Effects of propofol on mitochondrial function and intracellular calcium shift in bovine aortic endothelial model

BACKGROUND

Hypotension was commonly encountered in clinical practice during induction of anesthesia with propofol. The purpose of this study is to investigate the effect of propofol on mitochondrial membrane potential and morphology so as to infer its relation with intracellular calcium mobilization in bovine aortic endothelium.

METHODS

In this study, we used the cultured bovine aortic endothelial cells (Gm 7372a) to elucidate the impact of propofol upon the membrane potential and morphology of mitochondria in correlation with its effect on intracellular calcium shift. The intracellular calcium mobilization within the cells preincubated with or without propofol was evaluated using a fluorescent spectrophotometer (confocal microscope) after being treated with Fluo-3. The mobilization of intracellular calcium was demonstrated by the appearance of "hot spots" released from intracellular stores after the addition of an ionophore, ionomycin, to the incubation system. The membrane potential of mitochondria was measured by DiOC6 and the morphology of the mitochondria was evaluated by the treatment of TM Ros and compared with that by the treatment of the uncoupler, FCCP, as control.

RESULTS

The release of calcium "hot spots" from the intracellular stores (e.g. mitochondria) after the addition of ionomycin was visualized to decrease dramatically within the endothelial cells after preincubation with propofol. The membrane potential of mitochondria was significantly inhibited by pretreatment of propofol at 0.01 mM, 37 degrees C for 30 min. Morphologically, the integrity of mitochondria was distorted and fragmented in the presence of propofol as compared with that of control.

CONCLUSIONS

Our data showed that propofol in clinical concentration, 0.01 mM, could inhibit intracellular calcium shift from the intracellular stores and decrease the membrane potential and distort the morphology of mitochondria in bovine aortic endothelial cells. These inhibitions of the function and disfiguration of the morphology of mitochondria signify that the clinical hypotension induced by propofol might be of a potential mechanism.

AZFa candidate gene deletions in Taiwanese patients with spermatogenic failure

BACKGROUND AND PURPOSE

Deletions of the azoospermia factor subregion a (AZFa) genes in proximal Yq11 are not frequently reported. The majority of AZFa deletions are thought to be associated with more severe testicular phenotypes, such as Sertoli cell-only syndrome. There is a lack of data on AZFa gene deletions in East Asian populations. In this study, we investigated the deletion status of AZFa genes in Taiwanese men with spermatogenic failure.

METHODS

One hundred and eighty-three consecutive men with severe oligozoospermia or non-obstructive azoospermia were enrolled in this study. Genomic DNA was extracted from peripheral blood samples and polymerase chain reaction (PCR) was performed using primers specific to four AZFa genes: AZFaT1, DFFRY, DBY, and UTY. Sequence-tagged site markers (sY740, sY630, sY86, sY85, sY87, sY709, and sY88) were used to define the position of deletions. One hundred and twenty fertile men with normal spermatogenesis were enrolled as controls.

RESULTS

Of the 183 patients, two showed single AZFa gene deletions, resulting in an overall frequency of 1.1%. One of these two patients had DFFRY deletion and the other had DBY deletion; their testicular phenotypes were Sertoli cell-only syndrome and hypospermatogenesis, respectively. Neither patient had deletions extending from AZFa through AZFb or AZFc.

CONCLUSION

Our results suggest that AZFa gene deletion is infrequent in Taiwanese patients with severe oligozoospermia or non-obstructive azoospermia.

Preconditioning somatothermal stimulation on right seventh intercostal nerve territory increases hepatic heat shock protein 70 and protects the liver from ischemia-reperfusion injury in rats

Hyperthermic preconditioning attenuates the heat-induced cellular response to a subsequent severe heat challenge. However, it is impractical to perform whole-body hyperthermia in humans. This study was designed to test the hypotheses that hepatic heat shock protein 70 (Hsp70) could be induced by local somatothermal stimulation (LSTS) on right seventh intercostal nerve territory and that preconditioning the rats with LSTS protects the liver from subsequent ischemia-reperfusion injury. LSTS was brought about by application of a heating rod above right seventh intercostal nerve territory in male Sprague-Dawley rats. Hepatic gene expression of Hsp70 was assessed by Western blot and reverse transcription polymerase chain reaction (RT-PCR). Finally, serum ALT and AST and the lipid peroxidation product malondialdehyde (MDA) were evaluated in ischemic-reperfused rats preconditioned by application of LSTS on right seventh intercostal nerve territory. The results showed that hepatic gene expression of Hsp70 was upregulated in rats treated with LSTS. When animals were preconditioned with LSTS, followed by subsequent ischemia-reperfusion injury of the liver, there were significant decreases in liver enzymes (ALT/AST) and MDA formation in rats pretreated with one dose of LSTS (LSTS-1 group) as compared with those not treated with LSTS (control group) or treated with three doses of LSTS (LSTS-3 group). We conclude that mild local heat stress (one dose) on right seventh intercostal nerve territory upregulates hepatic gene expression of Hsp70 and protects the liver from subsequent ischemia-reperfusion injury. This might provide an easily applicable method for those patients facing ischemia-reperfusion challenge of the liver, as in liver resection and liver transplantation.

Development of a totally implantable pulsatile centrifugal pump as a ventricular assist device

The Taita No. 1 ventricular assist device (T-VAD) is a totally implantable pulsatile impeller centrifugal pump driven by a magnetically suspended motor. The flow can achieve 2.01 +/- 0.17 L/min against a pressure of 100 mm Hg under 0.266 +/- 0.017 amp and 13.55 +/- 0.41 voltage. The speed was around 3,500 rpm. It consumed less than 6 W of power, resulting in less heat production and mechanical bearing complications. The impeller vane was designed to have both radial and axial curves according to the stream surface and stream lines to reduce thrombosis and hemolysis. Eight calves weighing 80 to 100 kg (mean 87 +/- 12 kg) were used for experiments. With the calves under general anesthesia, left posterolateral thoracotomy was performed to connect the inflow tube with the atrial appendage and to anastomose the outflow tube with the descending aorta. The calves usually awoke and stood up within hours after discontinuation of anesthetics. The mean survival of the calves was 75 +/- 42 days (range 33-148 days). The terminations of experiments were mainly due to infection. During the course of pumping, no significant deterioration of liver or renal function was noted. The evaluation of serum samples from the implanted calves indicated that hemolysis was not associated with use of the T-VAD. The average daily free hemoglobin level was 8.08 +/- 3.05 mg/dl, which was less than the set limit of 20 mg/dl. The red blood cell and platelet count and hemoglobin of implanted animals were within the normal range. In our results, the T-VAD provided competent pulsatile function without severe blood damage or organ dysfunction.

Activity staining of isocitrate lyase after electrophoresis on either native or sodium dodecyl sulfate polyacrylamide gels

Isocitrate was cleaved into succinate and glyoxylate by isocitrate lyase (ICL) in the glyoxylate cycle. We used lactate dehydrogenase as an ancillary enzyme to further metabolize the glyoxylate to glycolate in the presence of NADH. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and 2,6-dichlorophenol-indolphenol (DCPIP) were used in the coupling reactions for detecting ICL activity after electrophoresis on either native or sodium dodecyl sulfate (SDS) polyacrylamide gels. This fast and sensitive method can be used in the process of ICL enzyme purification and characterization.

Physiologic analysis of cardiac cycle in an implantable impeller centrifugal left ventricular assist device

The purpose of this study was to determine the physiologic relationship between the cardiac cycle and the nonpulsatile impeller centrifugal Taita No.1 left ventricular assist device (T-LVAD) in a chronic animal study. The relationship of the cardiac cycle, pump flow, aortic pressure, left ventricle pressure, and pump power were analyzed by 5 phases in 4 stages. The isovolumetric ventricular phase is from mitral valve closure (MVC) to aortic valve opening (AVO) and is called Stage 1. The ejection phase is from AVO to aortic valve closure (AVC) and is called Stage 2. The isovolumetric relaxation phase is from AVC to MVC and is called Stage 3. The passive filling and atrial contraction phase is from MVC to mitral valve opening (MVO) and called Stage 4. Based on evidence from the physiologic volume change of the left ventricle, the change of pump flow of the T-LVAD in a cardiac cycle by variable voltages of pump control was evaluated using animal models. After left posteriolateral thoracotomy via the fifth intercostal space under general anesthesia, the nonpulsatile centrifugal T-LVAD was implanted into 2 healthy calves. The inflow of the T-LVAD was inserted into the left ventricle through the mitral valve via the left atrial appendage. The arterial blood pressure waveform was measured and recorded on the outflow of the T-LVAD. The 4 phases of a cardiac cycle were defined as MVC-AVO (Stage 1), AVO-AVC (Stage 2), AVC-MVO (Stage 3) and MVC-MVO (Stage 4) according to the outflow pressure of the outflow of the T-LVAD and differential pressure between the outflow and inflow of the T-LVAD. We carried out the real-time waveform measurement for electrocardiogram, the outflow pressure, the T-LVAD flow and the speed, as well as open loop and constant voltage (V). In a cardiac cycle, the sensing current of the T-LVAD was inverse to the speed. The flow of the T-LVAD at the 4 stages was measured individually and analyzed with different control voltages from 10 to 18 V. The highest flow ratio of MVC-AVC/AVC-MVC was noted when the T-LVAD worked on 14 V. By using analysis methodology of the flow ratio of a cardiac cycle, the optimal physiologically effective control of the T-LVAD might be achieved.

Protein kinase C epsilon suppresses Abeta production and promotes activation of alpha-secretase

Deposition of plaques containing Abeta is considered important in the pathogenesis of Alzheimer's disease. Phorbol esters that activate protein kinase C (PKC) promote alpha-secretase-mediated processing of the beta amyloid precursor protein (APP), which generally reduces formation of Abeta. To determine which PKC isozymes mediate this process, we studied CHO cells that express human APP751. Phorbol 12-myristate, 13-acetate (PMA)-stimulated APP secretion, which was reduced by a general PKC inhibitor bisindoylmaleimide I, but not by Gö 6976, which inhibits PKCalpha, beta, gamma, and mu. Since PKCdelta and epsilon were the only other PMA-sensitive isozymes present, we studied cells that express selective peptide inhibitors of these isozymes. Expression of the PKCepsilon inhibitor inhibited PMA-induced APPs secretion and suppression of Abeta production. In contrast, the PKCdelta inhibitor had no effect. These results provide evidence that PKCepsilon decreases Abeta production by promoting alpha-secretase mediated cleavage of APP.

Effects of estrogen and neurotransmitters on the primary cultures of tilapia brain from different ages

The effects of estrogen and neurotransmitters on the proliferation of brain cells were investigated in the primary cultures of tilapia brain from different ages. Treatment of brain cells that were cultured on day 1, 3, 5, 7, 10, 30, and 180 posthatching with serotonin (5-HT), resulted in a significant increase of the Brdu(+)-cell number. By contrast, norepinephrine (NE) resulted in a significant decrease and gamma-aminobutyric acid (GABA) had no effect. 17 beta-Estradiol (E(2)) significantly increased the Brdu(+)-cell number when the brain cells were cultured after 5 days of age, but had no effect when cultured on day 1 or 3 of age. These results indicate that the proliferation of brain cell is enhanced by 5-HT at each stage. This effect is mimicked by E(2) when given after 5 days of age. Conversely, NE has an effect to depress the proliferation of brain cells. Whereas, GABA has no effect.

Mitochondrial genomes of a bandicoot and a brushtail possum confirm the monophyly of australidelphian marsupials

Recent molecular analyses suggest that the position of bandicoots is the major difficulty in determining the root of the tree of extant marsupials. To resolve this, we analyse mitochondrial genome sequences of a bandicoot (Isoodon macrourus) and a brushtail possum (Trichosurus vulpecula) together with the previously available marsupial mitochondrial genomes, the Virginia opossum (Didelphis virginiana) and the wallaroo (Macropus robustus). Analyses of mitochondrial protein-coding and RNA genes strongly support the bandicoot as sister to the wallaroo and the brushtail possum. This result, combined with other recent molecular analyses, confirms the monophyly of Australidelphia (Australasian marsupials plus Dromiciops from South America). Further, RY coding was found to nullify AGCT coding nucleotide composition bias.

Antioxidant activities of trypsin inhibitor, a 33 KDa root storage protein of sweet potato (Ipomoea batatas (L.) Lam cv. Tainong 57)

Trypsin inhibitors (TIs), root storage proteins, were purified from sweet potato (Ipomoea batatas[L.] Lam cv. Tainong 57) roots by trypsin affinity column according to the methods of Hou and Lin (Plant Sci. 1997, 126, 11-19 and Plant Sci. 1997, 128, 151-158). A single band of 33 kDa TI was obtained by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels. This purified 33 kDa TI had scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. There was positive correlation between scavenging effects against DPPH (2 to 22%) and amounts of 33 kDa TI (1.92 to 46 pmol). The scavenging activities of 33 kDa TI against DPPH were calculated from linear regression to be about one-third of those of glutathione between 5 and 80 pmol. Using electron paramagnetic resonance (EPR) spectrometry for hydroxyl radical detection, it was found that 33 kDa TI could capture hydroxyl radical, and the intensities of EPR signal were significantly decreased from 1.5 to 6 pmol of 33 kDa TI compared to those of the controls. It is suggested that 33 kDa TI, one of the sweet potato root storage proteins, may play a role as an antioxidant in roots and may be beneficial to health when it is consumed.

Ca2+-dependent and Ca2+-independent excretion modes of salicylic acid in tobacco cell suspension culture

14C-salicylic acid (SA) was used to monitor SA metabolism and its regulation in tobacco cell suspension culture. Two SA concentrations (20 microM and 200 microM) were used for comparison. SA was quickly taken up in both treatments, and the 200 microM-treated cells absorbed approximately 15 times that of 20 microM-treated cells within 5 min. More than 85% and 50% of the absorbed SA were excreted in free form to the culture medium within 5 h from cells treated with 200 microM and 20 microM SA, respectively. SA excretion was significantly inhibited by EGTA and the inhibition could be reversed by the addition of exogenous Ca2+ to the culture medium in the 200 microM SA treatment. However, EGTA had little or no effect on SA excretion in the 20 microM SA treatment. The data suggest that tobacco suspension-cultured cells may contain both Ca2+-dependent and Ca2+-independent pathways for SA excretion. Reduced glutathione (an active oxygen species scavenger), staurosporine (a protein kinase inhibitor), and cycloheximide (an inhibitor of de novo protein synthesis) also blocked intracellular SA excretion to the culture medium in the 200 microM but not in the 20 microM SA treatment. These data support the existence of alternative SA excretion pathways in tobacco suspension-cultured cells. Tobacco cells may use both Ca2+-dependent and Ca2+-independent excretion pathways to cope with different intracellular SA status, and the pathway influenced by EGTA, reduced glutathione, staurosporine, and cycloheximide is activated by SA at 200 microM, but not at 20 microM.

Ca2+-dependent and Ca2+-independent excretion modes of salicylic acid in tobacco cell suspension culture

14C-salicylic acid (SA) was used to monitor SA metabolism and its regulation in tobacco cell suspension culture. Two SA concentrations (20 microM and 200 microM) were used for comparison. SA was quickly taken up in both treatments, and the 200 microM-treated cells absorbed approximately 15 times that of 20 microM-treated cells within 5 min. More than 85% and 50% of the absorbed SA were excreted in free form to the culture medium within 5 h from cells treated with 200 microM and 20 microM SA, respectively. SA excretion was significantly inhibited by EGTA and the inhibition could be reversed by the addition of exogenous Ca2+ to the culture medium in the 200 microM SA treatment. However, EGTA had little or no effect on SA excretion in the 20 microM SA treatment. The data suggest that tobacco suspension-cultured cells may contain both Ca2+-dependent and Ca2+-independent pathways for SA excretion. Reduced glutathione (an active oxygen species scavenger), staurosporine (a protein kinase inhibitor), and cycloheximide (an inhibitor of de novo protein synthesis) also blocked intracellular SA excretion to the culture medium in the 200 microM but not in the 20 microM SA treatment. These data support the existence of alternative SA excretion pathways in tobacco suspension-cultured cells. Tobacco cells may use both Ca2+-dependent and Ca2+-independent excretion pathways to cope with different intracellular SA status, and the pathway influenced by EGTA, reduced glutathione, staurosporine, and cycloheximide is activated by SA at 200 microM, but not at 20 microM.

Gonococcal meningitis and intra-abdominal abscess in the presence of a ventriculoperitoneal shunt

We report a case of gonococcal meningitis with an intraabdominal abscess in a 19-y-old woman, who had a ventriculoperitoneal shunt after craniotomy for astrocytoma. Percutaneous drainage was performed for the intraabdominal abscess. Ceftriaxone was administered with the ventriculoperitoneal shunt removal. The clinical course improved, but visual impairment last for 3 months following treatment.

Degeneration of nociceptive nerve terminals in human peripheral neuropathy

Patients with peripheral neuropathy have symptoms involving small-diameter nociceptive nerves and elevated thermal thresholds. Nociceptive nerves terminate in the epidermis of the skin and are readily demonstrated with the neuronal marker, protein gene product 9.5 (PGP 9.5). To investigate the pathological characteristics of elevated thermal thresholds, we performed PGP 9.5 immunocytochemistry on 3 mm punch skin biopsies (the forearm and the leg) from 55 normal subjects and 35 neuropathic patients. Skin innervation was evaluated by quantifying epidermal nerve densities. Epidermal nerve densities were reduced in neuropathic patients compared to normal subjects. Epidermal nerve densities were variably correlated with thermal thresholds. The proportion of neuropathic patients with reduced epidermal nerve densities was larger than the proportion of neuropathic patients with elevated thermal thresholds. These results indicated that degeneration of epidermal nerve terminals preceded the elevation of thermal thresholds. Skin biopsy together with immunocytochemical demonstration of epidermal innervation offers a new approach to evaluate small-fiber sensory neuropathy.

Pregnancy after intentional cryopreservation of percutaneous sperm aspiration specimens and intracytoplasmic sperm injection. A report of two cases

BACKGROUND

Microsurgical epididymal sperm aspiration (MESA) and percutaneous epididymal sperm aspiration (PESA) are two methods of obtaining spermatozoa from patients with irreparable obstructive azoospermia. Intentionally using frozen-thawed spermatozoa obtained from MESA had been reported to be successful. With minimal invasiveness, intentionally cryopreserved PESA specimens and intracytoplasmic sperm injection (ICSI) were carried out in two cases.

CASES

Two cases of irreparable obstructive azoospermia received PESA, and the spermatozoa were cryopreserved intentionally. Successful ICSI was performed later, utilizing frozen-thawed spermatozoa.

CONCLUSION

PESA and ICSI are promising methods for these patients. The major advantages are minimal invasiveness and flexibility for further treatment.

Effects of naturally occurring glucosides, solasodine glucosides, ginsenosides and parishin derivatives on multidrug resistance of lymphoma cells and leukocyte functions

Solamargine, solasonine, ginsenosides and parishin-related compounds were investigated for their effects on mdr efflux pump of lymphoma cells, and their effects on T cell proliferative assays and cell mediated immune functions, antibody-dependent cellular cytotoxicity (ADCC) and natural killer (NK) cell activity of human peripheral mononuclear cells. Solamargine and solasonine were the only drugs which inhibited all of the tested immune functions; however, ginsenoside Rc and Rd enhanced T cell proliferative assays and marginally increased the NK cell activity. The majority of the compounds were not able to reverse the multidrug resistance of mouse lymphoma cells. However, ginsenosides Rc, Rd and parishin C were able to moderately reduce the activity of the efflux pump. Parishin, parishin C and crude extract significantly enhanced the ADCC reaction.

Radix Angelica Sinensis extracts ameliorate scopolamine- and cycloheximide-induced amnesia, but not p-chloroamphetamine-induced amnesia in rats

The effects of the methanolic extract of Radix Angelica Sinensis (Umbellifera) (abbreviated as RAS extract) and n-hexane fraction of RAS extract (RAS(H) fraction) on the various drugs-induced amnesia in rats were studied by using passive avoidance task. RAS extract (1 g/kg) significantly prolonged the shortened step-through latency induced by SCOP and CXM, but not PCA. Furthermore, RAS(H) fraction (1 g/kg) also significantly prolonged the shortened step-through latency induced by SCOP and CXM but not PCA. RAS extract at any dose alone did not influence the step-through latency in the training trial produced by non-shocked rats, but it plus PCA prolonged the latency compared with PCA alone. However, RAS(H) fraction (1 g/kg) prolonged the latency in the training trial produced by non-shocked rats, but it plus any induced drugs did not differ from any induced drugs alone. These results suggest that the attenuating effects of RAS extract on the various drugs-induced amnesia were related to the memory processes. n-Hexane fraction of RAS extract might be one of the active fractions of RAS extract in the treatment of amnesia.

Hepatoprotective effects of Arctium lappa on carbon tetrachloride- and acetaminophen-induced liver damage

The root of Arctium lappa Linne (A. lappa) (Compositae), a perennial herb, has been cultivated for a long time as a popular vegetable. In order to investigate the hepatoprotective effects of A. lappa, male ICR mice were injected with carbon tetrachloride (CCl4, 32 microl/kg, i.p.) or acetaminophen (600 mg/kg, i.p.). A. lappa suppressed the SGOT and SGPT elevations induced by CCl4 or acetaminophen in a dose-dependent manner and alleviated the severity of liver damage based on histopathological observations. In an attempt to elucidate the possible mechanism(s) of this hepatoprotective effect, glutathione (GSH), cytochrome P-450 (P-450) and malondialdehyde (MDA) contents were studied. A. lappa reversed the decrease in GSH and P-450 induced by CCl4 and acetaminophen. It was also found that A. lappa decreased the malondialdehyde (MDA) content in CCl4 or acetaminophen-intoxicated mice. From these results, it was suggested that A. lappa could protect the liver cells from CCl4 or acetaminophen-induced liver damages, perhaps by its antioxidative effect on hepatocytes, hence eliminating the deleterious effects of toxic metabolites from CCl4 or acetaminophen.

Bacteremia in renal transplant recipients: retrospective analysis of 60 episodes in a teaching hospital

BACKGROUND

Bacteremia is a major cause of death in renal transplant recipients. However, an understanding of the clinical spectrum of bacteremia post kidney transplantation in Taiwan is lacking. This study was undertaken in an attempt to analyze the causative organisms, the sites of primary infection, and the possible significant determinants of mortality.

METHODS

Eighty-six positive blood cultures from renal transplant recipients were seen at the Taichung Veterans General Hospital from August 1993 to April 1999. Sixty blood cultures obtained from episodes that occurred in 43 kidney recipients were regarded as significant and included. All the data were obtained by reviewing medical records.

RESULTS

Forty-six episodes (76.7%) of bacteremia happened 6 months after transplantation. Gram-negative bacilli accounted for 73.3% (44/60) of the cases of bacteremia. Escherichia coli, constituting 26.7% (16/60) of the etiologic agents, was the most common pathogen. In 50.0% of all episodes, urinary tract infection was the main cause of bacteremia. The overall mortality rate in this series was 16.7%. Risk of death seemed higher if bacteremia occurred with a primary site of infection other than the urinary tract (26.7% vs 6.7%) and after methylprednisolone pulse therapy (33.3% vs 12.5%), though both correlations were not statistically significant.

CONCLUSIONS

This study may shed light on the empirical therapy and better management needed for treating bacteremia in renal transplant recipients in Taiwan and provide a nidus for further prospective surveys.

Weibull modeling of the Fenton's oxidation process

A modified version of the two-parameter Weibull survival curve is used to investigate its applicability to analyze the influence of the Fenton's Reagent on the decomposition of 2,4-dinitrophenol solutions (DNP). Fenton's Reagent is one type of advanced oxidation processes (AOPs) in which strong oxidants, hydroxyl radicals, are generated. Fenton's Reagent was maintained at a ratio of 0.5 mM H2O2 to 0.1 mM Fe2+ at the start of all experiments. By varying the initial DNP concentration, we are not only able to correlate parameters (a) and (b) defined in the modified curve to the Fenton's oxidation process, but also interpret their physical significance on the process. The scale parameter (a) can be used to illustrate the rate of the decomposition of DNP in solutions. The imbalance between decomposition rate and initial DNP concentration can be easily observed with the aid of parameter (a). By defining a specific decomposition rate function, the shape parameter (b) indicates the strength of the oxidation power provided by the Fenton's Reagent. When (b) > 1, the existence of a maximum specific decomposition rate shows a sufficient supply of the hydroxyl radicals, whereas a first-order decomposition of DNP is obtained when (b) = 1. A lack of oxidation power becomes obvious if (b) < 1, showing a high dose of initial DNP in a solution. Knowing the physical interpretation of both parameters, they are further applied to design the Fenton's oxidation process.

Measuring Fenton's reaction kinetics at one-second intervals

The concept of quench flow has been implemented to design a simple and yet easy-to-operate device to measure Fenton's reaction kinetics at one-second intervals. 2,4-dinitrophenol (DNP) was used as a model compound in this study. Experimental results show that more than 40% of DNP can be decomposed within the first second, followed by a stagnant reaction for a period of 29 seconds. Subsequently, a 5% drop in the ADMI (American Dye Manufacturing Index) color value was observed. The initial specific rates of DNP concentration and the ADMI color value were the same, indicating that ADMI color value can be potentially used as a process parameter in designing a computerized Fenton's oxidation process. The scanning spectrum recorded a reaction pattern with constant rates of decolorization and degradation of DNP occurring between 5 and 29 seconds, irrespective of different Fe2+/H2O2 ratios. Such a reaction pattern has not been reported elsewhere.