Adsorptive Elimination of a Cationic Dye and a Hg (II)-Containing Antiseptic from Simulated Wastewater Using a Metal Organic Framework

Several types of pollutants have acute adverse effects on living bodies, and the effective removal of these pollutants remains a challenge. Safranin O (a biological dye) and merbromin (a topical mercury-containing antiseptic) are considered organic pollutants, and there are only a few reports on their removal. Synthesized and well-characterized (through PXRD, FTIR, FESEM, and EDS analysis) MOF-5 was used for the first time in the removal of safranin O and merbromin from simulated wastewater and real wastewater. In both cases, MOF-5 effectively removed contaminants. We found that in simulated wastewater, the highest efficiency of removal of safranin O was 53.27% (for 15 mg/L) at pH 10, and for merbromin, it was 41.49% (for 25 mg/L) at pH 6. In the case of real wastewater containing natural ions (Na+, K+, F-, Cl-, SO42-, PO43-, Mg2+, and Ca2+) and other molecules, the removal efficiencies of these two dyes decreased (34.00% and 26.28% for safranin O and merbromin, respectively) because of the presence of other ions and molecules. A plausible mechanism for the removal of these pollutants using MOF-5 was proposed.

Tumor-homing peptide iRGD-conjugate enhances tumor accumulation of camptothecin for colon cancer therapy

Poor intracellular uptake of therapeutics in the tumor parenchyma is a key issue in cancer therapy. We describe a novel approach to enhance tumor targeting and achieve targeted delivery of camptothecin (CPT) based on a tumor-homing internalizing RGD peptide (iRGD). We synthesized an iRGD-camptothecin conjugate (iRGD-CPT) covalently coupled by a heterobifunctional linker and evaluated its in vitro and in vivo activity in human colon cancer cells. In vitro studies revealed that iRGD-CPT penetrated cells efficiently and reduced colon cancer cell viability to a significantly greater extent at micromolar concentrations than did the parent drug. Furthermore, iRGD-CPT showed high distribution toward tumor tissue, effectively suppressed tumor progression, and showed enhanced antitumor effects relative to the parent drug in a mouse model, demonstrating that iRGD-CPT is effective in vivo cancer treatment. These results suggest that intracellular delivery of CPT via the iRGD peptide is a promising drug delivery strategy that will facilitate the development of CPT derivatives and prodrugs with improved efficacy.

Engineered Polymer-siRNA Polyplexes Provide Effective Treatment of Lung Inflammation

Uncontrolled inflammation is responsible for acute and chronic diseases in the lung. Regulating expression of pro-inflammatory genes in pulmonary tissue using small interfering RNA (siRNA) is a promising approach to combatting respiratory diseases. However, siRNA therapeutics are generally hindered at the cellular level by endosomal entrapment of delivered cargo and at the organismal level by inefficient localization in pulmonary tissue. Here we report efficient anti-inflammatory activity in vitro and in vivo using polyplexes of siRNA and an engineered cationic polymer (PONI-Guan). PONI-Guan/siRNA polyplexes efficiently deliver siRNA cargo to the cytosol for highly efficient gene knockdown. Significantly, these polyplexes exhibit inherent targeting to inflamed lung tissue following intravenous administration in vivo. This strategy achieved effective (>70%) knockdown of gene expression in vitro and efficient (>80%) silencing of TNF-α expression in lipopolysaccharide (LPS)-challenged mice using a low (0.28 mg/kg) siRNA dosage.

A16 UNMET HEALTHCARE NEEDS AMONG PEOPLE WITH INFLAMMATORY BOWEL DISEASE: A NATIONAL CROSS-SECTIONAL POPULATION-REPRESENTATIVE STUDY

Background

Inflammatory bowel disease (IBD) is a chronic inflammatory disease primarily affecting the gastrointestinal tract. Despite treatment with the current standards of care, many IBD patients experience relapsing, remitting, and disabling bowel symptoms and significant disease complications. Ensuring patients have adequate access to high quality multidisciplinary healthcare is vital for the short- and long-term wellbeing of IBD patients.

Purpose

(1) Compare unmet healthcare needs of people with and without IBD. (2) Determine whether accessing regular medical care mediates the association between IBD and unmet healthcare needs. (3) Describe the reasons for unmet healthcare needs among people with and without IBD.

Method

We used the 2014 Canadian Community Health Survey, a population-representative national cross-sectional survey conducted by Statistics Canada. Respondents with a non-IBD bowel disorder or aged 18 or younger were excluded. Survey weights were used for descriptive statistics. We used multilevel logistic regression to compare perceived unmet healthcare needs among individuals with and without IBD, clustering by health region and controlling for age, immigration status, race, home ownership, marital status, annual household income, education level, and number of chronic conditions (0, 1, 2+). In a second model, we additionally controlled for having a regular family doctor, having consulted a specialist, and having consulted a psychologist to assess if regularly accessing medical care mediated the association between IBD and unmet healthcare needs. Individuals reporting unmet healthcare needs were asked about the reasons for their unmet healthcare needs. Responses are summarized with weighted percentages, plotted in a bar graph.

Result(s)

Among the 690 IBD and 62,832 non-IBD eligible survey respondents, 16.7% of people with IBD had an unmet healthcare need within the past 12 months, compared with 10.3% of those without IBD (OR 1.39, 95% CI 1.12 to 1.74). Additionally adjusting for regular access to medical care slightly attenuated the association between IBD and unmet healthcare needs (OR 1.29, 95% CI 1.03 to 1.62). Reasons for unmet healthcare needs differed among those with and without IBD (Figure). Specifically, doctors believing that care was unnecessary and the cost of care were more likely to be the reason people with IBD had an unmet healthcare need.

Image

Conclusion(s)

People with IBD are more likely to have an unmet healthcare need that was partially mediated by access to healthcare professionals. Our work highlights the need for further research into the types of unmet healthcare needs experienced by people living with IBD. This underscores the need for multidisciplinary healthcare teams to address the increased burden of unmet healthcare needs in the IBD population.

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None

Disclosure of Interest

G. Postill: None Declared, E. Benchimol Consultant of: Hoffman La-Roche Limited and Peabody & Arnold LLP for matters unrelated to medications used to treat inflammatory bowel disease. Dr. Benchimol has also acted as a consultant for McKesson Canada and the Dairy Farmers of Ontario for matters unrelated to medications used to treat inflammatory bowel disease., J. Im: None Declared, A. Tang: None Declared, E. Kuenzig: None Declared

A177 RISK OF VENOUS THROMBOEMBOLISM IN COVID-19 PATIENTS WITH INFLAMMATORY BOWEL DISEASE: A POPULATION-BASED MATCHED COHORT STUDY

Background

Venous thromboembolism (VTE), is associated with significant morbidity and mortality. Inflammation increases the risk of VTE, and it is a well-recognised complication of both inflammatory bowel disease (IBD) and COVID-19.

Purpose

To compare the risk of VTE among individuals with and without IBD following a positive COVID-19 test.

Method

Using health administrative data from Ontario, Canada we conducted a retrospective matched cohort study.All Ontario residents with a positive SARS-CoV-2 PCR test between January 1,2020 and December 30,2021 who had been diagnosed with IBD prior to their COVID-19 infection (identified using a validated algorithm) were matched to 5 individuals without IBD based on year of birth, sex, mean neighbourhood income quintile, date of positive COVID-19 test, and rural/urban residence. Individuals with a cancer diagnosis in the 5 years prior to their first COVID-19 positive test were excluded. Individuals were followed from positive COVID-19 PCR test until VTE event, death, migration out of Ontario or March 31, 2022.VTEs were identified from emergency department or hospitalization data using ICD-10 codes. Incidence rate of VTEs among individuals with IBD were assessed at 1, 6 and 12 months. Proportional cause-specific hazards models compared the risk of VTEs in people with and without IBD, treating death as a competing risk and controlling for vaccination status (2^nd dose ≥14 days prior to positive COVID-19 test) and a history of VTE (VTE in the 5 years prior to infection).

Result(s)

There were 4293 people with IBD (44% Crohn’s disease, mean age ±SD 46.1±17.2 y) matched to 20,207 with out IBD (mean age 45.3±16.8 y) with a positive SARS-CoV-2 PCR test. Within 1 month of a positive COVID-19 test, the crude incidence rate of VTE in individuals with IBD was 4.77(95%CI, 4.75-4.80) per 100,000 person-days compared to 8.25(95%CI, 8.20-8.30) per 100,000 among people without IBD.Within 6 months, these rates were 1.86(95%CI, 1.86-1.87) and 2.12(95%CI, 2.11-2.12) per 100,000 person-days among people with and without IBD, respectivley. Within 12 months, these rates were 1.59(95% CI, 1.58-1.59) and 1.42(95% CI, 1.42-1.42) per 100,000 person-days among people with and without IBD, respectively.After adjusting for vaccination status and history of VTE there was no difference in the risk of VTE for people with and without IBD (HR 1.08, 95%CI, 0.64 to 1.83).

Conclusion(s)

IBD patients with COVID-19 were not more likely to experience a VTE infection compared with the general popluation. The risk of VTE was highest soon after COVID-19 and declined thereafter.

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None

Disclosure of Interest

None Declared

Terminalia chebula: a novel natural product colorimetric sensor for Fe2+ and Fe3+ ions

Natural product like Terminalia chebula as Fe2+ and Fe3+ ions sensor was not reported in the literature till now. Herein, we first reported Terminalia chebula (T. chebula), a natural product used in Ayurveda, as a highly sensitive, simple, and cost-effective colorimetric sensor for the detection of Fe2+ and Fe3+ ions. Terminalia chebula showed a selective colorimetric sensing ability for iron (2+/3+) by changing color from green and pale yellow to blue, having limit of detection level of 43.7 μM and 60.8 μM for Fe2+ and Fe3+ ions, respectively. The concentration-dependent colorimetric determination of iron (2+/3+) was carried out, and the color change to distinguish between different concentrations was excellent. Using High Performance Liquid Chromatography, the fraction having sensing ability was isolated and purified. From the mass spectra of the purified fraction, it was concluded that, the major component responsible for the sensing ability was tri-O-galloyl-β-D-glucose. This chemosensor could be used to detect and quantify Fe2+ and Fe3+ in water samples, which is particularly a useful tool.

Mitochondria targeting molecular transporters: synthesis, lipophilic effect, and ionic complex

As mitochondria are potential therapeutic targeting sites for the treatment of human diseases, delivering cytotoxic drugs, antioxidants, and imaging molecules to mitochondria can provide new therapeutic opportunities. In an attempt to develop a new mitochondria-targeting vector, we synthesized sorbitol-based molecular transporters with multiple guanidines, measured their partition coefficients, compared their targeting efficiency using fluorescent images and Pearson's correlation coefficients, and studied cellular uptake mechanisms. To increase the targeting ability of these molecular transporters to mitochondria, alanine-naphthalene as a lipophilic group was attached to the molecular transporter, which improved translocation across cellular membranes and led to higher accumulation in mitochondria. The molecular transporter was able to form an ionic complex with antibiotics, resulting in low cell viability. These data demonstrate that the molecular transporter with a lipophilic group could be utilized as a potential drug delivery vector for treating mitochondrial dysfunction.

Nanomaterial-based bioorthogonal nanozymes for biological applications

Bioorthogonal transformations are chemical reactions that use pathways which biological processes do not access. Bioorthogonal chemistry provides new approaches for imaging and therapeutic strategies, as well as tools for fundamental biology. Bioorthogonal catalysis enables the development of bioorthogonal "factories" for on-demand and in situ generation of drugs and imaging tools. Transition metal catalysts (TMCs) are widely employed as bioorthogonal catalysts due to their high efficiency and versatility. The direct application of TMCs in living systems is challenging, however, due to their limited solubility, instability in biological media and toxicity. Incorporation of TMCs into nanomaterial scaffolds can be used to enhance aqueous solubility, improve long-term stability in biological environment and minimize cytotoxicity. These nanomaterial platforms can be engineered for biomedical applications, increasing cellular uptake, directing biodistribution, and enabling active targeting. This review summarizes strategies for incorporating TMCs into nanomaterial scaffolds, demonstrating the potential and challenges of moving bioorthogonal nanocatalysts and nanozymes toward the clinic.

Silver-Based Nanomaterials as Therapeutic Agents Against Coronaviruses: A Review

Since the identification of the first human coronavirus in the 1960s, a total of six coronaviruses that are known to affect humans have been identified: 229E, OC43, severe acute respiratory syndrome coronavirus (SARS-CoV), NL63, HKU1, and Middle East respiratory syndrome coronavirus (MERS-CoV). Presently, the human world is affected by a novel version of the coronavirus family known as SARS-CoV-2, which has an extremely high contagion rate. Although the infection fatality rate (IFR) of this rapidly spreading virus is not high (ranging from 0.00% to 1.54% across 51 different locations), the increasing number of infections and deaths has created a worldwide pandemic situation. To provide therapy to severely infected patients, instant therapeutic support is urgently needed and the repurposing of already approved drugs is presently in progress. In this regard, the development of nanoparticles as effective transporters for therapeutic drugs or as alternative medicines is highly encouraged and currently needed. The size range of the viruses is within 60-140 nm, which is slightly larger than the diameters of nanoparticles, making nanomaterials efficacious tools with antiviral properties. Silver-based nanomaterials (AgNMs) demonstrate antimicrobial and disinfectant effects mostly by generating reactive oxygen species (ROS) and are presently considered as a versatile tool for the treatment of COVID-19 patients. Other metal-based nanoparticles have been primarily reported as delivery agents or surface modifying agents, vaccine adjuvant against coronavirus. The present review summarizes and discusses the possible effectiveness of various surface-modified AgNMs against animal coronaviruses and presents a concept for AgNM-based therapeutic treatment of SARS-CoV-2 in the near future.

Highly stretchable superhydrophobic surface by silica nanoparticle embedded electrospun fibrous mat

HYPOTHESIS

Obtaining simultaneous stretchability and superhydrophobicity remains a great challenge in stretchable electronics, and wearable devices. Inspired by natural surfaces, such as lotus leaf, surface roughness and coating materials are the fundamental requirements to achieve superhydrophobicity.

EXPERIMENTS

We prepared an elastic fibrous mat by electrospinning of a composite solution made of thermoplastic elastomer as an organic polymer matrix, and silica nanoparticles as inorganic additives to support surface roughness. To enhance hydrophobicity, the pristine mat was immersed into a solution of fluorinated material, which can decrease the surface energy.

FINDINGS

The pristine fibrous mat showed high stretchability (with more than 1000% strain), and superhydrophobicity (with a contact angle of 156°, and a sliding angle of 7.8°). Superhydrophobicity did not disappear when the fibrous mat was stretched up to 1000%. Sliding angles were less than 10° under different strain levels only in longitudinal direction, suggesting the stretchable superhydrophobic surface is effective in rolling off the water droplet in one direction. The fibrous mat was repeatedly stretched 1000 times to 1000% strain; the material showed stable stretchability and superhydrophobicity. Based on these observations, the resulting fibrous mat appears to be in the Cassie-Baxter wetting state.

Versatility of cell-penetrating peptides for intracellular delivery of siRNA

The plasma membrane is a large barrier to systemic drug delivery into cells, and it limits the efficacy of drug cargo. This issue has been overcome using cell-penetrating peptides (CPPs). CPPs are short peptides (6-30 amino acid residues) that are potentially capable of intracellular penetration to deliver drug molecules. CPPs broadened biomedical applications and provide a means to deliver a range of biologically active molecules, such as small molecules, proteins, imaging agents, and pharmaceutical nanocarriers, across the plasma membrane with high efficacy and low toxicity. This review is focused on the versatility of CPPs and advanced approaches for siRNA delivery.

Identification of a new HLA-A*11 allele, A*11:251N

The new allele, A*11:251N, differs from A*11:01:01 by insertion of two nucleotides at position 204-205.

Identification of the novel HLA-B*15:18:01:04 in a Korean individual

HLA-B*15:18:01:04 differs from HLA-B*15:18:01:02 by single nucleotide substitution at position 2176 (G > A).

HLA-B*40:302, a novel allele identified by sequence-based typing in a Korean individual

B*40:302 differs from B*40:02:01:01 by a single nonsynonymous nucleotide substitution at codon 81 (CCG→CTG).

Identification of a novel allele, HLA-A*02:01:131, by full-length genomic sequencing

The HLA-A*02:01:131 allele differs by a single nucleotide at codon 236 compared with HLA-A*02:01:01:01.

HLA-DPB1*519:01, a new allele identified by sequence-based typing in a Korean individual

The new allele DPB1*519:01 showed one nucleotide difference with DPB1*13:01:01 at codon 234 (GTG/ATG).

Identification of a novel allele, HLA-C*02:02:33, by full-length genomic sequencing

The HLA-C*02:02:33 allele differs by a single nucleotide at codon 215 compared with HLA-C*02:02:02:01.

A novel allele, HLA-C*14:02:01:03, identified by full-length genomic sequencing

The HLA-C*14:02:01:03 differs by a single nucleotide at intron 5 (2157 C>T) compared with C*14:02:01:01.

Identification of a novel allele, HLA-C*01:135, by full-length genomic sequencing

The HLA-C*01:135 allele differs by a single nucleotide at codon 265 compared with HLA-C*01:02:01:01.

Oncogenic function of angiopoietin-2 in vitro and its modulation of tumor progression in colorectal carcinoma

Angiopoietin-2 (Ang-2) has been investigated in cancer primarily in terms of its angiogenic function, and its role as an oncogene has yet to be elucidated. The current study hypothesized that Ang-2 may be an oncogene and have a function in tumor progression. An investigation of the function of Ang-2 in the LoVo colorectal cancer (CRC) cell line in vitro, which expresses a high level of Ang-2, was performed by knocking down endogenous expression with a targeted short hairpin RNA. The aggressive phenotypic effects of Ang-2 on experimental and control group cells were assessed using cell proliferation, migration and invasion assays. The association between Ang-2 expression levels and clinicopathological factors was evaluated in 415 CRC tissues using immunohistochemistry. Suppressing Ang-2 expression decreased cellular proliferation, invasion and migration in an in vitro study. Ang-2 overexpression was observed in 46% of patients with CRC and was significantly associated with pT (P=0.048), pN (P<0.001), venous invasion (P=0.023), lymphatic invasion (P<0.001) and tumor-node-metastasis stage (P=0.022). Furthermore, Ang-2 overexpression was an independent prognostic factor in pN stages 1 and 2. These results reveal that Ang-2 may be an oncogene in colorectal carcinogenesis and its expression may exert aggressive phenotypic effects during tumor progression. In addition, Ang-2 expression may serve as a prognostic marker and a potential drug target.

Identification of a novel HLA-B allele, HLA-B*55:81

The new allele, B*55:81, differs from B*55:02:01:02 by 2 nucleotide substitutions in codon 116 (TTA → TAC).

Novel deletion mutation of HLA-B*40:02 gene in acquired aplastic anemia

Despite prevalence of clonal evolution in patients with aplastic anemia (AA), somatic mutation of human leukocyte antigen (HLA) gene is rarely reported. Herein, we reported a case of acquired AA (aAA) harboring a new four-base-pair deletion mutation within exon 4 of HLA-B*40:02 leading to frameshift and premature stop codon. The HLA-B*40:02 mutant allele was detected in the patient's peripheral blood sample not in patient's buccal epithelial cells. The patient received allogenic hematopoietic stem cell transplantation (HSCT) from HLA-matched sibling donor. On day 30 after HSCT, the mutant HLA allele was not detected by high-resolution sequence-based HLA typing. Serial chimerism analyses showed mixed chimeric status indicative of coexisting donor and recipient hematopoietic cells. Our data could provide additional support in view of pathophysiology of aAA that somatic mutation of HLA-B*40:02 allele is one of the possible origin of clonal escape to evade immune attack in patient with aAA.

Identification of a novel allele, HLA-A*26:01:01:03N, by full-length genome sequencing

The HLA-A*26:01:01:03N allele shows a single nucleotide difference compared with HLA-A*26:01:01:01 in intron 4(1846 G>A).

Large spin-orbit coupling and helical spin textures in 2D heterostructure [Pb2BiS3][AuTe2]

Two-dimensional heterostructures with strong spin-orbit coupling have direct relevance to topological quantum materials and potential applications in spin-orbitronics. In this work, we report on novel quantum phenomena in [Pb2BiS3][AuTe2], a new 2D strong spin-orbit coupling heterostructure system. Transport measurements reveal the spin-related carrier scattering is at odds with the Abrikosov-Gorkov model due to strong spin-orbit coupling. This is consistent with our band structure calculations which reveal a large spin-orbit coupling gap of εso = 0.21 eV. The band structure is also characterized by helical-like spin textures which are mainly induced by strong spin-orbit coupling and the inversion symmetry breaking in the heterostructure system.

Effects of dietary mixture of garlic (Allium sativum), coriander (Coriandrum sativum) and probiotics on immune responses and caecal counts in young laying hens

This study was conducted to evaluate the effects of a combined mixture of phytogenic extracts (garlic and coriander) and probiotics on growth performance and immune responses in laying hens based on the results of in vitro studies to screen for immunomodulatory potency of each ingredient. Several parameters of immunomodulatory potency were estimated using lamina propria leucocytes (LPLs) isolated from rat intestinal mucosa tissue. Results show that the combined mixture enhanced LPLs proliferation, increased LPL-mediated cytotoxicity against YAC-1 tumour cells, and decreased lipopolysaccharide (LPS)-induced cytokine production including tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in LPLs. For in vivo study, laying hens (n = 50/each diet group) were fed with control diet, a diet containing antibiotics (0.01% per kg feed) or the combined mixture (0.02% per kg feed) for 21 days. The dietary combined mixture improved egg production (p < 0.05) but not growth performance and carcass traits. Interestingly, the patterns of suppressing plasma IFN-γ productions during inflammation by LPS injection and decreasing caecal E. coli counts in the combined mixture group were comparable to those in the antibiotics group. Taken together, our results suggested that the 0.02% of combined mixture of phytogenic extracts and probiotics as ingredients has potential immunomodulatory effects in laying hens.

CLASSIFICATION OF CROPLANDS THROUGH FUSION OF OPTICAL AND SAR TIME SERIES DATA

Many satellite sensors including Landsat series have been extensively used for land cover classification. Studies have been conducted to mitigate classification problems associated with the use of single data (e.g., such as cloud contamination) through multi-sensor data fusion and the use of time series data. This study investigated two areas with different environment and climate conditions: one in South Korea and the other in US. Cropland classification was conducted by using multi-temporal Landsat 5, Radarsat-1 and digital elevation models (DEM) based on two machine learning approaches (i.e., random forest and support vector machines). Seven classification scenarios were examined and evaluated through accuracy assessment. Results show that SVM produced the best performance (overall accuracy of 93.87%) when using all temporal and spectral data as input variables. Normalized Difference Water Index (NDWI), SAR backscattering, and Normalized Difference Vegetation Index (NDVI) were identified as more contributing variables than the others for cropland classification.

RhoA is associated with invasion and poor prognosis in colorectal cancer

Colorectal cancer is one of the most common cancers and is the fourth leading cause of cancer death in Korea. Mortality of colorectal cancer is strongly associated with the metastatic spread of the disease. As such, it is important to find and characterize signaling pathways involved in colon cancer metastasis. We investigated the functional importance of RhoA using human cell lines as well as 150 colorectal cancer patient-derived samples as it remains unclear whether RhoA functions as either an oncogene or a tumor suppressor in colon cancer. RhoA was highly expressed in metastatic cancer cell lines. Although cancer cell proliferation was only moderately impaired after depletion of RhoA, RhoA-depleted cancer cells exhibited markedly reduced migration and invasion ability in vitro. Furthermore, we found that RhoA is associated with the invasion of lymph nodes and blood vessels in the patient colorectal cancer samples. Most notably, patients with higher RhoA expression had a significantly poorer 5-year survival rate after surgery. These results suggest that RhoA is a marker of poor prognosis in colorectal cancer and may be a promising target for cancer treatment.

Novel multi-layered 1-D nanostructure exhibiting the theoretical capacity of silicon for a super-enhanced lithium-ion battery

Silicon/carbon (Si/C) nanocomposites have recently received much attention as Li-ion battery negative electrodes due to their mutual synergetic effects in capacity and mechanical integrity. The contribution of Si to the total capacity of the Si/C nanocomposites determines their structural efficiency. Herein, we report on a multi-layered, one-dimensional nanostructure that exhibits the theoretical specific capacity of Si in the nanocomposite. Concentrically tri-layered, compartmentalized, C-core/Si-medium/C-shell nanofibers were fabricated by triple coaxial electrospinning. The pulverization of Si was accommodated inside the C-shell, whereas the conductive pathway of the Li-ions and electrons was provided by the C-core, which was proven by ex situ Raman spectroscopy. The compartmentalized Si in between the C-core and C-shell led to excellent specific capacity at a high current rate (>820 mA h g(-1) at 12000 mA g(-1)) and the realization of the theoretical specific capacity of the Li15Si4 phase of Si nanoparticles (3627 mA h g(-1)). The electrochemical characterization and inductively coupled plasma-atomic emission spectrometry provided direct evidence of full participation of Si in the electrochemical reactions.

Highly stretchable resistive pressure sensors using a conductive elastomeric composite on a micropyramid array

A stretchable resistive pressure sensor is achieved by coating a compressible substrate with a highly stretchable electrode. The substrate contains an array of microscale pyramidal features, and the electrode comprises a polymer composite. When the pressure-induced geometrical change experienced by the electrode is maximized at 40% elongation, a sensitivity of 10.3 kPa(-1) is achieved.

Micropatterned stretchable circuit and strain sensor fabricated by lithography on an electrospun nanofiber mat

This paper describes a novel approach for composite nanofiber mats and its application to fabricate a strain sensor. Electrospun poly(4-vinylpyridine) (P4VP) nanofiber mats are micropatterned by a lithographic approach that includes selective oxidation of the nanofibers and removal of unreacted fibers. The P4VP/HAuCl4 complex is converted to P4VP/Au composites by chemical reduction. We investigate the electrical resistivity of the composite mats according to the number of complexation-and-reduction cycles, the thickness of the fiber mats, and the annealing temperatures which control the percolation of the Au nanoparticles in the fiber mats. Nozzle printing of a polymeric solution on the patterned nanofiber mats simply produces an array of strain-sensitive and strain-invariant units. The patterns demonstrate high strain-sensing performance without any mechanical and electrical failure over 200 bending cycles in the strain range of ε<0.17.

Highly stretchable electric circuits from a composite material of silver nanoparticles and elastomeric fibres

Conductive electrodes and electric circuits that can remain active and electrically stable under large mechanical deformations are highly desirable for applications such as flexible displays, field-effect transistors, energy-related devices, smart clothing and actuators. However, high conductivity and stretchability seem to be mutually exclusive parameters. The most promising solution to this problem has been to use one-dimensional nanostructures such as carbon nanotubes and metal nanowires coated on a stretchable fabric, metal stripes with a wavy geometry, composite elastomers embedding conductive fillers and interpenetrating networks of a liquid metal and rubber. At present, the conductivity values at large strains remain too low to satisfy requirements for practical applications. Moreover, the ability to make arbitrary patterns over large areas is also desirable. Here, we introduce a conductive composite mat of silver nanoparticles and rubber fibres that allows the formation of highly stretchable circuits through a fabrication process that is compatible with any substrate and scalable for large-area applications. A silver nanoparticle precursor is absorbed in electrospun poly (styrene-block-butadiene-block-styrene) (SBS) rubber fibres and then converted into silver nanoparticles directly in the fibre mat. Percolation of the silver nanoparticles inside the fibres leads to a high bulk conductivity, which is preserved at large deformations (σ ≈ 2,200 S cm(-1) at 100% strain for a 150-µm-thick mat). We design electric circuits directly on the electrospun fibre mat by nozzle printing, inkjet printing and spray printing of the precursor solution and fabricate a highly stretchable antenna, a strain sensor and a highly stretchable light-emitting diode as examples of applications.

Atomic and electronic structures of amorphous Ge(2)Sb(2)Te(5); melt-quenched versus ideal glasses

To investigate an amorphous structure of Ge(2)Sb(2)Te(5) that satisfies the 8-N rule (so-called 'ideal glass'), we perform alternative melt-quench simulations on Si(2)As(2)Se(5) and replace atoms in the final structure with Ge-Sb-Te. The resulting structures have salient features of the 8-N rule such as the tetrahedral configuration for all Ge atoms and the localized Te lone pairs at the valence top. In addition, the average Ge-Te and Sb-Te distances are in good agreement with experiment. The energetic stability of the ideal glass supports the existence of this amorphous structure that is distinct from the melt-quenched glass. From the analysis of electronic structures and optical dielectric constants, it is concluded that the electronic character of the melt-quenched amorphous Ge(2)Sb(2)Te(5) lies in between the resonant p-bonding of the crystalline phase and the covalent bonding of the ideal glass.