200 research outputs found
Çöpler (Erzincan, İç-Doğu Anadolu) Porfiri-Epitermal Altın Yatağında Arjilik Alterasyona İlişkin Mineralojik Kanıtlar (Mineralogical Evidences on Argillic Alteration in the Çöpler Porphyry-Epithermal Gold Deposit) (Erzincan, East-Central Anatolia)
Çöpler porfiri-epitermal altın yatağı, Tetis Alpin-Himalaya orojenik kuşağında açılmalı tektonizma sonucu gelişen orta Eosen yaşlı plütonik sokulumlarla ilişkili bir altın yatağıdır. Plütonik kayaçlar (granodiyorit porfir, diyorit porfir) Geç Paleozoyik-Mesozoyik yaşlı metapelit ve metakarbonat kayaçlar içerisine sokulum yaparak porfiri-epitermal bir Cu-Au yatağı oluşturmuş ve hidrotermal alterasyon zonlarının (potasik, fillik, propilitik, arjilik) gelişimine neden olmuştur. Bu çalışmada, önceki araştırmacılarca yerel ve sınırlı alanda geliştiği belirtilen süperjen alterasyonun aksine, geniş yayılım sunan arjilik alterasyon zonlarının mineralojik-petrografik özelliklerinin ortaya konulması amaçlanmıştır. Bu kapsamda, optik ve taramalı elektron mikroskop (SEM ve SEM-EDS), X-ışınları kırınımı (XRD), O-H izotop jeokimyası ve K/Ar yaş tayini incelemeleri gerçekleştirilmiştir. Aşırı killeşmiş granodiyorit porfirlerde bile, ilksel porfiritik doku izlenebilmekte, ince-kristalli kil ve kuvarslar homojen ve yer yer mikrolaminasyonlar şeklinde gözlenmektedir. Simektit ve karışık-tabakalı illit-simektit (I-S) mineralleri yapraksıtüysü, illit ve kaolinitler levhamsı biçimler sergilemektedir. Kuvars ve jarositler özşekilli kristaller, kristobalitler kurtçuk görünümlü, bu çalışmada ilk kez belirlenen krandallitler ise ince-taneli granüler topluluklar şeklinde gözlenmektedir. Arjilik zona ait örnekler fillik zona yakın iç kesimlerde (ileri arjilik zon) kuvars + I-S, kuvars + krandallit + jarosit ve kristobalit, dış kesimlerde (arjilik zon) ise kuvars + simektit + kaolinit birliktelikleri sergilemektedir. Simektitler dioktahedral bileşime sahiptir (d060<1.500 Å, oktahedral Al=1.47-1.66). I-S mineralleri yüksek illit bileşenli (I85-S15) ve R3 tipi ara tabakalanmaya sahip olup, oktahedral Al ve yapraklar arası K içerikleri sırasıyla 1.66-1.71 ve 0.58-0.75 arasında değişmektedir. I-S’lerin O-H izotop bileşimi, düşük sıcaklık koşullarında ve magmatik suyun baskın olduğu bir oluşumu işaret etmektedir. Jarosit içeren örneğin K/Ar yaş verisi (43.6 ± 1.0 My), arjilik alterasyonun plütonik sokulum sırasında veya hemen sonrasında (<1 My) başladığına işaret etmektedir. Elde edilen bulgular, Çöpler porfiriepitermal altın yatağında geniş yayılım sunan, düşük sıcaklık (<200 ºC) ve asidik koşullarda gelişmiş, alüminyum fosfat ve demir sülfat minerallerinin de geliştiği bir arjilik alterasyonun varlığını ortaya koymaktadır.
(The Çöpler porphyry-epithermal gold deposit is associated with middle Eocene intrusive rocks related to an extensional tectonic phase in the Tethyan Alpine-Himalayan orogenic belt. The intrusive rocks (granodiorite porphyry and diorite porphyry) were emplaced into Late Paleozoic–Mesozoic metapelite and metacarbonate rocks creating the porphyry-epithermal Cu-Au deposit and hydrothermal alteration zones (potassic, phyllic, propylitic, argillic). The mineralogic-petrographic and geochemical properties of the extensive argillic alteration zones (not supergene alteration described previously) were determined by optical and scanning electron microscopy (SEM and SEM-EDS), X-ray diffraction (XRD), O-H isotope geochemistry and K-Ar dating. Within the primary porphyritic texture, fine-grained clay and quartz crystals are present as homogeneous and partly micro-laminations in the more intensely argillized granodiorite porphyry. Smectite and mixed-layer illite-smectite (I-S) minerals exhibit flaky/sponge-like and fibrous shapes, respectively, whereas illites and kaolinites show platy/tabular crystal shapes. Quartz and jarosite have euhedral crystals, cristobalites and crandallites (first determined here) are shown as worm-like and fine-grained granular aggregates, respectively, developed within the pores indicating direct precipitation from the hydrothermal fluids. The samples from the argillic zone display quartz + I-S in the inner parts (advanced argillic zone) close to phyllic zone, whereas quartz + smectite + kaolinite associations are towards outer parts (argillic zone). Smectites have a dioctahedral composition (d060<1.500 Å, octahedral Al=1.47-1.66 a.p.f.u). I-S minerals have a high illite component (I85-S15) with R3 type ordering of interlayering. The tetrahedral Al and interlayer K contents are 1.66-1.71 and 0.58-0.75, respectively. Oxygen and hydrogen isotope composition of I-S indicate the low temperature conditions from the magmatic water dominant fluids. K/Ar age data from jarosite-bearing sample (43.6±1.0 My) indicates that the argillic alteration started during or shortly after (<1 Ma) the plutonic intrusion. The data demonstrate the argillic alteration was widely distributed and developed under low temperature (<200 ºC), acidic conditions in association with the aluminum phosphate and iron phosphate minerals.
Are there Local Minima in the Magnetic Monopole Potential in Compact QED?
We investigate the influence of the granularity of the lattice on the
potential between monopoles. Using the flux definition of monopoles we
introduce their centers of mass and are able to realize continuous shifts of
the monopole positions. We find periodic deviations from the -behavior of
the monopole-antimonopole potential leading to local extrema. We suppose that
these meta-stabilities may influence the order of the phase transition in
compact QED.Comment: 11 pages, 5 figure
Pruning Algorithms for Low-Dimensional Non-metric k-NN Search: A Case Study
We focus on low-dimensional non-metric search, where tree-based approaches
permit efficient and accurate retrieval while having short indexing time. These
methods rely on space partitioning and require a pruning rule to avoid visiting
unpromising parts. We consider two known data-driven approaches to extend these
rules to non-metric spaces: TriGen and a piece-wise linear approximation of the
pruning rule. We propose and evaluate two adaptations of TriGen to
non-symmetric similarities (TriGen does not support non-symmetric distances).
We also evaluate a hybrid of TriGen and the piece-wise linear approximation
pruning. We find that this hybrid approach is often more effective than either
of the pruning rules. We make our software publicly available
Submucosal diclofenac for acute postoperative pain in third molar surgery: A randomized, controlled clinical trial
Diclofenac sodium is a widely used nonsteroidal anti-inflammatory drug (NSAID) for relief of inflammatory pain. A recent formulation combines this drug with hydroxypropyl-β-cyclodextrin (HPβCD) to improve its solubility and to enable subcutaneous administration. Previous studies confirmed the efficacy of this combination. This study’s aim was to evaluate the efficacy, safety, and local tolerability of diclofenac HPβCD administered as a local submucosal injection prior to lower third molar surgery. We conducted a prospective, randomized, double-blind, placebo-controlled, parallel-group phase II single-center study. Seventy-five patients requiring mandibular third molar surgery were randomized into 1 of 5 groups: 5 mg/1 mL diclofenac HPβCD, 12.5 mg/1 mL diclofenac HPβCD, 25 mg/1 mL diclofenac HPβCD, 50 mg/1 mL diclofenac HPβCD, or 1 mL placebo. The respective study drug was injected into the mucosal tissue surrounding the surgical site prior to surgery following achievement of local anesthesia. The primary outcome measure was the area under the curve (AUC) of cumulative pain scores from end of surgery to 6 h postsurgery. This demonstrated a global treatment effect between the active groups and placebo, hence confirming the study drug’s efficacy (P = 0.0126). Secondary outcome measures included the time until onset of pain and the time until patients required rescue medication, both showing statistical significance of the study drug compared to placebo (P < 0.0161 and P < 0.0001, respectively). The time until rescue medication ranged between 7.8 h (for 25 mg/1 mL diclofenac HPβCD) and 16 h (for 50 mg/1 mL diclofenac HPβCD). Interestingly, the 5-mg/1-mL solution appeared superior to the 12.5-mg/1-mL and 25-mg/1-mL solutions (time until rescue medication = 12.44 h). A total of 14% of patients experienced minor adverse drug reactions (ADRs), of which 2 cases demonstrated flap necrosis. These resolved without further intervention. The study results overall indicate efficacy, safety, and relative tolerability of diclofenac HPβCD used locally as a submucosal injection prior to third molar surgery (ClinicalTrials.gov NCT01706588)
Expression profiles of interferon-tau stimulated genes (isgs) in peripheral blood leucocytes (pbls) and milk cells in pregnant dairy cows
Numerical study of effect of elastomeric stress absorbers on stress reduction in bone-dental implant interface
Hybrid Meta-heuristics with VNS and Exact Methods: Application to Large Unconditional and Conditional Vertex p-Centre Problems
Large-scale unconditional and conditional vertex p-centre problems are solved using two meta-heuristics. One is based on a three-stage approach whereas the other relies on a guided multi-start principle. Both methods incorporate Variable Neighbourhood Search, exact method, and aggregation techniques. The methods are assessed on the TSP dataset which consist of up to 71,009 demand points with p varying from 5 to 100. To the best of our knowledge, these are the largest instances solved for unconditional and conditional vertex p-centre problems. The two proposed meta-heuristics yield competitive results for both classes of problems
Hematopoietic Cell Transplantation Cures Adenosine Deaminase 2 Deficiency: Report on 30 Patients.
Deficiency of adenosine deaminase 2 (DADA2) is an inherited inborn error of immunity, characterized by autoinflammation (recurrent fever), vasculopathy (livedo racemosa, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency, lymphoproliferation, immune cytopenias, and bone marrow failure (BMF). Tumor necrosis factor (TNF-α) blockade is the treatment of choice for the vasculopathy, but often fails to reverse refractory cytopenia. We aimed to study the outcome of hematopoietic cell transplantation (HCT) in patients with DADA2.
We conducted a retrospective study on the outcome of HCT in patients with DADA2. The primary outcome was overall survival (OS).
Thirty DADA2 patients from 12 countries received a total of 38 HCTs. The indications for HCT were BMF, immune cytopenia, malignancy, or immunodeficiency. Median age at HCT was 9 years (range: 2-28 years). The conditioning regimens for the final transplants were myeloablative (n = 20), reduced intensity (n = 8), or non-myeloablative (n = 2). Donors were HLA-matched related (n = 4), HLA-matched unrelated (n = 16), HLA-haploidentical (n = 2), or HLA-mismatched unrelated (n = 8). After a median follow-up of 2 years (range: 0.5-16 years), 2-year OS was 97%, and 2-year GvHD-free relapse-free survival was 73%. The hematological and immunological phenotypes resolved, and there were no new vascular events. Plasma ADA2 enzyme activity normalized in 16/17 patients tested. Six patients required more than one HCT.
HCT was an effective treatment for DADA2, successfully reversing the refractory cytopenia, as well as the vasculopathy and immunodeficiency.
HCT is a definitive cure for DADA2 with > 95% survival
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