producing pigments and organic acids have a crucial role in the discoloration and degradation of different types of stone in cultural heritage objects. Additionally, stone objects may support the communities of microorganisms that are active in the biodeterioration process. This investigation focuses on the mycological analyses of microbial biofilm from the Bhimkichak temple, in Malhar of Bilaspur District of Chhattisgarh state which is made of sandstone, and is heavily colonized by fungi. Eight fungal species on the sandstone were isolated. Aspergillus sp. was observed, a common species in the stone structure of this monument . The identified micro fungi cause discoloration as well as mechanical exfoliation of the building stone material which was analyzed through mechanical hyphae penetration and production of dark pigments and organic acids.RiassuntoI materiali lapidei appartenenti ai beni culturali sono a rischio di biodeterioramento a causa della proliferazione dei microrganismi che entrano nella composizione dei biofilm. I metaboliti microbici di questi biofilm sono responsabili del degrado del substrato sottostante e possono portare a un indebolimento fisico e alterazione cromatica della superficie lapidea [1,18]. La capacità dei funghi di produrre pigmenti e acidi organici ha un ruolo fondamentale nel degrado di differenti tipi di pietra costituenti beni culturali. Inoltre, i materiali lapidei possono sostentare le comunità microbiche che sono attive nei processi di biodeterioramento fornendo dei composti che possono essere metabolizzati. Questo lavoro si focalizza sull’analisi micologica del biofilm microbico proveniente dal tempio Bhimkichak a Malhar, nel distretto Bilaspur dello stato di Chhattinsgarh, che è stato costruito in arenaria ed è estesamente colonizzato da funghi. Inquesto lavoro, sono state isolate otto specie fungine appartenenti ad Aspergillus sp. I micro-funghi identificati provocano decolorazione ed esfoliazione meccanica del materiale lapideo, a causa della penetrazione meccanica delle ife e della produzione di pigmenti scuri e acidi organici.Résumé Les matériaux pierreux appartenant aux biens culturels sont à risque de bio-détérioration à cause de la prolifération des micro-organismes qui entrent dans la composition des bio-films. Les métabolites microbiens de ces bio-films sont responsables de la dégradation du substrat sous-jacent et peuvent amener à un affaiblissement physique et à une altération chromatique de la surface pierreuse [1,18]. La capacité des champignons de produire des pigments et des acides organiques a un rôle fondamental dans la dégradation de différents types de pierre constituant les biens culturels. En outre, les matériaux pierreux peuvent sustenter les communautés microbiennes qui sont actives dans les processus de bio-détérioration fournissant des composés qui peuvent être métabolisés. Ce travail se focalise sur l’analyse mycologique du bio-film microbien provenant du temple Bhimkichak à Malhar, dans le district Bilaspur de l’état de Chhattinsgarh, qui a été construit en grès et est amplement colonisé par des champignons. Dans ce travail, ont été isolées huit espèces fongiques appartenant à Aspergillus sp. Les micro-champignons identifiés provoquent la décoloration et l’exfoliation mécanique du matériau pierreux, à cause de la pénétration mécanique des hyphes et de la production de pigments sombres et d’acides organiques.ZusammenfassungZu den Kulturgütern zählende Steinmaterialien unterliegen aufgrund der Proliferation der in die Zusammenstellung der Biofilme eintretenden Mikroorganismen einer Verwitterungsgefahr. Die mikrobischen Metabolite dieser Biofilme sind für den Verfall des darunter liegenden Substrats verantwortlich und können eine physische Schwächung sowie eine farbliche Änderung der Steinfläche bewirken. [1,18]. Die Fähigkeit von Pilzen, Pigmente und organische Säuren zu produzieren, spielt im Rahmen der Verwitterung der unterschiedlichen, das Denkmal bildenden Steinarten eine grundlegende Rolle. Darüber hinaus können Steinmaterialien in die Verwitterungsprozesse aktiv eingebundene Mikrobengemeinschaften erhalten, da sie umwandelbare Verbindungen liefern. Diese Arbeit konzentriert sich auf eine im Tempel Bhimkichak in Malhar, im Bezirk Bilaspur des Staats Chhattinsgarh durchgeführte mykologische Analyse des mikrobischen Biofilms, im Rahmen derer die Sandsteinkonstruktion eine extreme Pilzbesiedelung aufwies. Im Verlauf dieser Tätigkeit wurden acht, dem Aspergillus sp. angehörige Pilzsorten isoliert. Die identifizierten Mikropilze verursachen durch die mechanische Penetration der Hyphen und die Produktion dunkler Pigmente sowie organischer Säuren einen Farb- verlust und die mechanische Abblätterung des Steinmaterials.ResumenLos materiales lapídeos que constituyen los bienes culturales están a riesgo de biodeterioro a causa de la proliferación de los microorganismos que entran en la composición de las biopelículas. Los metabolitos microbianos de estas biopelículas son responsables de la degradación del substrato subyacente y pueden causar una debilitación y alteración cromática de la superficie lapídea [1,18]. La capacidad de los hongos de producir pigmentos y ácidos orgánicos desempeña un papel fundamental en la degradación de diferentes tipos de piedra que constituyen los bienes culturales. Además, los materiales lapídeos pueden sustentar las comunidades microbianas activas en los procesos de biodeterioro proporcionando compuestos que se pueden metabolizar. Este artículo se centra en el análisis micológica de una biopelícula micróbica procedente del templo Bhimkichak en Malhar, en el distrito Bilaspur del Estado de Chhattinsgarh, construido en arenisca y ampliamente colonizado por hongos. En este trabajo, se han aislado ocho especies fungíneas que pertenecen a Aspergillus sp. Los micro-hongos identificados provocan la decoloración y exfoliación mecánica del material lapídeo, debido a la penetración mecánica de las hifas y a la producción de pigmentos oscuros y ácidos orgánicos.Резюме Каменный материал, являющий культурным достоянием, находится в состоянии биораспада по причине роста микроорганизмов, которые входят в составбиопленки. Микробные метаболиты этих биопленок виновны в ухудшении основного субстрата и могут привести к физическому ослаблению и изменению цвета каменной поверхности [1,18]. Способность грибов производить пигменты и органические кислоты играет очень важную роль в распаде различных видов камней, принадлежащих культурному наследию. Кроме этого, каменные материалы могут поддерживать микробные сообщества, активизирующиеся в процессах биоразложения, предоставляя компосты, которые могут быть метаболизированы. Данная работа сосредоточена на микологическом анализе микробной биопленки, взятой из храма Бхимкичак в Малхаре (район Биласпур, штат Чхаттинсгарх), который выстроен из песчаника и значительно покрыт грибами. В данной работе выделяются восемь видов грибов, относящихся к Aspergillus sp. Идентифицированные микрогрибы вызывают обесцвечивание и механическое отшелушивание каменного материала по причине механического проникновения гиф и выработке темных пигментов и органических кислот. Ամփոփում Մշակութային ժառանգության պատկանող քարե նյութերը բիոքայքայման ռիսկի են ենթարկվում շնորհիվ միկրոօրգանիզմների տարածմանը բիոֆիլմի կազմի մեջ: Այս բիոֆիլմերի մանրէաբանական նյութափոխանակիչները պատասխանատու են քարի մաշվելուն և կարող են հանգեցնել քարի մակերեսի ֆիզիկական թուլացման և գունաթափման [1,18]: Սնկերի ունակությունը արտադրել պիգմենտներ և օրգանական թթուներ մեծ ազդեցություն ունի տարբեր տիպի պատմական քարերի վրա: Ավելին, քարե նյութերը կարող են պահպանել մանրէաբանական խմբերը, որոնք ակտիվորեն նպաստում են քայքայմանը, տրամադրելով միացություններ, որ կարող են փոխակերպվել: Այս աշխատանքը նկարագրում է բիոֆիլմի միկոլոգիական մանրէաբանական վերլուծությանը Bhimkichak Malhar տաճարում, Chhattinsgarh պետության Bilaspur շրջանի, որը կառուցվել է ավազաքարով և լայնորեն բնակված է սունկերով: Այս աշխատանքում մեկուսացած են ութ տեսակի սունկեր որ պատկանում են Aspergillus Sp. տեսակին: Այս միկրո–սունկերը գունաթափում և մեխանիկական քայքայման են ենթարկում քարե նյութերը, որովհետև մեխանիկորեն մտնում էն քարի մեջ և արտադրում են մուգ գույնի պիգմենտներ և օրգանական թթուներ:
Quantum Gravitational Corrections to the Nonrelativistic Scattering Potential of Two Masses
We treat general relativity as an effective field theory, obtaining the full
nonanalytic component of the scattering matrix potential to one-loop order. The
lowest order vertex rules for the resulting effective field theory are
presented and the one-loop diagrams which yield the leading nonrelativistic
post-Newtonian and quantum corrections to the gravitational scattering
amplitude to second order in G are calculated in detail. The Fourier
transformed amplitudes yield a nonrelativistic potential and our result is
discussed in relation to previous calculations. The definition of a potential
is discussed as well and we show how the ambiguity of the potential under
coordinate changes is resolved.Comment: 27 pages, 17 figure
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