Fast MHz spectral-resolution dual-comb spectroscopy with electro-optic modulators.

Frequency-agile dual-comb spectroscopy (DCS) with electro-optic modulators (EOMs) promises to facilitate the implementation of DCS in many environmental applications. In this Letter, we demonstrate a 1 MHz resolution electro-optic dual-comb system with a measurement speed of 20 kHz. We generate an electro-optic frequency comb (EOFC) consisting of 50000 teeth with 1 MHz line spacing. Each comb tooth is well resolved by another EOFC with 2.5 GHz line spacing. We record transmittances of high Q-factor resonators within milliseconds. Our figure of merit is shown to be 36 times more sensitive than a configuration that would beat two combs of 1 MHz spacing.

The freeze-thaw cycle exacerbates the ecotoxicity of polystyrene nanoplastics to Secale cereale L. seedlings.

In the context of global climate change, recurrent freeze-thaw cycles (FTC) and concurrent exposure to polystyrene nanoplastics (PSNPs) directly impact crop growth and indirectly affect resilience to abiotic stress. In January 2023, experiments at the Environmental Biology Laboratory, Jilin University, Changchun, China, exposed rye seedlings to 100 nm PSNPs at concentrations of 0, 10, 50, and 100 mg/L for seven days, followed by three FTC. Scanning electron microscopy (SEM) demonstrated that PSNPs migrated from the roots to the leaves, with FTC significantly exacerbating their accumulation within plant tissues. Transmission electron microscopy (TEM) observations showed that FTC disrupted normal cell division, and combined stress from NPs damaged plant organs, particularly chloroplasts, thereby substantially inhibiting photosynthesis. FTC delayed plant phenological stages. Under combined stress, malondialdehyde (MDA) accumulation in plant tissues increased by 15.6%, while hydrogen peroxide (H2O2) content decreased. Simultaneously, the activities of peroxidase (POD) and catalase (CAT) increased by 34.2% and 38.6%, respectively. Molecular docking unveiled that PSNPs could bind to the active center of POD/CAT through hydrogen bonding or hydrophobic interactions. The Integrated Biomarker Response (IBR) index highlighted FTC as a crucial determinant for pronounced effects. Moreover, an apparent dose-dependent effect was observed, with antioxidant enzyme activities in rye seedlings induced by low pollutant concentrations and inhibited by high concentrations. These results indicate that FTC and PSNPs can disrupt plant membrane systems and cause severe oxidative damage. Overall, this study provides compelling scientific evidence of the risks associated with NPs exposure in plants subjected to abiotic stress.

Plasmonic filter paper for preconcentration, separation and SERS detection harmful chemicals in chili product by fluid flow.

We proposed a triple functional SERS substrate by immobilized Ag nanoparticles on the surface of filter paper. The high dense Ag nanoparticles were distributed on the SERS substrate via in-situ growth process. By optimizing the parameter in preparation process, the optimal filter paper SERS substrate was fabricated by using 30 mM of AgNO3 with 20 S growth time. Due to capillary-effect wicking of cellulose fiber, the paper SERS substrate provide simple, fast and pump-free function for transferring analyte onto sharp tip through development of fluid. The fluid flow also brings target concentrate effect within the tip area. Furthermore, the separation feasibility was obtained during the development process of fluid. The preconcentrated effects not only enhanced the SERS signal of analyte, but also improve the fluorescence visible effect. The filter paper SERS substrate was successfully used for separating, concentrating and detecting Sudan dye from chili product, the detection limit could achieve 10-6 M. This study developed a portable, cost-effective and eco-friendly SERS substrate for separating and detecting trace chemical in food.

Four-corner arthrodesis concentrator of nickel-titanium memory alloy for carpal collapse: a report on 18 cases.

PURPOSE: To evaluate the treatment of carpal collapse using a four-corner arthrodesis concentrator of nickel-titanium memory alloy. METHODS: From August 2006 to August 2010, 18 patients with carpal collapse had scaphoid excision and four-corner (capitate, lunate, triquetrum, and hamate) arthrodesis using a nickel-titanium memory alloy four-corner arthrodesis concentrator. The mean follow-up time was 30 months (range, 12-48). Various wrist parameters, including grip strength, wrist motion, and degree of pain were recorded and compared before and after surgery. RESULTS: The average fusion time was 2.3 months (range, 2-4). Neither nonunion nor wound infection was found in any of the patients. At one year follow-up, the grip strength had reached 80% of that of the healthy side, whereas the range of motion was greater than 50% of the contralateral side. After the surgery, the mean pain scores were improved. CONCLUSIONS: Four-corner arthrodesis using a nickel-titanium memory alloy four-corner arthrodesis concentrator effectively treated carpal collapse and preserved most wrist function.

High-reflectivity-resolution coherent optical frequency domain reflectometry using optical frequency comb source and tunable delay line.

We propose a high-reflectivity-resolution coherent optical frequency domain reflectometry (OFDR) with a novel scheme of delay shift averaging (DSAV) by using an optical frequency comb source and a tunable delay line to suppress the fading noise. We show theoretically and experimentally that the novel DSAV scheme is equivalent, in realizing a high reflectivity resolution, to our previously reported frequency shift averaging (FSAV) of the same number of teeth of the optical frequency comb [1], but does not need the expensive narrow-pass-band tunable optical filter required in the previous scheme. Furthermore, by using this new method in combination with FSAV, better reflectivity-resolution is obtained compared to using only conventional FSAV with a single-wavelength laser source.

Carbon quantum dots encapsulated in super small platinum nanocrystals core-shell architecture/nitrogen doped graphene hybrid nanocomposite for electrochemical biosensing of DNA damage biomarker-8-hydroxy-2'-deoxyguanosine.

In this work, carbon quantum dots (CQD) encapsulated in super small platinum nanocrystals core-shell architecture/nitrogen doped graphene hybrid nanocomposite (CQD@PDA@PtNCs-NGR) was design synthesized. Without using any capping reagent, stabilizer and surfactant, very small CQD was served as template and anchoring point for the synthesis of Pt NCs with a super small size (2.25 nm) and a uniform distribution. Meanwhile, dopamine (DA) was used as bridging agent, positioning agent and weak reducing agent to make Pt2+ grow on the CQD. Combine the high dispersed Pt NCs with high specific surface area and high conductivity of NGR, the CQD@PDA@PtNCs-NGR shows excellent electrocatalytic performance towards the biosensing of DNA damage biomarker- 8-Hydroxy-2'-deoxyguanosine (8-OH-dG). A very low detection limit of 0.45 nM and 0.85 nM (S/N = 3), a wide linear range of 0.013 µM-109.78 µM and a high sensitivity of 7.912 µA µM-1cm-2 and 4.190 µA µM-1cm-2 were obtained. The fabricated CQD@PDA@PtNCs-NGR realized the detection of 8-OH-dG in human urine practical sample. Furthermore, CQD@PDA@PtNCs-NGR was applied for the determination of 8-OH-dG generated from damaged DNA and damaged guanine (G), respectively. This work effectively combines the electrochemical signal of 8-OH-dG with DNA damage, confirms the mechanism of DNA damage, which might pave a new way to establish the associations between degree of DNA damage and 8-OH-dG.

Treatment of scaphoid fractures using a memory alloy nail-feet-fixation device.

BACKGROUND: Scaphoid fracture is a common carpal fracture, and its treatment often requires fixation devices. This study aimed to investigate the efficacy and safety of a memory alloy nail-feet-fixation (MANFF) device in treating scaphoid fractures. METHODS: Sixty-six patients with closed scaphoid fractures were treated using the MANFF device between August 2011 and November 2013. Surgical outcomes were assessed using the Mayo wrist score, including pain intensity, functional status, range of motion and grip strength. Postoperative radiographic evaluation was performed every month. RESULTS: Herbert score of fracture stability was A in 36 patients, B in 20 and C in 10. Forty-five patients were treated using the simple MANFF device, 10 with an auxiliary Kirschner wire and 11 underwent MANFF after autologous bone graft. Patients were followed-up for a mean of 6.5 ± 1.2 months (range, 6-12 months). Bone union was achieved in all patients. There was no infection, non-union, arthritic change, tendon issues or any other complications. At postoperative 6 months, 50 patients achieved excellent outcomes, nine achieved good outcomes, and seven achieved fair outcomes, with a mean score of 89.5 ± 6.3. Therefore, the rate of satisfactory outcomes (excellent and good) was 89.4%. CONCLUSIONS: Treatment of scaphoid fractures using the MANFF method has good surgical outcomes in bone union and patient satisfaction.

Treatment of Aseptic Necrosis of the Lunate Bone (Kienböck Disease) Using a Nickel-Titanium Memory Alloy Arthrodesis Concentrator: A Series of 24 Cases.

Avascular necrosis of the lunate bone (Kienböck disease) is caused by loss of blood supply of the bone. This study aimed to evaluate the efficacy and safety of a novel nickel-titanium (Ni-Ti) memory alloy arthrodesis concentrator in the treatment of this disease.A consecutive 24 patients with stage IIIb aseptic lunate necrosis were treated with scapho-trapezio-trapezoeid (STT) arthrodesis using a Ni-Ti arthrodesis concentrator from August 2008 to December 2012. Wrist pain, grip strength, carpal height, and scapholunate angle were measured and compared before and after the surgery. The wrist functions were evaluated using the Mayo scale.Patients were followed up for a mean of 12 months (range, 6-24 months). Grip strength of the affected side was significantly improved after the surgery (18 ± 4.74 kg vs. 30.21 ± 7.14 kg, P < 0.0001). Wrist pain score was significantly decreased from 5.88 ± 0.9 to 0.5 ± 0.51 (P < 0.0001). Carpal height and Mayo score were also significantly increased after the surgery (P < 0.0001). Scapholunate angle was significantly decreased after the surgery (68.38 ± 7.28° vs. 49.91 ± 4.28°, P < 0.0001). No implant breakage, loose implant, wound infection, or nonunion occurred.STT arthrodesis is effective for the treatment of stage IIIb lunate necrosis. The Ni-Ti memory alloy arthrodesis concentrator is a convenient tool for STT arthrodesis with excellent and reliable results.

[Cationic liposome ceftazidime combined with nano-hydroxyapatite/beta-tricalcium phosphate for treatment of chronic osteomyelitis of rabbits].

OBJECTIVE: To observe the effect of cationic liposomal ceftazidime (CLC) combined with nano-hydroxyapatite/beta-tricalcium phosphate (n-HA/beta-TCP) in the treatment of chronic osteomyelitis of rabbits. METHODS: Thirty healthy New Zealand white rabbits (4-6 months old; weighing, 2-3 kg) were selected to prepare the chronic osteomyelitis models. After 4 weeks, the gross observation, X-ray examination, and bacteriological and histopathological examinations were done; the models were made successfully in 27 rabbits. Of 27 rabbits, 24 were randomly divided into 4 groups (n = 6): only debridement was performed in group A; ceftazidime was given (90 mg/kg), twice a day for 8 weeks after debridement in group B; ceftazidime and n-HA/beta-TC were implanted after debridement in group C; and CLC and n-HA/beta-TCP were implanted after debridement in group D. Before and after treatments, X-ray examination was done, and Norden score was recorded. At 8 weeks after treatment, the specimens were harvested for gross observation and for gross bone pathological score (GBPS) using Rissing standard; half of the specimens was used for histological observation and Smeltzer scoring, the other half for bacteriological examination and calculation of the positive rate of bacteria culture. RESULTS: At 8 weeks after treatment, Norden score of group D was significantly lower than that of groups A, B, and C (P < 0.05), but no significant difference was found among groups A, B, and C (P > 0.05). At 8 weeks after treatment, sinus healed in groups C and D, but sinus was observed in groups A and B; the GBPS scores of groups C and D were significantly lower than those of groups A and B (P < 0.05). The Smeltzer scores of groups C and D were significantly lower than those of groups A and B (P < 0.05). The positive rates of bacteria culture of groups C (0) and D (0) were significantly lower than those of group A (25.0%) and group B (16.7%) (P < 0.05). CONCLUSION: CLC combined with n-HA/beta-TCP has good effect in treating chronic osteomyelitis of rabbits, and it has better effect in treating chronic osteomyelitis of rabbits than ceftazidime with n-HA/beta-TCP.

[Vancomycin cationic liposome combined with nano-hydroxyapatite/chitosan/konjac glucomannan scaffold for treatment of infected bone defects in rabbits].

OBJECTIVE: To investigate the anti-infection and bone repair effects of cationic liposome-encapsulated vancomycin combined with the nano-hydroxyapatite/chitosan/konjac glucomannan (n-HA/CS/KGM) composite scaffold in vivo. METHODS: Fifty-one 6-month-old New Zealand white rabbits, weighing 1.5-3.0 kg, were selected to prepare chronic infectious tibia bone defect model by using Staphylococcus aureus. After 4 weeks, 48 survival rabbits were randomly divided into 4 groups (n=12). After debridement, defect was treated with nothing in group A, with n-HA/CS/KGM composite scaffold in group B, with vancomycin and n-HA/CS/KGM composite scaffold in group C, and with cationic liposome-encapsulated vancomycin and n-HA/CS/KGM composite scaffold in group D. After 8 weeks of treatment, general observation, X-ray, HE staining, the bacterial culture, and the measurement of the longest diameter of bone defect were done. RESULTS: At 4 weeks after modeling, 48 rabbits were diagnosed as having osteomyelitis, including periosteal new bone formation, destruction of bone, and soft tissue swelling. The Norden score was 3.83 +/- 0.52. At 8 weeks after treatment, sinus healed in groups C and D, but sinus was observed in groups A and B; the gross bone pathological scores of group D were significantly better than those of groups A and B (P < 0.05). Bone defects were repaired completely in group D, the results of the longest diameter of bone defects in group D was significantly better than those in the other 3 groups (P < 0.05). New bone formation was observed in groups C and D, but periosteal reaction and marrow low-density shadow were observed in groups A and B; Norden score in group D was significantly better than those in groups A, B, and C (P < 0.05). HE staining showed that there were a large number of trabecular bone formation and fibrosis, with no obvious signs of infection in groups C and D, but neutrophil accumulation was observed in groups A and B; Smeltzer scores in groups C and D were significantly better than those in groups A and B (P < 0.05). Bacteriological results showed higher negative rate in groups C and D than in groups A and B (P < 0.05). CONCLUSION: Cationic liposome-encapsulated vancomycin and n-HA/CS/KGM composite scaffold can be a good treatment for infectious bone defects in rabbits, providing a new strategy for the therapy of bone defects in chronic infection.

[Treatment of chronic osteomyelitis of rabbit with liposomal gentamicin-impregnated allogeneic cortical bone].

OBJECTIVE: It is difficult to treat chronic osteomyelitis due to the formation of the Staphylococcus aureus biofilms. Liposomal gentamicin-impregnated allogeneic cortical bone can inhibit the formation of the Staphylococcus aureus biofilms. To explore the treatment of chronic osteomyelitis of rabbit by liposomal gentamicin-impregnated allogeneic cortical bone. METHODS: The liposomal gentamicin, liposomal gentamicin-impregnated allogeneic cortical bone and gentamicin-impregnated allogeneic cortical bone were produced. Then the chronic Staphylococcus aureus osteomyelitis models of rabbit were made in left lower limbs of 40 6-month-old rabbits and the right lower limbs were used as controls. After 2 weeks, the observations of gross and X-ray were done. Four rabbits died within 10 days after the models were made and other 36 rabbits were divided into 6 groups: group A (no antibiotics), group B (intravenous injection of gentamicin), group C (intravenous injection of liposomal gentamicin), group D (implantation of gentamicin-impregnated allogeneic cortical bone), group E (implantation of liposomal gentamicin-impregnated allogeneic cortical bone), and group F (implantation of allogeneic cortical bone). After 2 weeks of treatment, the bacterial culture, X-ray and HE staining were done. RESULTS: The chronic Staphylococcus aureus osteomyelitis model of rabbit was made successfully. The X-ray showed dissolution of bone and periosteal reaction in groups A, B, C, and F, and no obvious dissolution of bone and periosteal reaction in groups D and E. The Norden scores were (2.5 +/- 0.3), (2.1 +/- 0.2), (1.5 +/- 0.3), (1.5 +/- 0.2), (0.9 +/- 0.3), and (2.7 +/- 0.3) points in groups A-F, respectively; showing significant differences between group A and groups B-E (P < 0.05), between groups B, E, F and other groups (P < 0.05). The results of blood and marrow cultures for Staphylococcus aureus were positive in groups A and F, and negative in other 4 groups; the results of bone marrow culture for Staphylococcus aureus were positive in 6 rabbits of group B, 4 rabbits of group C and 3 rabbits of group D; and the results were negative in group E. HE staining showed: in groups A and F, abscess and dead bone formed, and no new bone formation were observed; in groups B and C, different degrees of neutrophil accumulation was seen; in group D, some neutrophil accumulation occurred, and osteoprogenitor cells and osteoclasts were seen around implanted bone; and in group E, no neutrophil accumulation was observed, a lot of granulation tissues formed, and osteoprogenitor cells and osteoclasts were seen around implanted bone. CONCLUSION: Implantation of liposomal gentamicin-impregnated allogeneic cortical bone has remarkably better effect in treating chronic osteomyelitis than intravenous injection of liposomal gentamicin and implantation of gentamicin-impregnated allogeneic cortical bone.