ER chaperone GRP78/BiP translocates to the nucleus under stress and acts as a transcriptional regulator.

Cancer cells are commonly subjected to endoplasmic reticulum (ER) stress. To gain survival advantage, cancer cells exploit the adaptive aspects of the unfolded protein response such as upregulation of the ER luminal chaperone GRP78. The finding that when overexpressed, GRP78 can escape to other cellular compartments to gain new functions regulating homeostasis and tumorigenesis represents a paradigm shift. Here, toward deciphering the mechanisms whereby GRP78 knockdown suppresses EGFR transcription, we find that nuclear GRP78 is prominent in cancer and stressed cells and uncover a nuclear localization signal critical for its translocation and nuclear activity. Furthermore, nuclear GRP78 can regulate expression of genes and pathways, notably those important for cell migration and invasion, by interacting with and inhibiting the activity of the transcriptional repressor ID2. Our study reveals a mechanism for cancer cells to respond to ER stress via transcriptional regulation mediated by nuclear GRP78 to adopt an invasive phenotype.

Unconstrained Piezoelectric Vascular Electronics for Wireless Monitoring of Hemodynamics and Cardiovascular Health.

The patient-centered healthcare requires timely disease diagnosis and prognostic assessment, calling for individualized physiological monitoring. To assess the postoperative hemodynamic status of patients, implantable blood flow monitoring devices are highly expected to deliver real time, long-term, sensitive, and reliable hemodynamic signals, which can accurately reflect multiple physiological conditions. Herein, an implantable and unconstrained vascular electronic system based on a piezoelectric sensor immobilized is presented by a "growable" sheath around continuously growing arterial vessels for real-timely and wirelessly monitoring of hemodynamics. The piezoelectric sensor made of circumferentially aligned polyvinylidene fluoride nanofibers around pulsating artery can sensitively perceive mechanical signals, and the growable sheath bioinspired by the structure and function of leaf sheath has elasticity and conformal shape adaptive to the dynamically growing arterial vessels to avoid growth constriction. With this integrated and smart design, long-term, wireless, and sensitive monitoring of hemodynamics are achieved and demonstrated in rats and rabbits. It provides a simple and versatile strategy for designing implantable sensors in a less invasive way.

Bimetallic Nickel Complexes as Effective and Versatile Catalysts for Copolymerization of Epoxides with Carbon Dioxide or Phthalic Anhydride: Catalysis and Kinetics.

This study reported three novel structurally well-characterized dihalide dinuclear nickel complexes containing benzotriazole-based 1,3-diamine-linked bisphenolate ligands, which were high-performance catalysts for ring-opening copolymerization (ROCOP) of cyclohexene oxide (CHO) and carbon dioxide (CO2). The dinickel diiodo 3 was shown to catalyze CO2 copolymerization of CHO with high activity (turnover frequency up to 2250 h-1), excellent selectivity (>99% polycarbonates, >99% carbonate repeated units), and good molecular weight controllability. Apart from CO2/CHO copolymerization, the most active complex 3 was found to effectively catalyze ROCOP of CHO with phthalic anhydride (PA). Not only has the controllable manner of 3 for PA/CHO copolymerization been proven but also a broad substrate scope for PA copolymerization of epoxides by the same complex has been achieved. Diverse terminal or internal epoxides were demonstrated to copolymerize PA by 3, producing the corresponding semiaromatic polyesters with good activity and excellent product selectivity. Kinetic studies for CHO copolymerization of CO2 or PA mediated by 3 were systematically investigated. For kinetics of PA/CHO copolymerization, it allowed us to propose the rate equation of -d[CHO]/dt = kp[3]1[PA]0[CHO]1, and such catalysis displayed a first-order dependence on both dinickel complex and CHO concentrations as well as a zero order for PA. This work offers a bimetallic dihalide nickel complex as an efficient and versatile catalyst for two different types of copolymerization catalysis.

Long noncoding RNA UFC1 acts as an oncogene via stimulating EZH2-induced inhibition of APC expression in renal cell carcinoma.

This study aimed to illustrate the biological functions of long noncoding RNA (lncRNA) UFC1 in the carcinogenesis and cancer development of renal cell carcinoma (RCC), and the potential molecular mechanism. UFC1 levels in RCC tissues and cell lines were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Diagnostic and prognostic potentials of UFC1 in RCC were assessed by depicting receiver operating characteristic (ROC) curves and Kaplan-Meier curves, respectively. After transfection with si-UFC1, proliferative and migratory changes in ACHN and A498 cells were detected by cell counting kit-8 (CCK-8) and transwell assay, respectively. Subsequently, chromatin immunoprecipitation (ChIP) was conducted to examine the enrichments of EZH2 (enhancer of zeste homolog 2) and H3K27me3 in the APC promoter region. Finally, rescue experiments were carried out to identify the co-regulation of UFC1 and APC on RCC cell behaviors. The results showed that UFC1 was highly expressed in RCC tissues and cell lines. ROC curves revealed the diagnostic potential of UFC1 in RCC. Besides, survival analysis showed that highly expressed UFC1 predicted poor prognosis in RCC patients. Knockdown of UFC1 in ACHN and A498 cells attenuated cell proliferative and migratory abilities. UFC1 was able to interact with EZH2, and the knockdown of UFC1 could upregulate APC. In addition, both EZH2 and H3K27me3 were enriched in the APC promoter region, which could be blocked by the knockdown of UFC1. Moreover, rescue experiments demonstrated that the silence of APC was able to abolish the inhibited proliferative and migratory abilities in RCC cells with UFC1 knockdown. LncRNA UFC1 inhibits APC level through upregulating EZH2, thus aggravating the carcinogenesis and cancer development of RCC.

Bleeding due to successive duodenal and rectal ulcers in an 81-year-old patient with severe COVID-19: a case report.

BACKGROUND: In the early stages of the coronavirus disease 2019 (COVID-19) outbreak, the most widely recognised symptoms of the disease were fever, cough, shortness of breath, myalgia, and fatigue. However, in addition to these symptoms, COVID-19 can cause systemic symptoms outside the lungs. Older patients with severe COVID-19 often require admission to the intensive care unit (ICU). Acute rectal ulcer bleeding, characterised by painless, profuse haematochezia, caused by solitary or multiple rectal ulcers, is one of the main causes of severe haematochezia in patients with COVID-19 in the ICU. However, recurrent duodenal ulcer bleeding followed by rectal ulcer bleeding has not previously been reported in older patients during ICU treatment for severe COVID-19. CASES PRESENTATION: Herein, we report the case of an 81-year-old woman admitted to the emergency department due to severe COVID-19 and transferred to the ICU 2 days later for treatment. During treatment in the ICU, the patient developed recurrent duodenal ulcer bleeding and underwent endoscopic electrocoagulation haemostasis and gastroduodenal artery embolisation. However, the night after the final haemostatic operation, due to rectal ulcer bleeding, the patient discharged bloody stools intermittently, which was effectively controlled using endoscopic electrocoagulation, topical medication, blood transfusion, and haemostatic drugs. CONCLUSIONS: To the best of our knowledge, this is the first report of duodenal ulcer bleeding followed by rectal ulcer bleeding in an older patient with severe COVID-19 infection. This report creates awareness for clinicians about the multiple and complex gastrointestinal symptoms that may occur during COVID-19 treatment.

Recent advances and applications to cultural heritage using ATR-FTIR spectroscopy and ATR-FTIR spectroscopic imaging.

Scientific investigation of cultural heritage objects plays a vital role in a responsible modern approach to conservation and archaeology. Recent advances in spectroscopy, such as the development of Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) spectroscopy and ATR-FTIR spectroscopic imaging, have opened up a window of opportunities for characterisation of materials in artefacts and collections from museums. This review summarises some of the recent advances and applications of these ATR-FTIR spectroscopic analytical techniques in the area of cultural heritage studies, including examples of cross-sections of oil paintings, paper, textiles, plastic objects, potteries, glasses and mineral artefacts. Two of the major advantages of ATR mode measurements are minimal or no requirements for sample preparation and its provision for high lateral spatial resolution. In addition to conventional single point detection, two-dimensional mapping and imaging is especially beneficial for chemical visualisation of multi-layered structure cultural objects. This review also explores the implications of these advantages as well as some limitations and provides a brief outlook for the possible future developments in this area.

Dinuclear Nickel Complexes Using Hexadentate Benzothiazole-Based Diamine-Bisphenolate Ligands: Highly Active Catalysts for Copolymerization of Carbon Dioxide with Epoxides.

We reported for the first time the utilization of hexadentate benzothiazole-based diamine-bisphenolate ligands to synthesize structurally well-characterized dinickel dicarboxylate complexes and studied their catalysis for copolymerization of carbon dioxide with epoxides. Dinickel carboxylate complexes having a 1,3-diamine-bridged backbone were demonstrated to be high-performance catalysts for alternating copolymerization of CO2 and cyclohexene oxide (CHO) with high product selectivity. Particularly, acetate-supported nickel complex 2 enabled us to promote such CO2-copolymerization of this kind with a maximum turnover frequency of up to 2600 h-1 and gave good molecular weight controllability under high-pressure conditions. It is worth noting that bimetallic Ni catalyst 2 was also capable of mediating the catalytic CO2-polymerization of alicyclic epoxides at atmospheric pressure. Kinetic investigations of CO2/CHO copolymerization by 2 allowed us to determine the rate equation of -d[CHO]/dt = kp[2]1[CHO]1, and such catalysis exhibited a first-order dependence on both dinickel complex and CHO concentrations.

Three-channel ion chromatograph for improved metabolic evaluation of urolithiasis.

BACKGROUND: Urolithiasis is a multi-etiological disease resulting from a combination of environmental and genetic factors. One of the most challenging aspects of this disease is its high recurrence rate. For most patients, an in-depth metabolic evaluation may reveal the presence of urinary stones. The fact that different urinary stone-related compounds (USRCs) are measured by different methods renders the metabolic evaluation of urolithiasis quite tedious and complex. METHODS: A three-channel ion chromatograph (IC) that automatically measures the concentration of common metabolic indicators of urolithiasis in urine (i.e., oxalate, citrate, uric acid, calcium, and magnesium) was developed to improve the efficiency. To validate its precision and specificity, standard curves were prepared using working solution of these indicators. 100 standard solutions of these indicators were measured with our new IC and three other ICs as the control instruments; analyte concentrations in 100 24-h urine samples from volunteers and 135 calculi patients were also measured. RESULTS: All analytes had good linear relationships in concentration ranges of 0-10 mg/L. The precision experiments in the standard and urine samples showed that the measurement errors of the newly developed IC were all less than 5%. In urine, the recovery rate ranged from 99.6 to 100.4%, the coefficient of variation ranged from 1.39 to 2.99%, and the results matched between our newly developed IC and the control ICs. The results of the efficiency test showed that we can finish the analysis at the average number of 14 people per day with the new IC. While the average number in the control group is 3.85/day (p = 0.000). CONCLUSIONS: Overall, this multi-channel system significantly improves the efficiency of metabolic evaluation while retaining accuracy and precision.

[Penoplasty with T-shaped incision and three-point fixation for concealed penis].

OBJECTIVE: To search for a safe and effective method of penoplasty with low incidence of complications for concealed penis by evaluating penoplasty with T-shaped incision and three-point fixation in comparison with modified Devine's technique. METHODS: We retrospectively analyzed 169 cases of concealed penis treated in our center by penoplasty with T-shaped incision and three-point fixation (group A, n = 110) or modified Devine's surgery (group B, n = 59). We compared the operation time, postoperative complications, and recurrence rate between the two groups of patients. RESULTS: Operations were successfully completed in all the cases, the urinary catheters removed at 3 days and the elastic bandages applied for 2 to 4 weeks. The patients were followed up for 4 to 12 months. The penis was satisfactorily exposed. The operative time was significantly shorter in group A than in B (ï¼»52.8 ± 6.9ï¼½ vs ï¼»61.5 ± 10.6ï¼½ min, P < 0.001), the postoperative complication rate was obviously lower in the former than in the latter (prepuce edema: 17.27% ï¼»19/110ï¼½ vs 33.89% ï¼»20/59ï¼½, P = 0.021; bleeding: 0.90% ï¼»1/110ï¼½ vs 3.38% ï¼»2/59ï¼½, P = 0.552; skin necrosis: 0.90% ï¼»1/110ï¼½ vs 5.08% ï¼»3/59ï¼½, P = 0.123; skin infection: 0.90% ï¼»1/110ï¼½ vs 5.08% ï¼»3/59ï¼½, P = 0.123), and so was the recurrence rate (0.90% ï¼»1/110ï¼½ vs 6.77% ï¼»4/59ï¼½, P = 0.032). CONCLUSIONS: Penoplasty with T-shaped incision and three-point fixation deserves to be popularized clinically for its advantages of minor invasion, clear exposure, reliable penile fixation, low incidence of postoperative complications and recurrence, and satisfactory outcomes.

[Etiological factors for calculus-associated seminal vesiculitis: Analysis of calculus composition in 6 cases].

OBJECTIVE: To explore the etiological factors for calculus-associated seminal vesiculitis by analyzing the composition of seminal vesicle calculus samples. METHODS: This retrospective study included 6 cases of recurrent hematospermia diagnosed with seminal vesicle calculus by non-contrast pelvic CT. The patients were aged 28 to 69 years, with persistent or recurrent hematospermia for 3 months to 6 years, and 5 of them with a history of acute urethritis. All the patients underwent seminal vesiculoscopy, which confirmed calculus-associated seminal vesiculitis. The calculus samples were obtained with a spiral dislodge and their composition was determined with a second-generation infrared calculus composition analyzer. The patients were followed up for 2 to 12 weeks postoperatively, during which non-contrast pelvic CT was employed for observation of recurrent calculus in the reproductive tract. RESULTS: Pelvic CT scanning indicated recurrence of seminal vesicle calculus in 3 cases at 12 weeks postoperatively, of which, 2 were accompanied with recurrent hematospermia, both observed at 4 weeks after operation. As for the composition of the calculus, the infrared calculus composition analyzer revealed struvite (magnesium ammonium phosphate hexahydrate) in 5 cases and a mixture of calcium oxalate dihydrate, calcium oxalate monohydrate, and carbonate apatite in the other one. CONCLUSIONS: Seminal vesicle calculi are most commonly composed of struvite, and infection is the main etiological factor for calculus-associated seminal vesiculitis.

[Application value of Toshiba 320-row dynamic volumetric CT angiography in the diagnosis of venous erectile dysfunction].

Objective: To investigate the application value of Toshiba 320-row dynamic volumetric CT angiography in the diagnosis of venous erectile dysfunction (VED). METHODS: We enrolled in this study 33 patients diagnosed with ED by audiovisual sexual stimulation screening in the outpatient department. Penile erection was induced in the patients by injection of 2 mg phentolamine plus 30 mg papaverine into the corpus cavernosum, followed by that of contrast agent of iobitridol through the vein and corpus cavernosum successively. Then 320-row dynamic volumetric CT angiography was performed and the images of the corpus cavernosum in the arterial and venous phases were collected and processed. RESULTS: Different degrees of abnormal venous drainage were observed in 29 of the patients, including 7 cases (24.1%) of back deep venous leakage, 6 cases (20.7%) of foot venous leakage, 3 cases (10.3%) of dorsal superficial venous leakage, 1 case (3.5%) of intervertebral venous leakage, 2 cases (6.9%) of cavernous venous leakage, and 10 cases (34.5%) of mixed venous leakage. Ten of the patients underwent surgery, dorsal deep penile vein ligation in 2 cases, dorsal deep vein embedding plus foot vein ligation in 4, and foot vein ligation in the other 4. Eight of the patients were followed up for 3－12 months post-operatively, during which 2 achieved obvious erectile improvement, while the other 6 gained normal penile erection. CONCLUSIONS: Toshiba 320-row dynamic volumetric CT angiography is a reliable method for the diagnosis of VED, which displays the precise location of venous leakage for clinical treatment, with the advantages of clearer images, lower doses of contrast agent and radiation, and faster examination than X-ray penile angiography.

Foldable and portable triboelectric-electromagnetic generator for scavenging motion energy and as a sensitive gas flow sensor for detecting breath personality.

An easily foldable and portable triboelectric-electromagnetic generator (TEMG) based on two polymer/Al layers and one copper coil has been designed to harvest ambient mechanical energy, where the copper coil is used both as a spring to achieve contact and separation of triboelectric layers and as a circuit to collect electromagnetic-induced electricity. The output performance of the TEMG is approximately reproducible after being folded many times. The working mechanism is discussed. The output performance of individual triboelectric generator (TEG) and electromagnetic generator (EMG) are systematically investigated. The maximum output current, voltage, and power are obtained to be 32.2 µA, 500 V, and 2 mW for the TEG, and 4.04 mA, 30 mV, and 15.8 µW for the EMG, respectively. The TEG with a higher internal resistance can be used as a current source, while the EMG with a lower resistance can be used as a voltage source. It can be used as a mobile light source via integrating the TEMG in clothes or bags, and as a self-powered gas flow sensor for detecting respiratory rate, which has a potential application in medical diagnoses. The simple structure and easy portability of the TEMG could be used widely in daily life to harvest ambient energy for electronic devices.

An adaptive fully convolutional network for bearing fault diagnosis under noisy environments.

Intelligent diagnostic algorithms based on convolutional neural networks (CNNs) have shown great potential in diagnosing various conditions. However, accurately and robustly diagnosing faults in noisy situations remains challenging. This study presents an adaptive fully convolutional network (AFCN) for identifying bearing defects in noisy environments. First, we use a novel large kernel convolution method for high-frequency noise reduction and wide-area temporal feature extraction. By utilizing a sequence of stacked residual adaptive convolution blocks, the AFCN achieves a selective emphasis on significant features and adaptive adjustment of feature weights at various convolution scales. The experimental results have shown that the AFCN achieves a diagnostic accuracy of over 90% for the faults in the CWRU dataset under the -8 dB noise and over 77% for the PU dataset in the case of -6 dB noise. The comparison results with five advanced baseline models have demonstrated the superiority of the AFCN in feature extraction, noise immunity, and robustness to the noise environment. The AFCN provides a better adaption to noise interference than conventional CNNs and other advanced adaptive networks.

Enhancing cellular behavior in repaired tissue via silk fibroin-integrated triboelectric nanogenerators.

Triboelectric nanogenerators (TENGs) have emerged as a promising approach for generating electricity and providing electrical stimuli in medical electronic devices. Despite their potential benefits, the clinical implementation of TENGs faces challenges such as skin compliance and a lack of comprehensive assessment regarding their biosafety and efficacy. Therefore, further research is imperative to overcome these limitations and unlock the full potential of TENGs in various biomedical applications. In this study, we present a flexible silk fibroin-based triboelectric nanogenerator (SFB-TENG) that features an on-skin substrate and is characterized by excellent skin compliance and air/water permeability. The range of electrical output generated by the SFB-TENG was shown to facilitate the migration and proliferation of Hy926, NIH-3T3 and RSC96 cells. However, apoptosis of fibroblast NIH-3T3 cells was observed when the output voltage increased to more than 20 V at a frequency of 2 Hz. In addition, the moderate electrical stimulation provided by the SFB-TENG promoted the cell proliferation cycle in Hy926 cells. This research highlights the efficacy of a TENG system featuring a flexible and skin-friendly design, as well as its safe operating conditions for use in biomedical applications. These findings position TENGs as highly promising candidates for practical applications in the field of tissue regeneration.

Structural Quality Factor of Flo-TENG under Stochastic Wave Excitation.

Triboelectric nanogenerators (TENGs) have recently emerged as a promising technology for efficient water wave energy harvesting. However, there is a paucity of clear guidance regarding the optimal designs of TENGs and their shells to achieve efficient absorption and conversion of water wave energy in real random waves. Herein, from the perspective of wave-body interaction and energy transfer, this paper proposes a structural quality factor (Qunit) for the quantitative evaluation of both the motion of floating triboelectric nanogenerator (Flo-TENG) shells and their capability to absorb and convert water wave energy efficiently. The factor is further subdivided into the amplitude structural quality factor (Qacc), which characterizes shell motion amplitude, and the frequency structural quality factor (Qf), which describes shell motion frequency. This paper systematically investigates the impact of various shell parameters such as bow shapes, curvatures, inclinations, and immersion ratios on Qacc and Qf. The findings indicate that variations in shell shape result in distinct Qunit values along different axial directions of wave propagation. These variations directly influence energy absorption efficiency in these directions. These results provide fundamental guidance for the design of high-performance Flo-TENG shells and the selection of internal energy harvesting directions to enable more efficient energy conversion.

Tetracosanuclear nickel complexes as effective catalysts for cycloaddition of carbon dioxide with epoxides.

A series of well-defined tetracosanuclear nickel complexes 3-7 facilely produced by one-pot synthesis were active catalysts for cycloaddition of CO2 and cyclohexene oxide (CHO). These nickel complexes were doughnut-like supramolecular coordination complexes involving eight repeating units, and each of them contains one Schiff base ligand and three nickel(II) ions. Notably, the 24-nuclear nickel cluster complex 3 in combination with nucleophilic additives was the most efficient catalyst to mediate CO2 coupling with CHO to generate CO2-based cis-cyclohexene carbonates. In addition to CO2/CHO cycloaddition, complex 3 was also found to effectively couple CO2 with other alicyclic epoxides, generating the corresponding cyclic carbonates. Additionally, kinetic investigations for CO2 cycloaddition of CHO using 3 were reported.

Polyethylene microplastic modulates lettuce root exudates and induces oxidative damage under prolonged hydroponic exposure.

Root exudates are pivotal in plant stress responses, however, the impact of microplastics (MPs) on their release and characteristics remains poorly understood. This study delves into the effects of 0.05 % and 0.1 % (w/w) additions of polyethylene (PE) MPs on the growth and physiological properties of lettuce (Lactuca sativa L.) following 28 days of exposure. The release characteristics of root exudates were assessed using UV-vis and 3D-EEM. The results indicated that PE increased leaf number but did not significantly affect other agronomic traits or pigment contents. Notably, 0.05 % PE increased the total root length and surface area compared to the 0.1 % addition, while a non-significant trend towards decreased root activity was observed with PE MPs. PE MPs with 0.1 % addition notably reduced the DOC concentration in root exudates by 37.5 %, while 0.05 % PE had no impact on DOC and DON concentrations. PE addition increased the SUVA254, SUVA260, and SUVA280 values of root exudates, with the most pronounced effect seen in the 0.05 % PE treatment. This suggests an increase of aromaticity and hydrophobic components induced by PE addition. Fluorescence Regional Integration (FRI) analysis of 3D-EEM revealed that aromatic proteins (region I and II) were dominant in root exudates, with a slight increase in fulvic acid-like substances (region III) under 0.1 % PE addition. Moreover, prolonged PE exposure induced ROS damage in lettuce leaves, evidenced by a significant increase in content and production rate of O2·-. The decrease in CAT and POD activities may account for the lettuce's response to environmental stress, potentially surpassing its tolerance threshold or undergoing adaptive regulation. These findings underscore the potential risk of prolonged exposure to PE MPs on lettuce growth.

Closed-Loop Wearable Device Network of Intrinsically-Controlled, Bilateral Coordinated Functional Electrical Stimulation for Stroke.

Innovative functional electrical stimulation has demonstrated effectiveness in enhancing daily walking and rehabilitating stroke patients with foot drop. However, its lack of precision in stimulating timing, individual adaptivity, and bilateral symmetry, resulted in diminished clinical efficacy. Therefore, a closed-loop wearable device network of intrinsically controlled functional electrical stimulation (CI-FES) system is proposed, which utilizes the personal surface myoelectricity, derived from the intrinsic neuro signal, as the switch to activate/deactivate the stimulation on the affected side. Simultaneously, it decodes the myoelectricity signal of the patient's healthy side to adjust the stimulation intensity, forming an intrinsically controlled loop with the inertial measurement units. With CI-FES assistance, patients' walking ability significantly improved, evidenced by the shift in ankle joint angle mean and variance from 105.53° and 28.84 to 102.81° and 17.71, and the oxyhemoglobin concentration tested by the functional near-infrared spectroscopy. In long-term CI-FES-assisted clinical testing, the discriminability in machine learning classification between patients and healthy individuals gradually decreased from 100% to 92.5%, suggesting a remarkable recovery tendency, further substantiated by performance on the functional movement scales. The developed CI-FES system is crucial for contralateral-hemiplegic stroke recovery, paving the way for future closed-loop stimulation systems in stroke rehabilitation is anticipated.

Terahertz surface plasmon sensor for distinguishing gasolines.

Gasolines of two different octane numbers are experimentally distinguished using a thin metal sheet perforated with a periodic hole array terahertz surface plasmon (SP) sensor. This sensor is proved to be very sensitive to the change in permittivities of analytes. The differences between the gasolines 93# and 97# in composition lead to various refractive indices, permittivities, and absorption coefficients, thus varying their interactions with surface waves on the sensor, which enables a distinction of 6 GHz between the two octane numbers in the transmission peaks. The freestanding SP sensor is effective and reliable and can be simply employed in analyte distinction, which has potential applications in the petroleum industry.

Surface plasmon-enhanced terahertz spectroscopic distinguishing between isomers in powder form.

The effect of a dielectric overlayer on terahertz transmission through a freestanding metallic array of subwavelength holes is experimentally presented. There is a remarkable resonance redshift from 0.600 to 0.498 THz at the surface plasmon (SP) metal-dielectric resonance mode with increasing film thickness. When the overlayer film is thicker than a critical thickness, the resonance frequency becomes steady at the final resonance frequency ω(f). On the basis of the dispersion relation of SPs, two kinds of glutamic acid enantiomers are distinguished by use of SP-enhanced terahertz spectra of metallic array of subwavelength holes according to the result of ω(f). The terahertz plasmonic hole array with the sensitive nature provides an approach to distinguish trace amount of powder substances, which has a promising application prospect in the fields of public security and biomedical science, such as distinguishing between isomers and identifying expensive medicines and drugs.