Hypoxia development in tumor is closely associated with its increased aggressiveness and strong resistance to therapy, leading to the poor prognosis in several cancer types. Clinically, invasive ...oxygen microelectrode and high dosage radiotherapy are often utilized to accurately detect and effectively fight hypoxia. Recently, however, there has been a surge of interdisciplinary research aiming at developing functional molecules and nanomaterials that can be used to noninvasively image and efficiently treat hypoxic tumors. In this review, we will provide an overview of the reports published to date on the imaging and therapy of hypoxic tumors. First, we will present the design concepts and engineering of various hypoxia-responsive probes that can be applied to image hypoxia noninvasively, in an order of fluorescent imaging, positron emission tomography, magnetic resonance imaging, and photoacoustic imaging. Then, we will summarize the up-to-date functional nanomaterials which can be used for the effective treatments of tumor hypoxia. The well-established chemical functions of these elaborately designed nanostructures will enable clinicians to adopt specific treatment concepts by overcoming or even utilizing hypoxia. Finally, challenges and future perspectives facing the researchers in the field will be discussed.
•PCM is a solution to reduce energy consumption and greenhouse gas emissions.•Evaluating the techniques used for the addition of nanoparticles to PCMs.•Discussing on effects of nanoparticles on the ...thermophysical properties of PCMs.•Examining the applications of nano-PCMs.•Phase change rate increases with the addition of nanoparticles.
Energy conservation management using latent heat storage (LHS) technique is nowadays employed as a solution to reduce energy consumption and greenhouse gas emissions. Phase change materials (PCMs) are the main candidate for LHS method. The main focus of this study is to evaluate the techniques used for the addition of nanoparticles to PCMs. The present paper is divided into three parts. The first part summarizes PCMs and nanoparticles. In the second part, the effects of nanoparticles on the most important thermophysical properties of PCMs are discussed. In the third part, the applications of nano-PCMs (NPCMs) in the fields such as thermal energy storage (TES), thermal control unit (TCU), photovoltaicthermal (PVT), solar still (SS) and building are examined. In general, all studies show that the phase change rate increases with the addition of nanoparticles. This means that the amount of energy stored/released during the phase change process is improved.
As low-cost electrocatalysts for oxygen reduction reaction applied to fuel cells and metal-air batteries, atomic-dispersed transition metal-nitrogen-carbon materials are emerging, but the genuine ...mechanism thereof is still arguable. Herein, by rational design and synthesis of dual-metal atomically dispersed Fe,Mn/N-C catalyst as model object, we unravel that the O
reduction preferentially takes place on Fe
in the FeN
/C system with intermediate spin state which possesses one e
electron (t
4e
1) readily penetrating the antibonding π-orbital of oxygen. Both magnetic measurements and theoretical calculation reveal that the adjacent atomically dispersed Mn-N moieties can effectively activate the Fe
sites by both spin-state transition and electronic modulation, rendering the excellent ORR performances of Fe,Mn/N-C in both alkaline and acidic media (halfwave positionals are 0.928 V in 0.1 M KOH, and 0.804 V in 0.1 M HClO
), and good durability, which outperforms and has almost the same activity of commercial Pt/C, respectively. In addition, it presents a superior power density of 160.8 mW cm
and long-term durability in reversible zinc-air batteries. The work brings new insight into the oxygen reduction reaction process on the metal-nitrogen-carbon active sites, undoubtedly leading the exploration towards high effective low-cost non-precious catalysts.
Crowdsourcing systems which utilize the human intelligence to solve complex tasks have gained considerable interest and adoption in recent years. However, the majority of existing crowdsourcing ...systems rely on central servers, which are subject to the weaknesses of traditional trust-based model, such as single point of failure. They are also vulnerable to distributed denial of service (DDoS) and Sybil attacks due to malicious users involvement. In addition, high service fees from the crowdsourcing platform may hinder the development of crowdsourcing. How to address these potential issues has both research and substantial value. In this paper, we conceptualize a blockchain-based decentralized framework for crowdsourcing named CrowdBC, in which a requester's task can be solved by a crowd of workers without relying on any third trusted institution, users’ privacy can be guaranteed and only low transaction fees are required. In particular, we introduce the architecture of our proposed framework, based on which we give a concrete scheme. We further implement a software prototype on Ethereum public test network with real-world dataset. Experiment results show the feasibility, usability, and scalability of our proposed crowdsourcing system.
Combining whole exome sequencing, transcriptome profiling, and T cell repertoire analysis, we investigate the spatial features of surgically-removed biopsies from multiple loci in tumor masses of 15 ...patients with non-small cell lung cancer (NSCLC). This revealed that the immune microenvironment has high spatial heterogeneity such that intratumoral regional variation is as large as inter-personal variation. While the local total mutational burden (TMB) is associated with local T-cell clonal expansion, local anti-tumor cytotoxicity does not directly correlate with neoantigen abundance. Together, these findings caution against that immunological signatures can be predicted solely from TMB or microenvironmental analysis from a single locus biopsy.
In this work, we rationally designed a series of crystalline and stable dioxin‐linked metallophthalocyanine covalent organic frameworks (COFs; MPc‐TFPN COF, M=Ni, Co, Zn) under the guidance of ...reticular chemistry. As a novel single‐site catalysts (SSCs), NiPc/CoPc‐TFPN COF exhibited outstanding activity and selectivity for electrocatalytic CO2 reduction (ECR; Faradaic efficiency of CO (FECO)=99.8(±1.24) %/ 96.1(±1.25) % for NiPc/CoPc‐TFPN COF). More importantly, when coupled with light, the FECO and current density (jCO) were further improved across the applied potential range (−0.6 to −1.2 V vs. RHE) compared to the dark environment for NiPc‐TFPN COF (jCO increased from 14.1 to 17.5 A g−1 at −0.9 V; FECO reached up to ca. 100 % at −0.8 to −0.9 V). Furthermore, an in‐depth mechanism study was established by density functional theory (DFT) simulation and experimental characterization. For the first time, this work explored the application of COFs as photo‐coupled electrocatalysts to improve ECR efficiency, which showed the potential of using light‐sensitive COFs in the field of electrocatalysis.
A series of stable dioxin‐linked metallophthalocyanine covalent organic frameworks (COFs) were developed and applied for photo‐coupled electrocatalytic CO2 reduction. This work represents a new insight for the future rational design of light sensitive crystalline materials for CO2 reduction.
A strategy to covalently connect crystalline covalent organic frameworks (COFs) with semiconductors to create stable organic–inorganic Z‐scheme heterojunctions for artificial photosynthesis is ...presented. A series of COF–semiconductor Z‐scheme photocatalysts combining water‐oxidation semiconductors (TiO2, Bi2WO6, and α‐Fe2O3) with CO2 reduction COFs (COF‐316/318) was synthesized and exhibited high photocatalytic CO2‐to‐CO conversion efficiencies (up to 69.67 μmol g−1 h−1), with H2O as the electron donor in the gas–solid CO2 reduction, without additional photosensitizers and sacrificial agents. This is the first report of covalently bonded COF/inorganic‐semiconductor systems utilizing the Z‐scheme applied for artificial photosynthesis. Experiments and calculations confirmed efficient semiconductor‐to‐COF electron transfer by covalent coupling, resulting in electron accumulation in the cyano/pyridine moieties of the COF for CO2 reduction and holes in the semiconductor for H2O oxidation, thus mimicking natural photosynthesis.
Here comes the sun: A strategy to covalently connect covalent organic frameworks with semiconductors to create organic–inorganic Z‐scheme heterojunctions was developed and applied for the CO2 photoreduction with H2O. This work delivers new insights for the future design of Z‐scheme organic–inorganic heterojunctions for artificial photosynthesis.
Phosphine‐mediated deoxygenative nucleophilic substitutions, such as the Mitsunobu reaction, are of great importance in organic synthesis. However, the conventional protocols require stoichiometric ...oxidants to trigger the formation of the oxyphosphonium intermediates for the subsequent nucleophilic additions. Through dual catalysis of photoredox and cobaloxime, we realized a radical strategy for the catalytic formation of acyloxyphosphonium ions that enables direct amidation. The deoxygenative protocol exhibits a broad scope and has been used in the late‐stage amidation of drug molecules. In addition to batch reactions, a continuous‐flow reactor was developed, enabling rapid peptide synthesis on gram scale. The successful assembly of a tetrapeptide on the solid support further demonstrated the versatility of this photocatalytic system. Moreover, experimental and computational studies are consistent with the hypothesis of acyloxyphosphonium ions being formed as the key intermediates.
A photocatalytic method for the synthesis of amides and peptides is reported. Synergistic cooperation between a cobaloxime and a photoredox catalyst removes the elements of H2O through the use of PPh3 as a gentle organic reductant. The deoxygenative method is compatible with gram‐scale peptide synthesis and applicable to peptide fragment condensation and SPPS, which may find applications in both organic synthesis and pharmaceutical production.
Abstract
The electrochemical CO
2
reduction to high-value-added chemicals is one of the most promising and challenging research in the energy conversion field. An efficient ECR catalyst based on a ...Cu-based conductive metal-organic framework (Cu-DBC) is dedicated to producing CH
4
with superior activity and selectivity, showing a Faradaic efficiency of CH
4
as high as ~80% and a large current density of −203 mA cm
−2
at −0.9 V vs. RHE. The further investigation based on theoretical calculations and experimental results indicates the Cu-DBC with oxygen-coordinated Cu sites exhibits higher selectivity and activity over the other two crystalline ECR catalysts with nitrogen-coordinated Cu sites due to the lower energy barriers of Cu-O
4
sites during ECR process. This work unravels the strong dependence of ECR selectivity on the Cu site coordination environment in crystalline porous catalysts, and provides a platform for constructing highly selective ECR catalysts.
Metallic conductive 1T phase molybdenum sulfide (MoS2) has been identified as promising anode for sodium ion (Na+) batteries, but its metastable feature makes it difficult to obtain and its ...restacking during the charge/discharge processing result in part capacity reversibility. Herein, a synergetic effect of atomic‐interface engineering is employed for constructing 2H‐MoS2 layers assembled on single atomically dispersed Fe−N−C (SA Fe−N−C) anode material that boosts its reversible capacity. The work‐function‐driven‐electron transfer occurs from SA Fe−N−C to 2H‐MoS2 via the Fe−S bonds, which enhances the adsorption of Na+ by 2H‐MoS2, and lays the foundation for the sodiation process. A phase transfer from 2H to 1T/2H MoS2 with the ferromagnetic spin‐polarization of SA Fe−N−C occurs during the sodiation/desodiation process, which significantly enhances the Na+ storage kinetics, and thus the 1T/2H MoS2/SA Fe−N−C display a high electronic conductivity and a fast Na+ diffusion rate.
These findings on the evolution of stabilized 1T‐MoS2 will strengthen our comprehensive knowledge of electronic structure optimization strategy and pave the way for the design of other heterostructures materials for high‐performance energy storage.
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