Design of Nanoparticle-Based Carriers for Targeted Drug Delivery

Nanoparticles have shown promise as both drug delivery vehicles and direct antitumor systems, but they must be properly designed in order to maximize efficacy. Computational modeling is often used both to design new nanoparticles and to better understand existing ones. Modeled processes include the release of drugs at the tumor site and the physical interaction between the nanoparticle and cancer cells. In this paper, we provide an overview of three different targeted drug delivery methods (passive targeting, active targeting, and physical targeting) and compare methods of action, advantages, limitations, and the current stages of research. For the most commonly used nanoparticle carriers, fabrication methods are also reviewed. This is followed by a review of computational simulations and models on nanoparticle-based drug delivery

A novel method of interference source direction-finding with an existing single antenna beam in communication satellites

Interference has recently become a critical factor in communication satellite performance, and the interference source location is one of the most important factors in resolving this issue. The article proposes an innovative method of interference source direction-finding suitable for communication satellites with an existing single antenna beam and single radio frequency (RF) channel, which utilizes the symmetry of the antenna pattern to search for interference sources. Compared to traditional position methods with time-frequency-synchronized multi-satellites or a directing antenna array in a single satellite, the method does not require any particular direction-finding payload in communication satellites and shares existing antennas and RF channels with communication systems in satellites. The ability to find the direction of the interference source is a software-defined function in the communication processor. The proposed method provides a novel way to solve the problems of interference source direction-finding with the least engineering complexity, and it has excellent coexistence with other existing systems in communication satellites. The computer simulation and out-field experiment results in this article show that the method has excellent performance with high direction-finding resolution within extensive coverage, offering significant value and bright prospects for resolving the growing interference issues in communication satellites

Muscle activation patterns and muscle synergies reflect different modes of coordination during upper extremity movement

A core issue in motor control is how the central nervous system generates and selects the muscle activation patterns necessary to achieve a variety of behaviors and movements. Extensive studies have verified that it is the foundation to induce a complex movement by the modular combinations of several muscles with a synergetic relationship. However, a few studies focus on the synergetic similarity and dissimilarity among different types of movements, especially for the upper extremity movements. In this study, we introduced the non-negative matrix factorization (NMF) method to explore the muscle activation patterns and synergy structure under 6 types of movements, involving the hand open (HO), hand close (HC), wrist flexion (WF), wrist extension (WE), supination (SU), and pronation (PR). For this, we enrolled 10 healthy subjects to record the electromyography signal for NMF calculation. The results showed a highly modular similarity of the muscle synergy among subjects under the same movement. Furthermore, Spearman’s correlation analysis indicated significant similarities among HO-WE, HO-SU, and WE-SU (p < 0.001). Additionally, we also found shared synergy and special synergy in activation patterns among different movements. This study confirmed the theory of modular structure in the central nervous system, which yields a stable synergetic pattern under the same movement. Our findings on muscle synergy will be of great significance to motor control and even to clinical assessment techniques

Postoperative hypothalamic-pituitary dysfunction and long-term hormone replacement in patients with childhood-onset craniopharyngioma

ObjectiveHypothalamic-pituitary axis dysfunction is a common complication in post-operative craniopharyngioma(CP) patients, and it greatly impacts the long-term quality of life of such patients. To better understand the effects of postoperative hypothalamic-pituitary dysfunction and long-term hormone replacement therapy in patients with childhood CP, we assessed approximately 200 patients with childhood-onset CP postoperatively.MethodsClinical details of patients with childhood-onset CP who underwent sellar tumor resection in Beijing Children’s Hospital and Beijing Tiantan Hospital from 2018 to 2019 were retrieved retrospectively. The participants were followed up to assess the effects of post-operative long-term hormone replacement therapy and assess the tumor recurrence rate.ResultsThe median age of admission was 8.1 (1.8, 14.3) years. Headache (45.5%), visual impairment (39.5%), and nausea (33.0%) were the most common clinical manifestations. ACP accounted for 95% of all CP cases. The incidence of central adrenal insufficiency and central hypothyroidism within the first week after surgery was 56.2% and 70.3%, respectively. At the same time 85.5% of the patients required at least one dose of desmopressin to control urine output. Total survival and tumor recurrence rates were 98.6% and 26.1%, respectively, with a median follow-up time of 29.7 (19.0, 40.3) months. During the follow-up period, 28.1% patients met the diagnostic criteria for short stature, while 54.4% fit the criteria for obesity. In addition, 94.4% of the patients were taking at least one kind of hormone substitution, and 74.7% were taking three or more. The prevalence of levothyroxine, glucocorticoid, desmopressin, and growth hormone replacement therapy was 87.3%, 77.5%, 78.9% and 31.0%, respectively. The proportion of patients treated with the substitutive combination of levothyroxine, hydrocortisone, and desmopressin was 54.9%.ConclusionThis study is a large-sample systematic postoperative endocrine function evaluation of patients with childhood-onset CP. Due to the high prevalence of post-operative hypothalamic-pituitary dysfunction, patients with CP usually require long-term multiple hormone substitution therapy. Individualized management and accurate hormone replacement dosage for postoperative childhood-onset CP patients are of great importance

Altered Brain Function in Treatment-Resistant and Non-treatment-resistant Depression Patients: A Resting-State Functional Magnetic Resonance Imaging Study

ObjectiveIn this study, we used amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) to observe differences in local brain functional activity and its characteristics in patients with treatment-resistant depression (TRD) and non-treatment-resistant depression (nTRD), and to explore the correlation between areas of abnormal brain functional activity and clinical symptoms.MethodThirty-seven patients with TRD, 36 patients with nTRD, and 35 healthy controls (HCs) were included in resting-state fMRI scans. ALFF and ReHo were used for image analysis and further correlation between abnormal brain regions and clinical symptoms were analyzed.ResultsANOVA revealed that the significantly different brain regions of ALFF and ReHo among the three groups were mainly concentrated in the frontal and temporal lobes. Compared with the nTRD group, the TRD group had decreased ALFF in the left/right inferior frontal triangular gyrus, left middle temporal gyrus, left cuneus and bilateral posterior lobes of the cerebellum, and increased ALFF in the left middle frontal gyrus and right superior temporal gyrus, and the TRD group had decreased ReHo in the left/right inferior frontal triangular gyrus, left middle temporal gyrus, and increased ReHo in the right superior frontal gyrus. Compared with the HC group, the TRD group had decreased ALFF/ReHo in both the right inferior frontal triangular gyrus and the left middle temporal gyrus. Pearson correlation analysis showed that both ALFF and ReHo values in these abnormal brain regions were positively correlated with HAMD-17 scores (P < 0.05).ConclusionAlthough the clinical symptoms were similar in the TRD and nTRD groups, abnormal neurological functional activity were present in some of the same brain regions. Compared with the nTRD group, ALFF and ReHo showed a wider range of brain area alterations and more complex neuropathological mechanisms in the TRD group, especially in the inferior frontal triangular gyrus of the frontal lobe and the middle temporal gyrus of the temporal lobe

Ultralight MOF-Derived Ni3S2@N, S-Codoped Graphene Aerogels for High-Performance Microwave Absorption

To develop high-performance microwave absorption materials with the features of lightweight, thin thickness, broad bandwidth, and strong absorption, an ultralight Ni3S2@N, S-codoped graphene aerogel with a density of 13.5 mg/cm3 has been fabricated by the use of metal-organic frameworks (MOFs) to directly initiate the gelation of graphene oxide strategy. In such a strategy, dual-functional 1D Ni-MOF nanorods not only act as the gelation agent but also afford the doping elements (N and S) originated from the organic species and the precursor for metal sulfide. Due to the synergistic effects of good impedance matching and multiple losses, the optimal reflection loss (RL) of as-prepared Ni3S2@N, S-codoped graphene aerogel reaches −46.9 dB at 17.1 GHz with only 2.0 mm and ultralow filling content (1.75 wt%). The maximum effective absorption bandwidth (EAB) reaches 6.3 GHz (11.7–18.0 GHz) at 2.38 mm, covering the whole Ku band. Moreover, the value of EAB with the RL less than −30 dB can be tuned to 12.2 GHz (5.8–18 GHz) at the absorber thickness ranging from 1.9 to 5.0 mm. This work provides insight for rational design and fabrication of multicomponent-containing graphene aerogels, showing the potential application in lightweight and high-performance microwave absorption