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At least 613 records · Page 34Linked to original sources
PubMed2005

[Studies on nano-diamond prepared by explosive detonation by Raman and infrared spectroscopy].

Nano-diamond was synthesized by TNT/RDX explosives detonation in a steel chamber and characterized by X-ray diffraction (XRD), laser Raman spectroscopy, and infrared spectroscopy. XRD results indicate that nano-diamond has cubic diamond structure. The parameter of unit cell of nano-diamond is 0.359 23 nm and is 0.72% larger than that of the bulk diamond. The high-density defects and other impurity atoms in the nano-diamond structure may lead to the large lattice constant. The examination results of Raman spectra show that the Raman band is broader and shifts to l ow frequency by 3 cm(-1), because the size of nano-diamond reaches nanometer order. There is little graphite in the nano-diamond. There are two peaks in FTIR of the nano-diamond, which are characteristic peaks of diamond at 1 262 and 1 134 cm(-1). Besides these two peaks, there are six peaks at 3 422, 1 643, 2 971, 2 930, 2 857 and 1 788 cm(-1) respectively. The FTIR bands at 2 930 and 2 857 cm(-1) are the antisymmetrical and symmetrical stretch vibration absorption spectra of CH2 respectively. The 3 422 cm(-1) is the stretch vibration absorption peak of O-H. The 1 634 cm(-1) confirms that there are H2O in the nano-diamond. The 2 971 cm(-1) is the antisymmetrical stretch vibration absorption peak of CH3. The 1 788 cm(-1) is the stretch vibration absorption peak of C=O. These indicate that there are H and O elements in the nano-diamond. From the mechanism of the nano-diamond, the authors discuss the reason for the vibration absorption peaks of O-H, CH2, CH3, and C=O, existing in the FTIR of the nano-diamond.

Algorithms↗
PubMed2005

[A case of carbon monoxide poisoning by explosion of coal mine presenting as visual agnosia: re-evaluation after 40 years].

We re-evaluated a case of carbon monoxide poisoning presenting as visual agnosia who had been injured by explosion of Miike-Mikawa coal mine 40 years ago. In an early stage, his main neuropsychological symptoms were visual agnosia, severe anterograde amnesia, alexia, agraphia, constructional apraxia, left hemispatial neglect and psychic paralysis of gaze, in addition to pyramidal and extra pyramidal signs. At the time of re-evaluation after 40 years, he still showed visual agnosia associated with agraphia and constructional apraxia. Concerning visual agnosia, recognition of the real object was preserved, while recognition of object photographs and picture was impaired. Thus, this case was considered to have picture agnosia as he could not recognize the object by pictorial cues on the second dimensional space. MRI examination revealed low signal intensity lesions and cortical atrophy in the bilateral parieto-occipital lobes on T1-weighted images. Therefore, the bilateral parieto-occipital lesions are likely to be responsible for his picture agnosia.

Aged↗
PubMed2006

Reflecting on theatre explosion danger.

Risk of explosion and fire in operating theatres used to be significant. For this Health Estate Journal 'Then and now' feature, Mike Arrowsmith BSc (Hons) CEng FIMechE FIHEEM, technical editor, provides commentary on an article which was published in December 1945 in the second issue of The Hospital Engineer, a publication then taking the form of a newsletter--of The Institution of Hospital Engineers. The 1945 article was formed from a short paper read at an Institution branch meeting, and a slightly amended version of the article text follows the commentary.

Explosions↗
PubMedDate not supplied

[Explosive "Roman find"].

A case of a 40-year-old hobby archeologist is presented who searched for remains from Roman times. After finding an oblong, cylindrical object, he opened it with a saw to examine it, which triggered an explosion killing the man. The technical investigation of the remains showed that the find was actually a grenade from the 2nd World War. The autopsy findings and the results of the criminological investigation are presented.

Adult↗
PubMedDate not supplied

[The blast injury as a result of underwater explosion].

Experiments on pigs were made for determination of safe distance to blast center for a diver using the isolating breathing apparatus IDA-71U and aqualung AVM-5. The animals were placed at the distance 12, 9, 7 and 5 m from the blast center. After the explosion, basic physiological parameters and severity of traumas were monitored. Differences in morphological characteristics of the damage done on the earth and under water were identified. Safe distance was 12 m.

Animals↗
PubMed1990

Laser initiated endotracheal tube explosion.

A 62-year-old male with a diagnosis of subglottic and tracheal stenosis resulting from a prolonged intubation was scheduled for a laser bronchoscopy and placement of a silicon T-shaped tube. His history was significant for two myocardial infarctions, an episode of congestive heart failure and exertional angina. A 6 mm polyvinyl chloride endotracheal tube, wrapped with aluminum tape, was placed in an existing tracheostomy stoma. During the course of the procedure, a sudden bright flash occurred followed by an explosive noise and black smoke rising in the anesthesia circuit and from the patient's mouth. The endotracheal tube was removed and the patient was treated for first and second degree burns in the supraglottic area and base of the tongue. In laser surgery of the airway, special care should be given to reducing the flammability of the inspired gases which can be best accomplished by the mixture of helium with oxygen. Helium acts to retard ignition of polyvinyl chloride tubes in concentrations of 60% or greater. The external surface of the tube can also be protected with the application of a metallic tape affixed in a spiral fashion. Finally, a protocol for the management and treatment of this emergency should be adopted and rehearsed.

Bronchoscopes↗
PubMed1988

[Lung injuries caused by explosion in rabbits. 1. The experimental model of the injury].

A model for producing blasts of medium strength was developed. The injuries lead to the death of 25 to 50% of the experimental rabbits. The injuries were tested physically by direct measurements. The explosion of 225 g TNT in the air in 110 cm distance killed 35% of the rabbits. The corpus of the rabbit absorbed 67% of the energy of the blast in 0.46 ms in average. The average of the maximum positive pressure in the blast was 25.4 +/- 3.1 bar.

Animals↗
PubMed1977

Pop bottle explosions.

To our knowledge, there are only two brief reports in the medical literature of injury sustained as a result of a carbonated soft-drink (pop) bottle explosion. We report three such cases and review pertinent data on this hazard.

Accidents, Home↗
PubMedDate not supplied

[Reconstruction of the explosion site of a hand granade on an automobile seat].

A hand grenade exploded in a VW-Bus killing the female passenger. The paper describes how examination of damage to the material of the drivers seat, seat cushion and to a blanket was able to provide information which helped to reconstruct the effects of the explosion and to determine the position of the grenade at the moment of detonation.

Adult↗
PubMed1996

Gas explosion during colonic surgery.

Explosions of the colon as a result of the use of diathermy in the presence of gas mixtures of oxygen, hydrogen and/or methane have been previously described in the literature. This danger is present during colonoscopic polypectomy as well as during colonic surgery. The following case is presented to alert to the potential hazards of bowel gas during electrosurgery.

Adult↗
PubMed1999

The onset of coulomb explosions in polyatomic molecules

With the development of high intensity femtosecond lasers, the ionisation and dissociation dynamics of molecules has become an area of considerable interest. Using the technique of femtosecond laser mass spectrometry (FLMS), the molecules carbon disulphide, pyrimidine, toluene, cyclohexanone and benzaldehyde are studied with pulse widths of 50 fs in the near infrared (IR) wavelength region (790 nm). Results are presented and contrasted for laser beam intensities around 10(15) and 10(16) W cm(-2). For the lower intensities, the mass spectra yield dominant singly charged parent ions. Additionally, the appearance of doubly charged parent ions is evident for carbon disulphide, toluene and benzaldehyde with envelopes of doubly charged satellite species existing in these local regions. Carbon disulphide also reveals a small triply charged component. Such atomic-like features are thought to be a strong fingerprint of FLMS at these intensities. However, upon increasing the laser intensity to approximately 10(16) W cm(-2), parent ion dominance decreases and the appearance of multiply charged atomic species occurs, particularly carbon. This phenomenon has been attributed to Coulomb explosions in which the fast absorption of many photons may produce transient highly ionised parent species which can subsequently blow apart. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗
PubMed2000

Nipping the Cambrian "explosion" in the bud?

In recent years, two schools of thought have emerged with regard to the Cambrian "explosion". One argues that it was very quick, with phyla tumbling into existence in a virtual geological instant. The other view has a more relaxed temporal perspective. It looks to slow aeons of cryptic metazoan history, which led to a final breakthrough in the Cambrian, not in evolution but of fossilization potential. Yet both views have serious difficulties. Now, in a recent issue of Biological Reviews, Graham Budd and Sören Jensen(1) argue for a third way. In an intriguing blend of functional morphology, the fossil record and cladistic thinking, they suggest that the assembly of metazoan bodyplans took place in a surprisingly straightforward manner.

Animals↗
PubMed2006

Theoretical analysis of the terahertz spectrum of the high explosive PETN.

The experimental solid-state terahertz (THz) spectrum (3 to 120 cm(-1)) of the high explosive pentaerythritol tetranitrate (PETN, C(5)H(6)N(4)O(12)) has been modeled using solid-state density functional theory (DFT) calculations. Solid-state DFT, employing the BP density functional, is in best qualitative agreement with the features in the previously reported THz spectrum. The crystal environment of PETN includes numerous intermolecular hydrogen-bonding interactions that contribute to large (up to 80 cm(-1)) calculated shifts in molecular normal-mode positions in the solid state. Comparison of the isolated-molecule and solid-state normal-mode calculations for a series of density functionals reveals the extent to which the inclusion of crystal-packing interactions and the relative motions between molecules are required for correctly reproducing the vibrational structure of solid-state THz spectra. The THz structure below 120 cm(-1) is a combination of both intermolecular (relative rotations and translations) and intramolecular (torsions, large amplitude motions) vibrational motions. Vibrational-mode analyses indicate that the first major feature (67.2 cm(-1)) in the PETN THz spectrum contains all of the optical rotational and translational cell modes and no internal (molecular) vibrational modes.

Journal Article↗
PubMed1995

Association of nerve growth factor mRNA levels with MK-801-induced explosive behaviors in mice.

MK-801, a noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptor, stimulated an outbred strain of NIH Swiss mice to display discrete episodes of explosive jumping behavior, designated as "popping." The rapid onset of the MK-801-induced "popping" seems to follow the rapid distribution of the drug to the frontal cortex, the area that contains high levels of NMDA receptors. We examined the effect of this drug on the levels of mRNA coding for nerve growth factor (NGF) in the frontal cortex in relation to the exhibited "popping" episodes. Mice treated with 1 mg/kg MK-801 could be split into two groups based on the total number of "popping" episodes in a 30 min post-injection period. These groups also differed in the steady-state levels of frontal cortex NGF mRNA. Animals that exhibited low numbers of "popping" had levels of NGF mRNA significantly higher than saline treated controls or mice that exhibited high numbers of "popping." Mice treated with 10 mg/kg MK-801 had a high frequency of "popping" that was impossible to separate into episodes. In addition, these mice had levels of frontal cortex NGF mRNA that were significantly lower than either group of mice treated with 1 mg/kg MK-801. These data indicated that there was an increased level of NGF mRNA under conditions where MK-801 induced a low level of "popping" behavior. However, when "popping" intensified, NGF mRNA levels were decreased, suggesting a possible behavioral antagonism of the NGF response.

Animals↗
PubMed2002

Forensic identification of explosive oxidizers by electrospray ionization mass spectrometry.

The mass spectrometry of a group of inorganic oxidizers was studied using the electrospray ionization technique. It was found that a series of cluster ions were predominant in both positive- and negative-ion mode, allowing for the characterization of the investigated oxidizers. The identity of the recorded cluster ions was further confirmed by using some isotopically labeled compounds and tandem mass spectrometry with collision-induced dissociation. The use of electrospray ionization mass spectrometry for positive identification of major oxidizer components in explosive formulations was demonstrated by three samples of forensic interest.

Journal Article↗
PubMed1997

Reproductive endocrinology of the explosively breeding desert spadefoot toad, Scaphiopus couchii.

The spadefoot toad, Scaphiopus couchii, is an explosively breeding, desert dwelling amphibian that shows two characteristics hypothesized to select for a dissociated breeding pattern: it lives in a harsh environment and it has a very short, but predictable breeding period. We tested the hypothesis that these factors select for a dissociated breeding cycle by measuring plasma steroid hormones and the gametogenic cycles in a free-living population of S. couchii. Blood and tissue samples were obtained from prebreeding, calling (males only), amplexed, and postbreeding toads. In males, plasma testosterone (T), dihydrotestosterone (DHT), and corticosterone (B) differed significantly among reproductive groups, with calling and amplexing toads having the highest levels of each of these steroids. In females, plasma T, DHT, B, progesterone (P), and estradiol (E2) were measured; all steroids except B changed significantly among mating groups. Plasma T and E2 were greatest in prebreeding and amplexed females, while P and DHT were highest only in amplexed females. Primary spermatogonia (SPG I), secondary spermatogonia (SPG II), spermatocytes, spermatids (SPT), and spermatozoa embedded in Sertoli cells (SPS) all changed significantly among male breeding groups. Although all stages were present in all breeding groups, early stages of spermatozoa (SPG I and SPG II) were greatest in postbreeding males, while late stages (SPT and SPS) were highest in prebreeding, calling, and amplexing males. In females, oocyte stages I, II, III, V, and VI and atretic follicles also differed significantly among mating groups. Prebreeding female ovaries were dominated by late-stage (V and VI) oocytes which were subsequently ovulated during amplexus. In postbreeding females, oogenesis was well under way as indicated by the rising numbers of stage II and III oocytes. These results indicate that aspects of gametogenesis occur during and after breeding in both sexes. Although the results demonstrate that gonadal activity was high during the period of sexual activity, suggesting that S. couchii most closely fits an associated pattern of reproduction as defined by Crews (1984, Horm. Behav. 18, 22-28), we also found that gonadal activity continued past the breeding season. For this reason, S. couchii does not completely conform to an associated pattern.

Animals↗