Rewritable groups

AbstractA group G is said to have the n-rewritable property Qn if for all elements g1,g2,…,gn∈G, there exist two distinct permutations σ,τ∈Symn such that gσ(1)gσ(2)⋯gσ(n)=gτ(1)gτ(2)⋯gτ(n). We show here that if G satisfies Qn, then G has a characteristic subgroup N such that |G:N| and |N′| are both finite and have sizes bounded by functions of n. This extends the result of Blyth (1988) in [3] which asserts that if G satisfies Qn and if Δ is the finite conjugate center of the group, then |G:Δ| and |Δ′| are both finite with |G:Δ| bounded by a function of n. As a consequence, any group with Qn satisfies the permutational property Pm with m bounded by a function of n

Evaluation of the Efficiency of SfM-Photogrammetry in Obtaining DEM from Google Earth Images

In this study, we seek to evaluate the efficiency of SfM Photogrammetry in obtaining Digital Elevation Model (DEM) from the free Google Earth browser, by simulating the aerial photography of the terrain displayed by this browser, calculating the resulting block of images, and obtaining DEM, and evaluate its accuracy to know the type of works in which this model can be used. Control data for image orientation are provided using Google Earth and free online services.The results showed that the huge number of dense point cloud generated by applying SfM to Google Earth images has contributed to obtaining a DEM with a vertical accuracy better than the vertical accuracy of the free digital elevation model SRTM1. The achieved vertical accuracy of the DEM produced by SfM was 3.58 m, whereas the vertical accuracy of the free SRTM1 was 4.65 m compared to a DEM derived 1/25000 scale topographic map. This type of DEM can be used in works that do not require high vertical accuracy such as hydrological works (watersheds) dealing with SRTM models

Effect of Concentrated Growth Factor alone and mixed with Hyaluronic Acid on Osseointegration of Delayed Implant.

Purpose: The aim of current study was evaluating effect of concentrated growth factor alone and mixed with hyaluronic acid on osseointegration of delayed implant. Subject and Methods: A total of 12 patients, ranging in age from 20 to 45 years old, were divided into two groups in random manner. Group A: Dental implants were placed associating with concentrated growth factor. Group B: Dental implants were placed associating with concentrated growth factor and hyaluronic acid. Treatment changes were evaluated for each group and compared between groups. Results: In the mean of implant stability a statistically significant difference existed within group A as implant stability increased from base line immediately after implant insertion to follow up period after six months, also statistically significant difference existed in the mean of Implant Stability within group B as implant stability decreased from base line immediately after implant insertion to follow up period after six months. Also, there was statistically significant difference in the mean of Implant Stability between the two groups. Conclusions: Concentrated growth factor alone have positive effect on bone osseointegration

Clinical and Histologic Evaluation of Using Block Xenograft Combined With Leukocyte-Platelet Rich Fibrin (L-PRF) Versus Intraoral Autogenous Bone Block Graft With L-PRF in Treating Localized Ridge Defects: A Randomized Clinical Trial

Background: Augmentation of vertical bone defects remains the corner stone in periodontal tissue engineering. The amount and quality of alveolar bone available in all dimensions affects the success of dental implants for restoration of edentulous areas. Adequate and healthy bone supports the degree of osseointegration which in turn affects the long-term success of oral implants. The primary aim of the study was to histologically evaluate autogenous block grafts versus synthetic block grafts for the treatment of atrophic vertical and horizontal bony defects (Siebert Class III) in the anterior esthetic zone of the mouth. The secondary aim was to clinically and radiographically evaluate the outcomes of the procedure. Methods: This was a randomized controlled clinical study with a statistically determined sample size of 10 patients per group and a total of 20 patients in both groups. Patients with vertical and horizontal bone loss were enrolled from the Department of Oral Medicine, Periodontology, and Oral Diagnosis of Ain Shams University and Misr International University. Bone augmentation procedures were performed using two techniques: autogenous bone block graft and xenograft bone block graft both with leukocyte-platelet rich fibrin (L-PRF). Results: Both autogenous and xenograft blocks in conjunction with L-PRF had a significant effect on vertical bone augmentation in cases of atrophic ridges in the esthetic region. Conclusion: Both autogenous and xenograft bone blocks in conjunction with L-PRF have a significant effect on vertical bone augmentation in cases of atrophic ridges in the esthetic region

Disruption of Immune Homeostasis in Human Dendritic Cells via Regulation of Autophagy and Apoptosis by

As fundamental processes of immune homeostasis, autophagy, and apoptosis must be maintained to mitigate risk of chronic inflammation and autoimmune diseases. Periodontitis is a chronic inflammatory disease characterized by oral microbial dysbiosis, and dysregulation of dendritic cell (DC) and T cell responses. The aim of this study was to elucidate the underlying mechanisms by which the oral microb

Systemic Antibiotic Therapy Reduces Circulating Inflammatory Dendritic Cells and Treg-Th17 Plasticity in Periodontitis

Periodontitis (PD) is a common dysbiotic inflammatory disease that leads to local bone deterioration and tooth loss. PD patients experience low-grade bacteremias with oral microbes implicated in the risk of heart disease, cancer, and kidney failure. Although Th17 effectors are vital to fighting infection, functional imbalance of Th17 effectors and regulatory T cells (Tregs) promote inflammatory diseases. In this study, we investigated, in a small pilot randomized clinical trial, whether expansion of inflammatory blood myeloid dendritic cells (DCs) and conversion of Tregs to Th17 cells could be modulated with antibiotics (AB) as part of initial therapy in PD patients. PD patients were randomly assigned to either 7 d of peroral metronidazole/amoxicillin AB treatment or no AB, along with standard care debridement and chlorhexidine mouthwash. 16s ribosomal RNA analysis of keystone pathoge

Exogenous and Endogenous Dendritic Cell-Derived Exosomes: Lessons Learned for Immunotherapy and Disease Pathogenesis

Immune therapeutic exosomes, derived exogenously from dendritic cells (DCs), the ‘directors’ of the immune response, are receiving favorable safety and tolerance profiles in phase I and II clinical trials for a growing number of inflammatory and neoplastic diseases. DC-derived exosomes (EXO), the focus of this review, can be custom tailored with immunoregulatory or immunostimulatory molecules for specific immune cell targeting. Moreover, the relative stability, small size and rapid uptake of EXO by recipient immune cells offer intriguing options for therapeutic purposes. This necessitates an in-depth understanding of mechanisms of EXO biogenesis, uptake and routing by recipient immune cells, as well as their in vivo biodistribution. Against this backdrop is recognition of endogenous exosomes, secreted by all cells, the molecular content of which is reflective of the metabolic state of these cells. In this regard, exosome biogenesis and secretion is regulated by cell stressors of chronic inflammation and tumorigenesis, including dysbiotic microbes, reactive oxygen species and DNA damage. Such cell stressors can promote premature senescence in young cells through the senescence associated secretory phenotype (SASP). Pathological exosomes of the SASP amplify inflammatory signaling in stressed cells in an autocrine fashion or promote inflammatory signaling to normal neighboring cells in paracrine, without the requirement of cell-to-cell contact. In summary, we review relevant lessons learned from the use of exogenous DC exosomes for immune therapy, as well as the pathogenic potential of endogenous DC exosomes

Phase-Phase and Phase-Code methods modification for precise detecting and predicting the GPS cycle slip error

There are three well-established detecting methods for cycle slip error, which are: Doppler measurement method, Phase-Code differencing method, and Phase-Phase Differencing Method. The first method depends on the comparison between observables and the fact that Doppler measurements are immune to cycle slip error. This method is considered as the most precise method for cycle slip detecting, because it succeed in detecting and predicting the smallest cycle slip size (1 cycle) in case the local oscillator has low bias. The second method depends on the comparison between observables (phase and code) and the code measurements are immune to the cycle slip error. But this method can’t detect or predict cycle slip size smaller than 10 cycles, because the code measurements have high noise. The third method depends on the comparison between observables (phase 1 and phase 2) and the phases measurements that have low noise. But this method can’t detect or predict cycle slip size smaller than 5 cycles, because the ionospheric change might have a high variation. For enhancing the precision of the last two methods in detecting the smallest cycle slip which size reaches 1 cycle, a new algorithm was developed in this research to determine the change in the ionospheric values and the code bias from epoch to epoch. That is done by solving all observables equations by least square technique. This modification on these methods succeed in detecting and predicting cycle slips of size of 1 cycle.Powszechnie znane są trzy metody wykrywania przeskoków fazowych (utraty cyklu, cycle slip) w fazowych pomiarach GPS. Są to: metoda Dopplerowska, metoda różnicy Faza-Kod i metoda różnicy pomiędzy fazami (Faza-Faza). Pierwsza z nich polega na porównaniu wartości obserwowanych i korzysta z faktu, że pomiary częstotliwości dopplerowskiej są odporne na przeskoki fazy. Metoda ta jest uważana za najbardziej dokładną spośród metod wykrywania utraty cyklu, albowiem pozwala wykrywać i przewidywać najmniejsze wartości utraty cyklu (1 cykl) pod warunkiem niewielkiego odstrojenia lokalnego generatora. Druga metoda polega na porównaniu wartości obserwowanych fazy i kodu z wykorzystaniem faktu, że pomiary kodowe są odporne na przeskoki cyklu. Jednakże metoda ta nie pozwala wykryć utraty cykli mniejszych niż dziesięć okresów z powodu wartości szumu pomiarów kodowych. Trzecia metoda polega na porównaniu wartości obserwowanych wyłącznie w domenie pomiarów fazowych w kolejnych epokach i uwzględnia fakt, że pomiary fazowe cechują się niższym zaszumieniem. Jednak ta metoda nie pozwala dostrzec przeskoków cyklu o wartości mniejszej niż 5 z powodów własności jonosfery. Dla zwiększenia dokładności ostatnich dwóch metod i możliwości wykrycia pojedynczych przeskoków cyklu zaproponowano nowy algorytm wykrywania przeskoków fazy wywołanych zmianami stanu jonosfery pomiędzy epokami. Zostało to osiągnięte poprzez rozwiązywanie wszystkich równań obserwacyjnych metodą najmniejszych kwadratów. Ta modyfikacja pozwoliła wykrywać nawet pojedyncze przeskoki cyklu