Enhancing the magnetic properties of Dy(III) single-molecule magnets in octahedral coordination symmetry by tuning the equatorial ligands.

Conventionally, octahedral (Oh) coordination symmetry of lanthanide centers is not ideal for constructing high-performance single-molecule magnets (SMMs). However, introducing a strong ligand field in the axial direction to increase crystal field splitting can potentially overcome this limitation. Herein, we successfully obtained two dysprosium(III) single-molecule magnets, [Dy(OCtBu3)X2(py)3] (X = Cl (1), I (2), py = pyridine), in Oh coordination symmetry. The two complexes differ only in the coordinating anions on the equatorial plane, yet their magnetic performances are distinctly different. When chloride is replaced by a weaker donor iodide, the energy barrier is dramatically improved from 29 cm-1 (1) to 860 cm-1 (2), highlighting the importance of weakening the transverse ligand field and maximizing the axial ligand field for high-performance SMMs.

Metal elements in atmospheric aerosols during different pollution events in the coastal region of the Yellow Sea: Concentration, solubility and deposition flux.

Atmospheric aerosol (including total suspended particulate (TSP) samples and fine particulate matter (PM2.5) samples) and precipitation samples were collected in Qingdao from May 2020 to June 2021. The concentrations of metal elements on fog days were 0.28-0.56 times that on clean days; those on haze-fog (HF), haze and dust days were 0.76-2.7, 1.2-3.6 and 1.7-5.7 times those on clean days, respectively. Compared with that on clean days, the solubility of metals on fog, HF and haze days increased by 4 %-193 %, but that on dust days decreased by 1 %-62 %. The dry deposition fluxes of dissolved Al, Fe, Zn, Pb, Cu and Cd were the highest on HF or haze days, which were 2.2-15 times clean days. The dry deposition fluxes of metals accounted for 56 %-89 % of the total deposition fluxes (including dry and wet deposition).

A Novel Low-Density-Biomass-Carbon Composite Coated with Carpet-like and Dandelion-Shaped Rare-Earth-Doped Cobalt Ferrite for Enhanced Microwave Absorption.

A novel low-density composite for the absorption of microwaves was prepared by loading La-doped spinel cobalt ferrite (La-CFO) onto biomass carbon (BC) derived from corn stalks using a hydrothermal method. This composite (La-CFO@BC) not only maintained the advantageous properties of low density and abundant porosity, but also exhibited a unique morphology, with La-CFO displaying a carpet-like structure interspersed with dandelion-shaped particles. The incorporation of La-CFO effectively tuned the electromagnetic parameters of the composite, thereby improving its impedance-matching attributes and its ability to absorb microwave radiation. At a frequency of 12.8 GHz for electromagnetic waves and with a thickness of 2.5 mm, La-CFO@BC demonstrated remarkable performance in microwave absorption, attaining a noteworthy minimum reflection (RLmin) of -53.2 dB and an effective absorption bandwidth (EAB) of 6.4 GHz. Furthermore, by varying the thickness of the La-CFO@BC within the range of 1.0 to 5.5 mm, the EAB could be broadened to 13.8 GHz, covering the entire X-band, the entire Ku-band, and a substantial portion of the C-band. This study demonstrated that La-CFO@BC was a promising alternative for electromagnetic wave attenuation, which offered superior performance in microwave absorption.

A High-Resolution Time Reversal Method for Target Localization in Reverberant Environments.

Reverberation in real environments is an important factor affecting the high resolution of target sound source localization (SSL) methods. Broadband low-frequency signals are common in real environments. This study focuses on the localization of this type of signal in reverberant environments. Because the time reversal (TR) method can overcome multipath effects and realize adaptive focusing, it is particularly suitable for SSL in a reverberant environment. On the basis of the significant advantages of the sparse Bayesian learning algorithm in the estimation of wave direction, a novel SSL is proposed in reverberant environments. First, the sound propagation model in a reverberant environment is studied and the TR focusing signal is obtained. We then use the sparse Bayesian framework to locate the broadband low-frequency sound source. To validate the effectiveness of the proposed method for broadband low-frequency targeting in a reverberant environment, simulations and real data experiments were performed. The localization performance under different bandwidths, different numbers of microphones, signal-to-noise ratios, reverberation times, and off-grid conditions was studied in the simulation experiments. The practical experiment was conducted in a reverberation chamber. Simulation and experimental results indicate that the proposed method can achieve satisfactory spatial resolution in reverberant environments and is robust.

Energy efficiency optimization in a parallel relay-assisted UWOC system with simultaneous lightwave information and power transfer.

In this paper, we investigate the energy efficiency optimization for a parallel relay-assisted underwater wireless optical communication (UWOC) system with simultaneous lightwave information and power transfer (SLIPT) over an aggregate channel. In this system, relay nodes are equipped with energy harvesting devices, getting energy from the direct current component of the received signal transmitted by the source node. These nodes utilize the harvested energy to transmit the signal to the destination node with the decoding and forwarding strategy. The harvested energy for each relay node is derived by the Gauss-Laguerre quadrature formula and the outage probability is deduced by the Meijer-G function. Then, the system's energy efficiency can be calculated and an energy efficiency maximization problem is built up with respect to the bias current. We propose a three-level-iteration algorithm to solve this problem. In the first level, the Dinkelbach method is used to represent energy efficiency in a parametric subtractive form. In the second level, we use the penalty function method to convert the object function and constraint. In the third level, the objective function is transformed into a quadratic function by using a successive convex approximate method, thereby solving for the bias current. The effects of system parameters on energy efficiency are also analyzed. Theoretical results and Monte Carlo simulations suggest that employing the solved bias current can significantly improve the system's energy efficiency.

Quantum Obfuscation of Generalized Quantum Power Functions with Coefficient.

Quantum obfuscation is one of the important primitives in quantum cryptography that can be used to enhance the security of various quantum cryptographic schemes. The research on quantum obfuscation focuses mainly on the obfuscatability of quantum functions. As a primary quantum function, the quantum power function has led to the development of quantum obfuscation because it is applicable to construct new obfuscation applications such as quantum encryption schemes. However, the previous definition of quantum power functions is constrained and cannot be beneficial to the further construction of other quantum functions. Thus, it is essential to extend the definition of the basic quantum power function in a more general manner. In this paper, we provide a formal definition of two quantum power functions called generalized quantum power functions with coefficients, each of which is characterized by a leading coefficient and an exponent that corresponds to either a quantum or classical state, indicating the generality. The first is the quantum power function with a leading coefficient, and the second is the quantum n-th power function, which are both fundamental components of quantum polynomial functions. In addition, obfuscation schemes for the functions are constructed by quantum teleportation and quantum superdense coding, and demonstrations of their obfuscatability are also provided in this paper. This work establishes the fundamental basis for constructing more quantum functions that can be utilized for quantum obfuscation, therefore contributing to the theory of quantum obfuscation.

SUMO-Activating Enzyme Subunit 1 Is Associated with Poor Prognosis, Tumor Progression, and Radio-Resistance in Colorectal Cancer.

Concurrent chemoradiotherapy is an effective treatment option for patients with low-grade colorectal cancer (CRC) in the local disease stage. At present, the principle of the Taiwan Medical Center is to treat CRC patients with combination radiotherapy and chemotherapy (high-dose 5-FU) for a period of about five weeks prior to surgery. Radical resection of the tumor is performed at least six to eight weeks after concurrent chemoradiotherapy (CCRT). However, this approach fails to produce the desired therapeutic effect in approximately 20% to 30% of patients, and such patients are unnecessarily exposed to the risks of radiation and drug toxicity posed by this therapy. Therefore, it is crucial to explore new biomarkers to predict the prognosis of CRC. SUMO-activating enzyme subunit 1 (SAE1) plays an important role in SUMOylation, a post-translational modification involved in cellular functions, such as cell proliferation, cell cycle, and apoptosis. In our study, to explore the clinical-pathological role of SAE1 protein in CRC, we evaluated the clinical data and paraffin sections from CRC patients. The expression of SAE1 was evaluated using immunohistochemical analysis, and clinical parameters were analyzed using chi-square and Kaplan-Meier survival tests. The results of in vitro proliferation and radiosensitive assays were compared between control groups and SAE1 siRNA groups. Western blotting was also used to detect the expressions of the SAE1, PARP, cyclin D1, p-NF-κB, and NF-κB proteins. Flow cytometry and colony formation assays were used to detect the effect of SAE-1 on radiosensitivity. In vivo, we detected the growth curve in a mouse xenograft model. The results showed that SAE-1 was revealed to be an independent prognostic biomarker of CRC. SAE1 knockdown inhibited CRC proliferation in vitro and in vivo, and led to the cleavage of PARP, downregulation of cyclin D1 protein expression, and downregulation of p-NF-κB/NF-κB. Additionally, SAE1 knockdown promoted radiosensitivity in CRC cells. Therefore, it was inferred that SAE1 may be used as a potential therapeutic target in CRC treatment.

Knockdown of long non-coding RNA LINC01123 plays a molecular sponge on miR-625-5p to inhibit the process of colorectal cancer cells via LASP1.

Colorectal cancer (CRC) at an advanced stage of cancer has a lower 5-year survival rate. Research on the molecular biological mechanisms of CRC is helpful for disease prevention and treatment. Long non-coding RNAs (lncRNAs) were shown to be suitable as therapeutic targets for CRC. Previously, our research team found that LINC01123 promoted proliferation and metastasis in CRC by regulating miR-625-5p and the LIM and SH3 protein 1 (LASP1). Therefore, this study speculated that the molecular sponge effect of LINC01123 on miR-625-5p affected the process of CRC via regulating LASP1. The LINC01123-silenced CRC cell models (using the LOVO and SW480 cells) and xenograft tumor models were established to verify the above conjecture. As a result, it was found that silencing LINC01123 inhibited viability, proliferation, metastasis, and invasion but promoted apoptosis in LOVO and SW480 cells. Additionally, the knockdown of LINC01123 inhibited the LASP1, N-cadherin, PCNA, and Bcl-2 protein levels and raised the E-cadherin, Bax, and Caspase-3 protein levels in vitro. Furthermore, it showed that LINC01123, as a molecular sponge, targeted the miR-625-5p/LASP1 axis. The results of the xenograft tumor assay further verified the above effects of LINCO1123-silenced on tumor growth in vivo. And the miR-625-5p mimics treatment promoted the aforementioned effects of silencing LINC01123 on CRC cells while overexpressing LASP1 has an antagonistic effect to silencing LINC01123. In conclusion, this study suggests that silencing LINC01123 inhibits the process of CRC via sponging to the miR-625-5p/LASP1 axis. This finding hopes to provide research fundamentals on the biological mechanism study of CRC.

Thoracic endovascular aortic repair of an anastomosis pseudoaneurysm after the Bentall procedure assisted by rapid ventricular pacing: A case report.

Background: Although commonly used for the treatment of descending aortic dissection, endovascular repair is challenging for ascending aortic pseudoaneurysms. Rapid ventricular pacing (RVP), a method that temporarily impedes cardiac output by stopping ventricular activity, heralds potential benefits for thoracic endovascular aortic repair (TEVAR) during precision landing. Recently, we successfully treated an anastomosis pseudoaneurysm after the Bentall procedure using TEVAR assisted by RVP. Case report: A 69-year-old male was admitted to our hospital with a ascending aortic anastomosis pseudoaneurysm. He had undergone a Bentall procedure and a coronary artery bypass grafting nine years prior. After extensive consultation, the decision was made to perform TEVAR with the assistance of RVP. After a covered stent graft was delivered to the precise location of the ascending aorta, RVP was performed at a frequency of 180 beats/min with a pacemaker. When a flattened arterial blood wave of <50 mmHg was observed, the stent graft was released precisely between the opening of the coronary graft and innominate artery. Angiography revealed the presence of an endoleak; therefore, a set of interlock coils were packed into the aneurysm. Subsequent angiography showed intact blood flow in the aorta, superior arch branches, and coronary graft vessels. The patient recovered uneventfully after the procedure. He was discharged six days later and was doing well at the eight-month follow-up. Conclusion: The case indicates that TEVAR assisted by RVP is a promising combination for ascending aortic pseudoaneurysm in selected patients.

Acute Renal Infarction Due to Symptomatic Isolated Spontaneous Renal Artery Dissection: A Rare and Fatal Disease.

OBJECTIVE: To report demographics and clinical, laboratory, and imaging features of acute renal infarction (ARI) due to symptomatic isolated spontaneous renal artery dissection (SISRAD) and to analyze outcomes after the initial therapy for SISRAD. METHODS: Thirteen patients with ARI due to SISRAD between January 2016 and March 2021 were enrolled in this retrospective study. We reviewed the demographics, clinical, laboratory, and imaging features (location of the infarct kidney, the branch artery involved by dissection, true lumen stenosis, false lumen thrombosis, and aneurysm), treatment modalities, and follow-up results; analyzed the difference between SISRAD and other causes of ARI; and propose an appropriate therapy strategy for SISRAD based on our data and literature. RESULT: Patients with ARI due to SISRAD were mostly young men (43 [24-53] years; 12/13 [92%]). No patients had atrial fibrillation or acute kidney injury at admission (0/13). All 13 patients received conservative treatment as the initial treatment. Sixty-two percent (8/13) of patients progressed, and 88% (7/8) of them had dissection aneurysm on the admission computed tomographic angiography (CTA) image. Seventy-five percent (6/8) of patients underwent endovascular intervention as follows, stent placement in 1 patient, renal artery embolization in 1, and stent placement with embolization in 4. Two patients with disease progression died: 1 during the conservative treatment period and 1 after the stent placement. Thirty-eight percent (5/13) of patients in remission continued to receive conservative treatment, none of whom had dissection aneurysm on the admission CTA. CONCLUSION: Symptomatic isolated spontaneous renal artery dissection is a rare and fatal disease. For young ARI patients with no previous history of tumors and cardiogenic diseases, CTA examination is recommended to exclude SISRAD. Dissection aneurysm seems to be a risk of progression for SISRAD in this series. Conservative treatment, a recognized initial treatment, has a good effect on patients without dissection aneurysm, and we recommend endovascular intervention as the initial treatment for the patient with dissection aneurysm at admission. Multicenter clinical studies are needed to explore a more-appropriate treatment for patients with SISRAD. CLINICAL IMPACT: This article report the related factors, risks, demographics and laboratory data of Acute renal infarction (ARI) due to Symptomatic isolated spontaneous renal artery dissection (SISRAD) and explore a better initial therapy strategy for SISRAD. It will help improve the effectiveness of SISRAD treatment and reduce the mortality rate from this rare but lethal disease.

Automatic Modulation Classification Using Hybrid Data Augmentation and Lightweight Neural Network.

Automatic modulation classification (AMC) plays an important role in intelligent wireless communications. With the rapid development of deep learning in recent years, neural network-based automatic modulation classification methods have become increasingly mature. However, the high complexity and large number of parameters of neural networks make them difficult to deploy in scenarios and receiver devices with strict requirements for low latency and storage. Therefore, this paper proposes a lightweight neural network-based AMC framework. To improve classification performance, the framework combines complex convolution with residual networks. To achieve a lightweight design, depthwise separable convolution is used. To compensate for any performance loss resulting from a lightweight design, a hybrid data augmentation scheme is proposed. The simulation results demonstrate that the lightweight AMC framework reduces the number of parameters by approximately 83.34% and the FLOPs by approximately 83.77%, without a degradation in performance.

Quantum hash function based on controlled alternate lively quantum walks.

Quantum hash function is an important area of interest in the field of quantum cryptography. Quantum hash function based on controlled alternate quantum walk is a mainstream branch of quantum hash functions by virtue of high efficiency and flexibility. In recent development of this kind of schemes, evolution operators determined by an input message depend on not only coin operators, but also direction-determine transforms, which usually are hard to extend. Moreover, the existing works ignore the fact that improper choice of initial parameters may cause some periodic quantum walks, and further collisions. In this paper, we propose a new quantum hash function scheme based on controlled alternate lively quantum walks with variable hash size and provide the selection criteria for coin operators. Specifically, each bit of an input message determines the magnitude of an additional long-range hop for the lively quantum walks. Statistical analysis results show excellent performance in the aspect of collision resistance, message sensitivity, diffusion and confusion property, and uniform distribution property. Our study demonstrates that a fixed coin operator, along with different shift operators, can effectively work on the design of a quantum hash function based on controlled alternate quantum walks, and shed new light on this field of quantum cryptography.

Physician-modified fenestration or in situ fenestration for preservation of isolated left vertebral artery in thoracic endovascular aortic repair.

Objective: To present our experience of preserving the isolated left vertebral artery (ILVA) with physician-modified fenestration (PM-F) or in situ fenestration (ISF) during thoracic endovascular aortic repair (TEVAR) for aortic pathologies involving aortic arch. Methods: This is a single-center, retrospective, observational cohort study. Between June 2016 and December 2021, 9 patients (8 men; median age 60.0 years old) underwent TEVAR with ILVA reconstruction (PM-F, n = 6; ISF, n = 3) were identified and analyzed. Results: The technical success rate was 100%. No early (<30 days) death occurred. No aortic rupture, major stroke or spinal cord injury was observed. The median follow up was 38.0 (rang: 1.0-66.0) months. One death occurred at 56 months, while the reason cannot be identified. No aortic rupture, major stroke or spinal cord injury was observed during follow up. No patient required reintervention. Out of the 22 successfully revascularized target vessels, 2 ILVAs were found occluded in 2 patients at 6 months and 7 months, respectively. However, these two patients were asymptomatic. Conclusions: Our initial experience reveals that PM-F or ISF for ILVA preservation was feasible, safe, and effective during TEVAR for complex thoracic aortic pathologies. However, the patency of preserved ILVA should be improved.

Fucoidan enhances the effect of chemotherapeutic drug against drug-resistant lung cancer cells.

Development of adjuvant chemotherapy drugs against drug-resistant lung cancer cells is necessary. The use of non-toxic adjuvant natural product combined with chemotherapy drugs will be an important treatment mode in the future. The purpose of the study investigates that fucoidan enhances chemotherapy drug poisoning drug-resistant lung cancer cell. Drug-resistant lung cancer cells are established in the study. Cell culture, MTT assay, wound healing assay, gelatin zymography assay, DNA fragmentation assay, apoptosis assay, reverse transcription polymerase chain reaction (RT-PCR) western blot analysis was adopted. The results showed that fucoidan synergized with doxorubicin increased efficacy of poisoning drug-resistant lung cancer cells and enhanced the ability of doxorubicin to inhibit the migration of drug-resistant lung cancer cells. It was observed that fucoidan synergized with doxorubicin induced the increase of apoptosis and inhibited expression of MMP-9, LC3, Beclin-1 and ß-catenin in drug-resistant lung cancer cells. Fucoidan synergized with doxorubicin significantly inhibited proliferation, migration and metastasis of drug-resistant lung cancer cells. Fucoidan strengthened doxorubicin to induce apoptosis and autophagy of drug-resistant lung cancer cells. This study confirms that the combined use of fucoidan and chemotherapeutic drugs can effectively poison drug-resistant lung cancer cells.

Understanding the Magnetic Relaxation Mechanism in Mixed-Valence Dilanthanide Complexes with Metal-Metal Bonding: A Theoretical Investigation.

Theoretical investigations on mixed-valence dilanthanide complexes (CpiPr5)2Ln2I3 (Ln = Tb, Dy, and Ho) indicate that the total spin of the 4f shell couples preferentially to the σ electron spin and then to the orbital angular momentum, improving the strength of spin-orbit coupling (SOC) for each magnetic center. On the other hand, the concentration of negative charges containing the delocalized σ electron in the axial direction leads to a large crystal-field (CF) splitting. Both strong SOC and large CF splitting lead to the largest energy barrier Ueff of such complexes up to now. In addition, our calculations show that the introduction of σ electron can better suppress the quantum tunneling of magnetization in the ground spin-orbit state, and the Ueff of (CpiPr5)2Ln2I3 is expected to originate from the contribution of both Ln ions under such strong Ln-σ exchange coupling.

Heterologous Expression of Recombinant Human Cytochrome P450 (CYP) in Escherichia coli: N-Terminal Modification, Expression, Isolation, Purification, and Reconstitution.

Cytochrome P450 (CYP) enzymes play important roles in metabolising endogenous and xenobiotic substances. Characterisations of human CYP proteins have been advanced with the rapid development of molecular technology that allows heterologous expression of human CYPs. Among several hosts, bacteria systems such as Escherichia coli (E. coli) have been widely used thanks to their ease of use, high level of protein yields, and affordable maintenance costs. However, the levels of expression in E. coli reported in the literature sometimes differ significantly. This paper aims to review several contributing factors, including N-terminal modifications, co-expression with a chaperon, selections of vectors and E. coli strains, bacteria culture and protein expression conditions, bacteria membrane preparations, CYP protein solubilizations, CYP protein purifications, and reconstitution of CYP catalytic systems. The common factors that would most likely lead to high expression of CYPs were identified and summarised. Nevertheless, each factor may still require careful evaluation for individual CYP isoforms to achieve a maximal expression level and catalytic activity. Recombinant E. coli systems have been evidenced as a useful tool in obtaining the ideal level of human CYP proteins, which ultimately allows for subsequent characterisations of structures and functions.

Photocontrollable Magnetism and Photoluminescence in a Binuclear Dysprosium Anthracene Complex.

By incorporating photoreactive anthracene moieties into binuclear Dy2O2 motifs, we obtain two new compounds with the formulas [Dy2(SCN)4(L)2(dmpma)4] (1) and [Dy2(SCN)4(L)2(dmpma)2(CH3CN)2] (2), where HL is 4-methyl-2,6-dimethoxyphenol and dmpma is dimethylphosphonomethylanthracene. Compound 1 contains face-to-face π-π interacted anthracene groups that meet the Schmidt rule for a [4 + 4] photocycloaddition reaction, while stacking of the anthracene groups in compound 2 does not meet the Schmidt rule. Compound 1 undergoes a reversible single-crystal-to-single-crystal structural transformation upon UV-light irradiation and thermal annealing, forming a one-dimensional coordination polymer of [Dy2(SCN)4(L)2(dmpma)2(dmpma2)]n (1UV). The process is concomitant with changes in the magnetic dynamics and photoluminescent properties. The spin-reversal energy barrier is significantly increased from 1 (55.9 K) to 1UV (116 K), and the emission color is changed from bright yellow for 1 to weak blue for 1UV. This is the first binuclear lanthanide complex that exhibits synergistic photocontrollable magnetic dynamics and photoluminescence. Ab initio calculations are conducted to understand the magnetostructural relationships of compounds 1, 1UV, and 2.

Secure Counting Query Protocol for Genomic Data.

Statistical analysis on genomic data can explore the relationship between gene sequence and phenotype. Particularly, counting the genomic mutation samples and associating with related phenotypes for statistical analysis can annotate the variation sites and help to diagnose genovariation. Expansion of the size of variation sample data helps to increase the accuracy of statistical analysis. It is feasible to securely share data from genomic databases on cloud platforms. In this paper, we design a secure counting query protocol that can securely share genomic data on cloud platforms. Our protocol supports statistical analysis of the genomic data in VCF (Variant Call Format) files by counting query. There are three participants of data owner, cloud platform and query party. Firstly, the genomic data is preprocessed to reduce the data size. Secondly, Paillier homomorphic is used so that genomic data can be securely shared and calculated on cloud platform. Finally, the results which be decrypted is used to implement counting function of the protocol. Experimental results show that the protocol can implement the query counting function after homomorphic encryption. The query time is less than 1 s, which provide a feasible solution to share genomic data securely on cloud platform for statistical analysis.

Microwave photonics broadband unambiguous frequency measurement based on a Sagnac loop and a linear optical filter.

We propose an instantaneous frequency measurement (IFM) scheme featured with unambiguous measurement utilizing a Sagnac loop with an embedded bi-directional phase modulator and an optical filter with a linear frequency response. The frequency of the microwave signal to be measured is instantaneously estimated by calculating an amplitude comparison function (ACF) of photocurrents from the upper and lower branches of the proposed structure. Compared to previous IFM schemes, the ACF in the proposed scheme is monotonic, by which the frequency of the unknown microwave signal can be uniquely confirmed without ambiguity. Only one laser source and a phase modulator are needed, which simplifies the measurement system. In addition, the monotonous ACF can guarantee measurement accuracy in a wide range, from low frequency to high frequency. The IFM system has robustness in optical and RF power shifts. Simulation results show that frequency measurement over the range of 30 GHz with a measurement error of 0.4 GHz is achieved.

Energy-efficient subchannel assignment and power allocation in VLC-IoT systems with SLIPT.

In this paper, we investigate joint subchannel assignment and power allocation for the energy efficiency (EE) optimization in an indoor visible light communication (VLC)-Internet of Things (IoT) system with simultaneous lightwave information and power transfer (SLIPT). A mixed-integer fractional nonlinear programming problem that is challenging to solve is formulated. To tackle this problem, the optimal transmission scheme is decomposed into subchannel assignment and power allocation. Firstly, a virtual cell formation and subchannel assignment (VCF-SA) scheme is proposed, which considers the location of IoT devices, quality of service requirements, and energy states. Secondly, a quadratic transformation-based power allocation (QTBPA) scheme is designed to transform the fractional nonlinear programming problem into a series of convex problems that can be solved iteratively. Simulation results illustrate the effectiveness of the proposed scheme in terms of system EE compared to the benchmarks. The impact of system parameters on the EE is also analyzed.