Effects of handling parameters on hydrogen sulfide emission from stored dairy manure

Hydrogen sulfide (H2S) emission from liquid manure in the process preceding field application is an important issue in fertigation systems. Given that H2S poses a significant health risk, it is important to determine the effects of different handling parameters on H2S emissions to prevent health risks to farmers. In this study, the effects of total solids (TS; 3, 5, 7, 9, and 11%) and mixing speed (100, 200, 300, and 400 rpm), duration (5, 15, 30, and 60 min), and frequency (one, two, three, and four times a day) on H2S emissions from two different dairy manures were investigated. The results indicate that the quantity of sulfur-containing substrate intake determines the potential of dairy manure to emit H2S because manure from cows fed with concentrate-based feed generates higher amounts of H2S than manure from cows fed with forage-based feed. The H2S concentration increased with TS concentration and reached a maximum of 1133 ppm at a TS of 9%; thereafter, it decreased with further increases in TS concentration. H2S emission increased with mixing speed with a peak concentration of 3996 ppm at 400 rpm. A similar trend was observed for mixing duration. However, there were no significant differences between the amounts H2S emitted at different frequencies of mixing (P > 0.05). The results indicate that mixing speed, duration, and TS are the major determinants of the quantity of H2S emitted from dairy manure. Therefore, to prevent health risks associated with H2S emission from dairy manure, it is recommended that the mixing speed and duration should be kept as low as possible, while a TS concentration of above 9% should be applied during the fertigation of dairy manure.

On the Interface Properties and Deep Level Defects in Ta2O5 Grown on Si by Plasma Enhanced Liquid Source-Cvd

We report, for the first time, on interface properties of the Ta2O5-Si system and on the deep level defects in Ta2O5 grown by plasma enhanced liquid source chemical vapor deposition (PE-LS-CVD) using Ta(OC2Hs)5. The capacitance voltage (C–V) measurement performed on Au/Ta2O5/n, p-Si MOS diodes resulted in very well defined C-V charactristics which compares well with the ideal C-V curve. The flat band voltage is as low as 0.15 V and the minimum density of the interface state is about 2.7 × 1011 cm−2 ev−1. In order to examine deep level defects in Ta2O5, we investigated variations of flat band voltage under application of high stress electric field (10MV/cm), by which hot carriers are injected in to deep levels. This charge transfer process results in increase of charges in Ta2O5 oxide which is attributed to the equivalent deep level defect densities, which is found to be of the order of 2 × 1011 cm−2 in the Ta2O5-Si system. These results strongly suggest low interface states and deep levels in the PE-LS-CVD grown Ta2O5-Si system, which may be brought about by low decomposed-carbon impurities in the film, confirmed by AES in our previous reports. These films can play a vital role as thin capacitors in I.C. technology.

Solution-process coating of vertical ZnO nanowires with ferroelectrics

We have developed a modified misted deposition process by combining substrate and mist heating for the deposition of ferroelectrics on 3D nanostructures. Arrays of vertical ZnO nanowires, sputter coated with Pd bottom electrodes, are used as the substrate. Scanning electron microscopy investigations show that conformal coating of ferroelectric Pb(Zr,Ti)O(3) (PZT) with good step coverage is obtained at deposition temperatures above 140 °C. The substrate heating also eliminates the common 'bundling' problem of the nanowire arrays. On the basis of data on x-ray diffraction, energy dispersive x-ray spectroscopy, and P-E hysteresis of PZT films on flat substrates, we obtain the optimum substrate temperature window to be 180-220 °C, in terms of best step coverage and an evident ferroelectricity. This is a significant step towards the end-goal of fully integrated ZnO nanowires with ferroelectric capacitors, which may be useful for the light-emitting applications of ZnO.

Diagnosis and management of idiopathic normal-pressure hydrocephalus: a prospective study in 151 patients

Object. The diagnosis and management of idiopathic normal-pressure hydrocephalus (NPH) remains controversial, particularly in selecting patients for shunt insertion. The use of clinical criteria coupled with imaging studies has limited effectiveness in predicting shunt success. The goal of this prospective study was to assess the usefulness of clinical criteria together with brain imaging studies, resistance testing, and external lumbar drainage (ELD) of cerebrospinal fluid (CSF) in determining which patients would most likely benefit from shunt surgery.

Methods. One hundred fifty-one patients considered at risk for idiopathic NPH were prospectively studied according to a fixed management protocol. The clinical criterion for idiopathic NPH included ventriculomegaly demonstrated on computerized tomography or magnetic resonance imaging studies combined with gait disturbance, incontinence, and dementia. Subsequently, all patients with a clinical diagnosis of idiopathic NPH underwent a lumbar tap for the measurement of CSF resistance. Following this procedure, patients were admitted to the hospital neurosurgical service for a 3-day ELD of CSF. Video assessment of gait and neuropsychological testing was conducted before and after drainage. A shunt procedure was then offered to patients who had experienced clinical improvement from ELD. Shunt outcome was assessed at 1 year postsurgery.

Conclusions. Data in this report affirm that gait improvement immediately following ELD is the best prognostic indicator of a positive shunt outcome, with an accuracy of prediction greater than 90%. Furthermore, bolus resistance testing is useful as a prognostic tool, does not require hospitalization, can be performed in an outpatient setting, and has an overall accuracy of 72% in predicting successful ELD outcome. Equally important is the finding that improvement with shunt surgery is independent of age up to the ninth decade of life in patients who improved on ELD.

Treatment of a scalp arteriovenous malformation by a combination of embolization and surgical removal

SUMMARY

The authors describe a 21-year-old man in whom a large arteriovenous malformation of the scalp was eliminated using a combined interventional, neuroradiological and neurosurgical approach. Embolization was utilized to reduce arterial blood supply to the malformation. Eudragit- E, as a liquid embolic material from a cationic polymer, methyl and butyl methacrylate, and dimethylaminoethyl methacrylate copolymer, was injected through the transarterial route and then by direct percutaneous puncture of the nidus. One week after embolization, the nidus was easily resected with minimal blood loss. A postoperative angiogram showed nearly total extirpation of the nidus as well as complete clinical recovery. Preoperative embolization in this case was a safe and effective ablative technique.

[Combination of stenting and coil embolization for carotid artery pseudoaneurysm causing symptomatic mass effect: case report]

A case of cervical pseudoaneurysm secondary to carotid artery dissection causing symptomatic mass effect was reported. A 60-year-old woman presented with the complaint of right neck swelling and dysphagia that was considered to be the mass effect of a pseudoaneurysm caused by dissection of the right common carotid artery (CCA). Although a self-expanding stent was deployed to cover the orifice of the pseudoaneurysm, the pseudoaneurysm had been enlarged because of thrombus formation on the inner wall. A microcatheter was guided through the stent mesh into the aneurysm, and Guglielmi detachable coils were placed to embolize the orifice. One month later, angiography revealed complete embolization of the aneurysm while preserving flow in the CCA. The mass effect attributable to the pseudoaneurysm was relieved symptomatically as well as radiologically. Carotid artery dissection with symptomatic mass effect can be treated successfully, using a combination of stent and coils. This method may be considered to be an alternative to conventional surgical treatment such as proximal ligation, extracranial-intracranial bypass, or direct surgical repair.

Contribution of edema and cerebral blood volume to traumatic brain swelling in head-injured patients

OBJECT

The pathogenesis of traumatic brain swelling remains unclear. The generally held view is that brain swelling is caused primarily by vascular engorgement and that edema plays a relatively minor role in the swelling process. The goal of this study was to examine the roles of cerebral blood volume (CBV) and edema in traumatic brain swelling.

METHODS

Both brain-tissue water and CBV were measured in 76 head-injured patients, and the relative contribution of edema and blood to total brain swelling was determined. Comparable measures of brain-tissue water were obtained in 30 healthy volunteers and CBV in seven volunteers. Brain edema was measured using magnetic resonance imaging, implementing a new technique for accurate measurement of total tissue water. Measurements of CBV in a subgroup of 31 head-injured patients were based on consecutive measures of cerebral blood flow (CBF) obtained using stable xenon and calculation of mean transit time by dynamic computerized tomography scanning after a rapid bolus injection of iodinated contrast material. The mean (+/- standard deviation) percentage of swelling due to water was 9.37+/-8.7%, whereas that due to blood was -0.8+/-1.32%.

CONCLUSIONS

The results of this study showed that brain edema is the major fluid component contributing to traumatic brain swelling. Moreover, CBV is reduced in proportion to CBF reduction following severe brain injury.

CSF dynamics in a patient with a programmable shunt

The Codman-Medos programmable shunt system was designed by Drs. Hakim to relieve under and over drainage problems. The system allows for non-invasive post-implantation adjustment of the opening pressure of the valve through a range of 30 to 200 mmH2O in 10 mm differentials. However, its wide adjustability does not simplify determination of the optimal pressure setting. The bolus injection method was used to study the intracranial pressure environment of nine adult hydrocephalic patients treated with the Codman-Medos programmable shunt. Changes in CSF hydrodynamics with manipulation of the pressure valve setting, and the effectiveness of the bolus injection method to determine the optimum valve pressure setting were investigated. Initial valve pressure setting at shunt implantation was determined on the basis of preoperative CSF dynamics test. Another CSF dynamics test was carried out after surgery, and the pressure setting was revised in necessary. The new setting was the maximum obtained within normal CSF hydrodynamics. If shunt overflow was suspected, pressure was set at a higher level. After resetting of the shunt, no patient encountered serious shunt-related problems in the follow-up period. This method was considerably useful for understanding of the intracranial pressure environment of patients with a programmable shunt, and determination of a better shunt setting.

Evaluation of homeostatic changes in CSF circulation: in vivo analysis of the effect of neurotransmitter accumulation in the extracellular space following transient global ischemia

Accumulation of potassium and excitatory amino acids (EAA) in the extracellular space (ECS) following ischemia has been well documented. Careful monitoring of these transients is crucial to gain a better understanding of CNS pathophysiology. This study was initiated to determine if CSF concentrations of EAAs reflect those measured in the ECS. Transient global ischemia, 20 minutes in duration, was produced by clamping the left subclavian and innominate arteries combined with hemorrhagic hypotension. The accumulation of glutamate and electrolytes were measured in CSF and the extracellular fluid (ECF) of cerebral cortex. Microdialysis (MD) was utilized to measure the extracellular concentrations while direct sampling of CSF was provided via cannulation of the cisterna magna. Hydrogen clearance and laser doppler methods were used to monitor regional cortical CBF. Our results show that extracellular concentrations of potassium ([K+]ECF) and glutamate significantly increased following the initiation of ischemia (p < 0.05). The extracellular concentration of these substances decreased with the restoration of CBF. In CSF, a similar trend was observed following re-circulation (p < 0.05). However, CSF glutamate levels did not return to pre-ischemic values.

Posttraumatic ventriculomegaly: hydrocephalus or atrophy? A new approach for diagnosis using CSF dynamics

Cerebrospinal fluid (CSF) dynamics were correlated to the changes in ventricular size during the first 3 months posttrauma in patients with severe head injury (Glasgow Coma Scale score < or = 8, 75 patients) to distinguish between atrophy and hydrocephalus as the two possible causes of posttraumatic ventriculomegaly. Using the bolus injection technique, the baseline intracranial pressure (ICP), pressure volume index, and resistance for CSF absorption (R0) provided a three-dimensional profile of CSF dynamics that was correlated with ventricular size and Glasgow Outcome Scale (GOS) score at 3, 6, and 12 months posttrauma. Patients were separated into five different groups based on changes in ventricular size, presence of atrophy, and CSF dynamics. Group 1 (normal group, 41.3%) demonstrated normal ventricular size and normal ICP. Group 2 (benign intracranial hypertension group, 14.7%) showed normal ventricular size and elevated ICP. Group 3 (atrophy group, 24%) displayed ventriculomegaly, normal ICP, and normal R0. Group 4 (normal-pressure hydrocephalus group, 9.3%) had ventriculomegaly, normal ICP, and high R0. Group 5 (high-pressure hydrocephalus group, 10.7%) showed ventriculomegaly and elevated ICP with or without high R0. The GOS score in the nonhydrocephalic groups (Groups 1, 2, and 3) was better than in the hydrocephalic groups (Groups 4 and 5). It is concluded from these results that 44% of head injury survivors may develop posttraumatic ventriculomegaly. Posttraumatic hydrocephalus, as identified by abnormal CSF dynamics, was diagnosed in 20% of survivors and their outcome was significantly worse. This study demonstrates the importance of using CSF dynamics as an aid in diagnosis of posttraumatic hydrocephalus and identifying those patients who may benefit from shunt placement.

Seasonal development of Leptotrombidium akamushi (Acari: Trombiculidae) under field temperatures

Engorged larvae of Leptotrombidium akamushi (Brumpt), a vector of scrub typhus, were reared in small plastic containers placed on the ground and fed fresh eggs of the collembolan Sinella curviseta Brook. Engorged larvae obtained in October developed into deutonymphs through protonymphs approximately 1 mo before winter and became dormant in the cold winter season (approximately 3 mo). Most deutonymphs developed into tritonymphs in April and adults in May. Females began laying eggs in mid-June and the numbers of unfed larvae showed a peak in August. The mites reared from July rapidly developed into adults by August, and laid eggs in September. Larvae were most abundant in October, and adults became dormant in the winter. The same adults laid eggs from early May to late June and, upon hatching, the larval population peaked in early July of the 2nd summer. Most larvae died before the 2nd winter. Eggs hatched approximately 3 wk after oviposition and longevity of unfed larvae was 2 mo. Because of this very short incubation period, L. akamushi larvae occur in the summer, whereas L. pallidum Nagayo, Miyagawa, Mitamura & Tamiya, and L. scutellare Nagayo, Miyagawa, Mitamura, Tamiya & Tenjin occur in the autumn, although 3 species lay eggs from May to August.

[Cefuzonam penetration into cerebrospinal fluid]

We studied the penetration of cefuzonam (CZON) into the cerebrospinal fluid (CSF) in 20 patients with neurosurgical diseases. Influences of the presence of meningeal reaction and the intensity of brain damage on CSF penetration of CZON were also examined. Concentrations of CZON in serum and CSF were determined using the thin-layer cup method before and 1, 2, 4, and 6 hours after 2 g of CZON was administered intravenously. The serum concentration at 1 hour was 60.4 +/- 31.3 (mean +/- S.D.) microgram/ml, then rapidly decreased to 2.1 +/- 2.3 micrograms/ml at 6 hours. In contrast, the CSF concentration gradually increased, reached a peak level of 0.319 +/- 0.313 micrograms/ml at 4 hours and then slowly decreased to 0.273 +/- 0.249 micrograms/ml at 6 hours. The CSF penetration ration: CZON ([CSF]/[serum]) was 5.6% at 4 hours. The peak CSF concentration in patients with meningeal reaction (0.465 +/- 0.364 micrograms/ml at 2 hours) was about 2-fold higher than that in those without the reaction (0.249 +/- 0.223 micrograms/ml at 4 hours). The peak CSF concentrations in patients with slight, moderate, and severe brain damage were 0.231 +/- 0.133 micrograms/ml at 4 hours, 0.270 +/- 0.232 micrograms/ml at 4 hours, and 0.680 +/- 0.467 micrograms/ml at 2 hours, respectively. CSF penetration of CZON was augmented in patients with meningeal reaction or severe brain damage. These findings indicate that the concentration of CZON in CSF after intravenous administration is sufficient for treatment of meningitis or infections after neurosurgical operations caused by such bacteria as Escherichia coli, Klebsiella pneumoniae, Haemophilus influenzae, and Streptococcus pneumoniae.

Measurement of vascular reactivity in head injured patients

It is has been demonstrated that clinical outcome following head injury is correlated with the reactivity of the cerebrovasculature to carbon dioxide changes. Since CBF measurements are difficult to perform in these patients, a new technique is proposed utilizing the ICP response to capnic stimuli. In 40 head injured patients, the responses of ICP, pressure volume index (PVI) and middle cerebral artery velocities to hypocapnia and to hypercapnia were determined. Hypocapnia reduced ICP and MCA velocity while hypercapnia was followed by ICP and MCA velocity increases. Both changes were in the same magnitude supporting the concept the global ICP response reflects vascular reactivity. The fact that the velocity response to hypocapnia in lesioned hemispheres was less compared to the ICP response indicates the loss of ability to dilate in injured vessels and is consistent with earlier findings relating reduced reactivity to poor outcome.