Removing Entry Barriers of Small-holder Organic Farming in Korea

There have been many research references which have mentioned entry barriers in organic farming. According to previous studies in Korea, it is difficult for majority of small-holders to convert their conventional farming into organic farming due to difficulty in pest and weed control, compost making, marketing organic produces and lower yield and income during the initial 3-4 years. In other words, various types of entry barriers exist when starting organic farming. There is lack of confidence in regulating pests and insects without pesticides as is the case with weed control

Clinical Persistence of Chlamydia trachomatis Sexually Transmitted Strains Involves Novel Mutations in the Functional αββα Tetramer of the Tryptophan Synthase Operon.

Clinical persistence of Chlamydia trachomatis (Ct) sexually transmitted infections (STIs) is a major public health concern. In vitro persistence is known to develop through interferon gamma (IFN-γ) induction of indoleamine 2,3-dioxygenase (IDO), which catabolizes tryptophan, an essential amino acid for Ct replication. The organism can recover from persistence by synthesizing tryptophan from indole, a substrate for the enzyme tryptophan synthase. The majority of Ct strains, except for reference strain B/TW-5/OT, contain an operon comprised of α and β subunits that encode TrpA and TrpB, respectively, and form a functional αββα tetramer. However, trpA mutations in ocular Ct strains, which are responsible for the blinding eye disease known as trachoma, abrogate tryptophan synthesis from indole. We examined serial urogenital samples from a woman who had recurrent Ct infections over 4 years despite antibiotic treatment. The Ct isolates from each infection episode were genome sequenced and analyzed for phenotypic, structural, and functional characteristics. All isolates contained identical mutations in trpA and developed aberrant bodies within intracellular inclusions, visualized by transmission electron microscopy, even when supplemented with indole following IFN-γ treatment. Each isolate displayed an altered αββα structure, could not synthesize tryptophan from indole, and had significantly lower trpBA expression but higher intracellular tryptophan levels compared with those of reference Ct strain F/IC-Cal3. Our data indicate that emergent mutations in the tryptophan operon, which were previously thought to be restricted only to ocular Ct strains, likely resulted in in vivo persistence in the described patient and represents a novel host-pathogen adaptive strategy for survival.IMPORTANCE Chlamydia trachomatis (Ct) is the most common sexually transmitted bacterium with more than 131 million cases occurring annually worldwide. Ct infections are often asymptomatic, persisting for many years despite treatment. In vitro recovery from persistence occurs when indole is utilized by the organism's tryptophan synthase to synthesize tryptophan, an essential amino acid for replication. Ocular but not urogenital Ct strains contain mutations in the synthase that abrogate tryptophan synthesis. Here, we discovered that the genomes of serial isolates from a woman with recurrent, treated Ct STIs over many years were identical with a novel synthase mutation. This likely allowed long-term in vivo persistence where active infection resumed only when tryptophan became available. Our findings indicate an emerging adaptive host-pathogen evolutionary strategy for survival in the urogenital tract that will prompt the field to further explore chlamydial persistence, evaluate the genetics of mutant Ct strains and fitness within the host, and their implications for disease pathogenesis

The competition number of a graph having exactly one hole

AbstractLet D be an acyclic digraph. The competition graph of D has the same set of vertices as D and an edge between vertices u and v if and only if there is a vertex x in D such that (u,x) and (v,x) are arcs of D. The competition number of a graph G, denoted by k(G), is the smallest number k such that G together with k isolated vertices is the competition graph of an acyclic digraph. In this paper, we show that the competition number of a graph having exactly one chordless cycle of length at least 4 is at most two. We also give a large family of such graphs whose competition numbers are less than or equal to one

Correlation and comparison of Risser sign versus bone age determination (TW3) between children with and without scoliosis in Korean population

<p>Abstract</p> <p>Background</p> <p>Most studies comparing the Risser staging for skeletal maturity are representing the American or European standards which are not always applicable to Asian population who have relatively less height and body mass. There is no article available that compares the Risser sign and bone age correlation between patients with idiopathic scoliosis and patients without scoliosis.</p> <p>Materials and methods</p> <p>To analyze and compare the skeletal age with the Risser sign between scoliosis and non-scoliosis group, a cross-sectional study was done in 418 scoliosis (untreated, bracing or surgically) and 256 non-scoliosis children of Korean origin. Relationship was found in both groups using Pearson correlation test.</p> <p>Results</p> <p>In scoliosis group, Pearson correlation exhibited significant correlation (p < 0.01) between Risser sign and chronological age (r²= 0.791 for girls, 0.787 for boys) and Risser sign and TW3 age (r²= 0.718 for girls, 0.785 for boys). Non-scoliosis group also showed significant relationship (p < 0.01) between Risser sign and chronological age (r²= 0.893 for girls, 0.879 for boys) and Risser sign and TW3 age (r²= 0.913 for girls, 0.895 for boys). Similarly, comparing Cobb angles of each patient according to their Risser staging, exhibited that if scoliosis remains untreated Cobb angle will increase with the increase in their Risser staging (r²= 0.363 for girls, 0.443 for boys; p < 0.01).</p> <p>Conclusion</p> <p>Our results showed that chronological age is equally as reliable as skeletal age method to compare with Risser sign, and therefore, we do not mean to imply that only the Risser sign compared with skeletal age should be considered in the decision making in idiopathic as well as non-scoliosis patients of Korean ethnicity. Concomitant indicators such as menarchal period, secondary sex characteristics, and recent growth pattern will likely reinforce our data comparing Risser sign with skeletal age in decision making.</p

Crosslinked polymeric dielectric materials and electronic devices incorporating same

Solution-processable dielectric materials are provided, along with precursor compositions and processes for preparing the same. Composites and electronic devices including the dielectric materials also are provided

Intraoperative blood loss during different stages of scoliosis surgery: A prospective study

<p>Abstract</p> <p>Background</p> <p>There are a number of reasons for intraoperative blood loss during scoliosis surgery based on the type of approach, type of disease, osteopenia, and patient blood profile. However, no studies have investigated bleeding patterns according to the stage of the operation. The objective of this prospective study was to identify intraoperative bleeding patterns in different stages of scoliosis surgery.</p> <p>Methods</p> <p>We prospectively analyzed the estimated blood loss (EBL) and operation time over four stages of scoliosis surgery in 44 patients. The patients were divided into three groups: adolescent idiopathic (group 1), spastic neuromuscular (group 2) and paralytic neuromuscular (group 3). The per-level EBL and operation times of the groups were compared on a stage-by-stage basis. The bone marrow density (BMD) of each patient was also obtained, and the relationship between per-level EBL and BMD was compared using regression analysis.</p> <p>Results</p> <p>Per-level operation time was similar across all groups during surgical stage (p > 0.05). Per-level EBL was also similar during the dissection and bone-grafting states (p > 0.05). However, during the screw insertion stage, the per-level EBL was significantly higher in groups 2 and 3 compared to group 1 (p < 0.05). In the correction stage, per-level EBL was highest in group 3 (followed in order by groups 2 and 1) (p < 0.05). Preoperative BMD indicated that group 3 had the lowest bone quality, followed by groups 2 and 1 (in order), but the preoperative blood indices were similar in all groups. The differences in bleeding patterns in the screw insertion and correction stages were attributed to the poor bone quality of groups 2 and 3. Group 3 had the lowest bone quality, which caused loosening of the bone-screw interface during the correction stage and led to more bleeding. Patients with a T-score less than -2.5 showed a risk for high per-level EBL that was nine times higher than those with scores greater than -2.5 (p = 0.003).</p> <p>Conclusions</p> <p>We investigated the blood loss patterns during different stages of scoliosis surgery. Patients with poor BMD showed a risk of blood loss nine times higher than those with good BMD.</p

Some statistical characteristics of large deepwater waves around the Korean Peninsula

The relationship between significant wave height and period, the variability of significant wave period, the spectral peak enhancement factor, and the directional spreading parameter of large deepwater waves around the Korean Peninsula have been investigated using various sources of wave measurement and hindcasting data. For very large waves comparable to design waves, it is recommended to use the average value of the empirical formulas proposed by Shore Protection Manual in 1977 and by Goda in 2003 for the relationship between significant wave height and period. The standard deviation of significant wave periods non-dimensionalized with respect to the mean value for a certain significant wave height varies between 0.04 and 0.21 with a typical value of 0.1 depending upon different regions and different ranges of significant wave heights. The probability density function of the peak enhancement factor is expressed as a lognormal distribution, with its mean value of 2.03, which is somewhat smaller than the value in the North Sea. For relatively large waves, the probability density function of the directional spreading parameter at peak frequency is also expressed as a lognormal distribution

Epidural cement leakage through pedicle violation after balloon kyphoplasty causing paraparesis in osteoporotic vertebral compression fractures - a report of two cases

Kyphoplasty is advantageous over vertebroplasty in terms of better kyphosis correction and diminished risk of cement extravasations. Literature described cement leakage causing neurological injury mainly after vertebroplasty procedure; only a few case reports show cement leakage with kyphoplasty without neurological injury or proper cause of leakage. We present a report two cases of osteoporotic vertebral compression fracture treated with kyphoplasty and developed cement leakage causing significant neurological injury. In both cases CT scan was the diagnostic tool to identify cause of cement leakage. CT scan exhibited violation of medial pedicle wall causing cement leakage in the spinal canal. Both patients displayed clinical improvement after decompression surgery with or without instrumentation. Retrospectively looking at stored fluoroscopic images, we found that improper position of trocar in AP and lateral view simultaneously while taking entry caused pedicle wall violation. We suggest not to cross medial pedicle wall in AP image throughout the entire procedure and keeping the trocar in the center of pedicle in lateral image would be the most important precaution to prevent such complication. Our case reports adds the neurological complications with kyphoplasty procedure and suggested that along with other precautions described in the literature, entry with trocar along the entire procedure keeping the oval shape of pedicle in mind (under C-arm) will probably help to prevent such complications