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Biomedical subjects

M Herskowitz

Publications and source records attributed to M Herskowitz.

8 recordsLinked to original sources
PubMed2005

Combustion of chlorinated VOC on nanostructured chromia aerogel as catalyst and catalyst support.

The chromia-based catalysts have been reported to combine the high activity and resistance to deactivation in oxidative removal of chlorinated VOC. However, their activity is limited by the low amount of chromia that can be deposited on supports maintaining the optimal state of surface species and high surface area. The pure nanostructured chromia was used as a catalytically active support for noble metals and transition-metal oxide oxidation catalysts. High efficiency of Pt-promoted CrOOH aerogel with surface area of 500 m2*g(-1) was demonstrated in full combustion of 1,2-dichloroethane (DCE) and chlorobenzene (CB). At gas hour space velocity (GHSV) of 46 000 h(-1), the total conversion to CO2/H2O/HCl was achieved at 330 degrees C (DCE) and 380 degrees C (CB). The combustion rate constants measured at standard conditions with 0.5% Pt/CrOOH catalyst were 1 or 2 orders of magnitude higher than measured with 15%Cr2O3/Al2O3 or 0.5%Pt/Al2O3, respectively. The effects of Pt, Au, Mn, and Ce additives on the performance of CrOOH aerogel in combustion of chlorinated VOC were analyzed related to the materials structure.

Aluminum Oxide↗
PubMed2001

Using sonochemical methods for the preparation of mesoporous materials and for the deposition of catalysts into the mesopores.

Ultrasound radiation can be used to synthesize a variety of mesporous materials. The reaction time is considerably shorter than the conventional methods. Ultrasonic waves can be further used for the insertion of amorphous nanosized catalysts into the mesopores. A detailed study demonstrates that the nanoparticles are deposited as a monolayer on the inner mesopores walls without blocking them. When the ultrasonically prepared catalyst/mesoporous-subtrate composite is used in catalysis a high conversion into product is obtained.

Journal Article↗
PubMed2000

Attenuation of ultrasound in porous media with dispersed microbubbles

The dispersion relation for a granular bed with a small amount of fine bubbles is formulated and analyzed. It is assumed that the grain size is much larger than the bubble's radius and that their volume concentration is small. The study is motivated by the problem of acoustic diagnostics of fixed bed chemical reactors operating in multiphase flow regime.

Journal Article↗
PubMed1994

Use of magnetic internal ureteral stents in pediatric urology: retrieval without routine requirement for cystoscopy and general anesthesia.

In children the use of internal ureteral stents has the added morbidity of requiring general anesthesia for stent retrieval. Magnetically tipped ureteral stents were developed to allow easy retrieval without the need for anesthesia or cystoscopy. For pyeloplasty we generally do not use a stent or nephrostomy tube but we treated 7 children 2 1/2 months to 11 years old in whom we believed there was an indication for stenting and in whom we used a magnetically tipped stent. The catheters were removed with a magnetically tipped catheter retriever without the need for anesthesia in 6 of the 7 cases and cystoscopy was not required in any case. Our initial impression is that when stenting is advised the magnetically tipped ureteral stent appears to be a good alternative, especially in children, since it avoids the need for anesthesia and cystoscopic retrieval.

Child↗
PubMed1988

Computed tomography of the abdomen in the diagnosis of splenic emboli.

Abdominal computed tomographic scans were performed in 25 consecutive patients with bacterial endocarditis. Six patients had splenic infarcts, only two of whom had symptoms. Three of the six patients had no evidence of emboli to other organs. In patients with endocarditis who have had clinically apparent emboli or who are, for other reasons, being considered for valvular surgery, a computed tomographic scan of the abdomen may help in decision making.

Adult↗
PubMedDate not supplied

Pitfalls and limitations of diuretic renography.

We report five pediatric cases that illustrate the methodologic pitfalls and limitations of diuretic renography in suspected ureteropelvic junction obstruction. False-positive studies may be related to such avoidable flaws in methodology as premature diuretic administration, inadequate diuretic dose, and bladder distension, or to recent pyeloplasty. False-negative results may occur despite optimum technique, necessitating a follow-up study for confirmation.

Child, Preschool↗