Bioinspired hydrogel-based nanofluidic ionic diodes: nano-confined network tuning and ion transport regulation

Biological ion channel-based mass transport and signal transduction play a crucial role in physiological activities, and biomimetic nanochannels in aqueous solutions for ion transport regulation have been extensively studied. Few studies on non-aqueous systems, gel-based nanochannels, mainly focus on the charged gel network or embedded electrolytes. However, the basic issue of how a nanoscale gel network affects the ion transport in nanochannels has been neglected. Here, we demonstrate a non-aqueous biomimetic nanochannel system by employing the agarose hydrogel in conical nanochannels. To tune the hydrogel network by adjusting the gel concentration, the ion transport behavior in gel-based nanochannels is systemically investigated. The experimental results show that the ion transport behaviors in gel-nanochannels with 2% gel present similar ion selectivity and rectification performance to the aqueous system, indicating fast investigation of gel-based systems with the knowledge of the extensively studied aqueous systems. Furthermore, a gel-based solid-state diode and logic circuits were fabricated.

Improved Ion Transport in Hydrogel-Based Nanofluidics for Osmotic Energy Conversion

In nature, ultrafast signal transfer based on ion transport, which is the foundation of biological processes, commonly works in a hydrogel-water mixed mechanism. Inspired by organisms' hydrogel-based system, we introduce hydrogel into nanofluidics to prepare a hydrogel hybrid membrane. The introduction of a space charged hydrogel improves the ion selectivity evidently. Also, a power generator based on the hydrogel hybrid membrane shows an excellent energy conversion property; a maximum power density up to 11.72 W/m² is achieved at a 500-fold salinity gradient. Furthermore, the membrane shows excellent mechanical properties. These values are achievable, which indicates our membrane's huge potential applications in osmotic energy conversion.

Asymptomatic COVID-19 infection in patients with cancer at a cancer-specialized hospital in Wuhan, China - Preliminary results

OBJECTIVE

Patients with cancer are usually immunosuppressive and susceptible to COVID-19 infection. Asymptomatic COVID-19 cases are infective and cannot be identified by symptom-based screening. There is an urgent need to control virus spread by asymptomatic carriers at cancer centres. We aim to describe the characteristics, screening methods, and outcomes of cancer patients with asymptomatic COVID-19 infection and to further explore anti-tumour treatment for this population.

PATIENTS AND METHODS

We reviewed patients with cancer who were admitted to Hubei Cancer Hospital in Wuhan from February 1, 2020, to April 4, 2020. We collected demographic data, laboratory findings, treatment information, nucleic acid and serum test results, chest computed tomography (CT) information and survival status of cancer patients diagnosed with asymptomatic COVID-19 infection.

RESULTS

A total of 16 cancer patients with asymptomatic COVID-19 infection were confirmed. The most common cancer type was breast cancer. The blood cell counts of most patients were in the normal range. Lymphocytes of 100% of asymptomatic carriers were in the normal range. Thirteen (81.3%) patients were positive for virus-specific IgM antibodies, and three (18.8%) were positive by PCR; only one (6.3%) patient showed novel coronavirus pneumonia features on CT. Three (18.3%) patients died, and the cause of death was considered malignancy caused by delaying anti-tumour treatment.

CONCLUSIONS

Our study shows that the lymphocytes of 100% of asymptomatic carriers were in the normal range. This result indicates that the host immunity of asymptomatic carriers is not significantly disrupted by COVID-19. Single PCR detection is not sufficient to screen among asymptomatic individuals, and a combination of PCR tests, serological tests and CT is of great importance. Unless the tumour is life-threatening or rapidly progressing, we advise restarting active anti-tumour therapy after PCR tests become negative.

pH-regulated thermo-driven nanofluidics for nanoconfined mass transport and energy conversion

Bioinspired nanochannels whose functions are similar to those of the biological prototypes attract increasing attention due to their potential applications in signal transmission, mass transport, energy conversion, etc. Up to now, however, it is still a challenge to extract low-grade waste heat from the ambient environment in an aqueous solution. Herein, a thermo-driven nanofluidic system was developed to extract low-grade waste heat efficiently based on directed ionic transport at a micro-/nanoscale. A steady streaming current increases linearly with the temperature gradient, achieving as high as 14 nA at a temperature gradient of 47.5 °C (δT = 47.5 °C) through a 0.5 cm2 porous membrane (106 cm-2). And an unexpected theoretical power of 25.48 pW using a single nanochannel at a temperature difference of 40 °C has been achieved. This bioinspired multifunctional system broadens thermal energy recovery and will accelerate the evolution of nanoconfined mass transport for practical applications.

Biomimetic Nacre-Like Silk-Crosslinked Membranes for Osmotic Energy Harvesting

As an approach to harvesting sustainable energy from ambient conditions, the osmotic energy between river water and seawater contributes to solving global issues such as the energy shortage and environmental pollution. Current attempts based on a reverse electrodialysis technique are limited mainly due to the economically unviable power density and inadequate mass transportation of membrane materials. Here, we demonstrate a benign strategy for designing a multilayer graphene oxide-silk nanofiber-graphene oxide biomimetic nacre-like sandwich as an osmotic power generator. Enhanced interfacial bonding endows the composite membranes with long-term stability in saline, and meanwhile, the two-dimensional nanofluidic channel configuration also reduces the ion transport resistance and provides large storage spaces for ions. Thus, the output power density of the proposed membrane-based generator achieves a value of up to 5.07 W m^-2 by mixing seawater and river water. Furthermore, we experimentally and theoretically demonstrate that the thermal-field drives the increased output power density due to the advances in ionic movement range and activity of electrode reaction, showing the promise of strengthened thermo-osmotic energy conversion.

Improved Ion Transport and High Energy Conversion through Hydrogel Membrane with 3D Interconnected Nanopores

To mimic and use the functions of the ion transport system that are central to biological processes, bioinspired ion-selective membranes are developed and show great potential in a variety of fields. However, the practical applications of them are now limited due to low pore density, low conductivity, or scale-up difficulty. Herein, we demonstrate a 2-hydroxyethyl methacrylate phosphate (HEMAP) hydrogel membrane with 3D interconnected nanopores and space charged through simple photopolymerization. The HEMAP hydrogel membrane exhibits high conductance and outstanding ion selectivity, and the membrane-based osmotic power generator shows the excellent output power density up to 5.38 W/m². Both experimentally and theoretically, the 3D interconnected structure is revealed to play a key role in enhancing charge-governed ion transport and energy conversion. This work highlights the advantages of 3D interconnected nanopores in ion diffusion and shows the potential of our designed hydrogel membrane in osmotic energy conversion, water desalination, and sensors.

Robust sulfonated poly (ether ether ketone) nanochannels for high-performance osmotic energy conversion

The membrane-based reverse electrodialysis (RED) technique has a fundamental role in harvesting clean and sustainable osmotic energy existing in the salinity gradient. However, the current designs of membranes cannot cope with the high output power density and robustness. Here, we construct a sulfonated poly (ether ether ketone) (SPEEK) nanochannel membrane with numerous nanochannels for a membrane-based osmotic power generator. The parallel nanochannels with high space charges show excellent cation-selectivity, which could further be improved by adjusting the length and charge density of nanochannels. Based on numerical simulation, the system with space charge shows better conductivity and selectivity than those of a surface-charged nanochannel. The output power density of our proposed membrane-based device reaches up to 5.8 W/m2 by mixing artificial seawater and river water. Additionally, the SPEEK membranes exhibit good mechanical properties, endowing the possibility of creating a high-endurance scale-up membrane-based generator system. We believe that this work provides useful insights into material design and fluid transport for the power generator in osmotic energy conversion.

The importance of proper and prompt treatment of ocular syphilis: a lesson from permanent vision loss in 52 eyes

BACKGROUND

Ocular involvement can occur at any stage of syphilis. Prompt diagnosis and proper treatment of ocular syphilis are vital to avoid long-term consequences.

OBJECTIVES

To describe the risk factors for ocular syphilis and clinical features of blindness caused by syphilis.

METHODS

We report risk factors for ocular syphilis amongst patients seen at the Shanghai Skin Disease Hospital between October 2009 and October 2017. We identify patients with ocular syphilis resulting in blindness and report the clinical characteristics, laboratory findings and treatment outcomes of these patients.

RESULTS

A total of 8310 new cases of syphilis were seen, of which 213 patients had ocular disease and 50 patients had blindness due to syphilis. Increasing age and higher RPR titres were associated with ocular involvement but there was no association with HIV status. Blindness in syphilis was restricted predominantly to patients with optic nerve involvement and not patients with isolated uveitis. Fifty patients (and a total of 67 eyes) met the WHO definition of blindness prior to treatment for syphilis. At the end of follow-up, vision had improved in 24 of 67 eyes (35.8%) after treatment. Successful treatment of uveitis was associated with the best improvement in visual acuity, whilst patient with underlying optic atrophy prior to treatment had the worst visual outcome.

CONCLUSIONS

Ocular involvement is an important manifestation of syphilis which may result in blindness. Our data demonstrate outcomes for ocular syphilis are poor if detected late; early recognition and diagnosis is therefore vital to avoid permanent visual loss.

[Comparisons of clinical characteristics and prognosis between patients with primary and secondary thyroid lymphoma]

Objective: To compare clinical characteristics and prognosis between patients with primary (PTL) and secondary thyroid lymphoma (STL) . Methods: A retrospective analysis was performed on 46 patients with thyroid lymphoma (PTL 19, STL 27) from January 2002 to October 2018. Results: ①PTL group included 4 males and 15 females, with a median age of 57 years. The STL group included 10 males and 17 females, with a median age of 61 years. Diffuse large B-cell lymphoma (DLBCL) was the main pathological subtype in both PTL and STL groups, with 14 cases (73.7%) and 20 cases (74.1%) respectively. In terms of clinical manifestations, goiter was the most common symptom in PTL patients 100.0% (19/19) , while 29.6% (8/27) STL had goiter (P<0.001) . The incidences of increased thyroglobulin antibody (TRAb) /thyroid peroxidase antibody (TPO) were 81.3% (13/16) in PTL group and 43.8% (7/16) in STL group (P=0.028) respectively. Concerning the clinical features of patients, only two PTL patients (10.5%) with advanced Ann Arbor stage (Ⅲ/Ⅳ) , while 21 (77.8%) STL experienced advanced Ann Arbor stage (P<0.001) . Elevated serum β(2)-MG were appeared in 1 (7.1%) PTL and 9 (47.4%) STL patients (P=0.013) , and advanced IPI score (3-5) was more common in STL than PTL (59.3% vs 5.3%, P<0.001) . ②Among the 17 PTL patients who received treatments, 15 (88.2%) achieved remission; as for STL patients received treatments, 23/25 (92.0%) were in remission. The 5-year overall survival (OS) rates of PTL (n=17) and STL groups (n=25) were (87.4±8.4) % and (70.0±13.1) % (P=0.433) respectively. ③The 5-year OS rate in 41 patients with B-cell thyroid lymphoma was (81.1±7.5) %. Univariate analysis showed that IPI score of 3-5 (P=0.040) and high level of serum IL-8 (P=0.022) were significantly associated with poor outcome. Conclusion: DLBCL was the most common subtype in both PTL and STL, and goiter was the major symptom in PTL. IPI score of 3-5 and high level of serum IL-8 were unfavorable prognostic factors for patients with B-cell thyroid lymphoma.

SAT0175 IMPACT OF ANTIMALARIAL ADHERENCE ON MORTALITY AMONG PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: A POPULATION-BASED COHORT STUDY

Background:

Evidence has consistently shown that adherence to AM is poor in systemic lupus erythematosus (SLE) patients. However, data on the impact of adherence to AM on mortality is scarce.

Objectives:

To assess the effect of AM adherence on all-cause mortality in SLE patients from the general population.

Methods:

This study used administrative databases from British Columbia, Canada. We created an incident SLE cohort between January 01, 1997, and March 31, 2015, using the physician billing data and a 7-year washout period. The inclusion criteria were at least two physician visits, at least two months apart, within two years, with an ICD-9 code (710.0) or ICD-10 code (M32.1, M32.8, M32.9) for SLE. Follow-up started at the first day of having both SLE and AM, i.e., at the SLE index date (second ICD code) for those whose first AM use occurred before the SLE index date, or the date of the first AM use if otherwise. Our outcome was all-cause mortality, obtained from the vital statistics registry. In the analysis, the follow-up time was divided into 30-days windows, for a total of 293,190 person-months. For each window, a measure of adherence, the proportion of days covered (PDC), was calculated and categorized as adherent (PDC≥0.90), non-adherent (0<PDC<0.90), and discontinuer (no drug or PDC = 0). We used both Cox’s proportional hazards models and marginal structural models (MSM) to estimate the effect of AM adherence on all-cause mortality. Both analysis controlled for baseline demographics (age, sex, residence, income quintile), as well as the following baseline and time-varying covariates: immunosuppressive and other medications, hospitalizations, impatient, and other visits, and Charlson comorbidity index. To account for the possibility of a few time-varying covariates being mediators in the causal pathway from AM adherence to mortality, which may cause the Cox model to yield biased estimates of the adherence effects, we conducted the MSM analysis that can produce valid estimates as it balances the distributions of time-varying confounders among the three adherence groups via inverse probability weighting.

Results:

We identified 3,385 individuals with incident SLE (mean age 47.3 years, 89% were women) who had at least one filled AM prescription. Over the mean follow-up of 6.66 years, 288 (8.5%) incident SLE patients died. The incidence rate (IR) of mortality for AM adherent, non-adherent, and discontinuer patients were 4.31, 11.86, and 19.51 per 1000 person-years, respectively. Using the Cox model, the adjusted hazard ratio (HRs) obtained for AM adherent and non-adherent SLE patients were 0.20 and 0.66, respectively, compared to discontinuer SLE patients (Table 1). Using MSM, those adjusted HRs were found as 0.18 and 0.64. Also, the adjusted HRs for adherers compared to the non-adherers were 0.30 (Cox) and 0.28 (MSM). A statistically significant linear trend in the HRs of mortality risk over the adherence levels was found (Table 1, Linear Trend).

Table 1.Adherence LevelsNo. of DeathsIR Ratios (95%CI)Adjusted Cox HRs (95%CI)Adjusted MSM HRs (95%CI)Discontinuer (Reference)198Non-adherent470.61(0.44-0.84)0.66(0.47-0.93)0.64(0.46-0.89)Adherent430.22(0.16-0.31)0.20(0.14-0.28)0.18(0.12-0.25)Contrast: Partial vs. Full0.36(0.24-0.55)0.30(0.19-0.46)0.28(0.18-0.42)Linear Trend0.32(0.25-0.41)0.29(0.23-0.37)

Conclusion:

SLE patients that adhere to AM therapy have a lower risk of death than patients who do not adhere or who discontinue AM (5 and 3 times, respectively) in both the MSM and Cox analysis. Our findings support the importance of AM adherence to prevent premature deaths in SLE patients.

Disclosure of Interests:

None declared

The quorum-sensing molecule 2-phenylethanol impaired conidial germination, hyphal membrane integrity and growth of Penicillium expansum and Penicillium nordicum

AIMS

The aim of the study was to investigate the antifungal effects of a quorum sensing-molecule, 2-phenylethanol, against the food spoilage moulds Penicillium expansum and Penicillium nordicum.

METHODS AND RESULTS

Conidial germination of the tested Penicillium spp. (three strains in total) were inhibited by treatments with 2-phenylethanol in a concentration-dependent manner. Germinated conidia was significantly reduced from 4·4-16·7% at 7·5 mmol l^-1 and completely inhibited at 15 mmol l^-1 2-phenylethanol. Integrity of conidial cell membranes was unaffected by 2-phenylethanol resulting in reversible inhibition pattern of germination. In contrast, membrane permeability of actively growing hyphae was severely compromised, showing 63·5 - 75·7% membrane damage upon treatment with 15 mmol l^-1 2-phenylethanol. The overall inhibitory effect of 2-phenylethanol on colony development and growth of P. expansum and P. nordicum was additionally confirmed.

CONCLUSIONS

2-phenylethanol inhibits conidial germination and growth of P. expansum and P. nordicum in a nonlethal, reversible and concentration-dependent manner.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study indicates that 2-phenylethanol can find potential application as an antifungal agent for biological control of moulds in the food industry.

Improved osmotic energy conversion in heterogeneous membrane boosted by three-dimensional hydrogel interface

The emerging heterogeneous membranes show unprecedented superiority in harvesting the osmotic energy between ionic solutions of different salinity. However, the power densities are limited by the low interfacial transport efficiency caused by a mismatch of pore alignment and insufficient coupling between channels of different dimensions. Here we demonstrate the use of three-dimensional (3D) gel interface to achieve high-performance osmotic energy conversion through hybridizing polyelectrolyte hydrogel and aramid nanofiber membrane. The ionic diode effect of the heterogeneous membrane facilitates one-way ion diffusion, and the gel layer provides a charged 3D transport network, greatly enhancing the interfacial transport efficiency. When used for harvesting the osmotic energy from the mixing of sea and river water, the heterogeneous membrane outperforms the state-of-the-art membranes, to the best of our knowledge, with power densities of 5.06 W m^-2. The diversity of the polyelectrolyte and gel makes our strategy a potentially universal approach for osmotic energy conversion.

Specific Recognition of Uranyl Ion Employing a Functionalized Nanochannel Platform for Dealing with Radioactive Contamination

Radioactive contamination is a highly concerning global environmental issue along with the development of the nuclear industry. On account of sophisticated operations and high cost of instrument detection methods, numerous efforts have been focused on rapid and simple detection of pollution elements and uranium is the most common one. It is an enormous challenge to push the limit of determination as low as possible while carrying out ultrasensitive detection. Here, we report an intelligent platform based on functionalized solid nanochannels to monitor ultratrace uranyl ions. The platform has a detection limit of 1 fM, which is far below the value that traditional instrumental methods can reach. What is more, the system also exhibits uranyl removal property. The mesenchymal stem cells cultivated in media containing uranyl can achieve excellent viability in the presence of the membranes. This work provides a new choice for handling global radioactive contamination of water.

Engineering Smart Nanofluidic Systems for Artificial Ion Channels and Ion Pumps: From Single-Pore to Multichannel Membranes

Biological ion channels and ion pumps with intricate ion transport functions widely exist in living organisms and play irreplaceable roles in almost all physiological functions. Nanofluidics provides exciting opportunities to mimic these working processes, which not only helps understand ion transport in biological systems but also paves the way for the applications of artificial devices in many valuable areas. Recent progress in the engineering of smart nanofluidic systems for artificial ion channels and ion pumps is summarized. The artificial systems range from chemically and structurally diverse lipid-membrane-based nanopores to robust and scalable solid-state nanopores. A generic strategy of gate location design is proposed. The single-pore-based platform concept can be rationally extended into multichannel membrane systems and shows unprecedented potential in many application areas, such as single-molecule analysis, smart mass delivery, and energy conversion. Finally, some present underpinning issues that need to be addressed are discussed.

Correction: Bioinspired hydrogel-based nanofluidic ionic diodes: nano-confined network tuning and ion transport regulation

Correction for ‘Bioinspired hydrogel-based nanofluidic ionic diodes: nano-confined network tuning and ion transport regulation’ by Congcong Zhu et al., Chem. Commun., 2020, 56, 8123–8126, DOI: 10.1039/D0CC01313G.

The Nab experiment: A precision measurement of unpolarized neutron beta decay

Neutron beta decay is one of the most fundamental processes in nuclear physics and provides sensitive means to uncover the details of the weak interaction. Neutron beta decay can evaluate the ratio of axial-vector to vector coupling constants in the standard model, λ = gA/gV, through multiple decay correlations. The Nab experiment will carry out measurements of the electron-neutrino correlation parameter a with a precision of δa/a = 10−3 and the Fierz interference term b to δb = 3 × 10−3 in unpolarized free neutron beta decay. These results, along with a more precise measurement of the neutron lifetime, aim to deliver an independent determination of the ratio λ with a precision of δλ/λ = 0.03% that will allow an evaluation of Vud and sensitively test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long asymmetric spectrometer that guides the decay electron and proton to two large area silicon detectors in order to precisely determine the electron energy and an estimation of the proton momentum from the proton time of flight. The Nab spectrometer is being commissioned at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Lab. We present an overview of the Nab experiment and recent updates on the spectrometer, analysis, and systematic effects.