Broad/narrowband switchable terahertz absorber based on Dirac semimetal and strontium titanate for temperature sensing.

A broadband and narrowband switchable terahertz (THz) absorber based on a bulk Dirac semimetal (BDS) and strontium titanate (STO) is proposed. Narrowband and broadband absorption can be switched by adjusting the Fermi level of the BDS. When the Fermi level of the BDS is 100 meV, the device is an absorber with three narrowband absorption peaks. The frequencies are 0.44, 0.86, and 1.96 THz, respectively, when the temperature of STO is 250 K. By adjusting the temperature of STO from 250 to 500 K, the blue shifts of the frequencies are approximately 0.14, 0.32, and 0.60 THz, respectively. The sensitivities of the three absorption peaks are 0.56, 1.27, and 2.38 GHz/K, respectively. When the Fermi level of the BDS is adjusted from 100 to 30 meV, the device can be switched to a broadband absorber with a bandwidth of 0.70 THz. By adjusting the temperature of STO from 250 to 500 K, the central frequency shifts from 1.40 to 1.79 THz, and the bandwidth broadens from 0.70 to 0.96 THz. The sensitivity of the central frequency is 1.57 GHz/K. The absorber also has a wide range of potential applications in multifunctional tunable devices, such as temperature sensors, stealth equipment, and filters.

Multifunctional terahertz absorber based on the Dirac semimetal and vanadium dioxide.

In this paper, a multifunctional terahertz (THz) absorber based on Dirac semimetal and vanadium dioxide (V O 2) is proposed. By modulating the temperature of V O 2, the absorber can be switched between the narrow band and wide band. When V O 2 is in the metallic state, the absorber has a broadband absorption effect with a bandwidth of approximately 4 THz. It has the advantages of insensitivity to polarization and wide-angle absorption. When V O 2 is in the insulating state, the absorber has two absorption peaks with absorptivity exceeding 90% and sensitivities of 297.7 and 402 GHz/RIU, and thus can be used as a highly sensitive sensor for cell detection. When the Fermi level of the Dirac semimetal is changed, the absorption characteristics can be modulated. The absorber has broad application prospects in multifunctional modulated devices.

High-performance dual-tunable terahertz absorber based on strontium titanate and bulk Dirac semimetal for temperature sensing and switching function.

In this study, a perfect metamaterial absorber based on strontium titanate and bulk Dirac semimetals is proposed. When the temperature of strontium titanate was 300K, the dual-band absorptions were 99.74% and 99.99% at 1.227 and 1.552 THz, respectively. The sensitivities based on a transverse magnetic (TM) wave were 0.95 and 1.22 GHz/K; the sensitivity based on a transverse electric (TE) wave was 0.76 GHz/K. The TE and TM waves were modulated by inserting a bulk Dirac semimetal between the concave and convex devices. The modulation depth of the TE wave was 97.9% at 1.1 THz; the extinction ratio was 16.9 dB. The modulation depth of the TE wave at 1.435 THz was 95.9%; the extinction ratio was 13.89 dB. The TM wave modulation depth at 1.552 THz was 95.9%; the extinction ratio was 13.98 dB. Irrespective of a TE or TM wave, the terahertz absorber has good switching and temperature-sensing performance based on strontium titanate and bulk Dirac semimetals as well as broad application prospects in temperature sensing and switching devices.

[Automatic Delineation of Clinical Target Volume and Organ at Risk by Deep Learning for Prostate Cancer Adaptive Radiotherapy].

Adaptive radiotherapy can modify the treatment plan online based on the clinical target volume (CTV) and organ at risk (OAR) contours on the cone-beam CT (CBCT) before treatment, improving the accuracy of radiotherapy. However, manual delineation of CTV and OAR on CBCT is time-consuming. In this study, a deep neural network-based method based on U-Net was purposed. CBCT images and corresponding mask were used for model training and validation, showing superior performance in terms of the segmentation accuracy. The proposed method could be used in the clinic to support rapid CTV and OAR contouring for prostate adaptive radiotherapy.

Facial-Meridional Isomerization and Reductive Elimination in [(R2P-o-C6H4)2N]PtMe3 (R = Ph, iPr).

Treatment of PtMe3I in tetrahydrofuran with either in situ prepared [R-PNP]Li ([R-PNP]- = [(R2P-o-C6H4)2N]-; R = Ph, iPr) or H[R-PNP] in the presence of triethylamine at room temperature affords quantitatively fac-[R-PNP]PtMe3. Thermolysis of fac-[R-PNP]PtMe3 in benzene solutions generates mer-[R-PNP]PtMe3 and ultimately [R-PNP]PtMe and ethane. Complexes mer-[R-PNP]PtMe3 represent the first meridional trialkylplatinum(IV) derivatives to date.

Elusive Scorpionates: C3-Symmetric, Formally Dianionic, Facially Tridentate Ligands.

The reaction of AlCl3 with [(2-HO-3,5-tBu2C6H2)3P] (H3[O3P]) results in AlCl[O3PH] ([O3PH]2- = [(2-O-3,5-tBu2C6H2)3PH]2-), which is a zwitterionic molecule containing an unprecedented C3-symmetric but formally dianionic chelate. Derivatization of [O3PH]2- gives [O3PR]2- (R = hydrocarbon), demonstrating the development of a novel class of long elusive scorpionates.

Genome-wide analysis of MATE transporters and molecular characterization of aluminum resistance in Populus.

Ionic aluminum (Al) in acidic soils, comprising approximately 50% of arable land globally, is highly toxic to most plant species. Populus grow naturally in acidic soils and tolerate high concentrations of Al. Multidrug and toxic compound extrusion (MATE) family genes in plants are involved in responses to Al tolerance. To date, however, the functional roles of the MATE genes in Populus remain unclear. In the present study, 71 putative MATE transporters were predicted in the genome of Populus trichocarpa. The chromosome distribution, phylogenetic relationships, and expression level analysis revealed that four candidate MATE genes belonging to subgroup IIIc might contribute to high Al tolerance in poplar. Further, the expression levels of two subgroup IIIc members, PtrMATE1 and PtrMATE2, were induced by Al stress. Transient expression in onion epidermal cells showed that PtrMATE1 was localized to the plasma membrane. Overexpression of PtrMATE1 increased Al-induced secretion of citrate from the root apex of transgenic plants. Al-induced inhibition of root growths were alleviated in both PtrMATE1 overexpression lines in Populus and in Arabidopsis compared with wild-type plants. In addition, PtrMATE1 expression was induced at 12 h after exposure to Al stress whereas PtrMATE2 expression was induced at 24 h, indicating that these proteins coordinately function in response to Al stress in poplar. Taken together, these results provide important insights into the molecular mechanisms involved in Al tolerance in poplar.

Enhancement of recombinant BmK AngM1 production in Pichia pastoris by regulating gene dosage, co-expressing with chaperones and fermenting in fed-batch mode.

The scorpion peptide BmK AngM1 was reported to exhibit evident analgesic effect, but its yield by extraction from scorpion venom limits the research and application. The heterologous expression of BmK AngM1 was achieved in Pichia pastoris in our previous study. In order to realize high-level expression of recombinant BmK AngM1 (rBmK AngM1), the gene dosage of BmK AngM1 was optimized in engineered strains. The yield of rBmK AngM1 in the four-copy strain reached up to 100 mg/L, which was further enhanced to 190 mg/L by co-expressing with chaperones of PDI, BiP, and HAC1. Moreover, the yield of rBmK AngM1 was up to 1200 mg/L by high-density fermentation in 10 L fermenter. Finally, 360 mg rBmK AngM1 was purified from 1 L cultures by a two-step purification method. The efficient and convenient techniques presented in this study could facilitate further scale-up for industrial production of rBmK AngM1.

The Role of Phonological Processing in Semantic Access of Chinese Characters: A Near-Infrared Spectroscopy Study.

The Stroop task was used to investigate the role of phonological processing in semantic access for written Chinese language. Fourteen children were recruited to perform the Stroop task, using color characters, their homophones and neutral characters as stimuli. Near-infrared spectroscopy (NIRS) was used to measure the brain activation in the prefrontal cortex (PFC) during the task. In view of better sensitivity, oxy-hemoglobin was chosen to indicate the task activation. In behavioral performance, there was a significant classical Stroop interference effect as indexed by longer response time and higher error rate for the color task than the neutral task, whereas there was no evident interference effect for the color homophones. The NIRS data agreed with the behavioral data, and showed a significant Stroop effect only for the color characters in the bilateral PFC. These results suggested that phonology may not play an important role in semantic activation of Chinese characters for children.

[Research Progress of Electromagnetic Metasurface Used for Radar Cross Section Reduction in Microwave and Terahertz Wave].

Electromagnetic metasurface with many special electromagnetic properties can be utilized to manipulate electromagnetic wave propagation and reflection. If the metasurfaces were designed for coding, random, phase discontinuities, perfect absorber and so on，they can manipulate the scattering or the reflection of electromagnetic wave and achieve the reduction of the radar cross section(RCS). This paper mainly presents the recent progress concerning the reduction of RCS using non - directional scattering or the absorption characteristic in microwave and terahertz wave. The analysis results show that coding electromagnetic metasurface can disperse the reflection into a variety of direction by designing the specific coding sequences for different elements. The coding metasurface which are composed of different digital elements, and the reflection phase difference of these digital elements is constant in a wide frequency range, and higher bit coding metasurface can flexible manipulate electromagnetic wave. The random electromagnetic metasurface can achieve broadband phase shifter by adjusting the size parameters of array element, and can diffuse characteristic by scattering into random wave of the reflection peaks for metal target. Phase discontinuities metasurface can achieve anomalous or diffuse of wave because the phase distribution is not uniform at the surface. The absorber metasurfaces which are designed reasonably with the physical dimensions of the devices can reduce reflection by absorbing electromagnetic wave energy. So, the electromagnetic metasurfaces have a large potential application for radar stealth, broadband communications, imaging and so on. Finally, we discussed the future development of RCS reduction by using the electromagnetic metasurface. In order to satisfy the needs of practical application, the research of metasurface will continue development in broadband, flexible, large angle and other aspects.

Homo- and Heteropolynuclear Clusters of Phosphine Triphenolates.

The synthesis and structural characterization of a series of homo- and heteropolynuclear clusters constructed with a potentially tetradentate phosphine triphenolate ligand are presented. Treatment of tris(3,5-di-tert-butyl-2-hydroxyphenyl)phosphine (H3[O3P]) with 3 equiv of nBuLi in diethyl ether at -35 °C affords hexanuclear Li6[O3P]2(OEt2)2 (1) as colorless crystals. In situ lithiation of H3[O3P] with 3 equiv of nBuLi in THF at -35 °C followed by metathetical reactions with MnCl2 or NiCl2(DME) gives crystals of forest green pentanuclear MnLi4[O3P]2(THF)3 (2) or dark brown tetranuclear Ni2Li2[O3P]2(THF)2 (3), respectively. Alkane elimination of ZnR2 (R = Me, Et) with H3[O3P] in THF at 25 °C generates high yields of colorless crystalline trinuclear Zn3[O3P]2(THF)2 (4). The cluster structures of 1-4 were all determined by single crystal X-ray diffraction studies. These molecules represent the first examples of metal complexes supported by phosphine triphenolate derivatives. The cluster 2 contains a paramagnetic core of high spin Mn(II) (S = 5/2) as indicated by solution and solid state magnetic susceptibility measurements.

[The expression of BmK AngM1 in Mut(s) and Mut(+) recombinants of Pichia pastoris].

BmK AngM1 is a long-chain scorpion toxin purified from the venom of Buthus martensii Karsch. It has been reported to exhibit evident analgesic effect and low toxicity, and has the potential to be a novel analgesic drug. The BmKAngM1 gene was transformed into Pichiapastoris GS115. Mut+ and Mut(s) recombinant strains were screened by phenotype and Mut+ recombinant strains were used to detect BmK AngMl gene copy number in the real-time PCR. Expression of BmK AngM1 in the Mut+ recombinant strain was compared with that of the Mut(s) recombinant strain with the same single copy of BmK AngM1 gene under the same condition. The results indicated that the transcription level of BmK AngM1 gene in the Mut(s) recombinant strain was 2.7 fold of that in the Mut recombinant strain in the real-time PCR, and the expression of BmK AngM 1 in the Mut(s) recombinant strain was 1.5 fold of that in the Mut+ recombinant strain. Therefore, Mut(s) recombinant strain showed better ability to express BmK AngM1 than Mut+ recombinant strain.

[Research progress in the application of biosensors by using metamaterial in terahertz wave].

In the present paper, the recent progress in terahertz metamaterials-based sensing is reviewed with the principle of metamaterial biosensor,metamaterial substrate, and structure design, respectively. The paper introduces the principle in detail, analyzes the sensitivity of the biosensor with the material and the thickness of the substrate and the structure of metamaterial. The analysis shows that we can enhance the sensitivity and resolution of biosensor by designing specific metamaterial structure, using low dielectric constant and low loss thin substrate, especially many materials have a specific response in the terahertz frequency. So, there is a large potential application for label-free sensing by using the terahertz metamaterials. This paper also presents the future development of THz metamaterial sensors.

Rural Hospitals Experienced More Patient Volume Variability Than Urban Hospitals During The COVID-19 Pandemic, 2020-21.

Fluctuations in patient volume during the COVID-19 pandemic may have been particularly concerning for rural hospitals. We examined hospital discharge data from the Healthcare Cost and Utilization Project State Inpatient Databases to compare data from the COVID-19 pandemic period (March 8, 2020-December 31, 2021) with data from the prepandemic period (January 1, 2017-March 7, 2020). Changes in average daily medical volume at rural hospitals showed a dose-response relationship with community COVID-19 burden, ranging from a 13.2 percent decrease in patient volume in periods of low transmission to a 16.5 percent increase in volume in periods of high transmission. Overall, about 35 percent of rural hospitals experienced fluctuations exceeding 20 percent (in either direction) in average daily total volume, in contrast to only 13 percent of urban hospitals experiencing similar magnitudes of changes. Rural hospitals with a large change in average daily volume were more likely to be smaller, government-owned, and critical access hospitals and to have significantly lower operating margins. Our findings suggest that rural hospitals may have been more vulnerable operationally and financially to volume shifts during the pandemic, which warrants attention because of the potential impact on these hospitals' long-term sustainability.

Mortality for Time-Sensitive Conditions at Urban vs Rural Hospitals During the COVID-19 Pandemic.

Importance: COVID-19 pandemic-related disruptions to the health care system may have resulted in increased mortality for patients with time-sensitive conditions. Objective: To examine whether in-hospital mortality in hospitalizations not related to COVID-19 (non-COVID-19 stays) for time-sensitive conditions changed during the pandemic and how it varied by hospital urban vs rural location. Design, Setting, and Participants: This cohort study was an interrupted time-series analysis to assess in-hospital mortality during the COVID-19 pandemic (March 8, 2020, to December 31, 2021) compared with the prepandemic period (January 1, 2017, to March 7, 2020) overall, by month, and by community COVID-19 transmission level for adult discharges from 3813 US hospitals in the State Inpatient Databases for the Healthcare Cost and Utilization Project. Exposure: The COVID-19 pandemic. Main Outcomes and Measures: The main outcome measure was in-hospital mortality among non-COVID-19 stays for 6 time-sensitive medical conditions: acute myocardial infarction, hip fracture, gastrointestinal hemorrhage, pneumonia, sepsis, and stroke. Entropy weights were used to align patient characteristics in the 2 time periods by age, sex, and comorbidities. Results: There were 18 601 925 hospitalizations; 50.3% of patients were male, 38.5% were aged 18 to 64 years, 45.0% were aged 65 to 84 years, and 16.4% were 85 years or older for the selected time-sensitive medical conditions from 2017 through 2021. The odds of in-hospital mortality for sepsis increased 27% from the prepandemic to the pandemic periods at urban hospitals (odds ratio [OR], 1.27; 95% CI, 1.25-1.29) and 35% at rural hospitals (OR, 1.35; 95% CI, 1.30-1.40). In-hospital mortality for pneumonia had similar increases at urban (OR, 1.48; 95% CI, 1.42-1.54) and rural (OR, 1.46; 95% CI, 1.36-1.57) hospitals. Increases in mortality for these 2 conditions showed a dose-response association with the community COVID-19 level (low vs high COVID-19 burden) for both rural (sepsis: 22% vs 54%; pneumonia: 30% vs 66%) and urban (sepsis: 16% vs 28%; pneumonia: 34% vs 61%) hospitals. The odds of mortality for acute myocardial infarction increased 9% (OR, 1.09; 95% CI, 1.06-1.12) at urban hospitals and was responsive to the community COVID-19 level. There were significant increases in mortality for hip fracture at rural hospitals (OR, 1.32; 95% CI, 1.14-1.53) and for gastrointestinal hemorrhage at urban hospitals (OR, 1.15; 95% CI, 1.09-1.21). No significant change was found in mortality for stroke overall. Conclusions and Relevance: In this cohort study, in-hospital mortality for time-sensitive conditions increased during the COVID-19 pandemic. Mobilizing strategies tailored to the different needs of urban and rural hospitals may help reduce the likelihood of excess deaths during future public health crises.

Titanium complexes of tridentate aminebiphenolate ligands containing distinct N-alkyls: profound N-substituent effect on ring-opening polymerization catalysis.

The synthesis, structural characterization, and reactivity studies of titanium complexes supported by tridentate amine biphenolate ligands of the type [RN(CH(2)-2-O-3,5-C(6)H(2)(tBu)(2))(2)](2-) {[R-ONO](2-); R = tBu (1a), iPr (1b), nPr (1c)} are described. Alcoholysis of Ti(OiPr)(4) with H(2)[1a-1c] in diethyl ether solutions at 25 °C generates quantitatively the corresponding [R-ONO]Ti(OiPr)(2) (2a-2c) as a yellow crystalline solid. X-ray diffraction studies of 2b and 2c showed them to be five-coordinate, trigonal-bipyramidal species. Ring-opening polymerization of ε-caprolactone (ε-CL) catalyzed by 2b and 2c proved to be living, as evidenced by the narrow molecular weight distributions of the derived polymers and the linear dependence of number-averaged molecular weights on the monomer-to-catalyst ratios or polymerization time. Kinetic studies revealed that the polymerization rates are first-order in the concentration of ε-CL and first-order in that of 2b and 2c. The propagation rate of 2c is ca. 15 times faster than that of 2b, highlighting a profound substituent effect of primary versus secondary N-alkyls. In sharp contrast, reactions employing catalytic 2a produce either low-molecular-weight oligomers or polymers characteristic of somewhat wider molecular weight distributions, depending on the polymerization temperatures.

Zirconium and hafnium complexes containing N-alkyl-substituted amine biphenolate ligands: unexpected ligand degradation and divergent complex constitutions governed by N-alkyls.

The reactivity and thermal stability of zirconium and hafnium complexes containing the N-alkyl-substituted amine biphenolate ligands of the type [RN(CH2-2-O-3,5-C6H2(tBu)2)2](2-) ([R-ONO](2-); R = tBu (1a), iPr (1b), or nPr (1c)) were investigated. The reactions of either [1a]M(OiPr)2 (M = Zr or Hf) with equimolar H2[1a] or M(OiPr)4(HOiPr) (M = Zr or Hf) with 2 equiv of H2[1a] at 25 °C in diethyl ether or 80 °C in toluene afford moderate yields of colorless crystals of M[1a](OiPr)(iPrOCH2-2-O-3,5-C6H2(tBu)2) (M = Zr (4a) or Hf (5a)). Controlled experiments revealed that the production of 4a and 5a proceeds via unexpected thermal degradation of H2[1a] that produces a highly reactive, transient ortho-quinone methide intermediate. Similar reactions employing H2[1b] and H2[1c], however, led to the formation of homoleptic bis-ligand complexes Zr[1b]2 (8b) and M[1c]2 (M = Zr (8c) or Hf (9c)) as colorless crystals. Decisive factors governing these divergent reaction pathways and complex constitutions are discussed. The X-ray structures of 4a, 5a, 8b, 8c, and 9c are presented.

Concentration of plasma neutrophil gelatinase-associated lipocalin in patients with chronic kidney disease.

BACKGROUND: The inclining incidence of chronic kidney disease which has led to high mortality and immense medical burden over the past decades has become a distressing concern in epidemiology. Unfortunately, the number of biomarkers that allow the monitoring of chronic kidney disease (CKD) is limited. Neutrophil gelatinase-associated lipocalin (NGAL) is an emerging biomarker which has been shown to be able to diagnose kidney injuries. METHODS: Eighty-one nondiabetic patients with chronic kidney disease, stage 2 to 5, were recruited for this study, and 17 healthy volunteers with eGFR greater than 90 mL/minute/1.73m(2) were selected as the control group. RESULTS: Our study demonstrated that the pNGAL level is elevated during CKD, and the pNGL level has a strong correlation with the concentration of sCr and eGFR. CONCLUSIONS: Plasma neutrophil gelatinase-associated lipocalin is a potent tool in the diagnosis of chronic kidney diseases and is shown to have high correlation with serum creatinine and estimated glomerular filtration rate.

[Research on application of fluorescence spectrum imaging method in Banlangen granule quality evaluation].

The curative effect of Banlangen granule is directly affected by its quality, so it is very important to choose a kind of effective method for testing it. The chemical treatment is needed as a pre-treatment for the quality testing by using common method at present, which will change or destroy the sample. For dealing with this problem, in the present paper, a fluorescence spectrum imaging experimental system based on LCTF (liquid crystal tunable filter) is set up to detect the characteristics fluorescence spectrum of Banlangen granules. The characteristic fluorescence spectrum curve of Banlangen standard material provided by Chinese Food Drugs Examination Research Institute is used as a reference substance for a comparison with other Banlangen granules. By normalizing the corresponding characteristic fluorescence spectrum of Banlangen granules of different raw materials, different manufacturers and different batches, the relationship between the characteristic fluorescence spectrum curve and the quality of Banlangen granule is discussed by using the method of comparative and cluster analysis. The experimental results show that the qualities of Banlangen granules are quite different from different manufacturers, which are basically reflected by the change in the intensity of fluorescence and peak position. All of these indicate that fluorescence spectrum imaging technology is a simple, rapid and nondestructive detection method for the quality control of Banlangen granule.

Influence and mechanism of water matrices on H2O2-based Fenton-like oxidation processes: A review.

Water matrices often coexist with the target pollutant during H2O2-based Fenton-like processes, which affects H2O2 activation and pollutant removal. Specifically, water matrices include inorganic anions (such as chloride, sulfate, nitrate, bicarbonate, carbonate and phosphate ions) and natural organic matters (such as humic acid (HA) and fulvic acid (FA)). In this review, the roles and mechanisms of water matrices in various Fenton-like systems were analyzed and summarized comprehensively. Carbonate and phosphate ions usually act as inhibitors. In contrast, the effects of other water matrices are usually controversial. Generally, water matrices can inhibit pollutants degradation through scavenging OH, forming low reactive radicals, adsorbing on catalyst sites, and changing solution pH. However, inorganic anions can exhibit a promotion effect, which is attributed to their complexation with copper ions in mixed contaminants as well as with cobalt and copper ions in catalysts. Furthermore, the photo-reactivity of nitrate and the generation of secondary radicals with long lifetime are conducive to the promotion of inorganic anions. Besides, HA (FA) can be activated by external energy or act as electron shuttle, thus displaying a facilitative effect. This review will provide guidance for the practical applications of the Fenton-like process.