Bat guano and historical evidence of climate changes in the west of Iran during the Late Holocene (Meghalayan Stage)

An 86 cm thick sequence of bat guano layers in the Kolatarika Cave in Kurdistan province in the west of Iran was analysed. The sequence was radiocarbon dated and covers an age of approximately 4060 years. The results of geochemical data, statistical studies, along with the investigation, analysis and explanation of historical sources indicate the presence of warm and dry climate conditions between ca 2100 BC and 800 CE. These were contemporaneous with the occurrence of periods of drought and famine during the Achaemenid and Sassanid empires, and might have been was one of the causes of their ‘collapse. The existence of humid climate conditions between 800 and 1450 AD was contemporaneous with the period of Medieval Climate Anomaly and the historically documented prosperity of farms and agriculture during the Seljuk dynasties, the Samanids, and the rise of rainfall and river floods during the period of the Abbasid caliphate. The presence of cold and humid climate conditions between ca 1600 and 1750 AD was consistent with the so-called Little Ice Age and the Maunder Minimum. After this period, the climate of this area changed to warm and dry which was contemporaneous with the occurrence of famine and subsequent droughts of the late Safavid and Qajar dynasties in Iran.Key words: palaeoclimate, geochemistry, Little Ice Age, Medieval Climate Anomaly, Kolatarika Cave, Iran.Poznoholocenske podnebne spremembe v zahodnem Iranu: analize netopirskega gvana in zgodovinskih dokumentovV članku predstavimo analize 86 centimetrov debelega zaporedja plasti netopirskega gvana v jami Kolatarika v provinci Kurdistan, Zahodni Iran. Radiometrično ugotovljen starostni razpon gvana obsega zadnjih 4060 let. Statistična obravnava geokemičnih analiz gvana in raziskava zgodovinskih virov kažeta na toplo in suho podnebje v obdobju 2100 pr. n. št. in 800 n. št. To sovpada s sušami in lakoto v času ahamenidskega in sasanidskega cesarstva, kar je bil najverjetneje tudi vzrok njunega propada. Analize gvana kažejo na vlažno podnebje med 800 n. št. in 1450 n. št., kar ustreza srednjeveški podnebni anomaliji in obdobju razvoja kmetijstva in blaginje v času dinastij Seldžukov in Samanidov. Vlažno podnebje s padavinami je povzročilo tudi poplavljanje rek v času abasidskega kalifata. Hladno in vlažno obdobje med letoma 1600 in 1700 sovpada z malo ledeno dobo oziroma Maunderjevim minimumom. Po tem obdobju podnebje postane toplejše in bolj suho, kar spet sovpada z lakoto in sušami v poznem obdobju safavidske in kadžarske dinastije v Iranu.Ključne besede: paleoklima, geokemija, mala ledena doba, srednjeveška podnebna anomalija, jama Kolatarika, Iran.

Replantation of an Avulsed Maxillary Incisor after 12 Hours: Three-Year Follow-Up

Tooth avulsion is defined as the complete displacement of the tooth out of its alveolar socket. The treatment of choice is immediate replantation or if that is not possible, placement of the tooth in an appropriate storage media. This report presents replantation of an avulsed maxillary central incisor after 12 hours of storage in milk. The tooth was replanted and splinted. One week later, it was treated endodontically and calcium hydroxide dressing was placed for 1 month; subsequently, the tooth was obturated with gutta-percha. During three years of follow-up, no evidence of ankylosis or inflammatory resorption was observed. After three years, the tooth was stable and remained functional and esthetically acceptable

Cloning and Expression of Randomly Mutated Bacillus subtilis α-Amylase Genes in HB101

The aim of this study was to isolate and express the randomly mutated α-amylase gene from B. subtilis strain 168. BS168F: 5′-gtgtcaagaatgtttgc-3′ and BS168R: 3′-gttttgttaaaagatga-5′ primers were used to amplify the amylase gene using the following cycle in error-prone PCR method: 94°C for 30 s, 40°C for 2 min, and 72°C for 2 min in 30 cycles that were followed with 72°C for 2 min as a post cycle. E. coli XL1 blue was used as host for plasmid construction. Amylase enzyme activity assay was performed using continuous spectrophotometric procedures. Results of sequencing showed that sequence was cloned from the first ATG and with the correct open reading frame. Having confirmed the integrity of the insert, the gene was ligated into expression vector pET-15b and then further confirmed using digestion analysis. Amylase activity showed 3 clones with higher enzymatic activity compared with the wild type. Error-prone PCR method produced a mutated gene that provides amylase activity much higher than that of wild type. Sequencing the mutated genes should shed light on the important region of the genes that could be manipulated in future studies