Laser treatment of cutaneous angiokeratomas: A systematic review

Abstract

Angiokeratomas can present therapeutic challenges, especially in cases of extensive lesions, where traditional surgical methods carry high risks of scarring and hemorrhage. Argon, pulsed dye (PDL), neodymium-doped yttrium aluminum garnet (Nd:YAG), copper vapor, potassium titanyl phosphate, carbon dioxide, and erbium-doped yttrium aluminum garnet (Er:YAG) lasers have emerged as alternative options. To review the use and efficacy of lasers in treating angiokeratomas. A PubMed search identified randomized clinical trials, cohort studies, case series, and case reports involving laser treatment of cutaneous angiokeratomas. Twenty-five studies were included. Quality ratings were assigned using the Oxford Centre for Evidence-Based Medicine scheme. Several laser modalities are effective in treating multiple variants of angiokeratomas. Vascular lasers like PDL, Nd:YAG, and argon are the most studied and of these, PDL offers the safest side effect profile. Nd:YAG may be more effective for hyperkeratotic angiokeratomas. Combination treatment with multiple laser modalities has also demonstrated some success. Lasers are a promising treatment option for angiokeratomas, but current use is limited by the lack of treatment guidelines. There are limited high quality studies comparing laser treatments to each other and to non-laser options. Additional studies are needed to establish guidelines and to optimize laser parameters.

Monopolar radiofrequency treatment in Asian skin: An update

Cosmeceutical effect of ethyl acetate fraction of Kombucha tea by intradermal administration in the skin of aged mice

Summary

Background/purpose

Natural ingredients have been always an interesting approach to prolong youthful appearance of skin. One of the natural compounds is Kombucha tea (KT), which has been mainly used as an energy drink in Asian countries for a long time. Previous reports indicated that it has pharmaceutical and favorable wound repairing effects. The beneficial properties of KT are thought to be mainly due to the presence of fermentation products such as flavonoids and other polyphenols with inhibition of hydrolytic and oxidative enzymes and anti-inflammatory effects. These properties prompted us to study the anti-aging potential of KT and investigate its effective fraction in aged mice,

Methods

Kombucha tea was fractionated into chloroform, butanol, and ethyl acetate, and flavonoid content was determined. Young and old mice were used as control. KT ethyl acetate fraction (KEAf), which had the highest flavonoid content, was intradermally administered to old mice.

Results

Administration of KEAf significantly increased the collagen content, NAD⁺/NADH level, and concomitantly improved skin connective tissue abnormalities in the aged skin. No sensitivity or irritation was observed.

Conclusion

This finding suggested that KEAf can be a suitable candidate as a cosmetic product to improve aging-related skin abnormalities and regeneration of aged skin.

Skin care and cosmeceuticals: Attitudes and trends among trainees and educators

Summary

Introduction

Patients often seek skin care recommendations from their dermatologist. The objective of this study was to determine the degree of education dermatology residents receive on skin care and cosmeceutical products, the source of education, and the attitude of trainees and their educators toward skin care and cosmeceuticals.

Methods

A cross-sectional survey of dermatology residents and faculty via an online survey administered June 2015 and August 2015, respectively.

Results

In total, 104 dermatology residents and 50 dermatology faculty members completed the survey. Among the dermatology residents and faculty, equal distribution was represented across the country. The majority of residents and faculty (62% and 69%, respectively) report discussing skin care with up to 25% of their patients. Among resident participants, 76.5% "agree or strongly agree" that skin care and cosmeceutical education should be part of their education and the majority of residents (74.5%) report their education has been "too little or nonexistent" during residency. In contrast, the majority of the faculty (60%) reports their resident education is "just the right amount or too much" (P < .001).

Conclusions

Skin care and cosmeceutical recommendations are often discussed in dermatology visits. Dermatology residents feel that education on these products should be a part of their residency training.

Impaired permeability and antimicrobial barriers in type 2 diabetes skin are linked to increased serum levels of advanced glycation end-product

Abstract

Background

The incidence of type 2 diabetes mellitus (DM) has been increasing rapidly, and the disease has become a serious sociomedical problem. Many skin problems, such as xerosis, pruritus, skin infections, and delayed wound healing, that might be related to chronic impairment of skin barrier function decrease the quality of life in DM patients. However, the status of the permeability and antimicrobial barrier of the skin in DM remains unknown.

Objective

This study aimed to elucidate skin barrier impairment in type 2 DM patients and its patho-mechanisms using classic animal models of type 2 DM.

Methods

Functional studies of the skin barrier and an analysis of stratum corneum (SC) lipids were compared between type 2 DM patients and age- and sex-matched non-diabetes controls. Also, functional studies on the skin barrier, epidermal lipid analyses, and electron microscopy and bio-molecular studies were performed using type 2 DM animal models, db/db and ob/ob mice.

Results

Type 2 DM patients presented with epidermal barrier impairments, including SC hydration, which was influenced by blood glucose control (HbA1c level). In the lipid analysis of SC, ceramides, fatty acids, and cholesterol were significantly decreased in type 2 DM patients compared with controls. Type 2 DM murine models presented with severe hyperglycemia, impairment of skin barrier homeostasis, decreases in epidermal proliferation and epidermal lipid synthesis, decreases in lamellar body (LB) and epidermal anti-microbial peptides (AMPs), an increase in receptors for advanced glycation end-product (AGE) in the epidermis, and an increase in serum AGE.

Conclusion

Impairment of the skin barrier was observed in type 2 DM, which results in part from a decrease in epidermal proliferation. Serum AGE and its epidermal receptors were increased in type 2 diabetic mice which display impaired skin barrier parameters such as epidermal lipid synthesis, LB production, epidermal AMP, and SC lipids.

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Solvent Transfer—Efficiency of Risk Management Measures

Abstract

A series of laboratory simulations were conducted in order to determine the airborne protection that might be afforded by different combinations of workplace exposure controls typically encountered when handling volatile solvents (e.g. solvent transfer). These conditions, referred to as risk management measures (RMMs) under the Registration, Evaluation and Authorisation of Chemicals Regulation (REACH), are typically described using standard phrases in safety data sheets [and specifically those of the European Phrase Catalogue (EUPhraC)]. Ethanol was used as a model compound and its emissions were monitored continuously with a portable IR spectrometer at 3000 cm⁻¹. The average emission reduction performance of the investigated RMMs (e.g. containment, extract ventilation, drum pump) exceeded 90%. They present suitable ways to reduce airborne solvent exposure in a workplace and confirmed the initial expectations derived at by the European Solvents Industry Group (ESIG) and the European Centre For Ecotoxicology and toxicology of Chemicals (ECETOC) Targeted Risk Assessment (TRA) model.

Comparison of Respirable Mass Concentrations Measured by a Personal Dust Monitor and a Personal DataRAM to Gravimetric Measurements

Abstract

In 2016, the Mine Safety and Health Administration required the use of continuous monitors to measure respirable dust in mines and better protect miner health. The Personal Dust Monitor, PDM3700, has met stringent performance criteria for this purpose. In a laboratory study, respirable mass concentrations measured with the PDM3700 and a photometer (personal DataRam, pDR-1500) were compared to those measured gravimetrically for five aerosols of varying refractive index and density (diesel exhaust fume, welding fume, coal dust, Arizona road dust (ARD), and salt [NaCl] aerosol) at target concentrations of 0.38, 0.75, and 1.5 mg m⁻³. For all aerosols except coal dust, strong, near-one-to-one, linear relationships were observed between mass concentrations measured with the PDM3700 and gravimetrically (diesel fume, slope = 0.99, R² = 0.99; ARD, slope = 0.98, R² = 0.99; and NaCl, slope = 0.95, R² = 0.99). The slope deviated substantially from unity for coal dust (slope = 0.55; R² = 0.99). Linear relationships were also observed between mass concentrations measured with the pDR-1500 and gravimetrically, but one-to-one behavior was not exhibited (diesel fume, slope = 0.23, R² = 0.76; coal dust, slope = 0.54, R² = 0.99; ARD, slope = 0.61, R² = 0.99; NaCl, slope = 1.14, R² = 0.98). Unlike the pDR-1500, mass concentrations measured with the PDM3700 appear independent of refractive index and density, suggesting that it could have applications in a variety of occupational settings.

Comparative analysis of the protective effects of curcumin and N -acetyl cysteine against paracetamol-induced hepatic, renal, and testicular toxicity in Wistar rats

Abstract

This study aimed to investigate the possible protective role of curcumin (CUR) vs. N-acetyl cysteine (NAC) against paracetamol (PCM)-induced oxidative damage and impairment of liver, kidney, and testicular functions, as well as hematotoxicity, in albino rats. A large single dose of PCM induced lipid peroxidation along with a significant decline in glutathione content and catalase activity in the liver, kidneys, and testicles. The apparent oxidative damage was associated with evident hepatic, renal, and testicular dysfunction, which was confirmed in histopathological lesions, and increased serum aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase activities. PCM decreased serum total protein, albumin, and globulin contents; increased bilirubin, urea, and creatinine contents; and induced hematotoxicity. PCM also reduced the sperm cell count, sperm motility, and alive sperm rate and increased the sperm abnormality rate. Pretreatment of PCM-intoxicated animals with CUR or NAC substantially alleviated the increase in malondialdehyde and maintained the antioxidants at control levels. These pretreatments also minimized liver, kidney, and testicular histopathological changes and normalized their functions. CUR similarly mitigated the PCM hemato- and hepatotoxicity compared with NAC. However, it exhibited a pronounced nephroprotection, rather than reproductive protection as did NAC. Our findings demonstrate that a large single dose of PCM is not only associated with hepatotoxicity but also nephrotoxicity and reproductive toxicity. Both CUR and NAC administration provided substantial organ protection with pronounced efficacy against PCM nephrotoxicity with CUR and reproductive toxicity with NAC, which was possibly mediated through their antioxidant activities, as well as their specific characteristics.

Characterization and valorization of biomass char: a comparison with biomass ash

Abstract

Organic matter derived from living, or recently living plant and animal, which can be used as fuel is called as biomass. It includes wood and agricultural waste such as dead plant etc. In India, majority of population depends largely upon agriculture as their primary source of income. Following every harvest, a huge amount of biomass is generated. It is mostly discarded as "agro waste"; however, recently, several uses of biomass and its derivatives have been reported. Thermochemical processing of biomass in absence of oxygen produces biomass char and flue gases which are of economic importance. However, it is necessary to characterize the physical and chemical properties of these components so as to utilize their potential benefit to the fullest. In this study, six different biomass remains that include mustard plant, groundnut plant, cotton plant, wheat plant, pigeon peas, and groundnut shell were pyrolyzed at 650 °C, in vertical downdraft fixed-bed biomass reactor. The flue gases were characterized in detail by gas chromatography. X-ray fluorescence, proximate, and ultimate analyses were performed on all BMC (biomass char) samples, and properties such as porosity, particle density, bulk density, point of zero charge, surface pH, surface charges, water-absorption capacity, and BET surface area were determined. SEM and FTIR were also carried out on all BMC samples. Our results showed that the surface area of biomass char varies from 38 to 138 m²/g. The solution pH for all BMC exceeds 8.6, thus confirmed the alkaline nature. Comparison between combustion products produced in the presence (biomass ash) and absence of oxygen (biomass char) is presented. BMC finds applications in agriculture, soil neutralizer, adsorbent, and soil additive. They have high amount of carbon and can act as a rich carbon source for the soil. Flue gases released contain methane and hydrogen which can also improve economic value for the char formation process.

The micronucleus test for the oral mucosa: global trends and new questions

Abstract

This study reviews global trends in the publication of papers on the micronucleus test of the exfoliated cells of the oral mucosa in mammals as an approach for environmental biomonitoring. This test has been widely used due to its precision for the detection of chromosome damage. Our temporal analysis showed a significant increase (p < 0.05) in the publication of papers on the oral mucosa over the past 33 years. Brazil was the country that published most papers (24% of the total), followed by India (16%), the USA (10%), Mexico (7%), and Turkey (6%). A further 30 countries contributed the other 37% of the papers. Overall, 99% of the micronucleus studies involved human subjects, and only 1% involved other mammals. As many wild mammals are subject to the same environmental pressures as humans, in particular chemical pollution, it seems likely that many species are equally susceptible to genotoxicogical damage. We emphasize the importance of applying this technique to the analysis of the oral mucosa of wild mammals, as well as the evaluation of its effectiveness, as observed in humans, and the expansion of the available approaches to the monitoring of environmental quality.

Degradation of the earthy and musty odorant 2,4,6-tricholoroanisole by persulfate activated with iron of different valences

Abstract

2,4,6-Trichloroanisole (TCA) is an odorous compound that is often detected in tap water and is difficult to be removed via water treatment. In this study, the transformation efficiency of TCA in the presence of persulfate (PS) activated by iron (Fe²⁺, Fe⁰, and Fe³⁺) was investigated for the first time. The effects of the activator dosage, oxidant dosage, pH, dosing method, chelating agents, humic acid, and temperature were evaluated. The degradation rate of TCA increased with increasing PS dosages (0.12–0.48 mM) and initial Fe²⁺ concentrations (0.12–0.96 mM), while it decreased with higher Fe²⁺ concentrations. Fe²⁺/PS and Fe⁰/PS systems achieved their best TCA removal efficiency at pH 7 and 2.5, respectively. According to the results of electron paramagnetic resonance (EPR), the contribution of SO₄⁻• to TCA degradation was much higher than that of •OH. Gradual addition of Fe²⁺ improved TCA degradation compared to single addition. Citric acid (CA) promoted TCA degradation under Fe²⁺/PS at the beginning of the reaction, but inhibited it after 10 min. Ethylenediaminetetraacetic acid (EDTA) improved the TCA removal rate with an EDTA/Fe²⁺ molar ratio of 0.5:1, while it decreased it at higher EDTA/Fe²⁺ molar ratios. Oxalic acid (OA) negatively affected TCA degradation with increasing OA/Fe²⁺ molar ratios. Among all of the chelating agents, only CA increased TCA degradation by Fe⁰/PS. Humic acid promoted TCA degradation by Fe²⁺/PS at the proper dosage (1 mg/L). Under our specific conditions and over the temperature ranging from 10 to 25 °C, no change was observed in the reaction kinetics. It was found that 2,4,6-trichlorophenol (TCP) was the only detected oxidation product. The presence of an Fe²⁺-Fe³⁺ redox cycle in iron-activated PS systems was confirmed by TCA degradation under the Fe³⁺/PS system.

A novel process for CO 2 capture by using sodium metaborate. Part I: effects of calcination

Abstract

This paper presents a comprehensive study on the carbonation of sodium metaborate (NaBO₂) and the synthesis of high added value chemicals via NaBO₂ and carbon dioxide (CO₂). Carbon dioxide (CO₂) is a greenhouse gas and NaBO₂ is a by-product of sodium borohydride (NaBH₄) hydrolysis reaction to produce H₂. Therefore their transformation into commercial chemicals is quite important in order to provide a mutual benefit to global warming issue and hydrogen economy. In the presented study, reaction parameters such as hydration factor, furnace type, calcination temperature, and environment are investigated at different levels and optimized. The effects of those key parameters on CO₂ fixation yield are discussed. It is found that 400 °C is a key temperature for dehydration and reaction steps. Both dehydrated NaBO₂ is obtained and maximum carbonation conversion is reached at 400 °C. Moreover, at relatively low temperatures (below 400 °C), a new reaction pathway is proposed and proved by thermodynamic calculations. Structural properties of NaBO₂ are exhibited differences regard to thermal exposure and the conversion is strictly related to the structural properties.

Silica nanoparticle exposure inducing granulosa cell apoptosis and follicular atresia in female Balb/c mice

Abstract

Given that the effects of ultrafine fractions (< 0.1 μm) on reproductive diseases are gaining attention, this study aimed to explore the influence of silica nanoparticle (SiNP)-induced female reproductive dysfunction. In this study, 80 female mice were randomly divided into four groups including a control group and three concentrations of SiNP groups (7, 21, 35 mg/kg). Mice were exposed to the vehicle control and silica nanoparticles by tracheal perfusion every 3 days a total of five times in 15 days. Then, half of the mice in each group were sacrificed on 15 and 30 days after the first dose, respectively. Our findings indicated that SiNPs can result in ovarian damage, cause an imbalance of sex hormones, increase the number of atretic and primary follicles, and induce oxidative stress and DNA strand breaks in ovary by day 15. The protein expressions of ATM, CHK-2, P53, E2F1, P73, BAX, Caspase-9, and Caspase-3 were significantly increased, while expressions of RAD51 were down-regulated after SiNP exposure by days 15. Estradiol increased, while progesterone increased in low dose and decreased in high dose after SiNP exposure by 15 days. However, these changes were recovered by 30 days. The results suggest that SiNPs can cause reversible damage to follicles in mice. SiNPs could primarily cause DNA damage and DNA damage response through oxidative stress, while DNA damage repair failure because of severe DNA damage activated the mitochondrial apoptosis pathway and therefore resulted in apoptosis of granulosa cell. In addition, the disorder of reproductive endocrine function caused by SiNPs could be another reason for SiNP-induced reproductive dysfunction in mice. These events in turn induce the follicles to undergo atresia.

Elucidation of functional chemical groups responsible of compost phytotoxicity using solid-state 13 C NMR spectroscopy under different initial C / N ratios

Abstract

More than 1 million tons of fresh organic wastes is produced in the Souss-Massa region in Morocco. Tomato organic residues represent more than 25% of the total organic wastes and are deposited in uncontrolled landfills. Thus, composting can represent a valuable and pertinent solution to this environmental problem. The objectives of this experiment are to identify the potential functional groups responsible for compost phytotoxicity and to determine the optimum initial carbon to nitrogen ratio (C/N) for maximum recovery of tomato residues. The experiment consisted of the variation of the initial C/N ratios (25, 30, 35, and 40) using mixtures of different raw materials (tomato residues, melon residues, olive mill pomace, and sheep manure). Physicochemical parameters (pH, electrical conductivity, C/N ratio, and humic acid/fulvic acid ratio) were determined and spectroscopic analyses (UV-vis and NMR-¹³C) were performed during the composting process along with quality parameters (germination and phytotoxicity tests) at the end. The results showed that the compost with the initial C/N ratio of 35 is the most humified with the least phytotoxic effect. The germination and phytotoxicity tests were negatively correlated with the methoxyl/N-alkyl-C ratio and O-alkyl-C. These two functional groups are probably the origin of phytotoxicity expression in compost quality tests. Thus, a simple and precise quality test could be performed to evaluate directly the phytotoxicity and maturity of compost.

Tracheocutaneous Fistula Closure with Turnover Flap and Polydioxanone Plate

Summary: An alternative surgical treatment is proposed for closure of tracheocutaneous fistulas. The authors present a new technique for reconstruction of persistent tracheocutaneous fistula resultant from temporary tracheostomy. The single-stage closure under local anesthesia involves a fistulous tract turnover flap with a perforated 0.15 mm polydioxanone plate between the flap and the subcutaneous closure. This article presents 3 cases of persistent tracheocutaneous fistula treated by this method. At follow-up examination after follow-up, no recurrent fistula formation had occurred, and no respiratory deformity was present.

Time for Values: Responding Educationally to the Call from the Past

Abstract

This paper rethinks the fostering task of the teacher in a time when it, paradoxically, has tended to become marginalized and privatized despite its public urgency. Following post-holocaust thinkers such as Hannah Arendt and Zygmunt Bauman, the position explored here is radical in the sense that it takes 'the crisis of traditions' and the erosion of a common moral ground or value basis seriously, and it is conservative in the sense that it insists on responding educationally to the call from the past by returning to (a) the moral character of our existence and (b) our own embeddedness in the incompleteness of living traditions. The argument is that there is a difference between educating for common values—which entails a belief in pre-existing commonalities—and making values common in and through education. The latter, we argue, entails an aspiration for continuously creating new commonalities and for cultivating the ability to act and judge as a thinking moral agent in specific, lived and worldly cases. In this sense, the fostering task of the teacher is to create commonality of what is not (yet) common, turning the liberal democratic values of the past into contested objects of study.

The environmental pollutant BDE-209 regulates NO/cGMP signaling through activation of NMDA receptors in neurons

Abstract

The common flame retardant decabrominated diphenyl ether (BDE-209) is a persistent organic pollutant. Epidemiological studies have revealed that prenatal or postnatal exposure to BDE-209 can result in delayed cognitive development, and BDE-209 has been shown to be toxic to cultured neurons with maturation interference effects. However, its neurotoxic mechanism remains unclear. Nitric oxide/cyclic guanosine monophosphate (NO/cGMP) signaling plays an important role in regulating neuronal maturation. We examined the influence of BDE-209 (100, 200, and 400 nM) on NO production and cGMP levels signaling in rodent neurons in vitro, with or without pretreatment N-methyl-D-aspartate (NMDA) receptor antagonism. We found that nanomolar concentrations of BDE-209 affected levels of the second messengers NO and cGMP, and that these effects could be blocked by NMDA receptor antagonism. Moreover, BDE-209 activation of NMDA receptors inhibited the expression of phosphodiesterases (PDEs), which modulate intracellular cGMP levels, and increased the Bcl-2/Bax ratio, favoring apoptosis induction. Our studies implicate the NMDA-NO/cGMP pathway in the pathogenic mechanism through which BDE-209 induces neurotoxicity.

Dry flue gas desulfurization by-product application effects on plant uptake and soil storage changes in a managed grassland

Abstract

Environmental regulations mandate that sulfur dioxide (SO₂) be removed from the flue gases of coal-fired power plants, which results in the generation of flue gas desulfurization (FGD) by-products. These FGD by-products may be a viable soil amendment, but the large amounts of trace elements contained in FGD by-products are potentially concerning. The objective of this study was to evaluate the effects of land application of a high-Ca dry FGD (DFGD) by-product on trace elements in aboveground biomass and soil. A high-Ca DFGD by-product was applied once at a rate of 9 Mg ha⁻¹ on May 18, 2015 to small plots with mixed-grass vegetation. Soil and biomass were sampled prior to application and several times thereafter. Aboveground dry matter and tissue As, Co, Cr, Hg, Se, U, and V concentrations increased (P < 0.05) following application, but did not differ (P > 0.05) from pre-application levels or the unamended control within 3 to 6 months of application. Soil pH in the amended treatment 6 months after application was greater (P < 0.05) than in the unamended control. Soil Ca, S, and Na contents also increased (P < 0.05), following by-product application compared to the unamended control. High-Ca DFGD by-products appear to be useful as a soil amendment, but cause at least a temporary increase in tissue concentrations of trace elements, which may be problematic for animal grazing situations.

Spatial distributions of hexachlorobutadiene in agricultural soils from the Yangtze River Delta region of China

Abstract

Hexachlorobutadiene (HCBD) is one of the persistent organic pollutants (POPs) listed by the Stockholm Convention and poses potential risks to human health and ecosystems. To reveal the regional-scale pollution status of HCBD in agricultural soils from fast-developing areas, an extensive investigation was conducted in the core Yangtze River Delta (YRD), China. The detectable concentrations of HCBD in 241 soil samples ranged from 0.07 to 8.47 ng g⁻¹ dry weight, with an average value of 0.32 ng g⁻¹ and a detection rate of 59.3%. Industrial emissions and intensive agricultural activities were the potential source of HCBD. The concentrations of HCBD were highly associated with the soil physicochemical properties such as organic matter contents. Higher concentrations of HCBD were found in paddy fields than other land-use types. The concentrations of HCBD were much lower than those of organochlorine pesticides and polychlorinated biphenyls. Significant positive correlations were found between HCBD and most organochlorine pesticides. HCBD was not found in ten vegetable samples due to its low concentration and detection rate. A positive relationship was observed between the level of HCBD and the biomass of fungi, indicating that the fungi in soils might be influenced by the existence of HCBD. The potential risks of HCBD to ecosystems and health of inhabitants were estimated to be negligible. The finding from this study provides an important basis for soil quality assessment and risk management of HCBD in China.

Biochar effects on uptake of cadmium and lead by wheat in relation to annual precipitation: a 3-year field study

Abstract

Biochar has been widely studied for its ability to reduce plant uptake of heavy metals by lowering metal bioavailabilities through adsorption and pH-driven fixation reactions. However, the long-term effect of biochar on heavy metal bioavailabilities in alkaline soils under natural redox condition is rarely studied. Here, we report a study examining the effects of biochar on bioavailability and partitioning of cadmium (Cd) and lead (Pb) among different soil fractions over 3 years in a field study with wheat (Triticum aestivum L.). Plots were established on two similar soils having low and high levels of contamination, both of which were amended in the first year with wheat straw biochar at 0, 20, and 40 t ha⁻¹. Precipitation patterns varied greatly over the study period, with 2014 having record drought, which was followed by 2 years having extreme flooding events. Results showed a significant increase in grain yield and reductions in Cd and Pb concentrations in wheat grain in the biochar-amended soils in 2014. In contrast, bioavailable (exchangeable) heavy metal concentrations and plant uptake of Cd and Pb were significantly higher in the subsequent very wet years in 2015 and 2016, where the effects of biochar were much more variable and had an overall lesser effect on reducing heavy metal uptake. The results suggest that fluctuations in soil pH and redox caused by periodic drought and flood cycles strongly drive metal cycling through mobilization and immobilization of metals associated with different mineral phases. Under these conditions, biochar may have reduced efficacy for reducing heavy metal uptake in wheat.