Electrodeposited iridium oxide pH electrode for measurement of extracellular myocardial acidosis during acute ischemia

In the present paper, fabrication, characterization, and physiological applications of a solid-state pH electrode are described. The pH sensing layer was based on an anodic electrodeposited iridium oxide film (AEIROF). Sputtered platinum electrodes (1 mm diameter) fabricated on flexible Kapton films or platinum wires were used as planar or cylindrical supports. Each electrode site was coated with Nafion to attenuate the interference of anionic redox species and to protect the electrode surface during in vivo measurements. Performance of the AEIROF was evaluated, for the first time, as a pH electrode and proved to have a slightly super-Nernstian response with slope of -63.5 +/- 2.2 mV/pH unit for both wire and planar sputtered platinum electrodes. Linear pH responses were obtained in the pH range 2-10. The electrodes have a working lifetime of at least 1 month with accuracy of about 0.02 pH unit and fast response time. The electrodes showed very low sensitivities for different species, such as Na+, K+, Li+, NH4+, Ca2+, Mg2+, dissolved oxygen, lactate, ascorbate, and urate, which are important for physiological applications. The electrodes were applied in extracellular pH measurements during brief regional ischemia in a swine heart and no-flow ischemia in an isolated rabbit papillary muscle. A first report on extracellular pH, K+, and lactate simultaneous measurements during no-flow ischemia using the AEIROF pH electrode and the previously described K+ and lactate electrodes is presented as well.     

Pollutant Removal and Peak Flow Mitigation by a Bioretention Cell in Urban Charlotte, N.C.

Bioretention is a stormwater treatment practice that has gained popularity due to its aesthetics, potential to reduce flooding, and early documented improvements to stormwater quality. A bioretention cell in an urban setting was examined in Charlotte, N.C. from 2004 to 2006. Flow-weighted, composite water quality samples were collected for 23 events and analyzed for TKN, NH4-N, NO2-3-N, TP, TSS, BOD-5, Cu, Zn, Fe, and Pb. Grab samples were collected from 19 storms for fecal coliform and 14 events for Escherichia coli (E. coli). There were significant reductions (p<0.05) in the concentrations of TN, TKN, NH4-N, BOD-5, fecal coliform, E. Coli, TSS, Cu, Zn, and Pb. Iron concentrations significantly increased (p<0.05). NO2-3-N concentrations were essentially unchanged. Efficiency ratios for TN, TKN, NH4-N, TP, and TSS were 0.32, 0.44, 0.73, 0.31, and 0.60, respectively. Fecal coliform and E. coli efficiency ratios were 0.69 and 0.71, respectively. Efficiency ratios for Zn, Cu, and Pb were 0.77, 0.54, and 0.31, respectively. Concentrations of Fe increased by 330%. The peak outflow of the bioretention cell for 16 storms with less than 42?mm of rainfall was at least 96.5% less than the peak inflow, with a mean peak flow reduction being 99%. These results indicated that in an urban environment, bioretention systems can reduce concentrations of most target pollutants, including pathogenic bacteria indicator species. Additionally, bioretention can effectively reduce peak runoff from small to midsize storm events.     

丝网印刷制备银/氯化银电极研究与应用进展

随着电化学传感器、生物传感器以及医用电极应用环境的发展,对银/氯化银参比电极和银/氯化银医用电极的可设计性、柔韧性、适应工业大批量生产等方面有了新要求.采用丝网印刷工艺制备再经低温固化成型的银/氯化银电极作为一种具备以上优点的低成本电极,已经成为了传感检测领域研究与应用的热点.从3个方面综述了丝网印刷制备银/氯化银电极...     

聚对氨基苯甲酸/石墨烯-全氟磺酸 聚四氟乙烯

将石墨烯（Gr） nafion复合物滴涂到玻碳电极表面,然后通过电聚合将对氨基苯甲酸（p ABA）修饰至电极表面制成聚对氨基苯甲酸/Gr nafion修饰玻碳电极。利用差分脉冲溶出伏安法研究了Cu2+在修饰电极上的电化学行为。试验发现Gr nafion膜和聚合膜poly(p ABA)的协同作用,提高了Cu2+在电极表面的富集程度,有效地促进了电子在修饰电极上的传递速度。对实验参数进行优化,并通过考察发现传感器有良好的重现性,且一些常见的阳离子和阴离子对Cu2+响应信号不产生干扰。在50×10-7 ~40×10-5 mol/L范围内,铜离子浓度与峰电流呈良好的线性关系,相关系数为0995。方法检出限为50×10-9 mol/L（S/N=3）。方法应用于废水样中Cu2+的测定,结果同ICP AES法的测定结果相一致,相对标准偏差为24%~36%。由于循环伏安曲线中Cu2+和Cd2+的溶出峰电位差较大,且没有相互干扰,所以该电极可用于Cu2+和Cd2+的同时测定。     

Comparison of Two Model Concepts for Simulation of Nitrogen Removal at a Full-Scale Biological Nutrient Removal Pilot Plant

The experimental studies conducted at the Hanover-Gümmerwald pilot wastewater treatment plant (WWTP) focused on minimizing nitrogen loads discharged during stormwater events. The data collected during the plant operation were used for a long-term process simulation. The aim of this study was to compare predictive capabilities of two different mechanistic models (ASM2d and ASM3P) in terms of nitrogen removal. The influent wastewater composition was generated using on-line measurements of only three parameters (COD, N–NH4+, P–PO43?) and the model predictions were primarily compared with on-line data (concentrations of N–NH4+, N–NO3?) originating from the aerobic zone of the bioreactor. The simulation results confirmed the experimental data concerning the capabilities of the system for handling increased flows during stormwater events. The predicted peaks of N–NH4+ at the line with the quadruple dry weather flow rate were normally exceeding 8?g?N?m?3 (similar to the observations), whereas no (or minor) peaks of N–NH4+ were predicted for the line with the double dry weather flow rate. The relationships between ASM2d and ASM3P predictions for N–NH4+ and N–NO3? were highly correlated (r2 = 0.83–0.99) with the slopes remaining close to 1.0. Both models appear to be equally suitable for practical applications in common municipal WWTPs.     

Effects of lanthanum on POD expression and DNA methylation of purple pepper under salt stress

Pepper seedlings were hydroponically cultivated in 0-20 mg/L extraneous lanthanum chloride （La3＋） for different numbers of days to investigate its regulating effects under salt stress. The results showed that, depending on the salt stress of 0.75 g/L, a lower concentration of La3＋ （1.0 rag/L） might result in the lowest death rate, increase POD activity and change the band type of the stem and root on the 8th day. Furthermore, a methylation analysis by the methylation-sensitive amplified polymorphism （MSAP） technique indicated that a lower concentration of La3＋ （1.0 mg/L） triggered the lowest methylation level of 26.1%, of which the hypermethylation events were the primary type of methylation. In addition, the sequencing of 14 differ- entially expressed polymorphic fragments and the subsequent blast search revealed that La3＋ could induce methylation events in salt-tolerance sequences.     

Friedreich's ataxia: point mutations and clinical presentation of compound heterozygotes

The effects of ammonium nitrate, ammonium chloride, ammonium sulfate, and sodium nitrate on survival and growth of Pacific treefrog (Pseudacris regilla) and African clawed frog (Xenopus laevis) embryos were determined in static-renewal tests. The 10-day LC50s for the three ammonium compounds for P. regilla ranged from 25.0-32. 4 mg/L NH4 -N. The 10-day sodium nitrate LC50 for P. regilla was 578. 0 mg/L NO3-N. LC50s for X. laevis exposed for 4 or 5 days to the three ammonium compounds ranged from 27.5-60.2 mg/L NH4-N. The sodium nitrate LC50 for X. laevis ranged from 438.4-871.6 mg/L NO3-N. The lowest LOAEL based on length or weight was 6.1 mg/L NH4-N for the two species. The lowest LOAELs for NO3-N were 111.1 mg/L for P. regilla and 56.7 mg/L for X. laevis. Calculated unionized NH3 comprised 0.5-1.8% of measured NH4-N concentrations. Potential harm to amphibian populations could occur if NH4-N and NO3-N in agricultural runoff or drainage impacts sensitive life stages for a sufficiently long period.     

Attenuation of Roadway-Derived Heavy Metals by Wood Chips

Wood chips were evaluated for their ability to attenuate heavy metals in roadway runoff. Column experiments with controlled synthetic runoff composition and flow rate were used to assess effects of flow rate (intercepted sheetflow from a 3-m wide roadway section), runoff salt concentration, wood exposure to alternating wetting and drying cycles, wood aging, competition among dissolved heavy metals, and removal of particle-associated heavy metals. Overall, wood chips damped the “pulse” of copper in the synthetic runoff such that the effluent was characterized by lower concentrations (3–25% of input) over longer periods of time, but with little retention of the total copper mass. The most effective treatment was wood chips aged up to 9 months. Increased aging and chip water content reduced effluent concentrations, relative to no treatment. Flow rate had no effect on effluent concentrations. The presence of salt (>2?mS/cm) or dissolved lead (500?μg/L) in the runoff caused greater copper effluent concentrations than the no treatment case. Removal of suspended particles (and associated contaminants) was greater than 85% with an estimated capacity of 0.16?g/gwood. Field evaluation with concentrated flow to a gutter containing a wood chip treatment showed little effect on total or dissolved copper and zinc runoff concentrations and indicated that wood chips may be a source of contaminants in subsequent storm events. Applications of wood chips to treat roadway runoff would not provide a significant decrease in total maximum daily load contributions (e.g., kg/d); however, there may be some scenarios for which wood chip treatments to decrease peak storm water concentrations of dissolved heavy metals in sheetflow runoff is desirable.     

Mg~(2+)对硫酸锰电解液理化性质的影响

控制试验溶液中Mn~(2+)浓度18.75g/L、(NH_4)_2SO_4浓度100g/L,研究Mg~(2+)浓度对硫酸锰电解液理化性质的影响。结果表明,随着Mg~(2+)浓度的增加,不同温度梯度下硫酸锰电解液的密度、电导率以及黏度均呈上升趋势,而表面张力逐渐下降。当Mg~(2+)浓度一定时,随着温度的升高,硫酸锰电解液的密度、黏度及表面张力呈下降趋势,而电导率逐渐增加。     

Calibrated Models of Deicing Agent Solids, Pavement Texture, and Specific Conductivity of Highway Runoff

Field data and existing theory suggest that pavement texture governs the seasonal persistence of deicing agent solids and the storm scale variability of the specific conductivity of highway runoff. We measured precipitation, runoff, and specific conductivity for 50 storms over four deicing seasons at a highway drainage system in southeastern Massachusetts. An average pavement texture of 2.44?mm was measured and 5.17×105?kg of calcium magnesium acetate, salt, and premix applications was reported as well. Catchments and a depression storage layer model the highway drainage system, which routes hyetographs and slowly dissolving deicing agent solids to storm scale hydrographs and specific conductivity pollutographs. We equate the average pavement texture to the depression storage layer depth, which receives applied deicing agent solids, controls their dissolution during a storm, and governs their seasonal scale persistence. The observed average pavement texture, precipitation, and deicing agent applications yield first flush (storm scale) specific conductivity values in the depression storage layer that range from a winter maximum of 15?mS/cm to summer values two orders of magnitude lower. The winter maximum, or seasonal scale first flush of specific conductivity, would be lower for rougher pavement due to slower dissolution. The rougher pavement would also induce stronger persistence of deicing agent solids throughout the year, so that appreciable storm scale first flushes would occur in the summer.     

In-vitro and in-vivo comparative analysis of four tissue pH monitoring systems

The purpose of this investigation was to identify the type of pH-reference electrode combination that is the most suitable and reliable in clinical applications involving long-term postoperative monitoring of microvascular reconstructive transplants and diagnosis of compartment syndrome. Four types of pH-sensing devices were chosen for the study: a standard glass pH electrode, a polymer-based pH electrode, an ISFET pH sensor, and a fiberoptic pH sensor. Various combinations of electrodes were tested in vitro for typically four days. The glass and polymer electrodes maintained stable pH readings, averaging drifts of 0.14 +/- 0.07 and 0.14 +/- 0.08 pH units per 96 hours, respectively. The fiberoptic sensors displayed an average drift of 0.20 +/- 0.15 pH units per 96 hours. ISFET sensors displayed nearly linear drifts, averaging 1.36 +/- 0.54 pH units per 96 hours. When placed in healthy animal tissue, glass and polymer electrode pH readings followed the arterial blood pH values, measured by a blood gas analyzer. In compromised tissue, both glass and polymer electrodes recorded falling pH levels correctly, indicating ischemic conditions. Generally, ISFET sensors in healthy tissue produced pH readings that did not correlate well with arterial blood pH values. Fiberoptic sensors monitored healthy-tissue pH correctly; however, mechanical disturbances of the fiberoptic sensor and occasional discontinuation of computer operation would shift the pH output significantly (at times by 0.2 pH units), resulting in subsequent inaccurate pH readings. The glass electrode was the only sensor evaluated clinically. It correctly indicated tissue viability in all clinical cases, involving both healthy and ischemic tissue. The authors conclude that the glass pH electrode has the best combination of characteristics for clinical tissue pH measurements.     

Volumetric Filtration of Rainfall Runoff. II: Event-Based and Interevent Nutrient Fate

This study examines in situ phosphorus treatment using a combined unit operation and process, a volumetric clarifying filter (VCF). Urban rainfall-runoff transports phosphorus in dissolved and particulate phases with the latter phase distributed across the particulate matter (PM) gradation. From a clean initial condition, the VCF was monitored across 19 events without maintenance, to examine partitioning and phosphorus distribution on PM. For the monitoring period, site influent total phosphorus (TP) is 0.342 mg/L of which 0.081 mg/L is dissolved; and subsequently reduced to 0.095 and 0.031 mg/L, respectively, by the VCF. PM-bound phosphorus is categorized as suspended, settleable and sediment fractions based on PM size and separation behavior. Site influent PM-based concentrations (mg/g) are 0.22 for sediment, 0.42 for settleable and 3.27 for the suspended fraction with each fraction further enriched in the VCF, based on effluent monitoring. A categorical analysis and odds ratio testing of PM-based phosphorus specific capacities (mg/g) indicate that a significant fraction of phosphorus can bind to suspended PM preferentially over settleable and sediment PM as a PM-based concentration. At the end of the event-based monitoring the inter-event change in phosphorus and nitrogen, chemistry is examined as a function of runoff storage time. Runoff retention generates nitrate reduction and ammonia (NH3+NH4+) production; predominately as ammonium. Phosphorus partitioning is stable during runoff storage with a dissolved fraction between one fourth to one-third of TP. Predominant species are H2PO4? for a pH<7 and HPO42? for a pH>7.     

Limits to milk flow and energy allocation during lactation of the hispid cotton rat (Sigmodon hispidus)

INTRODUCTION: Epicardial and endocardial defibrillation electrode systems affect myocardial electrophysiology and sympathetic function differently. Thus, we postulate that antiarrhythmic drugs will interact with these electrode systems differently. METHODS AND RESULTS: Defibrillation energy requirements (DER) at 20% (ED20), 50% (ED50), and 80% (ED80) success were measured at baseline and during lidocaine (10 mg/kg per hour) or D5W treatment for epicardial and endocardial electrodes. Pigs were randomized to treatment (lidocaine or D5W) and electrode system, which resulted in four experimental groups: (1) epicardial electrode + D5W; (2) epicardial electrode + lidocaine; (3) endocardial electrode + D5W; and (4) endocardial electrode + lidocaine. ED50 DER (mean +/- SEM) values at baseline for groups 1-4 were 10.6+/-1, 8.5+/-1, 12.6+/-1, and 12.3+/-1 J, respectively. DER values for groups 1 and 3 during D5W were similar to baseline. Conversely, lidocaine increased ED50 DER values from 8.5+/-1 to 13.5+/-2 J (P < 0.05) in group 2 animals (epicardial electrodes). When lidocaine was administered to group 4 animals (endocardial electrodes), however, ED50 DER values remained similar to baseline values (12.3+/-1 to 14.3+/-2 J, P = NS). Lidocaine increased ED50 DER values by 59% with the epicardial electrode system, which was significantly greater than the 16% increase with the endocardial electrode system (P < 0.05). Electrophysiologic response and electrode impedance were similar between electrode systems. CONCLUSION: Lidocaine increases DER values to a greater extent when using epicardial versus endocardial electrode system. Thus, drug-device interactions are dependent on the electrode system. These data suggest that the electrophysiologic milieu created by endocardial defibrillation mitigates the effects that lidocaine has on DER values.     

Pollutant Mass Flushing Characterization of Highway Stormwater Runoff from an Ultra-Urban Area

Water quality of highway stormwater runoff from an ultra-urban area was characterized by determining the event mean concentration (EMC) for several pollutants and by evaluating pollutant flushing. Thirty-two storm events were monitored between June 2002 and October 2003. Mean EMCs in mg/L were 0.035, 0.11, 0.22, 1.18, 420, 3.4, 0.14, 1.0, and 0.56 for Cd, Cu, Pb, Zn, total suspended solids (TSS), total Kjeldahl nitrogen (TKN), NO2–N, NO3–N, and TP. First flush as defined by flushing of 50% of the total pollutant mass load in the first 25% of the event runoff volume occurred in 33% of the storm events for NO2?, 27% for TP, 22% for NO3? and TKN, 21% for Cu, 17% for TSS, 14% for Zn, and 13% for Pb. Median values for the mass flushed in the first 25% of runoff volume were greater than the mass flushed in any 25% portion beyond the first for all pollutants. The mass in later 25% volume portions were greater than in the first 25% volume in at least 17% of the events for all pollutants, indicating that a significant amount of the pollutant load can be contained in later portions of the runoff volume. Nonetheless, management of the first 1.3?mm (1/2?in.) of runoff was able to capture 81–86% of the total pollutant mass.     

Accuracy of the one-point in vivo calibration of "wired" glucose oxidase electrodes implanted in jugular veins of rats in periods of rapid rise and decline of the glucose concentration

The hypothesis of the feasibility of one-point in vivo calibration of intravenously implanted glucose sensors during periods of rapid rise and decline of venous blood glucose concentration was tested. Miniature (5 x 10(-4) cm2 mass transporting area) glucose electrodes with 10-90% response times < 2 min, that did not consume oxygen, were implanted in jugular veins of systemically heparinized rats and used in 4-h experiments, during which the blood glucose concentration was amperometrically monitored. The glucose electrodes were made by electrically connecting ("wiring") reaction centers of glucose oxidase through an electron-conducting redox hydrogel to gold electrode surfaces. The redox polymer and enzyme constituting the electrode sensing layer were immobilized by cross-linking, and thus the electrodes had no diffusional and readily leached redox mediator. One hour after their implantation, the electrodes accurately tracked the blood glucose concentration when calibrated in vivo by a one-point calibration, when the glucose concentration was steady, when rising rapidly, and when declining steeply. For an assumed 2-min lag time, the sensor readings were well correlated with the true blood glucose concentrations, with linear regression analysis yielding a slope of 0.97 +/- 0.07 and an intercept (bias) of 0.3 +/- 0.3 mM. The correlation coefficient, r2, was 0.949 +/- 0.020, and the percent difference through the 2-22 mM range was 1.9 +/- 1.0%. The results suggest that, in combination with understanding and modeling of transient physiological differences between the subcutaneous and the blood glucose concentrations, it will be possible to calibrate by one-point in vivo calibration subcutaneously implanted sensors, even while the glucose concentration changes rapidly.     

L-天冬氨酸-L-半胱氨酸-石墨烯修饰玻碳电极测定铅的研究

利用 L-半胱氨酸-石墨烯-L-天冬氨酸纳米复合膜构建Pb²⁺的新型电化学传感器实现了环境水样中铅的灵敏测定。首先将石墨烯和L-半胱氨酸通过电聚合制备了L-半胱氨酸-石墨烯修饰玻碳电极,然后利用戊二醛通过共价键合连接上L-天冬氨酸,制备了L-天冬氨酸-L-半胱氨酸-石墨烯修饰玻碳电极。由于L-天冬氨酸的良好选择性以及石墨烯的好导电性能,提高了传感器对Pb²⁺的信号响应和选择性。试验结果表明,测定1×10^-7 mol/L的Pb²⁺,10倍量的Cu²⁺、Ca²⁺、Co²⁺、Cd²⁺、Mn²⁺、Zn²⁺、Ni²⁺、Hg²⁺几乎不干扰测定(峰电流改变小于5%)。在pH4.5的醋酸盐缓冲溶液中,铅离子的浓度与峰电流呈良好的线性关系,线性范围为2.0×10^-9~6.0×10^-6 mol/L,检出限为6.0×10^-10 mol/L (S/N=3)。该修饰电极用于环境水样中铅的测定,测定值与ICP-AES的测定值基本一致。     

Automated Separation and Conductimetric Determination of Inorganic Nitrogen

Experiments were conducted for the evaluation of a continuous flow conductimetric method that measures the inorganic nitrogen compounds ammonia (NH3) and combined nitrite (NO2?) and nitrate (NO3?). Approximately 300 analyses were performed using the method during experiments to estimate the method detection level, to determine the bias and precision, and to determine the equivalency of the method to others found in Standard Methods. An estimated method detection level of 0.01 mg N∕L (NH3–N, NO3?–N, or NO2?–N) was measured. Precision values for ammonia and nitrate standards at concentrations ranging from 0.1 to 75 mg∕L NH3–N or NO3?–N did not exceed 5.5 and 4%, respectively. Recovery values for ammonia and nitrate standards at the same concentration range did not exceed 104.8 and 103%, respectively. At concentrations of 0.05 mg∕L NH3–N or NO3?–N, the precision values were 12.5 and 11%, respectively, which were high relative to others obtained in this study but are within the range of values reported in Standard Methods.     

Activation of the Na+-K+(NH4+)-2Cl(-)- cotransporter from rat submandibular glands in response to VIP

A cellular suspension from rat submandibular glands was prepared with collagenase. The intracellular pH (pHi) was estimated with 2',7'-bis-(2-carboxy-ethyl)-5(6)-carboxyfluorescein (BCECF). After exposure to NH4Cl, the pHi transiently increased (diffusion of NH3) and then dropped (influx of NH4+). Isoproterenol increased 2.5-fold the rate of NH4+ influx; bumetanide, an inhibitor of the Na+-K+-2Cl(-)-cotransporter blocked the response to isoproterenol, confirming that the beta-adrenergic agonist stimulated the cotransporter. Forskolin (1 micromol/L) mimicked the response to isoproterenol. VIP (1 nmol/L(-1) micromol/L) also increased the activity of the cotransporter. Cyclic AMP rather than calcium was the mediator of this activation since 1) carbachol which increased the [Ca2+]i fivefold increased the uptake of NH4+ by only 50%; 2) only high concentrations of VIP significantly increased the [Ca2+]i; 3) incubation in the presence of EGTA had no effect on the response to VIP; 4) low concentrations (nmol/L) of the neuropeptide increased the intracellular level of cAMP; and 5) the stimulation of the cotransporter by VIP, forskolin, and isoproterenol was inhibited by H8, an inhibitor of cAMP-dependent protein kinase. It is concluded that the Na+-K+-2Cl(-)-cotransporter of rat submandibular glands is activated by isoproterenol, forskolin, and neuropeptides of the VIP family by a mechanism involving cAMP-dependent processes. The activation of the cotransporter by VIP could partly explain the potentiating effect of VIP on the response to sialagogues like substance P or muscarinic agonists.     

Cerium Oxide Film Prepared from Molten Salts

Cerium oxide film formed on the nickel electrode at 453 K in LiNO3-KNO3 molten salts. The molten salt back ground and the cathode process of Leeds on the nickel electrode were studied by using cyclic voltammetry. The cathodic reaction mechanism of the molten salt background was: O2+e O22; O2+2NO-3 → 2NO2+2O2. According to the results of SEM and XPS, cerium oxide film, which is composed of CeO2, can form on the nickel electrode at - 1.850 V vs. Ag/AgNO3 (0.1 mol/L) reference electrode.     

Factors Affecting Hydrogen Production from Food Wastes by Clostridium-Rich Composts

This study used the technique of response surface approach to analyze the combined effects of heat-shocking temperature and time on anaerobic grass composts. Results indicate that the grass composts under heat-shocking temperature and time of 80°C and 3?h, respectively, could yield high populations of hydrogen-producing microorganisms. Metabolic results demonstrate that the composts are reliable, having considerable hydrogen-producing Clostridia. The multivariate analysis with response surface by considering specific hydrogen-producing potential and rate simultaneously indicate that the cultural media with Fe2+ = 132?mg/L; NH4+ = 537?mg/L; and PO43? = 1,331?mg/L were optimal for the hydrogen-producing Clostridia-rich composts using high-solids food wastes. The specific hydrogen production potential and rate were 77±3?mL?H2/gTVS and 520±20?mL?H2/g?TVS/day, respectively. The former was 38% of theoretical hydrogen-producing potential of Clostridium sp. using glucose. Of these factors, ammonium and phosphate are nutrients for the hydrogen-producing Clostridia growth while iron exerts a synergistic influence on them in the conversion of the food wastes into hydrogen.