Enhanced oxidation resistance and electrical conductivity copper nanowires–graphene hybrid films for flexible strain sensors

Enhanced oxidation resistance and electrical conductivity copper nanowires–graphene hybrid films were fabricated and which exhibited high sensitivity as flexible strain sensors to monitor human motions.

A novel h-BN–RGO hybrids for epoxy resin composites achieving enhanced high thermal conductivity and energy density

In recent decades, significant attention has been focused on developing composite materials with high thermal conductivity utilizing h-BN, which has outstanding thermal conductivity.

Energy level systems and transitions of Ho:LuAG laser resonantly pumped by a narrow line-width Tm fiber laser

We presented a Ho:LuAG ceramic laser in-band pumped by a narrow emission line-width Tm fiber laser at 1907 nm. All of potential transitions between 5I7 and 5I8 manifold were discussed to form the Ho's in-band-pump energy level systems, which were not described in details earlier. For the emission band centered at ~2095 nm, both laser absorption and emission transition separately consisted of two groups were first analyzed and observed. Using output couplers (OCs) with different transmittances (T = 6, 10 and 20%), the similar ~0.5 W continuous-wave (CW) output power under an incident pump power of ~4.9 W was obtained, with twin (or triplet) emission bands respectively. The blue shift of center emission wavelengths was observed with the increase of transmittances.

Room temperature housing results in premature cancellous bone loss in growing female mice: implications for the mouse as a preclinical model for age-related bone loss

Room temperature housing (22 °C) results in premature cancellous bone loss in female mice. The bone loss was prevented by housing mice at thermoneutral temperature (32 °C). Thermogenesis differs markedly between mice and humans and mild cold stress induced by standard room temperature housing may introduce an unrecognized confounding variable into preclinical studies.

INTRODUCTION

Female mice are often used as preclinical models for osteoporosis but, in contrast to humans, mice exhibit cancellous bone loss during growth. Mice are routinely housed at room temperature (18-23 °C), a strategy that exaggerates physiological differences in thermoregulation between mice (obligatory daily heterotherms) and humans (homeotherms). The purpose of this investigation was to assess whether housing female mice at thermoneutral (temperature range where the basal rate of energy production is at equilibrium with heat loss) alters bone growth, turnover and microarchitecture.

METHODS

Growing (4-week-old) female C57BL/6J and C3H/HeJ mice were housed at either 22 or 32 °C for up to 18 weeks.

RESULTS

C57BL/6J mice housed at 22 °C experienced a 62 % cancellous bone loss from the distal femur metaphysis during the interval from 8 to 18 weeks of age and lesser bone loss from the distal femur epiphysis, whereas cancellous and cortical bone mass in 32 °C-housed mice were unchanged or increased. The impact of thermoneutral housing on cancellous bone was not limited to C57BL/6J mice as C3H/HeJ mice exhibited a similar skeletal response. The beneficial effects of thermoneutral housing on cancellous bone were associated with decreased Ucp1 gene expression in brown adipose tissue, increased bone marrow adiposity, higher rates of bone formation, higher expression levels of osteogenic genes and locally decreased bone resorption.

CONCLUSIONS

Housing female mice at 22 °C resulted in premature cancellous bone loss. Failure to account for species differences in thermoregulation may seriously confound interpretation of studies utilizing mice as preclinical models for osteoporosis.

1D Ni-Co oxide and sulfide nanoarray/carbon aerogel hybrid nanostructures for asymmetric supercapacitors with high energy density and excellent cycling stability

The fabrication of supercapacitor electrodes with high energy density and excellent cycling stability is still a great challenge. A carbon aerogel, possessing a hierarchical porous structure, high specific surface area and electrical conductivity, is an ideal backbone to support transition metal oxides and bring hope to prepare electrodes with high energy density and excellent cycling stability. Therefore, NiCo₂S₄ nanotube array/carbon aerogel and NiCo₂O₄ nanoneedle array/carbon aerogel hybrid supercapacitor electrode materials were synthesized by assembling Ni-Co precursor needle arrays on the surface of the channel walls of hierarchical porous carbon aerogels derived from chitosan in this study. The 1D nanostructures grow on the channel surface of the carbon aerogel vertically and tightly, contributing to the enhanced electrochemical performance with ultrahigh energy density. The energy density of NiCo₂S₄ nanotube array/carbon aerogel and NiCo₂O₄ nanoneedle array/carbon aerogel hybrid asymmetric supercapacitors can reach up to 55.3 Wh kg^-1 and 47.5 Wh kg^-1 at a power density of 400 W kg^-1, respectively. These asymmetric devices also displayed excellent cycling stability with a capacitance retention of about 96.6% and 92% over 5000 cycles.

High-Strength, Tough, Fatigue Resistant, and Self-Healing Hydrogel Based on Dual Physically Cross-Linked Network

Hydrogels usually suffer from low mechanical strength, which largely limit their application in many fields. In this Research Article, we prepared a dual physically cross-linked hydrogel composed of poly(acrylamide-co-acrylic acid) (PAM-co-PAA) and poly(vinyl alcohol) (PVA) by simple two-steps methods of copolymerization and freezing/thawing. The hydrogen bond-associated entanglement of copolymer chains formed as cross-linking points to construct the first network. After being subjected to the freezing/thawing treatment, PVA crystalline domains were formed to serve as knots of the second network. The hydrogels were demonstrated to integrate strength and toughness (1230 ± 90 kPa and 1250 ± 50 kJ/m(3)) by the introduction of second physically cross-linked network. What̀s more, the hydrogels exhibited rapid recovery, excellent fatigue resistance, and self-healing property. The dynamic property of the dual physically cross-linked network contributes to the excellent energy dissipation and self-healing property. Therefore, this work provides a new route to understand the toughness mechanism of dual physically cross-linked hydrogels, hopefully promoting current hydrogel research and expanding their applications.

Mechanical Chameleon through Dynamic Real-Time Plasmonic Tuning

The development of camouflage methods, often through a general resemblance to the background, has recently become a subject of intense research. However, an artificial, active camouflage that provides fast response to color change in the full-visible range for rapid background matching remains a daunting challenge. To this end, we report a method, based on the combination of bimetallic nanodot arrays and electrochemical bias, to allow for plasmonic modulation. Importantly, our approach permits real-time light manipulation readily matchable to the color setting in a given environment. We utilize this capability to fabricate a biomimetic mechanical chameleon and an active matrix display with dynamic color rendering covering almost the entire visible region.

Low cost, high performance flexible asymmetric supercapacitor based on modified filter paper and an ultra-fast packaging technique

A low cost, high performance flexible PF–RGO//PF–RGO–PANI asymmetric supercapacitor based on modified filter paper is reported together with an ultra-fast and layer by layer packaging technique.

Boron nitride@graphene oxide hybrids for epoxy composites with enhanced thermal conductivity

Boron nitride/graphene oxide hybrids prepared by an electrostatic self-assembly strategy were used as fillers for epoxy composites with high thermal conductivity.

Diabetes telemonitoring reduces the risk of hypoglycaemia during Ramadan: a pilot randomized controlled study

AIM

This pilot study evaluated the short-term benefits of a telemonitoring-supplemented focused diabetic education compared with education alone in participants with Type 2 diabetes who were fasting during Ramadan.

METHODS

In this pilot mixed-method study, we identified 37 participants and randomly allocated them to either a telemonitoring group (n = 18) or a group receiving Ramadan-focused pre-education only (usual care; n = 19). The telemonitoring group received goal-setting and personalized feedback.

RESULTS

The telemonitoring group was less likely to experience hypoglycaemia than the usual care group (odds ratio: 0.1273; 95% confidence interval: 0.0267-0.6059). No significant differences were noted in glycaemic control at the end of study. Participants viewed telemedicine as a more convenient alternative although technological barriers remain a concern.

CONCLUSIONS

The results of this study reinforce the need for monitoring as well as educational initiatives for Muslims with diabetes who fast during Ramadan. Telemonitoring offers an attractive option requiring further research. (Clinical Trial Registry No. NCT02189135).

The hybrid nanostructure of MnCo2O4.5 nanoneedle/carbon aerogel for symmetric supercapacitors with high energy density

Current applications of carbon-based supercapacitors are limited by their low energy density. One promising strategy to enhance the energy density is to couple metal oxides with carbon materials. In this study, a porous MnCo2O4.5 nanoneedle/carbon aerogel hybrid nanostructure was synthesized by assembling MnCo2O4.5 nanoneedle arrays on the surface of channel walls of hierarchical porous carbon aerogels derived from chitosan for the supercapacitor application. The synthetic process of the hybrid nanostructure involves two steps, i.e. the growth of Mn-Co precursors on carbon aerogel by a hydrothermal process and the conversion of the precursor into MnCo2O4.5 nanoneedles by calcination. The carbon aerogel exhibits a high electrical conductivity, high specific surface area and porous structure, ensuring high electrochemical performance of the hybrid nanostructure when coupled with the porous MnCo2O4.5 nanoneedles. The symmetric supercapacitor using the MnCo2O4.5 nanoneedle/carbon aerogel hybrid nanostructure as the active electrode material exhibits a high energy density of about 84.3 Wh kg(-1) at a power density of 600 W kg(-1). The voltage window is as high as 1.5 V in neutral aqueous electrolytes. Due to the unique nanostructure of the electrodes, the capacitance retention reaches 86% over 5000 cycles.

One-pot synthesis of bimodal silica nanospheres and their effects on the rheological and thermal–mechanical properties of silica–epoxy composites

Bimodal silica nanospheres were prepared in one pot and were used as reinforcement fillers to modify epoxy resins.

Hierarchical porous carbon aerogel derived from bagasse for high performance supercapacitor electrode

Renewable, cost-effective and eco-friendly electrode materials have attracted much attention in the energy conversion and storage fields. Bagasse, the waste product from sugarcane that mainly contains cellulose derivatives, can be a promising candidate to manufacture supercapacitor electrode materials. This study demonstrates the fabrication and characterization of highly porous carbon aerogels by using bagasse as a raw material. Macro and mesoporous carbon was first prepared by carbonizing the freeze-dried bagasse aerogel; consequently, microporous structure was created on the walls of the mesoporous carbon by chemical activation. Interestingly, it was observed that the specific surface area, the pore size and distribution of the hierarchical porous carbon were affected by the activation temperature. In order to evaluate the ability of the hierarchical porous carbon towards the supercapacitor electrode performance, solid state symmetric supercapacitors were assembled, and a comparable high specific capacitance of 142.1 F g(-1) at a discharge current density of 0.5 A g(-1) was demonstrated. The fabricated solid state supercapacitor displayed excellent capacitance retention of 93.9% over 5000 cycles. The high energy storage ability of the hierarchical porous carbon was attributed to the specially designed pore structures, i.e., co-existence of the micropores and mesopores. This research has demonstrated that utilization of sustainable biopolymers as the raw materials for high performance supercapacitor electrode materials is an effective way to fabricate low-cost energy storage devices.

Low-voltage graphene field-effect transistors based on octadecylphosphonic acid modified solution-processed high-k dielectrics

In this study, a solution-processed bilayer high-k dielectric (Al2O(y)/TiO(x), abbrev. as ATO) was used to realize the low-voltage operation of graphene field-effect transistors (GFETs), in which the graphene was grown by atmospheric pressure chemical vapor deposition (APCVD). Upon modifying the interface between graphene and the dielectric by octadecylphosphonic acid (ODPA), outstanding room-temperature hole mobility up to 5805 cm(2) V(-1) s(-1) and electron mobility of 3232 cm(2) V(-1) s(-1) were obtained in a small gate voltage range from -3.0 V to 3.0 V under a vacuum. Meanwhile, an excellent on/off current ratio of about 8 was achieved. Our studies demonstrate an effective route in which utilizing the low-temperature solution-processed dielectrics can achieve low-voltage and high performance GFETs.

Crack-free and scalable transfer of carbon nanotube arrays into flexible and highly thermal conductive composite film

Carbon nanotube (CNT) arrays show great promise in developing anisotropic thermal conductive composites for efficiently dissipating heat from high-power devices along thickness direction. However, CNT arrays are always grown on some substrates and liable to be deformed and broken into pieces during transfer and solution treatment. In the present study, we intentionally synthesized well-crystallized and large-diameter (~80 nm) multiwalled CNT (MWCNT) arrays by floating catalyst chemical vapor deposition (FCCVD) method. Such arrays provided high packing density and robust structure from collapse and crack formation during post solution treatment and therefore favored to maintain original thermal and electrical conductive paths. Under optimized condition, the CNT arrays can be transferred into flexible composite films. Furthermore, the composite film also exhibited excellent thermal conductivity at 8.2 W/(m·K) along thickness direction. Such robust, flexible, and highly thermal conductive composite film may enable some prospective applications in advanced thermal management.

Facile preparation of monodisperse, impurity-free, and antioxidation copper nanoparticles on a large scale for application in conductive ink

Monodisperse copper nanoparticles with high purity and antioxidation properties are synthesized quickly (only 5 min) on a large scale (multigram amounts) by a modified polyol process using slightly soluble Cu(OH)2 as the precursor, L-ascorbic acid as the reductant, and PEG-2000 as the protectant. The resulting copper nanoparticles have a size distribution of 135 ± 30 nm and do not suffer significant oxidation even after being stored for 30 days under ambient conditions. The copper nanoparticles can be well-dispersed in an oil-based ink, which can be silk-screen printed onto flexible substrates and then converted into conductive patterns after heat treatment. An optimal electrical resistivity of 15.8 μΩ cm is achieved, which is only 10 times larger than that of bulk copper. The synthesized copper nanoparticles could be considered as a cheap and effective material for printed electronics.

Development of an automated model to predict the risk of elderly emergency medical admissions within a month following an index hospital visit: A Hong Kong experience

Objectives:

To develop an automated risk prediction model to identify elderly patients at high risk of emergency admission to medical wards within 28 days following an index hospital visit.

Methods:

A retrospective data analysis of 41 hospitals and 48 specialist outpatient clinics in Hong Kong. The study subjects were elderly patients aged 65 years or above, who had index hospital visit(s) in the year of 2005, which included hospitalizations at medical wards and attendances at the accident and emergency departments or specialist outpatient clinics for medical conditions. Multiple logistic regression was used to estimate the risk of emergency medical admission in 28 days after an index hospital visit. Model validation was performed against the complete cohort in 2006.

Results:

Over a million of episodes were included in the derivation cohort. A total of 14 predictor variables included patient socio-demographics, service utilization in the previous year, presence and number of chronic diseases and type of index episode. The model has a good discriminative ability with the area under receiver-operating characteristic curve at 0.819 and 0.824 for the derivation and validation cohorts, respectively. The model has a sensitivity of 70.3 per cent, specificity of 78.4 per cent, positive predictive value of 21.7 per cent and negative predictive value of 96.9 per cent.

Conclusion:

This simple, accurate and objective risk prediction model has been computerized into an automated screening tool to recruit high-risk elderly patients discharged from all public hospitals in Hong Kong into the Community Health Call Centre service with an aim to prevent avoidable hospitalizations.

Magnetic alignment of hexagonal boron nitride platelets in polymer matrix: toward high performance anisotropic polymer composites for electronic encapsulation

We report magnetic alignment of hexagonal boron nitride (hBN) platelets and the outstanding material properties of its polymer composite. The magnetically responsive hBN is produced by surface modification of iron oxide, and their orientations can be controlled by applying an external magnetic field during polymer curing. Owing to the anisotropic properties of hBN, the epoxy composite with aligned hBN platelets shows interesting properties along the alignment direction, including significantly reduced coefficient of thermal expansion, reaching ∼28.7 ppm/°C, and enhanced thermal conductivity, 104% higher than that of unaligned counterpart, both of which are observed at a low filler loading of 20 wt %. Our modeling suggests the filler alignment is the major reason for these intriguing material properties. Finite element analysis reveals promising applications for the magnetically aligned hBN-based composites in modern microelectronic packaging.

Laparoscopic Heller's cardiomyotomy achieved lesser recurrent dysphagia with better quality of life when compared with endoscopic balloon dilatation for treatment of achalasia

Achalasia is a rare primary motility disorder of esophagus; treatments include endoscopic balloon dilatation (EBD) and laparoscopic Heller's cardiomyotomy (LC). This study compared EBD versus LC for treatment of achalasia with focus on quality of life (QoL) and prevalence of post-treatment gastroesophageal reflux disease. This was a retrospective cohort study of all patients diagnosed with achalasia older than 16 treated with either EBD or LC from January 1998 to April 2008. Patients' demographic data, comorbidities, postintervention GERD symptoms, QoL, recurrence of dysphagia, reintervention rate, hospital stay, and time to resumption of diet were collected. Sixty-eight patients were recruited into the study (EBD n= 50; LC n= 18). A significant improvement in QoL was found in patients undergoing LC (0.917 vs. 0.807, P= 0.006). A higher proportion of patients treated with EBD developed post-treatment gastroesophageal reflux symptoms (60.5% vs. 43.8%) when compared with LC, although statistically insignificant (P= 0.34). Patients treated with balloon dilatation had a greater percentage of recurrence of dysphagia (55.1% vs. 26.7%; P= 0.235) and need of reintervention (42.1% vs. 9.1%; P= 0.045). However, these patients had a shorter median hospital stay (1d [range 0-4]) and earlier resumption of diet (0d [range 0-3]). Although EBD is associated with a quicker perioperative recovery, LC accomplished a better QoL, lower incidence of recurrence of dysphagia, and need of reintervention after treatment for achalasia.

Reversible superhydrophobic-superhydrophilic transition of ZnO nanorod/epoxy composite films

Tuning the surface wettability is of great interest for both scientific research and practical applications. We demonstrated reversible transition between superhydrophobicity and superhydrophilicity on a ZnO nanorod/epoxy composite film. The epoxy resin serves as an adhesion and stress relief layer. The ZnO nanorods were exposed after oxygen reactive ion etching of the epoxy matrix. A subsequent chemcial treatment with fluoroalkyl and alkyl silanes resulted in a superhydrophobic surface with a water contact angle up to 158.4° and a hysteresis as low as 1.3°. Under UV irradiation, the water contact angle decreased gradually, and the surface eventually became superhydrophilic because of UV induced decomposition of alkyl silanes and hydroxyl absorption on ZnO surfaces. A reversible transition of surface wettability was realized by alternation of UV illumination and surface treatment. Such ZnO nanocomposite surface also showed improved mechanical robustness.

A combined etching process toward robust superhydrophobic SiC surfaces

Large-scale porous SiC was fabricated by a combination of Pt-assisted etching and reactive ion etching. It was found that the surface roughness of combined etchings increased dramatically in comparison with metal-assisted etching or reactive ion etching only. To reduce the surface energy, the porous SiC surface was functionalized with perfluorooctyl trichlorosilane, resulting in a superhydrophobic SiC surface with a contact angle of 169.2° and a hysteresis of 2.4°. The superhydrophobicity of the SiC surface showed a good long-term stability in an 85 °C/85% humidity chamber. Such superhydrophobicity was also stable in acidic or basic solutions, and the pH values showed little or no effect on the SiC surface status. In addition, enhancement of porosity-induced photoluminescence intensity was found in the superhydrophobic SiC samples. The robust superhydrophobic SiC surfaces may have a great potential for microfluid device, thermal ground plane, and biosensor applications.

The fabrication of vertically aligned and periodically distributed carbon nanotube bundles and periodically porous carbon nanotube films through a combination of laser interference ablation and metal-catalyzed chemical vapor deposition

Scalable fabrication of carbon nanotube (CNT) bundles is essential to future advances in several applications. Here, we report on the development of a simple, two-step method for fabricating vertically aligned and periodically distributed CNT bundles and periodically porous CNT films at the sub-micron scale. The method involves laser interference ablation (LIA) of an iron film followed by CNT growth via iron-catalyzed chemical vapor deposition. CNT bundles with square widths ranging from 0.5 to 1.5 µm in width, and 50-200 µm in length, are grown atop the patterned catalyst over areas spanning 8 cm(2). The CNT bundles exhibit a high degree of control over square width, orientation, uniformity, and periodicity. This simple scalable method of producing well-placed and oriented CNT bundles demonstrates a high application potential for wafer-scale integration of CNT structures into various device applications, including IC interconnects, field emitters, sensors, batteries, and optoelectronics, etc.

Validation study of the Chinese Identification Pain Questionnaire for neuropathic pain

OBJECTIVES

For diagnosing neuropathic pain, a simple 6-item patient-completed identification pain questionnaire has been validated among Caucasians. We aimed to study the validity and reliability of this questionnaire among Hong Kong Chinese patients.

DESIGN

Questionnaire survey.

SETTING

Two pain clinics and two neurology clinics in Hong Kong.

PATIENTS

Patients with either neuropathic pain or nociceptive pain were recruited randomly from the four clinics. The patients completed the questionnaire themselves and the diagnosis of neuropathic pain and nociceptive pain was made by the pain specialists. We determined the optimal cutoff, positive and negative predictive values, sensitivity, specificity, the area under the receiver operating characteristic curve, and test-retest reliability of the translated version.

RESULTS

Among the 92 participants, 60 (65%) had neuropathic pain and 32 (35%) had nociceptive pain. At an optimal cutoff score of 3 or higher, the positive predictive value was 87% while the negative predictive value was 55%, and it correctly classified 71% of cases. The specificity and sensitivity were 81% and 65%, respectively. The area under the curve was 0.78 (P<0.001). Test-retest reliability in the 10 randomly selected patients showed a good intraclass correlation of 0.72.

CONCLUSION

The Chinese Identification Pain Questionnaire is a valid and reliable scale that may be used as an initial diagnostic tool for neuropathic pain among Hong Kong Chinese patients.

Survey on medical records and EHR in Asia-Pacific region: languages, purposes, IDs and regulations

OBJECTIVES

To clarify health record background information in the Asia-Pacific region, for planning and evaluation of medical information systems.

METHODS

The survey was carried out in the summer of 2009. Of the 14 APAMI (Asia-Pacific Association for Medical Informatics) delegates 12 responded which were Australia, China, Hong Kong, India, Indonesia, Japan, Korea, New Zealand, the Philippines, Singapore, Thailand, and Taiwan.

RESULTS

English is used for records and education in Australia, Hong Kong, India, New Zealand, the Philippines, Singapore and Taiwan. Most of the countries/regions are British Commonwealth. Nine out of 12 delegates responded that the second purpose of medical records was for the billing of medical services. Seven out of nine responders to this question answered that the second purpose of EHR (Electronic Health Records) was healthcare cost cutting. In Singapore, a versatile resident ID is used which can be applied to a variety of uses. Seven other regions have resident IDs which are used for a varying range of purposes. Regarding healthcare ID, resident ID is simply used as healthcare ID in Hong Kong, Singapore and Thailand. In most cases, disclosure of medical data with patient's name identified is allowed only for the purpose of disease control within a legal framework and for disclosure to the patient and referred doctors. Secondary use of medical information with the patient's identification anonymized is usually allowed in particular cases for specific purposes.

CONCLUSION

This survey on the health record background information has yielded the above mentioned results. This information contributes to the planning and evaluation of medical information systems in the Asia-Pacific region.

Lack of association of ABCB1 and PXR polymorphisms with response to treatment in epilepsy

It is proposed that overexpression of P-glycoprotein (P-gp), encoded by the ABC subfamily B member 1 (ABCB1) gene, is involved in resistance to antiepileptic drugs (AEDs) in about 30% of patients with epilepsy. Genetic variation and haplotype patterns are population specific which may cause different phenotypes such as response to AEDs. Although several studies examined the link between the common polymorphisms in the ABCB1 gene with resistance to AEDs, the results have been conflicting. This controversy may be caused by the effect of some confounders such as ethnicity and polytherapy. Moreover, expression of the ABCB1 gene is under the control of pregnane X receptor (PXR). Evidence showed that PXR gene contribute to the response to treatment. The aim of this study was to assess the association of ABCB1 and PXR genetic polymorphisms with response to the carbamazepine (CBZ) or sodium valproate (VPA) monotherapy in epilepsy. Genotypes were assessed in 685 Chinese, Indian, and Malay epilepsy patients for ABCB1 (C1236T, G2677T, C3435T) and PXR (G7635A) polymorphisms. No association between these polymorphisms and their haplotypes, and interaction between them, with response to treatment was observed in the overall group or in the Chinese, Indian, and Malay subgroups. Our data showed that these polymorphisms may not contribute to the response to CBZ or VPA monotherapy treatment in epilepsy.

Facile fabrication of superhydrophobic octadecylamine-functionalized graphite oxide film

We demonstrated a facile strategy of producing superhydrophobic octadecylamine (ODA)-functionalized graphite oxide (GO) films. ODA was chemically grafted on GO sheets by the nucleophilic substitution reaction of amine groups with epoxy groups. The long hydrocarbon chain in ODA reduces the surface energy of the GO sheet. The fabricated ODA-functionalized GO film exhibited a high contact angle (163.2°) and low hysteresis (3.1°). This method is promising in terms of low-cost and large-scale superhydrophobic coatings and has potential applications for surface modification of GO paper or other GO-based composite materials.

Fast preparation of printable highly conductive polymer nanocomposites by thermal decomposition of silver carboxylate and sintering of silver nanoparticles

We show the fast preparation of printable highly conductive polymer nanocomposites for future low-cost electronics. Highly conductive polymer nanocomposites, consisting of an epoxy resin, silver flakes, and incorporated silver nanoparticles, have been prepared by fast sintering between silver flakes and the incorporated silver nanoparticles. The fast sintering is attributed to: 1) the thermal decomposition of silver carboxylate-which is present on the surface of the incorporated silver flakes-to form in situ highly reactive silver nanoparticles; 2) the surface activation of the incorporated silver nanoparticles by the removal of surface residues. As a result, polymer nanocomposites prepared at 230 °C for 5 min, at 260 °C for 10 min, and using a typical lead-free solder reflow process show electrical resistivities of 8.1×10(-5), 6.0×10(-6), and 6.3×10(-5) Ω cm, respectively. The correlation between the rheological properties of the adhesive paste and the noncontact printing process has been discussed. With the optimal rheological properties, the formulated highly viscous pastes (221 mPa s at 2500 s(-1)) can be non-contact-printed into dot arrays with a radius of 130 μm. The noncontact printable polymer nanocomposites with superior electrical conductivity and fast processing are promising for the future of printed electronics.

Silicon surface structure-controlled oleophobicity

Superoleophobic surfaces display contact angles >150 degrees with liquids that have lower surface energies than does water. The design of superoleophobic surfaces requires an understanding of the effect of the geometrical shape of etched silicon surfaces on the contact angle and hysteresis observed when different liquids are brought into contact with these surfaces. This study used liquid-based metal-assisted etching and various silane treatments to create superoleophobic surfaces on a Si(111) surface. Etch conditions such as the etch time and etch solution concentration played critical roles in establishing the oleophobicity of Si(111). When compared to Young's contact angle, the apparent contact angle showed a transition from a Cassie to a Wenzel state for low-surface-energy liquids as different silane treatments were applied to the silicon surface. These results demonstrated the relationship between the re-entrant angle of etched surface structures and the contact angle transition between Cassie and Wenzel behavior on etched Si(111) surfaces.

Mechanically robust superhydrophobicity on hierarchically structured Si surfaces

Improvement of the robustness of superhydrophobic surfaces is critical in order to achieve commercial applications of these surfaces in such diverse areas as self-cleaning, water repellency and corrosion resistance. In this study, the mechanical robustness of superhydrophobic surfaces was evaluated on hierarchically structured silicon surfaces. The effect of two-scale hierarchical structures on robustness was investigated using an abrasion test and the results compared to those of superhydrophobic surfaces fabricated from polymeric materials and from silicon that contains only nanostructures. Unlike the polymeric and nanostructure-only surfaces, the hierarchical structures retained superhydrophobic behavior after mechanical abrasion.

Superhydrophobic and low light reflectivity silicon surfaces fabricated by hierarchical etching

Silicon is employed in a variety of electronic and optical devices such as integrated circuits, photovoltaics, sensors, and detectors. In this paper, Au-assisted etching of silicon has been used to prepare superhydrophobic surfaces that may add unique properties to such devices. Surfaces were characterized by contact angle and contact angle hysteresis. Superhydrophobic surfaces with reduced hysteresis were prepared by Au-assisted etching of pyramid-structured silicon surfaces to generate hierarchical surfaces. Consideration of the Laplace pressure on hydrophobized hierarchical surfaces gives insight into the manner by which contact is established at the liquid/composite surface interface. Light reflectivity from the etched surfaces was also investigated to assess application of these structures to photovoltaic devices.

Iatrogenic Tako-Tsubo cardiomyopathy

We report a rare case of Tako-Tsubo cardiomyopathy developed after excision of left atrial myxoma and adrenaline infusion given for blood pressure augmentation in a 56-year-old lady. Although the risk for developing Tako-Tsubo cardiomyopathy associated with adrenaline use has not been established, caution is still warranted.

Hierarchical silicon etched structures for controlled hydrophobicity/superhydrophobicity

Silicon surface hydrophobicity has been varied by using silane treatments on silicon pyramid surfaces generated by KOH anisotropic etching. Results demonstrated that by altering the surface hydrophobicity, the apparent contact angle changed in accord with the Wenzel equation for surface structures with inclined side walls. Hierarchical structures were also constructed from Si pyramids where nanostructures were added by Au-assisted electroless HF/H2O2 etching. Surface hydrophobicity and superhydrophobicity were achieved by surface modification with a variety of silanes. Stability of the Cassie state of superhydrophobicity is described with respect to the Laplace pressure as indicated by the water droplet meniscus in contact with the hierarchical structures. The contact angle hysteresis observed is also discussed with respect to water/substrate adhesion.