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Biomedical subjects

J F Liu

Publications and source records attributed to J F Liu.

90 records · Page 5Linked to original sources
PubMed1978

Nonhistone proteins HMG1 and HMG2 change the DNA helical structure.

Two chromatin nonhistone proteins (from calf thymus) of the high mobility group, HMG1 and HMG2, reduce the linking number (topological winding number) of a circular DNA if the covalent closure of the DNA is carried out in their presence. This indicates that these proteins can either unwind the double helix, or induce a supercoiling of the DNA.

Bacteriophages↗
PubMedDate not supplied

Outcome of laparoscopic anterior 180-degree partial fundoplication for gastroesophageal reflux disease.

Although Nissen fundoplication controls gastroesophageal reflux disease effectively, it is associated with an incidence of side effects. For this reason we have investigated the use of a laparoscopic 180-degree anterior fundoplication as a technique that has the potential to control reflux, but with less associated postoperative dysphagia and fewer gas-related side effects. Good short-term (6-month) outcomes have been previously reported within the content of a randomized trial. This report details the technique we used and describes the outcome of this procedure with longer follow-up in a much larger group of patients. The outcome for patients with gastroesophageal reflux disease who underwent a laparoscopic anterior 180-hemifundoplication was determined. Clinical follow-up was carried out prospectively by an independent scientist who applied a standardized questionnaire yearly following surgery. This questionnaire evaluated symptoms of reflux, postoperative problems including dysphagia, gas bloat, ability to belch, and overall satisfaction with clinical outcome. From July 1995 to May 1999, a total ofc107 patients underwent a laparoscopic anterior hemifundoplication. Four patients underwent further surgery for recurrent heartburn, and persistent troublesome dysphagia occurred in one. At 1 year 89% of patients remained free of reflux symptoms, and at 3 years 84% remained symptom free. Of those with symptoms of reflux, approximately half of them had only mild symptoms. The overall incidence and severity of dysphagia for liquids and solids was not altered by partial fundoplication. Epigastric bloating that could not be relieved by belching was uncommon, and only 11% of the patients at 1 year and 10% at 3 years following surgery were unable to belch normally. Overall satisfaction with the outcome of surgery remained high at 3 years' follow-up. Laparoscopic anterior partial fundoplication is an effective operation for gastroesophageal reflux, with a low incidence of side effects and a good overall outcome.

Adolescent↗
PubMedDate not supplied

Flow injection spectrophotometric determination of copper, iron, manganese, and zinc in animal feeds using a common manifold.

A rapid and simple procedure was developed for the determination of copper, iron, manganese, and zinc in animal feeds using an identical flow injection spectrophotometric manifold but different chromogenic reagents and different detection wavelengths. Bis(cyclohexanone)oxalydihydrazone, formaldoxime, 1,10-phenanthroline, and xylenol orange were adopted as chromogenic reagents for Cu, Mn, Fe, and Zn, respectively. Detection conditions such as manifold parameters, buffer pH, reagent concentration, temperature, and acidity of sample solution were optimized. Analytical characteristics of the method and interference of metal ions commonly present in feeds were studied. By changing the reagents and detection wavelengths, which can be done quickly, the proposed low cost flow injection system can determine Cu, Fe, Mn, or Zn in the range of 0.5-10 mg/L with a sampling throughput of 120/h.

Animal Feed↗
PubMedDate not supplied

Determination of manganese in feedstuffs by flow injection spectrophotometry based on rapid formation of permanganate at room temperature.

A simple and rapid flow injection spectrophotometric procedure was developed for determination of manganese. In the presence of pyrophosphate and acetate, manganese was immediately oxidized to permanganate by periodate at room temperature in slightly alkaline medium. Under optimized conditions, the determination was made with a sampling rate of 120/h, a linear range of 0-30 mg/L Mn(II), a detection limit (S/N = 3) of 0.08 mg/L, and a relative standard deviation of 0.6% (n = 11) at 10 mg/L Mn(II). The proposed method was used to determine manganese in trace mineral premixes and feedstuffs. Results agreed well with those obtained by the standard atomic absorption spectroscopy method.

Animal Feed↗
PubMedDate not supplied

Identical flow injection spectrophotometric manifold for determination of protein, phosphorus, calcium, chloride, copper, manganese, iron, and zinc in feeds or premixes.

A simple procedure using an identical manifold was developed for determination of nitrogen (protein) phosphorus, calcium, chloride, copper, manganese, iron, and zinc in feeds and feedstuffs. By changing appropriate reagents and detection wavelength, these 8 elements were determined successively with a simple identical double-line flow injection (FI) manifold. Fl spectrophotometric determinations were made by the blue indophenol reaction for ammonium, the molybdenum blue method for phosphate, the cresolphthalein complexone procedure for calcium, and the mercuric thiocyanate procedure for chloride. The chromogenic reagents for copper, iron, manganese, and zinc determination were bis(cyclohexanone)oxalydihydrazone (Cuprizone), 1,10-phenanthroline, formaldoxime, and xylenol orange, respectively. Sample digestion catalyst, Fl manifold, and some chemical parameters were optimized. The proposed procedure had a sampling rate of 90/h for each analyte. The determination ranges (mg/L) were 10-60 for N, 1-15 for P and Ca, 540 for Cl, and 0.5-15 for Cu, Fe, Mn, and Zn, respectively. Results of the analyses of animal feed and feedstuff samples by this procedure did not differ significantly from those obtained by proven manual methods.

Animal Feed↗
PubMedDate not supplied

Characteristics of premaxillary supernumerary teeth: a survey of 112 cases.

The purpose of this study was to investigate the characteristics of premaxillary supernumerary teeth among children in Taiwan. The study population consisted of 112 children, ranging in age from four years to fourteen years. The characteristics of supernumerary teeth were obtained from radiographs and clinical examination, and were confirmed by surgical intervention. The results showed that males were affected approximately three times as frequently as female. About 36 percent of the patients had more than one supernumerary tooth and more than 96 percent of supernumerary teeth occurred in the central incisor region. About 46 percent of the supernumerary teeth were in the vertical position, 34 percent of the supernumerary teeth were erupted; and the eruption rate of conical shaped and tuberculate shaped supernumerary teeth were similar.

Adolescent↗