p-Phenylenediamine-Bridged Binder-Electrolyte-Unified Supramolecules for Versatile Lithium Secondary Batteries

The binder is an essential component in determining the structural integrity and ionic conductivity of Li-ion battery electrodes. However, conventional binders are not sufficiently conductive and durable to be used with solid-state electrolytes. In this study, a novel system is proposed for a Li secondary battery that combines the electrolyte and binder into a unified structure, which is achieved by employing para-phenylenediamine (pPD) moiety to create supramolecular bridges between the parent binders. Due to a partial crosslinking effect and charge-transferring structure of pPD, the proposed strategy improves both the ionic conductivity and mechanical properties by a factor of 6.4 (achieving a conductivity of 3.73 × 10-4 S cm-1 for poly(ethylene oxide)-pPD) and 4.4 (reaching a mechanical strength of 151.4 kPa for poly(acrylic acid)-pPD) compared to those of conventional parent binders. As a result, when the supramolecules of pPD are used as a binder in a pouch cell with a lean electrolyte loading of 2 µL mAh-1 , a capacity retention of 80.2% is achieved even after 300 cycles. Furthermore, when it is utilized as a solid-state electrolyte, an average Coulombic efficiency of 99.7% and capacity retention of 98.7% are attained under operations at 50 °C without external pressure or a pre-aging process.

Facet-Dependent Passivation for Efficient Perovskite Solar Cells

Understanding the interplay between the surface structure and the passivation materials and their effects associated with surface structure modification is of fundamental importance; however, it remains an unsolved problem in the perovskite passivation field. Here, we report a surface passivation principle for efficient perovskite solar cells via a facet-dependent passivation phenomenon. The passivation process selectively occurs on facets, which is observed with various post-treatment materials with different functionality, and the atomic arrangements of the facets determine the alignments of the passivation layers. The profound understanding of facet-dependent passivation leads to the finding of 2-amidinopyridine hydroiodide as the material for a uniform and effective passivation on both (100) and (111) facets. Consequently, we achieved perovskite solar cells with an efficiency of 25.10% and enhanced stability. The concept of facet-dependent passivation can provide an important clue on unidentified passivation principles for perovskite materials and a novel means to enhance the performance and stability of perovskite-based devices.

Unveiling facet-dependent degradation and facet engineering for stable perovskite solar cells

A myriad of studies and strategies have already been devoted to improving the stability of perovskite films; however, the role of the different perovskite crystal facets in stability is still unknown. Here, we reveal the underlying mechanisms of facet-dependent degradation of formamidinium lead iodide (FAPbI₃) films. We show that the (100) facet is substantially more vulnerable to moisture-induced degradation than the (111) facet. With combined experimental and theoretical studies, the degradation mechanisms are revealed; a strong water adhesion following an elongated lead-iodine (Pb-I) bond distance is observed, which leads to a δ-phase transition on the (100) facet. Through engineering, a higher surface fraction of the (111) facet can be achieved, and the (111)-dominated crystalline FAPbI₃ films show exceptional stability against moisture. Our findings elucidate unknown facet-dependent degradation mechanisms and kinetics.

Oriented Crystal Growth during Perovskite Surface Reconstruction

Surface passivation has become a key strategy for an improvement in power conversion efficiency (PCE) of perovskite solar cells (PSCs) since PSCs experienced a steep increase in PCE and reached a comparably matured point. Recently, surface passivation using a mixed salt of fluorinated alkyl ammonium iodide and formamidinium bromide demonstrated a remarkable improvement in both performance and stability, which can be tuned by the length of the alkyl chain. Nevertheless, the role of the alkyl chain in manipulating surface-limited crystal growth was not fully understood, preventing a further progress in interface control. In this study, we found that the length of the fluorine-substituted alkyl chain governed the crystal formation dynamics by manipulating surface tensions of different crystal orientations. The overall enhancement of the (001) plane, being the most favored, commonly resulted from the surface reformation of the perovskite film regardless of the chain length, while the highly oriented (001) over (111) was monitored with a particular chain length. The enhanced crystal orientation during surface recrystallization was responsible for the low trap density and thus effectively suppressed charge recombination at the interface, resulting in a considerable increase in open-circuit voltage and fill factor.

Controlled synthesis of solid-shelled non-spherical and faceted microbubbles

The ability to control the shape of hollow particles (e.g., capsules or bubbles) holds great promise for enhancing the encapsulation efficiency and mechanical/optical properties. However, conventional preparation methods suffer from a low yield, difficulty in controlling the shape, and a tedious production process, limiting their widespread application. Here, we present a method for fabricating polyhedral graphene oxide (GO)-shelled microbubbles with sharp edges and vertices, which is based on the microfluidic generation of spherical compound bubbles followed by shell deformation. Sphere-to-polytope deformation is a result of the shell instability due to gradual outward gas transport, which is dictated by Laplace pressure across the shell. The shape-variant behaviours of the bubbles can also be attributed to the compositional heterogeneity of the shells. In particular, the high degree of control of microfluidic systems enables the formation of non-spherical bubbles with various shapes; the structural motifs of the bubbles are easily controlled by varying the size and thickness of the mid-shell in compound bubbles, ranging from tetrahedra to octahedra. The strategy presented in this study provides a new route for fabricating 3D structured solid bubbles, which is particularly advantageous for the development of high-performance mechanical or thermal material applications.

Percolated Plasmonic Superlattices of Nanospheres with 1 nm-Level Gap as High-Index Metamaterials

Nanophotonics relies on precise control of refractive index (RI) which can be designed with metamaterials. Plasmonic superstructures of nanoparticles (NPs) can suggest a versatile way of tuning RI. However, the plasmonic effects in the superstructures demand 1 nm-level exquisite control over the interparticle gap, which is challenging in a sub-wavelength NPs. Thus far, a large-area demonstration has been mostly discouraged. Here, heteroligand AuNPs are prepared, which are stable in oil but become Janus particles at the oil-water interface, called "adaptive Janus particles." NPs are bound at the interface and assembled into 2D arrays over square centimeters as toluene evaporates, which distinctively exhibits the RI tunability. In visible and NIR light, the 2D superstructures exhibit the highest-ever RI (≈7.8) with varying the size and interparticle gap of NPs, which is successfully explained by a plasmonic percolation model. Furthermore, fully solution-processable 2D plasmonic superstructures are proved to be advantageous in flexible photonic devices such as distributed Bragg reflectors.

Lead-Sealed Stretchable Underwater Perovskite-Based Optoelectronics via Self-Recovering Polymeric Nanomaterials

To harness the full potential of halide perovskite based optoelectronics, biological safety, compatibility with flexible/stretchable platforms, and operational stability must be guaranteed. Despite substantial efforts, none has come close to providing a solution that encompasses all of these requirements. To address these issues, we devise a multifunctional encapsulation scheme utilizing hydrogen bond-based self-recovering polymeric nanomaterials as an alternative for conventional glass-based encapsulation. We show that Pb in physically damaged halide perovskite solar cells can be completely contained within the self-recovering encapsulation upon submersion in a simulated rain bath, as indicated by in vitro cytotoxicity tests. In addition, self-recovering encapsulation accommodates stable device operation upon casual bending and even stretching, which is in stark contrast to conventional glass-based encapsulation schemes. We also demonstrate the concept of assembling user-defined scalable modular optoelectronics based on halide perovskite solar cells and light emitting diodes through the use of self-recovering conductive nanocomposites. Finally, long-term operational stability of over 1000 h was achieved under harsh accelerated conditions (50 °C/50% RH and 85 °C/0% RH) with the incorporation of an ultrathin atomic layer deposited TiO₂ barrier underneath the multifunctional encapsulation. In light of these merits, the encapsulation scheme based on self-recovering polymeric nanomaterials is proposed as a simple, but practical solution to a multifaceted challenge in the field of halide perovskites.

Abstract 136: Modeling of prognostication and immune profiling, based on genomic analysis in the tumor microenvironment of pancreatic adenocarcinoma via machine learning

The extensive tumor microenvironment (TME) in pancreatic adenocarcinoma (PAD) modulates cancer progression and impact prognosis. Although gene analysis has enhanced understanding of cancer biology, few models exist to model prognosis in association with mRNA expression in the TME. Clinical outcomes data and mRNA-seq of 156 and 64 patients (pts) were obtained from TCGA and Bailey at el. [1] for testing and validation, respectively. Expressivity of 191 genes enriched in cellular and structural elements of TME and clinical data were analyzed by multivariate nonlinear regression aided by machine learning for confined optimization with model-data error minimization. Statistics including Kaplan-Meier (KM), Cox Hazard (CH), and correlation analysis was used. Most pts (85.89% and 85.94%, respectively) were in stage II, and pts in stage I/III/IV were excluded. Prognostication was modeled with higher risk score (RS) representing worse prognosis: RS = -7.6526 x (Age-5.5679) + 0.0813 x (P/G0.3677) + 0.7069, where P/G is a ratio of genes associated with poor to good prognosis (Table 1). Based on RS, pts were clustered into 2 groups (high and low RS) with 2 KM curves showing p<0.0001 and p=0.014 in test and validation sets. Immune profiling of high and low RS groups in both test and validation sets shows that in low RS group, genes related to both immune activation (IA) and inhibition (II) (Table 2) are highly co-expressed, implying that co-expression of IA and II contributes to PAD’s poor prognosis even in pts with immune system activation. In high RS group, genes related to cancer stem cells (CD44 and EPCAM) significantly contributed to poor prognosis. Machine learning-assisted modeling of RS and gene analysis suggest that IA genes are suppressed by co-expression of high degree of II, contributing to poor prognosis in PAD. RS enables prognostication of pts encountered in the clinic when genomic profiles are provided. [1] Nature 531, 47-52 (2016).

Table 1genes associated with good and poor prognosis out of 191 genes (identification via KM and CH with p<0.05)Good prognosisFCRL3, LILRA4, IL3RA, IL10, CCL22, DOK3, CXCR4, PDGFA, ICOSLG, TNFRSF4Poor prognosisTNFSF10, CD44

Table 2gene groups of immune activation (IA) and immune inhibition (II)IA gene groupscytotoxic T, B, NK, T-helper 1 cells, IFN, cytolytic activity, T cell co-stimulation, and antigen presentationII gene groupsregulatory T cells, desmoplasia, immunosuppressive chemokines, immune checkpoints, angiogenesis, cancer stem cells, epithelial-mesenchymal transition, and neutrophils

Note: This abstract was not presented at the meeting.

Citation Format: Sunyoung S. Lee, Seok Joon Kwon, Ahmed Elkhanany, Andrew Baird, Seongwon Lee, Jillian Dolan, Stuart Baird, Shinyoung Park, Renuka Iyer. Modeling of prognostication and immune profiling, based on genomic analysis in the tumor microenvironment of pancreatic adenocarcinoma via machine learning [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 136.

Shear-solvo defect annihilation of diblock copolymer thin films over a large area

Achieving defect-free block copolymer (BCP) nanopatterns with a long-ranged orientation over a large area remains a persistent challenge, impeding the successful and widespread application of BCP self-assembly. Here, we demonstrate a new experimental strategy for defect annihilation while conserving structural order and enhancing uniformity of nanopatterns. Sequential shear alignment and solvent vapor annealing generate perfectly aligned nanopatterns with a low defect density over centimeter-scale areas, outperforming previous single or sequential combinations of annealing. The enhanced order quality and pattern uniformity were characterized in unprecedented detail via scattering analysis and incorporating new mathematical indices using elaborate image processing algorithms. In addition, using an advanced sampling method combined with a coarse-grained molecular simulation, we found that domain swelling is the driving force for enhanced defect annihilation. The superior quality of large-scale nanopatterns was further confirmed with diffraction and optical properties after metallized patterns, suggesting strong potential for application in optoelectrical devices.

Modeling of prognostication and differential genomic expression in the tumor microenvironment of clear cell renal cell carcinoma

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Background: Stroma in the tumor microenvironment (TME) influences prognosis and response to therapy. Few mathematical models exist to prognosticate patients (pts), based on mRNA expressivity in the TME. Methods: Clinical outcomes data and mRNA-seq of 533 pts with clear cell renal cancer were obtained from TCGA. Expressivity of 191 genes enriched in cellular and structural elements of TME and clinical data were analyzed via machine learning, multivariate nonlinear regression with confined optimization, and Kaplan-Meier (KM) analysis. Results: Prognostication was modeled with higher risk score (RS) representing worse prognosis in each stage (Table). P/G is the ratio of genes associated with poor (61 genes) to good (14) prognosis (refer to presentation). Based on RS, pts in each stage were clustered into 2 groups (high and low RS), showing 2 KM curves with p < 0.001 in each stage. Analysis of immune profiles in these 2 groups shows that in stage 1, expression of genes related to immune activation (IA) is not statistically different in high and low RS groups, but expression of genes related to immune inhibition (II) is higher in high RS group. In high RS groups of stage 2-4, IA genes are highly co-expressed with II genes. In high RS groups of all stages, expression of both IA and II genes increases as stage increases. In low RS groups, IA genes increase as stage increases, but II genes do not. Conclusions: Machine learning and mathematical modeling of RS and gene analysis show that IA genes are suppressed by high degree of II in high RS groups of advanced stages, contributing to worse prognosis. RS enables prognostication of pts encountered in the clinic, given genomic profiles. [Table: see text]

A Plesiohedral Cellular Network of Graphene Bubbles for Ultralight, Strong, and Superelastic Materials

Advanced materials with low density and high strength impose transformative impacts in the construction, aerospace, and automobile industries. These materials can be realized by assembling well-designed modular building units (BUs) into interconnected structures. This study uses a hierarchical design strategy to demonstrate a new class of carbon-based, ultralight, strong, and even superelastic closed-cellular network structures. Here, the BUs are prepared by a multiscale design approach starting from the controlled synthesis of functionalized graphene oxide nanosheets at the molecular- and nanoscale, leading to the microfluidic fabrication of spherical solid-shelled bubbles at the microscale. Then, bubbles are strategically assembled into centimeter-scale 3D structures. Subsequently, these structures are transformed into self-interconnected and structurally reinforced closed-cellular network structures with plesiohedral cellular units through post-treatment, resulting in the generation of 3D graphene lattices with rhombic dodecahedral honeycomb structure at the centimeter-scale. The 3D graphene suprastructure concurrently exhibits the Young's modulus above 300 kPa while retaining a light density of 7.7 mg cm^-3 and sustaining the elasticity against up to 87% of the compressive strain benefiting from efficient stress dissipation through the complete space-filling closed-cellular network. The method of fabricating the 3D graphene closed-cellular structure opens a new pathway for designing lightweight, strong, and superelastic materials.

Chemical and genetic diversity of high-seed-yield sorghum (Sorghum bicolor M.) germplasms

This study evaluated the chemical and genetic diversity of high-seed-yield sorghum germplasms from Korea, the United States, and South Africa. We identified significant differences in the chemical contents of whole plants at the heading stage in all cultivars, including differences in crude protein, fat, fiber, ash, neutral detergent fiber, acid detergent fiber, mineral, and fatty acid contents. Our results suggest that Banwoldang is the most appropriate cultivar for roughage because of its high protein yield. We identified significant differences in the tannin, flavonoid, amylose, mineral, crude fat, fatty acid, and 3-deoxyanthocyanin contents in the whole grain from all cultivars, but not in the mineral or crude fat contents. Tannin levels were generally low. IS645 contained the highest levels of flavonoids and linolenic acid compounds, and Moktak had the highest amylose and deoxyanthocyanidin content in the grain. To assess genetic diversity, we used 10 simple sequence repeat (SSR) primer sets to identify 38 alleles with 3-8 alleles per locus. Based on phylogenetic analysis of the SSR markers, the sorghum cultivars were divided into three major groups. Comparison of clusters based on chemical compositions with those based on SSRs showed that the groups formed by the three native Korean cultivars clustered similarly in molecular dendrograms. Association analysis was conducted for the 10 SSR marker; 48 chemical and growth traits were present for two marker traits (seed color and whole plant fatty acid content) with significant marker-trait associations. These markers could be used to select sorghum cultivars for breeding programs.

A Plasmonic Platform with Disordered Array of Metal Nanoparticles for Three-Order Enhanced Upconversion Luminescence and Highly Sensitive Near-Infrared Photodetector

Three-order enhanced upconversion luminescence from upconversion nanoparticles is suggested by way of a promising platform utilizing a disordered array of plasmonic metal nanoparticles. Its application toward highly sensitive NIR photodetectors is discussed.

Perioperative predictors for refractory hyperglycemia during the neohepatic phase of liver transplantation

BACKGROUND

Hyperglycemia in the neohepatic phase of liver transplantation (LT) tends to decrease toward completion of the surgical procedure. Refractory hyperglycemia in the neohepatic phase (RH) is influenced by multiple perioperative factors and may be connected to posttransplant outcomes. We attempted to demonstrate the relationship of RH to posttransplant outcomes and to establish a predictive model for RH in living donor liver transplantation (LDLT).

METHODS

Perioperative data of 211 patients who underwent LDLT from 2009 and 2012 were reviewed, including declines in the blood glucose levels during the neohepatic phase. Perioperative variables including the posttransplant model for end-stage liver disease (MELD) score until day 30 were compared between patients with normal declines in blood glucose and patients with RH. Selected variables after intergroup comparisons were examined by means of multivariate logistic regression to establish a predictive model for RH occurrence.

RESULTS

The mean blood glucose decline was 22.3 ± 31.5 mg/dL during the neohepatic phase, and 84 of 203 patients (41.4%) had no decline in blood glucose. In intergroup comparisons, preoperative factors associated with RH included sex, Child-Pugh-Turcotte class, MELD score, emergency, liver enzymes, and graft-to-recipient weight ratio. During surgery, surgical time, serum lactate, and arterial pH were associated with RH. After surgery, the RH group showed slower recovery of the MELD score (15.2 versus 11.9 days) and higher MELD scores until day 10 (P < .05). After the multivariate analysis, recipient sex, emergency, surgical time (≤9 h), and the final intraoperative serum lactate level (≥5.0 mmol/L) were included in the predictive model for RH.

CONCLUSIONS

RH was associated with delayed functional recovery of the liver graft in LT. Recipient sex, emergency, surgical time, and the final intraoperative serum lactate level were identified as predictors of RH. Close monitoring of intraoperative blood glucose in LDLT may be an early prognostic indicator.

Effect of an organic buffer layer on the stability of zinc oxide thin-film transistors

Compared with other materials, zinc oxide (ZnO) exhibits stability in air, high-electron mobility, transparency and low light sensitivity. We investigated these properties in ZnO thin-film transistors (TFTs) containing a cross-linked poly(vinyl alcohol) (C-PVA) (1:3) buffer layer stacked between the semiconductor and gate dielectric. We measured the impact of this C-PVA layer on gate bias stress. We measured the transfer characteristics of the saturation region to determine the threshold voltage and the field-effect mobility of the transistors. We recorded a threshold voltage of 11.53 V in the ZnO TFTs with the C-PVA buffer layer, the field-effect mobility was 0.2 cm2/Vs. There was a positive shift in the threshold voltage of deltaV(TH) approximately 10 V in response to the application of a gate bias stress of 20 V. The positive shift in the threshold voltage was lower than that in pristine ZnO TFTs. This finding suggests that the shift in threshold voltage was due to reduced charge trapping at the semiconductor-gate dielectric interface. Our report indicates that the organic buffer layer enhanced the stability of ZnO TFTs.

High-throughput and combinatorial gene expression on a chip for metabolism-induced toxicology screening

Differential expression of various drug-metabolizing enzymes (DMEs) in the human liver may cause deviations of pharmacokinetic profiles, resulting in interindividual variability of drug toxicity and/or efficacy. Here, we present the 'Transfected Enzyme and Metabolism Chip' (TeamChip), which predicts potential metabolism-induced drug or drug-candidate toxicity. The TeamChip is prepared by delivering genes into miniaturized three-dimensional cellular microarrays on a micropillar chip using recombinant adenoviruses in a complementary microwell chip. The device enables users to manipulate the expression of individual and multiple human metabolizing-enzyme genes (such as CYP3A4, CYP2D6, CYP2C9, CYP1A2, CYP2E1 and UGT1A4) in THLE-2 cell microarrays. To identify specific enzymes involved in drug detoxification, we created 84 combinations of metabolic-gene expressions in a combinatorial fashion on a single microarray. Thus, the TeamChip platform can provide critical information necessary for evaluating metabolism-induced toxicity in a high-throughput manner.

High sensitivity detection of active botulinum neurotoxin by glyco-quantitative polymerase chain-reaction

The sensitive detection of highly toxic botulinum neurotoxin (BoNT) from Clostridium botulinum is of critical importance because it causes human illnesses if foodborne or introduced in wounds and as an iatrogenic substance. Moreover, it has been recently considered a possible biological warfare agent. Over the past decade, significant progress has been made in BoNT detection technologies, including mouse lethality assays, enzyme-linked immunosorbent assays, and endopeptidase assays and by mass spectrometry. Critical assay requirements, including rapid assay, active toxin detection, sensitive and accurate detection, still remain challenging. Here, we present a novel method to detect active BoNTs using a Glyco-quantitative polymerase chain-reaction (qPCR) approach. Sialyllactose, which interacts with the binding-domain of BoNTs, is incorporated into a sialyllactose-DNA conjugate as a binding-probe for active BoNT and recovered through BoNT-immunoprecipitation. Glyco-qPCR analysis of the bound sialyllactose-DNA is then used to detect low attomolar concentrations of BoNT and attomolar to femtomolar concentrations of BoNT in honey, the most common foodborne source of infant botulism.

Signal amplification by glyco-qPCR for ultrasensitive detection of carbohydrates: applications in glycobiology

Tiny amounts of carbohydrates (ca. 1 zmol) can be detected quantitatively by a real-time method based on the conjugation of carbohydrates with DNA markers (see picture). The proposed method (glyco-qPCR) provides uniform, ultrasensitive detection of carbohydrates, which can be applied to glycobiology, as well as carbohydrate-based drug discovery.

Fall detection algorithm for the elderly using acceleration sensors on the shoes

The rate of increase in the number of aging population in Korea is very rapid among OECD-member countries. And fall accident is one of the most common factors that threaten the health of the elderly. Therefore, it is needed to develop a fall detection system for the elderly. Most fall detection systems use accelerometers attached on the torso. And in various studies, it was verified that these systems have high sensitivity and high specificity. However, the elderly would feel uncomfortable when banding a sensor on the chest every day. Therefore, in this study, we attached an accelerometer on the shoes to detect fall in the elderly. This prototype system would be improved as a smaller, low-power system in the next study. Also, applying energy harvesting device to this shoe system is being developed to reduce the weight of battery.

Trimer hydroxylated quinone derived from apocynin targets cysteine residues of p47phox preventing the activation of human vascular NADPH oxidase

Enzymatically derived oligophenols from apocynin can be effective inhibitors of human vascular NADPH oxidase (Nox). An isolated trimer hydroxylated quinone (IIIHyQ) has been shown to inhibit endothelial NADPH oxidase with an IC(50) ~30 nM. In vitro studies demonstrated that IIIHyQ is capable of disrupting the interaction between p47(phox) and p22(phox), thereby blocking the activation of the Nox2 isoform. Herein, we report the role of key cysteine residues in p47(phox) as targets for the IIIHyQ. Incubation of p47(phox) with IIIHyQ results in a decrease of ~80% of the protein free cysteine residues; similar results were observed using 1,2- and 1,4-naphthoquinones, whereas apocynin was unreactive. Mutants of p47(phox), in which each Cys was individually replaced by Ala (at residues 111, 196, and 378) or Gly (at residue 98), were generated to evaluate their individual importance in IIIHyQ-mediated inhibition of p47(phox) interaction with p22(phox). Specific Michael addition on Cys196, within the N-SH3 domain, by the IIIHyQ is critical for disrupting the p47(phox)-p22(phox) interaction. When a C196A mutation was tested, the IIIHyQ was unable to disrupt the p47(phox)-p22(phox) interaction. However, the IIIHyQ was effective at disrupting this interaction with the other mutants, displaying IC(50) values (4.9, 21.0, and 2.3μM for the C111A, C378A, and C98G mutants, respectively) comparable to that of wild-type p47(phox).

Unnatural polyketide analogues selectively target the HER signaling pathway in human breast cancer cells

Receptor tyrosine kinases are critical targets for the regulation of cell survival. Cancer patients with abnormal receptor tyrosine kinases (RTK) tend to have more aggressive disease with poor clinical outcomes. As a result, human epidermal growth factor receptor kinases, such as EGFR (HER1), HER2, and HER3, represent important therapeutic targets. Several plant polyphenols including the type III polyketide synthase products (genistein, curcumin, resveratrol, and epigallocatechin-3-galate) possess chemopreventive activity, primarily as a result of RTK inhibition. However, only a small fraction of the polyphenolic structural universe has been evaluated. Along these lines, we have developed an in vitro route to the synthesis and subsequent screening of unnatural polyketide analogues with N-acetylcysteamine (SNAc) starter substrates and malonyl-coenzyme A (CoA) and methylmalonyl-CoA as extender substrates. The resulting polyketide analogues possessed a similar structural polyketide backbone (aromatic-2-pyrone) with variable side chains. Screening chalcone synthase (CHS) reaction products against BT-474 cells resulted in identification of several trifluoromethylcinnamoyl-based polyketides that showed strong suppression of the HER2-associated PI3K/AKT signaling pathway, yet did not inhibit the growth of nontransformed MCF-10A breast cells (IC(50)>100 microM). Specifically, 4-trifluoromethylcinnamoyl pyrone (compound 2 e) was highly potent (IC(50)<200 nM) among the test compounds toward proliferation of several breast cancer cell lines. This breadth of activity likely stems from the ability of compound 2 e to inhibit the phosphorylation of HER1, HER2, and HER3. Therefore, these polyketide analogues might prove to be useful drug candidates for potential breast cancer therapy.

Nanoparticle-mediated cytoplasmic delivery of proteins to target cellular machinery

Despite recent advances in nanomaterial-based delivery systems, their applicability as carriers of cargo, especially proteins for targeting cellular components and manipulating cell function, is not well-understood. Herein, we demonstrate the ability of hydrophobic silica nanoparticles to deliver proteins, including enzymes and antibodies, to a diverse set of mammalian cells, including human cancer cells and rat stem cells, while preserving the activity of the biomolecule post-delivery. Specifically, we have explored the delivery and cytosolic activity of hydrophobically functionalized silica nanoparticle-protein conjugates in a human breast cancer cell line (MCF-7) and rat neural stem cells (NSCs) and elucidated the mechanism of cytosolic transport. Importantly, the proteins were delivered to the cytosol without extended entrapment in the endosomes, which facilitated the retention of biological activity of the delivered proteins. As a result, delivery of ribonuclease A (RNase A) and the antibody to phospho-Akt (pAkt) resulted in the initiation of cell death. Delivery of control protein conjugates (e.g., those containing green fluorescent protein or goat antirabbit IgG) resulted in minimal cell death, indicating that the carrier-mediated toxicity was low. The results presented here provide insight into the design of nanomaterials as protein carriers that enable control of cell function.

In vitro precursor-directed synthesis of polyketide analogues with coenzyme a regeneration for the development of antiangiogenic agents

Polyketide analogues are produced via in vitro reconstruction of a precursor-directed polyketide biosynthetic pathway. Malonyl-CoA synthetase (MCS) was used in conjunction with chalcone synthase (CHS), thereby allowing efficient use of synthetic starter molecules and malonate as extender. Coenzyme-A was recycled up to 50 times. The use of a simple immobilization procedure resulted in up to a 30-fold higher yield of pyrone CHS products than that obtained with the free enzyme solutions.

Human amnion-derived mesenchymal stem cells are a potential source for uterine stem cell therapy

OBJECTIVES

Human amnion is an easy-to-obtain novel source of human mesenchymal stem cells, which poses little or no ethical dilemmas. We have previously shown that human amnion-derived mesenchymal (HAM) cells exhibit certain mesenchymal stem cell-like characteristics with respect to expression of stem cell markers and differentiation potentials.

MATERIALS AND METHODS

In this study, we further characterized HAM cells' potential for in vivo therapeutic application.

RESULTS

Flow cytometric analyses of HAM cells show that they express several stem cell-related cell surface markers, including CD90, CD105, CD59, CD49d, CD44 and HLA-ABC, but not CD45, CD34, CD31, CD106 or HLA-DR. HAM cells at the 10th passage showed normal karyotype. More interestingly, the AbdB-like HOXA genes HOXA9, HOXA10 and HOXA11 that are expressed in the mesenchyme of the developing female reproductive tract and pregnant uteri are also expressed in HAM cells, suggesting similarities between these two mesenchymal cell types. Progesterone receptor is also highly expressed in HAM cells and expression of genes or proteins in HAM cells could be manipulated with the aid of lentivirus technology or cell-permeable peptides. To test potentials of HAM cells for in vivo application, we introduced enhanced green fluorescence protein (EGFP)-expressing HAM cells to mice by intrauterine infusion (into uteri) or by intravenous injection (into the circulation). Presence of EGFP-expressing cells within the uterine mesenchyme after intrauterine infusion or in lungs after intravenous injection was noted within 1-4 weeks.

CONCLUSIONS

Collectively, these results suggest that HAM cells are a potential source of mesenchymal stem cells with therapeutic potential.

High-throughput, microarray-based synthesis of natural product analogues via in vitro metabolic pathway construction

The generation of biological diversity by engineering the biosynthetic gene assembly of metabolic pathway enzymes has led to a wide range of "unnatural" variants of natural products. However, current biosynthetic techniques do not allow the rapid manipulation of pathway components and are often fundamentally limited by the compatibility of new pathways, their gene expression, and the resulting biosynthetic products and pathway intermediates with cell growth and function. To overcome these limitations, we have developed an entirely in vitro approach to synthesize analogues of natural products in high throughput. Using several type III polyketide synthases (PKS) together with oxidative post-PKS tailoring enzymes, we performed 192 individual and multienzymatic reactions on a single glass microarray. Subsequent array-based screening with a human tyrosine kinase led to the identification of three compounds that acted as modest inhibitors in the low-micromolar range. This approach, therefore, enables the rapid construction of analogues of natural products as potential pharmaceutical lead compounds.

Transgalactosylation in a water-solvent biphasic reaction system with beta-galactosidase displayed on the surfaces of Bacillus subtilis spores

The ever-increasing industrial demand for biocatalysis necessitates innovations in the preparation and stabilization of biocatalysts. In this study, we demonstrated that beta-galactosidase (beta-Gal) displayed on Bacillus spores by fusion to the spore coat proteins (CotG) may be used as a whole-cell immobilized biocatalyst for transgalactosylation in water-solvent biphasic reaction systems. The resulting spores had a specific hydrolytic activity of 5 x 10(3) U/g (dry weight) of spores. The beta-Gal was tightly attached to the spore surface and was more stable in the presence of various organic solvents than its native form was. The thermostability of the spore-displayed enzyme was also increased, and the enzyme was further stabilized by chemically cross-linking it with glutaraldehyde. With spore-displayed beta-Gal, octyl-beta-D-galactopyranoside was synthesized at concentrations up to 27.7 mM (8.1 g/liter) with a conversion yield of 27.7% (wt/wt) after 24 h from 100 mM lactose and 100 mM octanol dissolved in phosphate buffer and ethyl ether, respectively. Interestingly, the spores were found to partition mainly at the interface between the water and solvent phases, and they were more available to catalysis between the two phases, as determined by light microscopy and confocal fluorescence microscopy. We propose that spore display not only offers a new and facile way to construct robust biocatalysts but also provides a novel basis for phase transfer biocatalytic processes.

Chip-based polyketide biosynthesis and functionalization

We demonstrate construction and novel compound synthesis from a synthetic metabolic pathway consisting of a type III polyketide synthase (PKS) known as 1,3,6,8-tetrahydroxynaphthalene synthase (THNS) from Streptomyces coelicolor and soybean peroxidase (SBP) in a microfluidic platform. THNS immobilized to Ni-NTA agarose beads is prepacked into a microfluidic channel, while SBP is covalently attached to the walls of a second microfluidic channel precoated with a reactive poly(maleic anhydride) derivative. The result is a tandem, two-step biochip that enables the synthesis of novel polyketide derivatives. The first microchannel, consisting of THNS, results in the conversion of malonyl-CoA to flaviolin in yields up to 40% with a residence time of 6 min. This conversion is similar to that obtained in several-milliliter batch reactions after 2 h. Linking this microchannel to the SBP microchannel results in biflaviolin synthesis. During the course of this work, we discovered that the substrate specificity of THNS could be manipulated by simply changing the reaction pH. As a result, the starter acyl-CoA specificity can be broadened to yield a series of truncated pyrone products. When combined with variations in the ratio of acyl-CoA and malonyl-CoA (extender substrate) feed rates, high yields of the pyrone products could be achieved, which is further structurally diversified from self- and cross-coupling in the SBP microchannel. The ability to rapidly evaluate the effects of reaction conditions and synthetic multienzyme pathways on a microfludic platform provides a new paradigm for performing metabolic pathway engineering, namely, the reconstruction of pathways for use in new compound discovery.

Effect of Low Glutamine/Glucose on Hypoxia-Induced Elevation of Hypoxia-Inducible Factor-1 in Human Pancreatic Cancer MiaPaCa-2 and Human Prostatic Cancer DU-145 Cells

PURPOSE AND EXPERIMENTAL DESIGN

Tumor microenvironment is characterized by regions of fluctuating and chronic hypoxia, low extracellular pH, and nutrient depletion. Although it is well known that hypoxia stimulates the accumulation of hypoxia-inducible factor-1alpha (HIF-1alpha), the role of low extracellular pH and nutrient depletion on hypoxia up-regulation of HIF-1alpha is not well known. In this study, human pancreatic cancer MiaPaCa-2 and human prostatic cancer DU-145 cells were exposed to hypoxia in the presence or absence of glucose, glutamine, and/or pyruvate.

RESULTS

We observed that low glucose and low glutamine, but not low pyruvate, effectively suppressed the elevation of HIF-1alpha level during hypoxia (0.1-1% oxygen). Deprivation of glutamine or glucose inhibited the accumulation of HIF-1alpha in the presence of MG-132, a protease inhibitor, regardless of oxygen tensions. Data from reverse transcription-PCR analysis revealed that the levels of HIF-1alpha mRNA were not significantly changed at different concentrations of glutamine or glucose under hypoxia. The amount of HIF-1alpha suppression was proportional to protein synthesis inhibition.

CONCLUSIONS

Our data suggest that glutamine or glucose deprivation inhibits the accumulation of HIF-1alpha under hypoxic conditions by disrupting translational processes rather than transcriptional or proteasomal degradation processes.

A High-Throughput Screen for Porphyrin Metal Chelatases: Application to the Directed Evolution of Ferrochelatases for Metalloporphyrin Biosynthesis

Porphyrins are of particular interest in a variety of applications ranging from biocatalysis and chemical synthesis to biosensor and electronic technologies as well as cancer treatment. Recently, we have developed a versatile system for the high-level production of porphyrins in engineered E. coli cells with the aim of diversifying substitution patterns and accessing porphyrin systems not readily available through chemical synthesis. However, this approach failed to produce significant amounts of the metalloporphyrin in vivo from overproduced protoporphyrin due to insufficient metal insertion. Therefore, we systematically assessed the activity of the B. subtilis ferrochelatase in vivo and in vitro. A true high-throughput-screening approach based on catalytic in vivo ferrochelatase activity was developed by using fluorescence-activated cell sorting (FACS). This assay was used to screen a library of 2.4 x 10(6) ferrochelatase mutants expressed in protoporphyrin-overproducing recombinant E. coli cells. Several selected protein variants were purified, and their improved catalytic activity was confirmed in vitro. In addition to ferrochelatase activity, metal transport into E. coli was identified as another limitation for in vivo heme overproduction. Overexpression of the metal transporter zupT as part of the assembled pathway increased the overall metalloporphyrin production twofold. This report represents the most exhaustive in vitro evolution study of a ferrochelatase and demonstrates the effectiveness of our novel high-throughput-screening system for directed evolution of ferrochelatases based on their catalytic activity.

Cerebral microbleeds are regionally associated with intracerebral hemorrhage

BACKGROUND

Cerebral microbleeds (CMB) may be indicative of a hemorrhage-prone microangiopathy.

OBJECTIVE

To determine if increased numbers of these lesions are predictive of intracerebral hemorrhage (ICH), especially in terms of a distributional association.

METHODS

The authors examined consecutively 227 patients with acute stroke. CMB were counted using T2*-weighted gradient echo MRI data, and old lacunes and leukoaraiosis were also evaluated. The associations between the vascular risk factors and ICH were analyzed. With use of multivariate logistic regression analysis, the locations of the CMB or the old lacunes, which were categorized as being in the corticosubcortical area, the deep gray matter area, or the infratentorial area, were examined with regard to their relationships to the locations of the ICH.

RESULTS

The degrees of the CMB (r = 0.43, p < 0.01) and leukoaraiosis (r = 0.20, p < 0.01) were well correlated with the presence of ICH. Multivariate analysis revealed that the grades of the CMB were associated with the presence of ICH (p < 0.01, odds ratio [OR] = 2.67). CMB in the corticosubcortical area (p < 0.01, OR = 5.50) or deep gray matter (p < 0.01, OR = 2.55) were strongly associated with the presence of ICH in the same area, but no such association was observed in the case of CMB in the infratentorial area or in the case of old lacunes in any area.

CONCLUSIONS

Cerebral microbleeds are strongly associated with the presence of intracerebral hemorrhage, and the distributional associations are also quite strong.

High-level production of porphyrins in metabolically engineered Escherichia coli: systematic extension of a pathway assembled from overexpressed genes involved in heme biosynthesis

Due to their spectroscopic properties porphyrins are of special interest for a variety of applications, ranging from drug development or targeting to material sciences and chemical and biological sensors. Since chemical syntheses are limited in terms of regio- and stereoselective functionalization of porphyrins, a biosynthetic approach with tailored enzyme catalysts offers a promising alternative. In this paper, we describe assembly of the entire heme biosynthetic pathway in a three-plasmid system and overexpression of the corresponding genes with Escherichia coli as a host. Without further optimization, this approach yielded remarkable porphyrin production levels, up to 90 micro mol/liter, which is close to industrial vitamin B(12) production levels. Different combinations of the genes were used to produce all major porphyrins that occur as intermediates in heme biosynthesis. All these porphyrin intermediates were obtained in high yields. The product spectrum was analyzed and quantified by using high-performance liquid chromatography. Intriguingly, although protoporphyrin IX could be produced at high levels, overexpressed Bacillus subtilis ferrochelatase could not convert this substrate appreciably into heme. However, further investigation clearly revealed a high level of expression of the ferrochelatase and a high level of activity in vitro. These results may indicate that heme has a regulatory impact on the iron uptake of E. coli or that the ferrochelatase is inactive in vivo due to an incompatible enzyme interaction.

Papyriflavonol A, a new prenylated flavonol from Broussonetia papyrifera

A new prenylated flavonol, papyriflavonol A, was isolated from the root barks of Broussonetia papyrifera. The structure of this compound was elucidated as 5,7,3',4'-tetrahydroxy-6,5'-di-(gamma,gamma-dimethylallyl)-flavonol (1) by spectroscopic analysis.

Two imported cases of cutaneous larva migrans

Cutaneous larva migrans (CLM) is a rare serpiginous cutaneous eruption caused by accidental penetration and migration in the skin with infective larvae of nematode that normally do not have the human as their host. Although CLM has a worldwide distribution, the infection is most frequent in warmer climates. More recently, they have been increasingly imported from the tropics or subtropics by travelers. We experienced two patients who had pruritic serpiginous linear eruption in their skin for a few weeks after traveling to the endemic areas (Brazil and Thailand, respectively). After the treatment with albendazole, the skin lesions resolved with post-inflammatory hyperpigmentation. We report herein two cases of cutaneous larva migrans successfully treated with albendazole.

Surgery and prognostic factors for gastric stromal tumor

Morphologic studies of gastric stromal tumors (GSTs) indicate that mitotic counts (MCs) and tumor size are major discriminants predictive of biologic behavior. The purpose of this study is to improve the understanding of GST behavior, including the prognostic factors and surgical treatment of GSTs. A retrospective analysis (1990--1997) of the clinical course for 116 patients with GSTs was completed, with a median follow-up of 43 months. Tumors were categorized as malignant GSTs (n = 17) when the MC was > 5/50 high-power fields (HPF) and the size > 5 cm or as benign GSTs (n = 99) when the MC was < or = 5/50 HPF and the size < or = 5 cm, MC < or = 5/50 HPF and size > 5 cm, or MC > 5/50 HPF and size < or = 5 cm. None of 99 benign tumors recurred or metastasized, whereas 7 of 17 malignant tumors recurred. MCs had a close correlation with tumor size. Immunohistochemical studies using CD34, smooth muscle actin, S-100 protein, and synaptophysin have shown positive rates of 61%, 33%, 14%, and 3%, respectively. Smooth muscle actin reactivity was more common in the benign tumors (p = 0.046) and synaptophysin reactivity in the malignant tumors (p = 0.010). Univariate analysis showed that the following clinicopathologic factors were potentially related to poor survival of patients: (1) MC > 5/50 HPF (p = 0.0001); (2) severe pleomorphism (p = 0.0062); (3) necrosis (p = 0.0173); (4) marked cellularity (p = 0.0112); (5) presence of ulceration of overlying gastric mucosa (p = 0.0091); (6) tumor size > 5 cm (p = 0.0195); and (7) exogastric growth pattern (p = 0.0344). Tumors with MC > 5/50 HPF and size > 5 cm were found to be strong indicators of an unfavorable prognosis. The type of surgery and tumor site did not affect the prognosis of the patients.

Insulin-like growth factor-1 protects H9c2 cardiac myoblasts from oxidative stress-induced apoptosis via phosphatidylinositol 3-kinase and extracellular signal-regulated kinase pathways

Oxidative stress plays a critical role in cardiac injuries during ischemia/reperfusion. Insulin-like growth factor-1 (IGF-1) promotes cell survival in a number of cell types, but the effect of IGF-1 on the oxidative stress has not been elucidated in cardiac muscle cells. Therefore, we examined the role of IGF-1 signaling pathway in cell survival against H2O2-induced apoptosis in H9c2 cardiac myoblasts. H2O2 treatment induced apoptosis in H9c2 cells, and pretreatment of cells with IGF-1 suppressed apoptotic cell death. The antiapoptotic effect of IGF-1 was blocked by LY294002 (an inhibitor of phosphatidylinositol 3-kinase) and by PD98059 (an inhibitor of extracellular signal-regulated kinase (ERK)). The protective effect of IGF-1 was also blocked by rapamycin (an inhibitor of p70 S6 kinase). Furthermore, H9c2 cells stably transfected with constitutively active PI 3-kinase (H9c2-p110*) and Akt (H9c2-Gag-Akt) constructs were more resistant to H2O2 cytotoxicity than control cells. Although H2O2 activates both p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK), IGF-1 inhibited only JNK activation. Activated PI 3-kinase (H9c2-p110*) and pretreatment of cells with IGF-1 down-regulated Bax protein levels compared to control cells. Taken together, our results suggest that IGF-1 transmits a survival signal against oxidative stress-induced apoptosis in H9c2 cells via PI 3-kinase and ERK-dependent pathways and the protective effect of IGF-1 is associated with the inhibition of JNK activation and Bax expression.

Localized multiple glomus tumors of the face and oral mucosa

We describe a 54-year-old patient with an unusual localization of localized multiple glomus tumors. She had several nodules on the left mandibular area, lower lip, and anterior part of the buccal mucosa. A biopsy taken from the left mandibular area showed cystically dilated vessels lined by endothelial cells and a few outer layers of glomus cells in the dermis to subcutis. Localized multiple glomus tumors are rare, and both their facial and oral mucocal localization are extremely rare.

High thoracic midline dorsal column myelotomy for severe visceral pain due to advanced stomach cancer

OBJECTIVE

To report the results of high thoracic midline dorsal column myelotomy in eight consecutive patients who experienced severe visceral pain caused by advanced stomach cancer.

METHODS

Eight patients were transferred from the department of general surgery because of failed pain control after an operation and chemotherapy for advanced stomach cancer. Preoperatively, the pain was not controlled with strong opiates. The patients' neurological status was normal. Their general conditions varied from 50 to 80 on the Karnofsky scale. Under general anesthesia, patients received high thoracic midline dorsal column myelotomies after T1 or T2 laminectomy.

RESULTS

Five of the eight patients exhibited favorable outcomes after surgery. The remaining three did not experience preoperative pain but developed new pain at a different site. One patient exhibited a posterior column sign and paresthesia below the level of the myelotomy without motor deficit and analgesia. Two patients exhibited transient paresthesia below the T6 level, but the paresthesia improved after administration of corticosteroids. There was no mortality related to the procedure.

CONCLUSION

Controlling visceral pain resulting from advanced cancer is very difficult, although various surgical procedures have been tried. Poorly localized, deep and diffuse visceral pain is more difficult to manage than well-localized somatic pain. Dorsal column myelotomy at a high thoracic cord level effectively controls severe abdominal pain and should be considered as a new palliative operation for patients with severe visceral pain.

The influence of gastrectomy on the change of bone metabolism and bone density

OBJECTIVES

Abnormalities of bone metabolism could be followed in gastrectomized patients as a late complication. Nowadays, many biochemical and radiologic measurements are applied to detect these abnormalities. The aim of our study is to determine the valuable parameter as an appropriate screening test during long-term follow-up periods and define the usefulness of new biochemical markers for bone metabolism by comparing with traditional markers.

METHODS

Fifteen patients who had undergone partial gastrectomy were chosen randomly and fifteen healthy controls were compared. Then, several biochemical and radiologic tests were measured. We excluded subjects who proved to have other causes of bone metabolism abnormalities. Ten patients and 10 controls were finally selected.

RESULTS

Comparing the data with those of a corresponding control group, the lumbar bone density measured by quantitative computed tomography (QCT) was statistically significantly lower in the patient group (p < 0.01). The urinary deoxypyridinoline, a biochemical marker for bone resorption, was statistically higher in the patient group (p < 0.025). Osteocalcin, Procollagen I C-terminal peptide (PICP) and Type I collagen C-terminal telopeptide (ICTP) were slightly but not significantly higher in the patient group. The serum parathyroid hormone (PTH) and 25-hydroxy vitamin D levels were similar in both groups.

CONCLUSION

We could suggest that urinary deoxypyridinoline and QCT are appropriate parameters as screening tests for the detection of bone metabolism abnormalities in gastrectomized patients during long-term follow-up. Urinary deoxypyridinoline may be a simple and rapid test which could replace cumbersome 24-hour urinary hydroxyproline.

Realization of sinc waves in ultrasound imaging systems

It is known that the transmit pulse waveforms of a limited-diffraction beam in a linear array transducer should be varied according to transducer element location, dictating the use of sophisticated hardware. In order to overcome this disadvantage while achieving the same field response, we propose a method of synthesizing limited-diffraction beams by combined signal processing of pulsed plane waves propagating in distinct directions over several consecutive insonification time intervals. The method is capable of achieving both higher transmit power and better lateral resolution over a larger depth of field. Although its field response is not uniform throughout the imaging points, this is not a major problem since the response is quite uniform within a region of interest. The proposed method requires the use of multiple insonifications for transmit focusing, and, therefore, can be applied in imaging slowly-moving or still objects. Both simulation and experimental results corroborate its superiority in terms of the lateral resolution at all imaging depths.

Purification and characterization of a second type thioredoxin peroxidase (type II TPx) from Saccharomyces cerevisiae

A yeast peroxidase that reduces H2O2 and alkyl hydroperoxides with the use of reducing equivalents provided by thioredoxin was identified previously and named thioredoxin peroxidase (TPx) [Chae, H. Z., Chung, S. J., and Rhee, S. G. (1994) J. Biol. Chem. 269, 27670-27678]. A second type thioredoxin-dependent peroxidase, named type II TPx, has now been purified from yeast, and several peptide sequences have been obtained. Using those sequences, the corresponding cDNA has been identified from the GenBank database. Comparison of the predicted sequence of 176 amino acids of type II TPx with that of the 195 residues of TPx, now renamed type I TPx, revealed no substantial homology except for a short segment preceding Cys62 of type II TPx. Kinetic characterization of the reactions catalyzed by type I and II TPxs revealed that type I preferentially reduces H2O2 rather than alkyl hydroperoxides, whereas type II shows the reverse specificity. Type II TPx contains three cysteine residues at positions 31, 62, and 120. Experiments with mutant proteins in which these three cysteine residues were replaced individually with serine suggest that Cys62-SH constitutes the site of oxidation by peroxides and that the oxidized Cys62 reacts with the Cys120-SH group of another type II TPx molecule to form an intermolecular disulfide linkage. The formed disulfide can then be reduced by thioredoxin, but not by glutathione. Thus, type II TPx mutants lacking Cys62 or Cys120 showed no detectable TPx activity, whereas mutation of Cys31 had no effect on TPx activity. An antioxidant function of type II TPx in intact cells was demonstrated by the observation that Escherichia coli cells overexpressing wild-type protein were less sensitive to inhibition of growth by alkyl hydroperoxides than were control cells or cells overexpressing the mutant protein lacking Cys62.