517 research outputs found
Effect of orthophosphate on the transaldolase reaction.
In previous studies' with a dialyzed supernatant fraction from rat liver it was observed that the formation of heptulose phosphate from fructose g-phosphate was significantly inhibited by inorganic phosphate. It has since been shown (1, 2) that the activity of the dialyzed liver fraction can be related to its content of transketolase and transaldolase and it became of interest to determine whether the inhibition of the over-all process by phosphate was due to its effect on one or both of the enzymes involved in this process. Preliminary experiments indicated that both transketolase and transaldolase were inhibited by inorganic phosphate when the enzymes were tested in the usual assay procedures. The effect of phosphate on transaldolase is reported in the present paper
Microwave Harmonic Emission in MgB2 Superconductor: Comparison with YBaCuO
We report results of microwave second-harmonic generation in ceramic samples
of MgB2, prepared by different methods. The SH signal has been investigated as
a function of the temperature and the static magnetic field. The results are
discussed in the framework of models reported in the literature. We show that
the peculiarities of the SH signal are related to the specific properties of
the sample. A comparison with the results obtained in ceramic and crystalline
YBa(2)Cu(3)O(7) shows that the second-harmonic emission in MgB2 is weaker than
that observed in ceramic YBa(2)Cu(3)O(7).Comment: 13 pages, 6 figures; Proceedings of Third Workshop on Metamaterials
and Special Materials for Electromagnetic Applications and TLC (Rome, 30-31
March, 2006
Sleep apnoea and metabolic dysfunction.
Obstructive sleep apnoea (OSA) is a highly prevalent condition often associated with central
obesity. In the past few years, several studies have analysed the potential independent contribution of OSA
to the pathogenesis of metabolic abnormalities, including type 2 diabetes, the metabolic syndrome and nonalcoholic
fatty liver disease. New perspectives in OSA patient care have been opened by the promotion of
lifestyle interventions, such as diet and exercise programmes that could improve both OSA and the
metabolic profile. The rich clinical literature on this subject, together with the growing amount of data on
pathophysiological mechanisms provided by animal studies using the chronic intermittent hypoxia model,
urged the organising Committee of the Sleep and Breathing meeting to organise a session on sleep apnoea
and metabolic dysfunction, in collaboration with the European Association for the Study of Diabetes. This
review summarises the state-of-the-art lectures presented in the session, more specifically the relationship
between OSA and diabetes, the role of OSA in the metabolic consequences of obesity, and the effects of
lifestyle interventions on nocturnal respiratory disturbances and the metabolic profile in OSA patient
Microwave response of bulk MgB2 samples of different granularity
The microwave response of three high-density bulk MgB2 samples has been
investigated in the linear and nonlinear regimes. The three samples,
characterized by different mean size of grains, have been obtained by reactive
infiltration of liquid Mg in powdered B preforms. The linear response has been
studied by measuring the microwave surface impedance; the nonlinear response by
detecting the power radiated by the sample at the second-harmonic frequency of
the driving field. Our results suggest that bulk MgB2 prepared by the liquid Mg
infiltration technique is particularly promising for manufacturing resonant
cavities operating at microwave frequencies.Comment: 4 pages, 2 embedded figures; Proceedings of 7th EUCAS Conference
(11-15 September 2005, Vienna - Austria
Fatal intrahepatic hemorrhage after nadroparin use for total hip arthroplasty.
Low-molecular-weight heparins have become the predominant choice for deep venous thrombosis prophylaxis and treatment. However, their use may cause bleeding complications. Intrahepatic bleeding is exceptional and only very few cases have been described. The authors present a unique case of fatal intrahepatic hematoma complicating nadroparin use in a 65-year-old woman with a hepatic cyst who was admitted to hospital for unilateral total hip arthroplasty. At autopsy, hemoperitoneum (2,000 ml of blood and clots) was evident. A ruptured sub-capsular hematoma involving the right lobe of the liver was observed. The hemorrhage within the cyst induced by the nadroparin use was likely responsible for the subsequent hepatic hematoma, liver rupture, and death. This case highlights the need for pathologists and surgeons to be aware of the possibility of intrahepatic hematoma in patients who have received low-molecular-weight heparins, undergone major surgery and present postoperative hemodynamic instability, especially in those with preoperative diagnosis of hepatic cyst
Efficacy of atropine 0.01% for the treatment of childhood myopia in European patients
Purpose: To evaluate the efficacy and safety of atropine 0.01% in slowing myopia progression in European paediatric patients. Methods: Retrospective, medical records review study. Medical charts of paediatric patients with a myopia progression > 0.5 D/year treated with atropine 0.01% for at least 1 year were included. Patients receive a complete ophthalmic examination before and 12 months after initiation of atropine treatment. A group of myopic untreated children serves as a control group. The rate of myopia progression at baseline and 12 months after treatment with atropine was evaluated. The rate of myopia progression in treated and untreated patients was also compared. Adverse events were recorded. Results: Medical records of 52 treated and 50 control subjects were analysed. In the atropine group, the mean rate of myopia progression after 12 months of treatment ( 120.54 \ub1 0.61 D) was significantly slower compared with the baseline progression ( 121.20 \ub1 0.64 D; p < 0.0001) and to the progression in the control group ( 121.09 \ub1 0.64; p < 0.0001). The responders patients were 41/52 (79%), whereas 11/52 patients (21%) showed a progression > 0.50 D despite treatment. The only adverse event was temporary photophobia in five patients (9.6%), severe adverse events were not reported, and none of the patients discontinued the treatment. Conclusion: Low-dose atropine significantly slowed the rate of myopia progression in European paediatric patients with a favourable safety profile
Crystalline D -Gluconate 6-Phosphate Dehydrogenase"
A method for t.he purification of n-gluconate 6-phosphate dchydrogenase from brewers' yeast has been described by Horecker and Smyrniotis. (1). The enzyme preparation also catalyzed the oxidation of n-glucose 6-phosphate and isocitrate and in addition contained significant amounts of n-ribose 5-phosphate isomerasc. The utility of the enzyme for the assay of n-gluconate 6-phosphato and for the preparation of n-ribulose 5-phosphate was seriously affected by the prcsencc of thcsc contaminating activitics. For a further investigation of the properties of the enzyme and of the nature of the two-step reaction, a more highly purified preparation was necessary. A method has now been developed which yields from Candida yeast a crystalline preparation which is free of detectable quantitics of I)-glucose 6-phosphata dchydrogenase and r)-ribose 5-phosphate isomerasc. To remove the former enzyme, advantage was taken of its lability to heat after treatment with charcoal (2, 3). n-Glucose 6-phosphate dchydrogcnasc is known to bc unstable in t,he absence of triphosphopyridine nuclcotidc. With the purified enzyme, only n-ribulosc 5-phosphate is formed, and this ester can thus be obtained free of n-ribose 5-phosphate and n-xylulose j-phosphate. Since the crystalline enzyme preparation catalyzes the osidation of reduced triphosphopyridine nucleotide by CO, and o-ribulose phosphate at a rate equal to that observed with crude enzyme preparations, wc have concluded that a single enzyme is rcsponsible for both oxidation and decarboxylation reactions. We have also undertaken an investigation of the specificity of the Mg++ requirement (1) and havn found that at high concentrations of NaCl, full activity is obtained in the absence of Mg++. There is reason to believe that the nature of t,he anion plays a role in the activation of the enzyme
Superconducting Microwave Cavity Made of Bulk MgB2
We report the successful manufacture and characterization of a microwave
resonant cylindrical cavity made of bulk MgB2 superconductor (Tc = 38.5 K),
which has been produced by the Reactive Liquid Mg Infiltration technique. The
quality factor of the cavity for the TE011 mode, resonating at 9.79 GHz, has
been measured as a function of the temperature. At T = 4.2 K, the unloaded
quality factor is 2.2x10^5; it remains of the order of 10^5 up to T ~ 30 K. We
discuss the potential performance improvements of microwave cavities built from
bulk MgB2 materials produced by reactive liquid Mg infiltration.Comment: 7 pages, 2 embedded figures, accepted for publication in Supercond.
Sci. Techno
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