The methanogenic Archaea bring a broadened perspective to the field of nitrogen fixation. Biochemical and genetic studies show that nitrogen fixation in Archaea is evolutionarily related to nitrogen fixation in Bacteria and operates by the same fundamental mechanism. At least six nif genes present in Bacteria (nif H, D, K, E, N and X) are also found in the diazotrophic methanogens. Most nitroge...

Nitrogen fixation (C(2)H(2) reduction) by algae in flooded soil was limited by interactions within the algal community. Nitrogen fixation by either indigenous algae or Tolypothrix tenuis was reduced severalfold by a dense suspension of the green alga Nephrocytium sp. Similarly, interactions between the nitrogen-fixing alga (cyanobacterium) Aulosira 68 and natural densities of indigenous algae l...

BACKGROUND In order to reduce the incidence of adjacent segment disease (ASD), the current study was designed to establish Chinese finite element models of normal 3rd~7th cervical vertebrae (C3-C7) and anterior cervical corpectomy and fusion (ACCF) with internal fixation , and analyze the influence of screw sagittal angle (SSA) on stress on endplate of adjacent cervical segments. METHODS Mimi...

The involvement of epiphytic microorganisms in nitrogen fixation was investigated in a shallow freshwater pond near Ithaca, N.Y. The acetylene reduction technique was used to follow diel and seasonal cycles of nitrogen fixation by epiphytes of Myriophyllum spicatum. Acetylene-reducing activity was maximal between noon and 6 p.m., but substantial levels of activity relative to daytime rates cont...

Fractures of the distal end of the radius should be treated on the same principles as other fractures involving joints. Displaced articular fractures require open reduction to allow anatomical reconstruction of both the radiocarpal and the radio-ulnar joints. For extra-articular fractures with severe comminution and shortening this enables the radial length to be re-established achieving radio-...

The aim of this study was to find out whether number and position of K-wires influence the stability of distal radius fractures treated by percutaneous wire fixation. Patients who underwent K-wire fixation for unstable fractures of the distal radius over a period of three years were included in this retrospective study. Radiographs taken immediately after the procedure and radiographs taken aft...

The purpose of this study is to show that accurate reduction and firm fixation of fractures involving the ankle followed by joint exercises within a few days of operation leads to rapid return of function with consistently good results. Method of treatment-The injuries in this series were treated by open reduction and internal fixation of one or more fractures in order to stabilise the ankle su...

INTRODUCTION The aim of this study was to examine resistance to angulation and displacement of the internal fixation of a proximal first metatarsal lateral displacement osteotomy, using a locking plate system compared with a conventional crossed screw fixation. MATERIALS AND METHODOLOGY Seven anatomical human specimens were tested. Each specimen was tested with a locking screw plate as well a...

PURPOSE To compare the outcome after early versus late surgery for closed ankle fractures in terms of the length of hospital stay and infection rate. METHODS Records of 95 men and 119 women aged 14 to 92 (mean, 46) years who underwent open reduction and internal fixation for ankle fractures during three 6-month periods in 2004, 2007, and 2010 were reviewed. 82 and 132 patients underwent surge...

Fine-wire external fixation is accepted as a minimally invasive technique, which can provide better outcomes than traditional open methods in the management of complex fractures of the tibial plateau. Available fixators vary in their biomechanical stability, and we believe that a stable beam-loading system is essential for consistently good outcomes. We assessed, prospectively, the clinical, ra...