Controlled growth of single-crystalline erbium chloride silicate with long-lived fluorescence.

Single-crystalline erbium chloride silicates have attracted extensive attention due to their high gain compatibility and silicon compatible properties. Long-lived near-infrared fluorescence is critical for reducing a pump density threshold when erbium containing materials are used as active devices. Here we developed a single-source chemical vapor deposition (CVD) method to grow high-quality single-crystalline erbium chloride silicate nanostructures. The growth mechanism is found composing of two steps, where silicon source comes from the minor evaporation of silicon substrate. The prepared single-crystalline erbium chloride silicate nanowires own diameter of about 200 nm with few lattice defects, and the fluorescence lifetime reaches up to 7.4 ms. A nanoscale thermometer based on their visible band fluorescence is realized.

Erbium chloride silicate-based vertical cavity surface-emitting laser at the near-infrared communication band.

Silicon-based integrated optoelectronics has become a hotspot in the field of computers and information processing systems. An integrated coherent light source on-chip with a small footprint and high efficiency is one of the most important unresolved devices. Here, we realize a silicon-based vertical cavity surface-emitting laser in the near-infrared communication band by making efforts in both controlled preparation of high-gain erbium silicate materials and novel design of high optical feedback microcavity. Single-crystal erbium/ytterbium silicate microplates with erbium concentration as high as 5 × 1021 cm-3 are controlled prepared by a chemical vapor deposition method. They can produce strong luminescence with quite a long lifetime (2.3 ms) at the wavelength of 1.5 µm. By embedding the erbium silicate microplates between two dielectric Bragg reflectors, we construct a vertical cavity surface-emitting laser at 1.5 µm, with a lasing threshold as low as 20 µJ/cm2 and Q factor of nearly 2000. Our study provides a new pathway to achieve a sub-micrometer coherent light source for optical communication.

The immune response mechanism of Nilaparvata lugens against a combined infection of rice ragged stunt virus and Metarhizium anisopliae.

BACKGROUND: Previous studies of brown planthopper (BPH), Nilaparvata lugens, showed that carrying the plant pathogenic virus, rice ragged stunt virus (RRSV), enhanced the lethality of the entomopathogenic fungus, Metarhizium anisopliae (YTTR). The underlying mechanism for this was not established but a serine protease cascade was hypothesized to be involved. RESULTS: Two immune response genes, NlKPI and NlVenomase, were identified and shown to be involved. The synthesized double-strand RNA (dsRNA) techniques used in this study to explore gene function revealed that treatment with dsRNA to silence either gene led to a higher BPH mortality from M. anisopliae infection than the dsRNA control treatment. NlKPI and NlVenomase play vital roles in BPH immunity to defend against alien pathogens. Both genes participate in the immune response process of BPH against co-infection with RRSV and M. anisopliae YTTR by regulating the expression of antimicrobial peptides and phenoloxidase activity. CONCLUSION: Our study provided new targets for BPH biocontrol and laid a solid foundation for further research on the interaction of virus-insect-EPF (entomopathogenic fungus). © 2023 Society of Chemical Industry.

Simulation and evaluation of increased imaging service capacity at the MRI department using reduced coil-setting times.

The wait times for patients from their appointments to receiving magnetic resonance imaging (MRI) are usually long. To reduce this wait time, the present study proposed that service time wastage could be reduced by adjusting MRI examination scheduling by prioritizing patients who require examinations involving the same type of coil. This approach can reduce patient wait times and thereby maximize MRI departments' service times. To simulate an MRI department's action workflow, 2,447 MRI examination logs containing the deidentified information of patients and radiation technologists from the MRI department of a medical center were used, and a hybrid simulation model that combined discrete-event and agent-based simulations was developed. The experiment was conducted in two stages. In the first stage, the service time was increased by adjusting the examination schedule and thereby reducing the number of coil changes. In the second stage, the maximum number of additional patients that could be examined daily was determined. The average number of coil changes per day for the four MRI scanners of the aforementioned medical center was reduced by approximately 27. Thus, the MRI department gained 97.17 min/d, which enabled them to examine three additional patients per month. Consequently, the net monthly income of the hospital increased from US$17,067 to US$30,196, and the patient wait times for MRI examinations requiring the use of flexible torso and head, shoulder, 8-inch head, and torso MRI coils were shortened by 6 d and 23 h, 2 d and 15 h, 2 d and 9 h, and 16 h, respectively. Adjusting MRI examination scheduling by prioritizing patients that require the use of the same coil could reduce the coil-setting time, increase the daily number of patients who are examined, increase the net income of the MRI department, and shorten patient wait times for MRI examinations. Minimizing the operating times of specific examinations to maximize the number of services provided per day does not require additional personnel or resources. The results of the experimental simulations can be used as a reference by radiology department managers designing scheduling rules for examination appointments.

The specific binding of chlorogenic acid to human serum albumin.

Chlorogenic acid (CGA) is one of the most abundant polyphenol compounds in human diet. It is also an active component in traditional Chinese medicines which are used to treat various diseases. In this study, fluorescence spectroscopy in combination with UV-Vis absorption spectroscopy was employed to investigate the specific binding of CGA to human serum albumin (HSA) under the physiological conditions. In the mechanism discussion, it was proved that the fluorescence quenching of HSA by CGA is a result of the formation of CGA-HSA complex. Binding parameters calculating from Stern-Volmer method and Scatchard method showed that CGA bind to HSA with the binding affinities of the order 10(4) l mol(-1). The thermodynamic parameters studies revealed that the binding was characterized by negative enthalpy and positive entropy changes and the electrostatic interactions play a major role for CGA-HSA association. Site marker competitive displacement experiments demonstrated that CGA specific bind to site I (subdomain IIA) of HSA. The binding distance r (3.10 nm) between donor (Trp-214) and acceptor (CGA) was obtained according to fluorescence resonance energy transfer. Furthermore, the effect of metal ions on CGA-HSA system was studied.

Determination of the specific interaction between palmatine and bovine serum albumin.

The binding of palmatine to bovine serum albumin (BSA) was studied under physiological conditions (pH = 7.40) by molecular spectroscopic approach. It was proved that the fluorescence quenching of BSA by palmatine is a result of the formation of palmatine-BSA complex. Binding parameters were determined using the modified Stern-Volmer equation and Scatchard equation, to measure the specific binding between palmatine and BSA. The thermodynamic parameters calculated, ∆G°, ∆H° and ∆S° indicate that the electrostatic interactions play a major role in the palmatine-BSA association. Site marker competitive displacement experiments demonstrated that palmatine binds with specific affinity to site II (subdomain IIIA) of BSA. Furthermore, the specific binding distance r (3.36 nm) was obtained according to fluorescence resonance energy transfer. The results of synchronous fluorescence spectra and UV-Visible absorption spectra show that the conformation of bovine serum albumin has been changed.

Site-selective binding of human serum albumin by palmatine: spectroscopic approach.

In this study, fluorescence spectroscopy in combination with UV-vis absorption spectroscopy and circular dichroism (CD) spectroscopy was employed to investigate the high affinity binding of palmatine to human serum albumin (HSA) under the physiological conditions. In the mechanism discussion it was proved that the fluorescence quenching of HSA by palmatine is a result of the formation of palmatine/HSA complex. Binding parameters calculating from Stern-Volmer method and Scatchard method showed that palmatine bind to HSA with the binding affinities of the order 10(4) L.mol(-1). The thermodynamic parameters studies revealed that the binding was characterized by negative enthalpy and positive entropy changes and the electrostatic interactions play a major role for palmatine-HSA association. Site marker competitive displacement experiments demonstrating that palmatine bind with high affinity to site I (subdomain IIA) of HSA. The specific binding distance r (2.91 nm) between donor (Trp-214) and acceptor (palmatine) was obtained according to fluorescence resonance energy transfer (FRET). Furthermore, the CD spectral result indicates that the secondary structure of HSA was changed in the presence of palmatine.

Binding of berberine to bovine serum albumin: spectroscopic approach.

Fluorescence spectroscopy in combination with UV-vis absorption spectroscopy was employed to investigate the binding of an important traditional medicinal herb berberine to bovine serum albumin (BSA) under the physiological conditions. In the mechanism discussion, it was proved that the fluorescence quenching of BSA by berberine is a result of the formation of berberine-BSA complex. Fluorescence quenching constants were determined using the Stern-Volmer equation and Scatchard equation to provide a measure of the binding affinity between berberine and BSA. The results of thermodynamic parameters ΔG, ΔH, ΔS at different temperatures indicate that the electrostatic interactions play a major role for berberine-BSA association. Site marker competitive experiments indicated that the binding of berberine to BSA primarily took place in site II. Furthermore, the Effect of supramolecules to berberine-BSA system, and the distance r between donor (BSA) and acceptor (berberine) was obtained according to fluorescence resonance energy transfer (FRET).

Manganese waste water treatment by fungi derived from manganese slag.

The aim of this study was to isolate a mould from the surface of manganese slag which had strong resistance and high adsorption of Mn(2 + ), and to determine the effects of initial Mn(2 + ) concentration, incubation temperature, rotation speed and inoculation amount on adsorption of Mn(2 + ) from manganese waste water solution. The result showed that a mould (A5) which was isolated from manganese slag had the adsorption rate of Mn(2 + ) to 97.5% at the initial pH value 6, inoculation amount 2%, rotation speed 150 r/min, a concentration of Mn(2 + ) 500 mg/L, and a temperature of 28 degrees C cultivated for 50 h. As there is no research on adsorption of Mn(2 + ) from manganese waste water by fungi before, this research showed a theoretical guidance on this field.

Lanthanide salts of heteropoly molybdotungstosilicate LnHSiMo10W2O40·xH2O (Ln = Pr, Nd, Sm, Gd, Tb, Dy, Yb) binding to bovine serum albumin: a fluorescence quenching study.

In the present work, the interaction between a series of novel lanthanide salts of heteropoly molybdotungstosilicate LnHSiMo(10)W(2)O(40)·xH(2)O (LnW(2); Ln = Pr (x = 23), Nd (x = 24), Sm (x = 26), Gd (x = 20), Tb (x = 23), Dy (x = 21), Yb (x = 25)), and bovine serum albumin (BSA) was investigated by spectroscopic approach at different temperatures under imitated physiological conditions. In the mechanism discussion, it was proved that the fluorescence quenching of BSA by LnW(2) is a result of the formation of LnW(2)-BSA complex. Binding affinity between LnW(2) and BSA was determined using Scatchard equation and the modified Stern-Volmer equation, and the corresponding electronic structure-affinity relationship were discussed. The results of thermodynamic parameters ∆G, ∆H, ∆S at different temperatures indicate that the electrostatic interactions play a major role in LnW(2)-BSA binding process. Moreover, the enthalpy change (∆H) and entropy change (∆S) were in accordance with the "enthalpy-entropy compensation" equation obtained from this and previous work. Furthermore, the distance r between donor (BSA) and acceptor (LnW(2)) was obtained according to fluorescence resonance energy transfer.

Affinity and specificity of ciprofloxacin-bovine serum albumin interactions: spectroscopic approach.

Fluorescence spectroscopy in combination with UV-Vis absorption spectroscopy were employed to investigate the binding of an antibacterial drug Ciprofloxacin (CPFX) to bovine serum albumin (BSA) under the physiological conditions. In the discussion of the quenching mechanism, it was proved that the fluorescence quenching of BSA by CPFX is a result of the formation of CPFX-BSA complex. Binding parameters were determined using the modified Stern-Volmer equation and Scatchard equation to provide a measure of the binding affinity between CPFX and BSA. The results of thermodynamic parameters DeltaG, DeltaH, DeltaS, at different temperatures indicate that the electrostatic interactions play a major role for CPFX-BSA association. Site marker competitive experiments indicated that the binding of CPFX to BSA primarily took place in site I. Furthermore, the effect of metal ions to CPFX-BSA system was studied, and the distance r between donor (BSA) and acceptor (CPFX) was obtained according to fluorescence resonance energy transfer (FRET). The conformation of BSA upon CPFX binding was evaluated by measuring synchronous fluorescence properties of the CPFX-BSA complex.

Biological activation of heteropoly complex of molybdotungstosilicate containing lanthanum K10H 3La(SiMo6W5O39)2x26H2O: spectroscopic approach and microcalorimetry.

In this paper, the biological activation of heteropoly complex of molybdotungstosilicate containing lanthanum K(10)H(3)La(SiMo(6)W(5)O(39))(2)x26H(2)O (LaW(5)) was investigated by spectroscopic approach and microcalorimetry under the human physiological conditions. Fluorescence spectroscopy in combination with UV-Vis absorption spectroscopy was employed to investigate the binding of LaW(5) to bovine serum albumin (BSA). In the mechanism discussion, it was proved that the fluorescence quenching of BSA by LaW(5) is a result of the formation of LaW(5)-BSA complex. Binding parameters were determined using the Stern-Volmer equation. The results of thermodynamic parameters G, H, S at different temperatures indicate that van der Waals interactions and hydrogen bonds play a major role for LaW(5)-BSA association. The distance r between donor (BSA) and acceptor (LaW(5)) was obtained according to fluorescence resonance energy transfer. Furthermore, the calorimetric method was used to monitor the biological activity of LaW(5) in Escherichia coli.

A series of novel rare Earth molybdotungstosilicate heteropolyoxometalates binding to bovine serum albumin: spectroscopic approach.

Heteropolyoxometalate complexes have been widely applied in many fields. In this paper, the interaction between a series of novel rare earth molybdotungstosilicate heteropolyoxometalates, K(10)H(3)[Ln(SiMo(6)W(5)O(39))(2)].xH(2)O (abbr. LnW(5), Ln = Pr (x = 30), Gd (x = 29), Dy (x = 28), and Yb (x = 31)), and bovine serum albumin (BSA) was investigated by spectroscopic approach under the physiological conditions. In the mechanism discussion, it was proved that the fluorescence quenching of BSA by LnW(5) is a result of the formation of LnW(5)-BSA complex. Fluorescence quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between LnW(5) and BSA. The binding affinity ranked in the order GdW(5) > DyW(5) > PrW(5) > YbW(5). The results of thermodynamic parameters DeltaG, DeltaH, and DeltaS at different temperatures indicate that van der Waals interactions and hydrogen bonds play a major role for LnW(5)-BSA association. Furthermore, the distance r between donor (BSA) and acceptor (LnW(5)) was obtained according to fluorescence resonance energy transfer.

[Prevalence of fimA genotypes of Porphyromonas gingivalis and periodontal health status].

OBJECTIVE: To detect the distribution of fimA genotype of P. gingivalis in periodontally healthy adults and chronic periodontitis patients, and to investigate the relationship between the prevalence of fimA genotype of P. gingivalis and periodontal health status. METHODS: Subgingival plaque samples were collected from 136 periodontally healthy adults and 115 chronic periodontitis patients. The occurrence of P. gingivalis was determined by P. gingivalis 16S rRNA PCR. Distribution of fimA genotype was assessed in P. gingivalis positive samples by PCR using primers pairs homologous to the different fimA genes. RESULTS: P. gingivalis was detected in 22.1% of the healthy subjects and 81.7% of chronic periodontitis patients. A single fimA genotype was detected in most subgingival plaque samples. In P. gingivalis-positive healthy adults, the most prevalent fimA genotype of P. gingivalis was type I fimA. In contrast, a majority of chronic periodontitis patients carried type II fimA, followed by IV fimA and I b fimA. The univariate analysis illustrated that chronic periodontitis was associated with occurrences of type I fimA (OR = 0.97), I b (OR =13.26), II (OR = 36.62), III (OR = 4.57), IV (OR = 22.86), and V (OR = 1.19). CONCLUSION: II fimA genotype of P. gingivalis followed by IV and I b were an important virulence factor that may account for the pathogenesis of chronic periodontitis, suggesting an increased pathogenic potential of these types.

[Distribution of Haemopuilus actinomycetemcomitans in chronic periodontitis patients and periodontally healthy subjects].

OBJECTIVE: To investigate the prevalence of H. actinomycetemcomitans in Chinese chronic periodontitis (CP) patients and periodontally healthy adults. METHODS: 116 chronic periodontitis patients and 111 periodontally healthy adults were included. In each CP patient, subgingival plaque samples were collected from two sites of different molars with the greatest probing depth (PD) and one periodontally healthy site (PD < or =3 mm). The samples of periodontally healthy adults were obtained from the mesio-buccal site of one first upper molar. Bacteria DNA were extracted for detection of H. actinomycetemcomitans by 16S rRNA PCR. RESULTS: The prevalence for H. actinomycetemcomitans of diseased sites (33.62%) was significantly higher than that of healthy sites from CP patients (0.86%) and the periodontally sites (0.90%) (P < 0.01). No significant difference was observed between male and female CP patients (P > 0.05). A decreasing trend of H. actinomycetemcomitans was observed as the age increased. And the pocket depth and clinical attachment losswas associated with the occurrence of H. actinomycetemcomitans in a positive mode. And H. actinomycetemcomitans was more often detected in the bleeding sites on probing. CONCLUSION: H. actinomycetemcomitans was more frequently detected in periodontitis sites than periodontally healthy sites. For CP patients, a higher prevalence was associated with the seriously involved sites than those moderate and mild implicated sites. H. actinomycetemcomitans is considered to be the one of the periopathogens involved in the etiology of chronic periodontitis.