Direct Observation of Enzymes Replicating DNA Using a Single-molecule DNA Stretching Assay

We describe a method for observing real time replication of individual DNA molecules mediated by proteins of the bacteriophage replication system. Linearized λ DNA is modified to have a biotin on the end of one strand, and a digoxigenin moiety on the other end of the same strand. The biotinylated end is attached to a functionalized glass coverslip and the digoxigeninated end to a small bead. The assembly of these DNA-bead tethers on the surface of a flow cell allows a laminar flow to be applied to exert a drag force on the bead. As a result, the DNA is stretched close to and parallel to the surface of the coverslip at a force that is determined by the flow rate (Figure 1). The length of the DNA is measured by monitoring the position of the bead. Length differences between single- and double-stranded DNA are utilized to obtain real-time information on the activity of the replication proteins at the fork. Measuring the position of the bead allows precise determination of the rates and processivities of DNA unwinding and polymerization (Figure 2)

Functional Regeneration of Supraspinal Connections in a Patient With Transected Spinal Cord Following Transplantation of Bulbar Olfactory Ensheathing Cells With Peripheral Nerve Bridging

Treatment of patients sustaining a complete spinal cord injury remains an unsolved clinical problem because of the lack of spontaneous regeneration of injured central axons. A 38-year-old man sustained traumatic transection of the thoracic spinal cord at upper vertebral level Th9. At 21 months after injury, the patient presented symptoms of a clinically complete spinal cord injury (American Spinal Injury Association class A-ASIA A). One of the patient's olfactory bulbs was removed and used to derive a culture containing olfactory ensheathing cells and olfactory nerve fibroblasts. Following resection of the glial scar, the cultured cells were transplanted into the spinal cord stumps above and below the injury and the 8-mm gap bridged by four strips of autologous sural nerve. The patient underwent an intense pre- and postoperative neurorehabilitation program. No adverse effects were seen at 19 months postoperatively, and unexpectedly, the removal of the olfactory bulb did not lead to persistent unilateral anosmia. The patient improved from ASIA A to ASIA C. There was improved trunk stability, partial recovery of the voluntary movements of the lower extremities, and an increase of the muscle mass in the left thigh, as well as partial recovery of superficial and deep sensation. There was also some indication of improved visceral sensation and improved vascular autoregulation in the left lower limb. The pattern of recovery suggests functional regeneration of both efferent and afferent long-distance fibers. Imaging confirmed that the grafts had bridged the left side of the spinal cord, where the majority of the nerve grafts were implanted, and neurophysiological examinations confirmed the restitution of the integrity of the corticospinal tracts and the voluntary character of recorded muscle contractions. To our knowledge, this is the first clinical indication of the beneficial effects of transplanted autologous bulbar cells

In-situ formation of Ag nanoparticles in the MAO coating during the processing of cp-Ti

Silver nanoparticle (Ag-NP) containing antibacterial micro-arc oxidation (MAO) coatings have already been synthesized over titanium-based materials via the MAO process employed in silver acetate (AgC2H3O2) containing electrolyte. However, the way of incorporation and in-situ formation of Ag-NPs within the MAO coating have not been documented yet. Present work was initiated to reveal the mechanism of Ag-NP formation within the MAO coatings. Thus, the structure of the MAO coating fabricated on commercial purity titanium in the AgC2H3O2-containing electrolyte was investigated by electron microscopy techniques. To this end, the cross-sectional high-resolution electron microscopy studies were carried out on lamella cut out with the focused ion beam technique, and these investigations were backed by X-ray photoelectron spectroscopy measurements of chemical composition on the surface of the MAO coating. These studies revealed that Ag is dispersed in the form of nanoparticles throughout the coating and that a higher density was confirmed closer to the micro-pores

Digital subtraction radiographic analysis of the combination of bioabsorbable membrane and bovine morphogenetic protein pool in human periodontal infrabony defects

Objectives: This study assessed the bone density gain and its relationship with the periodontal clinical parameters in a case series of a regenerative therapy procedure. Material and Methods: Using a split-mouth study design, 10 pairs of infrabony defects from 15 patients were treated with a pool of bovine bone morphogenetic proteins associated with collagen membrane (test sites) or collagen membrane only (control sites). The periodontal healing was clinically and radiographically monitored for six months. Standardized presurgical and 6-month postoperative radiographs were digitized for digital subtraction analysis, which showed relative bone density gain in both groups of 0.034 ± 0.423 and 0.105 ± 0.423 in the test and control group, respectively (p>0.05). Results: As regards the area size of bone density change, the influence of the therapy was detected in 2.5 mm2 in the test group and 2 mm2 in the control group (p>0.05). Additionally, no correlation was observed between the favorable clinical results and the bone density gain measured by digital subtraction radiography (p>0.05). Conclusions: The findings of this study suggest that the clinical benefit of the regenerative therapy observed did not come with significant bone density gains. Long-term evaluation may lead to a different conclusions

Assessment of the prevalence of radix entomolaris and distolingual canal in mandibular first molars in 15 countries: a multinational cross-sectional study with meta-analysis

Aim: The aim of this study was two-folded: i) to assess the prevalence of Distolingual Canal (DLC) and Radix Entomolaris (RE) in Mandibular First Molars (M1Ms), using Cone Beam Computed Tomography (CBCT) images and ii) to assess the impact of sociodemographic factors on the prevalence of these conditions worldwide. Methods: CBCT images were scanned retrospectively and the ones including bilateral M1Ms were included in the study. The evaluation was performed by 1 researcher in each country, trained with CBCT technology. A written and video instruction program explaining the protocol to be followed step-by-step was provided to all observers to calibrate them. The CBCT imaging screening procedure consisted of evaluating axial sections from coronal to apical. The presence of DLC and RE in M1Ms (yes/no) was identified and recorded. Results: Six thousand three hundred four CBCTs, representing 12,608 M1Ms, were evaluated. A significant difference was found between countries regarding the prevalence of both RE and DLC (P .05). Conclusion: The overall prevalence of RE and DLC in M1Ms was 3% and 22%. Additionally, both RE and DLC showed substantial bilaterally. These variations should be considered by endodontic clinicians during endodontic procedures in order to avoid potential complications

The neighbourhood of the rural area and the large cities

Dążenie do wielofunkcyjności wsi oraz poszukiwanie nowych miejsc dla realizacji inwestycji z zakresu budownictwa mieszkaniowego sprawia, że wieś traktowana jest dziś nie tylko jako miejsce produkcji rolnej. O sposobie wykorzystania czynników produkcji - a przecież jednym z nich jest ziemia - w gospodarce rynkowej decyduje rachunek ekonomiczny. Wskutek powyższego spadek opłacal-ności produkcji rolnej doprowadza do ograniczenia działalności rolniczej i prze-znaczenia ziemi na inne cele. Przekształcenia w przestrzeni wiejskiej pociągają za sobą szeroko pojęte zmiany w lokalnej społeczności - wzrasta w niej udział osób nieposiadających go-spodarstwa rolnego i całkowicie niezwiązanych z rolnictwem. Tradycyjnie pojmowane procesy urbanizacyjne zakładały przepływ ludności wiejskiej do miasta. Tymczasem coraz silniej występuje tendencja odwrotna. Ze względu na niewielką liczebność społeczności wiejskich ważnym zagadnieniem są kontakty na linii rdzenni mieszkańcy wsi - nowoprzybyli. Trudności w asymilacji nowoprzybyłych mieszkańców i podział społeczności na dwie, reprezentujące odmienne wartości i interesy, grupy może być początkiem wytworzenia się specyficznych wewnętrznych barier rozwoju lokalnego. Skutek sąsiedztwa wsi i dużego miasta można ukazać m.in. na przykładzie regionu Dolnego Śląska. Będący największym miastem regionu Wrocław niejako konsumuje sąsiadującą przestrzeń wiejską - wg danych GUS w podregionie Wro-cław w roku 1995 powierzchnia użytków rolnych wynosiła 13.068 ha, a w roku 2005 już tylko 9.684 ha. Trudno oczekiwać braku wpływu człowieka na istniejący stan zagospodarowania przestrzennego. Sposób wykorzystania przestrzeni i zarazem postrzegania najbardziej pożądanych funkcji, które można w danej przestrzeni realizować po prostu się zmieniają. Sąsiadujące z dużym miastem obszary wiejskie są ofiarami zjawiska tzw. rozlewania się miasta. Powoduje to nie tylko łatwo zauważalne w przestrzeni, ale i znacznie trudniej identyfikowane zmiany w społeczności lokalnej.The quest for the multifunctionality of rural areas and the search for new places for the implementation of the housing investment is the reason that village today is treated not only as a place of agricultural production. Economic balance decides of the use of the factors of production– and, after all, one of them is earth – in a market economy. As a result the decline in profitability of agricultural production leads to the limitations of agricultural activity and the destination of the earth for other purposes. Transformations in the rural area entail broad changes in the local community. The share of people without farm and completely unconnected with the agriculture increases in it. Traditionally understood urbanization processes envisaged movement of the rural population to the city. Meanwhile, increasingly, there is an opposite tendency. Due to the small size of the rural communities an important issue are contacts on the line native inhabitants of the village and the newcomers. The difficulties in assimilation of newcomers, the breakdown of the communities in two, representing different values and interests of the group may be the start of the creation of the specific internal barriers of local development. The effect of the neighbourhood of villages and the big cities can be due, inter alia, on the example of the region of Lower Silesia. Wrocław, being the largest city in the region somewhat consumes an adjacent rural space – according to the GUS (main office of statistics) data in Wrocław’s sub-region, in the year 1995 utilised agricultural area was 13.068 ha, and in 2005 there were only 9.684 ha left. It is difficult to expect the absence of the human impact on the existing spatial planning. How to make use of space and also perceptions of the most desired functions which can be pursue in a given space are simply changing. Rural areas neighbouring with the large city are victims of the phenomenon of so-called spillover town. This creates not only easily visible in the space, but much harder identified changes in the local community

Hydrostatic extrusion of UFG aluminium

The feasibility of hydrostatic extrusion (HE) of ultrafine grained (UFG) AA1070 has been investigated. The UFG material was produced by equal channel angular pressing (ECAP) using a scaled-up, two-turn, S-shape channel. Four passes of ECAP were followed by three passes of HE, which reduced the billet cross-section from a 26 x 26 mm2 square to 5 mm diameter round section. The average grain size of 0.6 micron after ECAP was reduced to 0.4 micron by HE. The strength and hardness increased by ECAP were further increased by HE. Ductility was reduced by ECAP, however, it remained constant during HE. The suggested sequence of operations seems to be a feasible option for producing UFG billets for shaping elongated products

Przerobione plastycznie stopy magnezu ZM21, ZW3 i WE43 wytworzone metoda wyciskania hydrostatycznego z przeciwciśnieniem

Cold hydrostatic extrusion with and without back pressure of commercial ZM21, ZW3 and WE43 magnesium alloys has been performed at originally designed hydrostatic extrusion press operating up to 2000 MPa with back pressure up to 700 MPa. Alloys were cold extruded in one pass into rods between 5 and 9 mm in the outer diameter with product velocities between 1 and 10 m/min and extrusion ratios above 2. Application of back pressure extended formability of all magnesium alloys. It was due to hydrostatic pressure superimposed on the extruded product what inhibits the cracks generation and propagation. Cold deformation restrained the grain growth and softening processes while severe deformation in one pass increased grain refinement and density of internal defects. Ultimate tensile strength ranging from 370 MPa (ZM21) through 400 MPa (ZW3) up to 410 MPa (WE43), with respective yield stresses from 270 MPa through 300 MPa up to 350 MPa and the respective elongation from 13% through 12% to 7% were obtained in extruded rods, which are the best reported data in literature up to this day. Wrought magnesium alloys after hydrostatic extrusion can serve as semi-products for structures that call for high strength, for example as biodegradable implants or fastening components in form of bolts, rivets, nuts, pins, joints, etc.Przeprowadzono wyciskanie hydrostatyczne na zimno z przeciwciśnieniem handlowych stopów magnezu ZM21, ZW3 i WE43. Eksperymenty prowadzono na oryginalnej, własnej konstrukcji prasie do wyciskania hydrostatycznego pracującej do 2000 MPa z przeciwciśnieniem do 700 MPa. Stopy odkształcano na zimno w jednej operacji wytwarzając pręty o średnicach pomiędzy 5 mm a 9 mm z liniową szybkością wyciskania pomiędzy 1 m/min i 10 m/min i stopniami redukcji powyżej 2. Zastosowanie przeciwciśnienia zwiększyło zdolność do odkształcenia plastycznego wszystkich badanych stopów magnezu. Stało się tak dzięki nałożeniu na wyciskany produkt ciśnienia hydrostatycznego co powstrzymuje generowanie i propagacje pęknięć. Odkształcanie na zimno powstrzymuje rozrost ziaren i procesy zmiękczania podczas gdy duże odkształcenie plastyczne w jednej operacji zwiększa rozdrobnienie ziaren oraz gęstość defektów mikrostruktury. Po wyciskaniu wytrzymałość na rozciąganie wynosiła od 370 MPa (dla ZM21) przez 400 MPa (ZW3) do 410 MPa (WE43) z granicą plastyczności, odpowiednio 270 MPa, 300 MPa i 350 MPa i wydłużeniem, odpowiednio 13%, 12% i 7%. Są to najwyższe własności podawane w literaturze światowej na dzień dzisiejszy. Stopy magnezu przerobione plastycznie metodą wyciskania hydrostatycznego mogą służyć jako półprodukty do wykonania elementów konstrukcyjnych wymagających wysokich wytrzymałości, jak np. biodegradowalne implanty kostne czy elementy złączne w postaci śrub, nitów, nakrętek, szpilek, łączników, itp

Hip strategy alterations in patients with history of low disc herniation and non-specific low back pain measured by surface electromyography and balance platform

Purpose: The appearance of pathology in the lumbar spine, such as a previous episode of low disc herniation or non-specific low back pain contributes to improper activation of the hip muscles. The aim of the study was to detect alterations in hip strategy manifested by differences in balance parameters and rectus femoris and gluteus maximus activity in people with previous episode of pain radiation to one lower limb caused by low disc herniation or non-specific low back pain. Methods: We studied 11 patients with history of low-disc herniation, 9 patients with history of non-specific low back pain and 10 healthy subjects. Hip strategy alterations were detected by measuring rectus femoris and gluteus maximus activity in bilateral surface polyelectromyographic recordings and by stability measurements on a balance platform. Results: In the surface polyelectromyography study, in both patients' group the value of the average amplitude was higher and the amount of the fluctuations was lower than in healthy subjects. There were no significant differences in stability parameters. Conclusions: A changed pattern of hip muscles activity was detected in the patients without changes in stability parameters. Greater disorder occurs in people in with previous episode of pain radiation to one lower limb caused by low disc herniation than in people with non-specific low back pain