Application of Hyperspectral Technology with Machine Learning for Brix Detection of Pastry Pears.

Sugar content is an essential indicator for evaluating crisp pear quality and categorization, being used for fruit quality identification and market sales prediction. In this study, we paired a support vector machine (SVM) algorithm with genetic algorithm optimization to reliably estimate the sugar content in crisp pears. We evaluated the spectral data and actual sugar content in crisp pears, then applied three preprocessing methods to the spectral data: standard normal variable transformation (SNV), multivariate scattering correction (MSC), and convolution smoothing (SG). Support vector regression (SVR) models were built using processing approaches. According to the findings, the SVM model preprocessed with convolution smoothing (SG) was the most accurate, with a correlation coefficient 0.0742 higher than that of the raw spectral data. Based on this finding, we used competitive adaptive reweighting (CARS) and the continuous projection algorithm (SPA) to select key representative wavelengths from the spectral data. Finally, we used the retrieved characteristic wavelength data to create a support vector machine model (GASVR) that was genetically tuned. The correlation coefficient of the SG-GASVR model in the prediction set was higher by 0.0321 and the root mean square prediction error (RMSEP) was lower by 0.0267 compared with those of the SG-SVR model. The SG-CARS-GASVR model had the highest correlation coefficient, at 0.8992. In conclusion, the developed SG-CARS-GASVR model provides a reliable method for detecting the sugar content in crisp pear using hyperspectral technology, thereby increasing the accuracy and efficiency of the quality assessment of crisp pear.

A Potential Resuscitation Route on Battlefield: Immediate Intraperitoneal Fluid Administration Post-burn Shows Satisfactory Fluid Absorption and Anti-shock Effects.

INTRODUCTION: Timely fluid resuscitation remains the key to the early treatment of severe burns. Intraperitoneal (IP) fluid administration is a simple, rapid resuscitation strategy via a puncture in the abdominal wall. This study aimed to evaluate the fluid absorption and anti-shock effects of IP delivery in the early stage after severe burns. MATERIALS AND METHODS: A 30% total body surface area full-thickness burn model was established using male C57BL/6 mice. A total of 126 mice were randomly assigned into six groups (n = 21): the sham injury group (SHAM), the burn group without fluid resuscitation (NR), and the four IP resuscitation groups (IP-A/B/C/D, each being intraperitoneally administered with 60, 80, 100, and 120 mL/kg of sodium lactate Ringer's solution post-injury). Three-hour post-burn, six mice in each group were randomly selected and sacrificed for blood and tissue sampling to detect the IP fluid absorption rate and evaluate organ damage because of low perfusion. The remaining 15 mice in each group were observed for the vital signs within 48-h post-injury, and their survival rate was calculated. RESULTS: The 48-h survival rate increased in the IP-A (40.0%), IP-B (66.7%), IP-C (60.0%), and IP-D (13.3%) groups, compared with the NR group (0%). The mean arterial pressure, body temperature, and heart rate of mice were significantly stabilized in the IP groups. For the first 3-h post-injury, the absorption rates of groups IP-A (74.3% ± 9.5%) and IP-B (73.3% ± 6.9%) were significantly higher than those of groups IP-C (59.7% ± 7.1%) and IP-D (48.7% ± 5.7%). The levels of arterial blood pH, partial pressure of oxygen, partial pressure of carbon dioxide, lactate, and hematocrit were better maintained in the IP groups. Intraperitoneal resuscitation remarkably reduced the injury scores in burn-induced histopathology of the liver, kidneys, lungs, and intestines, accompanied by decreased alanine transaminase, creatinine, interleukin-1, and tumor necrosis factor-α in plasma, and augmented superoxide dismutase 2 and inhibited malondialdehyde in tissues. Group IP-B has the best performance for these indices. CONCLUSIONS: Intraperitoneal administration of isotonic saline post-burn can be adequately and rapidly absorbed, thereby boosting circulation and perfusion, precluding shock, alleviating organ damage caused by ischemia and hypoxia, and significantly increasing the survival rate. This technique, with a potential to be a supplement to existing resuscitation methods on the battlefield, is worth further investigation.

Effects and Mechanisms of Peritoneal Resuscitation on Acute Kidney Injury After Severe Burns in Rats.

INTRODUCTION: Acute kidney injury (AKI) is a common complication in severe burn patients with poor prognosis and high mortality. Reduced kidney perfusion induced by the decreased effective circulating blood volume after severe burn is a common cause of AKI. Routine intravenous resuscitation (IR) is difficult or delayed in extreme conditions such as war and disaster sites. Peritoneal resuscitation (PR) is a simple, rapid resuscitation strategy via a puncture in the abdominal wall. This study investigated whether PR is a validated resuscitation strategy for AKI after severe burns in rats and explored its mechanisms. MATERIALS AND METHODS: Eighty Sprague-Dawley rats were randomized into four groups: (1) sham group; (2) IR group, which was characterized by the full thickness burn of 50% of the total body surface area received IR immediately post-injury; (3) early PR group, in which rats with the same burn model received PR immediately post-injury; and (4) delayed resuscitation (DR) group, in which rats with the same burn model received no resuscitation within 3-hour post-injury. PR and DR groups animals received IR after 3-hour post-injury. The survival rate, mean arterial pressure, renal histopathology, renal function, indicators of renal injury, and renal hypoxia-inducible factor-1α and NADPH oxidase 4 (NOX4) proteins of rats were measured at 3 h, 12 h, and 24 h post-injury. RESULTS: Compared with rats in the DR group, rats in the PR group had a significantly improved survival rate (100% vs. 58.3% at 24 h, P = 0.0087), an increased mean arterial pressure (92.6 ± 6.6 vs. 65.3 ± 10.7, 85.1 ± 5.7 vs. 61.1 ± 6.9, 90.1 ± 8.7 vs. 74.9 ± 7.4 mmHg, at 3 h, 12 h, and 24 h, P < 0.01), a reduced renal water content rate (51.6% ± 5.0% vs. 70.1% ± 6.8%, 57.6% ± 7.7% vs. 69.5% ± 8.7%, at 12 h and 24 h, P < 0.01), attenuated histopathological damage, reduced serum creatinine expression (36.36 ± 4.27 vs. 49.98 ± 2.42, 52.29 ± 4.31 vs. 71.32 ± 5.2, 45.25 ± 2.55 vs. 81.15 ± 6.44 µmol/L, at 3 h, 12 h, and 24 h, P < 0.01) and BUN expression (7.62 ± 0.30 vs. 10.80 ± 0.58, 8.61 ± 0.32 vs. 28.58 ± 1.99, 8.09 ± 0.99 vs. 20.95 ± 1.02 mmol/L, at 3 h, 12 h, and 24 h, P < 0.01), increased kidney injury markers neutrophil gelatinase-associated lipocalin expression (95.09 ± 7.02 vs. 101.75 ± 6.23, 146.77 ± 11.54 vs. 190.03 ± 9.87, 112.79 ± 15.8 vs. 194.43 ± 11.47 ng/mL, at 3 h, 12 h, and 24 h, P < 0.01) and cystatin C expression (0.185 ± 0.006 vs. 0.197 ± 0.006, 0.345 ± 0.036 vs. 0.382 ± 0.013, 0.297 ± 0.012 vs. 0.371 ± 0.028 ng/mL, at 3 h, 12 h, and 24 h, P < 0.01), and reduced renal hypoxia-inducible factor-1α and NADPH oxidase 4 protein expression (P < 0.01). There was no significant difference between rats in the PR group and the IR group in the above indicators. CONCLUSIONS: Early PR could protect severe burn injury rats from AKI. It may be an alternative resuscitation strategy in severe burn injury when IR cannot be achieved.

Transcriptome reveals the dysfunction of pancreatic islets after wound healing in severely burned mice.

BACKGROUND: Severely burned patients have a higher risk of diabetes mellitus after healing, but its mechanism remains unclear. Therefore, the purpose of the study was to explore the influence of burns on pancreatic islets of mice after wound healing. METHODS: Forty-two male C57BL/6 mice were randomized into a sham group and a burn group and subjected to sham treatment or a third-degree burn model of 30% total body surface area. Fasting blood glucose was detected weekly for 8 weeks after severe burns. Glucose-stimulated insulin secretion was measured 8 weeks post severe burns. Islets of the two groups were isolated and mRNA libraries were sequenced by the Illumina sequencing platform. The expressions of differentially expressed genes (DEGs) related to the cell cycle and the amounts of mitochondrial DNA were detected by quantitative real-time polymerase chain reaction after gene ontology, gene set enrichment analysis, and protein-protein network analysis. Hematoxylin-eosin staining of pancreatic tail tissue and adenosine triphosphate (ATP) assay of islets were performed. RESULTS: The levels of fasting blood glucose were significantly higher within 8 weeks post severe burns. Glucose-stimulated insulin secretion was impaired at the eighth week post severe burns. Totally 128 DEGs were selected. Gene ontology and gene set enrichment analysis indicated that the pathways related to the cell cycle, protein processing, and oxidative phosphorylation were downregulated. The expressions of DEGs related to the cell cycle showed a consistent trend with mRNA sequencing data, and most of them were downregulated post severe burns. The cell mass of the burn group was less than that of the sham group. Also, the concentration of ATP and the amount of mitochondrial DNA were lower in the burn group. CONCLUSION: In the model of severe-burned mice, disorders in glucose metabolism persist for 8 weeks after burns, which may be related to low islet cell proliferation, downregulation of protein processing, and less ATP production.

Isolated cryptococcal osteomyelitis of the ulna in an immunocompetent patient: A case report.

BACKGROUND: Cryptococcal osteomyelitis is a bone infection caused by cryptococcus. As an opportunistic infection, bone cryptococcosis usually occurs in patients with immunodeficiency diseases or in those undergoing immunosuppressive therapy and often displays characteristics of disseminated disease. Isolated cryptococcal osteomyelitis is extremely unusual in immunocompetent person. The pathogenic fungus often invades vertebrae, femur, tibia, rib, clavicle, pelvis, and humerus, but the ulna is a rare target. CASE SUMMARY: A 79-year-old woman complaining of chronic pain, skin ulceration and a sinus on her right forearm was admitted, and soon after was diagnosed with cryptococcal osteomyelitis in the right ulna. Unexpectedly, she was also found to have apparently normal immunity. After treatment with antifungal therapy combined with surgery debridement, the patient's osteomyelitis healed with a satisfactory outcome. CONCLUSION: Although rare, cryptococcal osteomyelitis should be considered in the differential diagnosis of osteolytic lesions even in immunocompetent patients, and good outcomes can be expected if early definitive diagnosis and etiological treatment are established.

Efficient multicycle terahertz pulse generation based on the tilted pulse-front technique.

Controlling the time-domain oscillation of a terahertz (THz) wave offers promising capabilities for THz-based all-optical particle acceleration and strong-field THz nonlinear physics. However, the lack of highly efficient and frequency-modulable multicycle THz sources is impeding the spread of strong-field THz science and applications. Here, we show that by simply adding an echelon into a single-cycle THz source based on optical rectification in lithium niobate crystals via the tilted pulse-front technique, multicycle THz pulses can be efficiently generated with an 800 nm-to-THz efficiency of 0.1% at room temperature. The radiated THz properties can be engineered by precisely designing the echelon structure. Our proposed multicycle THz generation method has the advantages of high efficiency, ease of operation, and quick switching between single-cycle and multicycle working modes, all of which are important in the application of high-field THz radiation.

Tideglusib promotes wound healing in aged skin by activating PI3K/Akt pathway.

BACKGROUND: Aging disturbs the skin morphology and function, manifested as thinned epithelium and impaired wound healing. As a major type of skin cells, epidermal stem cells (EpiSCs) are inevitably affected by aging. The effect of age on EpiSCs and wound healing needs to be further explored. METHODS: Skin RNA-seq data of young (5 months) and old (30 months) CB6F1 mice were obtained from GEO Series GSE35322 with 10 in each age group. Differentially expressed genes were analyzed, and EpiSCs-related pathways were enriched by KEGG. The age-related changes of the screened PI3K/Akt pathway were validated by Western Blot and immunofluorescence of epidermis of SD rats (2, 17, and 23 months, n = 6). The expression of upstream protein EGFR was assessed by immunofluorescence in skin of mice (4, 13, and 23 months, n = 6) and human (respectively, 23, 28, 30 years old in the young group and 69, 73, 78 years old in the old group) skin. Inhibitors of EGFR were used to verify its effects on EpiSCs and wound healing. The small molecule drug Tideglusib was tested for its effects on signaling pathways of EpiSCs and wound healing of aged rats. Western Blot was used for the detection of signaling pathways in in vitro experiments. Cell migration assays were used to assess cell migration ability. Flow cytometry was used to detect changes in cell cycle and apoptosis levels. Sulforhodamine B assay and CCK-8 assay were used to evaluate cell proliferation and viability, respectively. Student's t test and one-way analysis of variance (ANOVA) followed by the multiple comparisons Bonferroni test were used for statistical analysis. The 0.05 level of confidence was accepted as a significant difference. RESULTS: EpiSCs-related PI3K/Akt pathway was enriched by KEGG and verified by decreased phosphorylation of Akt (32.1 ± 13.8%, P < 0.01) and mTOR (38.9 ± 11.8%, P < 0.01) in aged epidermis of rats. Furthermore, the expression of PI3K/Akt-upstream EGFR decreased with age in the epidermis of mouse (27.6 ± 5.5%, P < 0.01) and human (25.8 ± 9.3%, P < 0.01). With EGFR blocked by Erlotinib, EpiSCs showed reduced phosphorylation of Akt (30.4 ± 10.6%, P < 0.01) and mTOR (39.8 ± 12.8%, P < 0.01), impaired proliferation and migration after incubated for 24 h and 36 h (P < 0.05), and higher levels of apoptosis (11.9 ± 1.7%, P < 0.05), and rats showed slower wound healing from d7 to d14 after wounding (P < 0.01). In addition to slower wound healing rates, aged rats also showed a decrease in the efficacy of EGF, partly due to the downregulated EGFR expression. By activating PI3K/Akt pathway, Tideglusib promoted the proliferation and migration of EpiSCs with apoptosis inhibited (P < 0.01) and accelerated wound healing in aged rats from d7 to d14 after wounding (P < 0.05). Notably, the combined use of Tideglusib and EGF could further enhance wound healing in aged rats. CONCLUSIONS: The decreased expression of EGFR in epidermis with age resulted in decreased activity of the PI3K/Akt pathway and limited EGF efficacy. Tideglusib could assist wound healing in aged rats via activating PI3K/Akt pathway, which may be considered as an ingredient for medical and cosmetics use.

Elevated Serum Procalcitonin to Predict Severity and Prognosis of Extensive Burns.

PURPOSE: To analyze the factors affecting the elevation of serum procalcitonin (PCT) in patients with extensive burns, and explore its potential value in evaluating the severity and prognosis. METHODS: Clinical data of 139 patients with extensive burns admitted to our burn center from January 2014 to December 2019 were retrospectively analyzed. Spearman's Rank correlation coefficient was used to analyze the factors influencing the elevated PCT levels. The predictive power of PCT for death was evaluated by receiver operating characteristic (ROC) and multiple logistic regression analysis. RESULTS: 72 cases exhibited elevated serum PCT concentrations during the shock phase, but none of them had obvious signs of infection. PCT level in the shock phase was positively correlated with burn area, depth, degree of inhalation injury, delay in fluid resuscitation, APACHE II, and SOFA scores. The peak values of PCT during shock and infection phases were significantly higher in the non-survivors than in the survivors. The areas under the ROC curve for predicting death were 0.788 and 0.926, respectively, and 5.4 ng/mL (OR = 5.33) and 8.5 ng/mL (OR = 14.49) were the high-risk thresholds for death prediction. CONCLUSIONS: Serum PCT level in the shock phase is a potential indicator for evaluating the severity of burns, while the PCT level during the infection period can be used as an early warning indicator for severe systemic infection. High levels of PCT peaks during the shock and infection periods indicate an increased risk of poor prognosis, and targeted treatment is required accordingly.

Highly efficient generation of GV/m-level terahertz pulses from intense femtosecond laser-foil interactions.

The terahertz radiation from ultraintense laser-produced plasmas has aroused increasing attention recently as a promising approach toward strong terahertz sources. Here, we present the highly efficient production of millijoule-level terahertz pulses, from the rear side of a metal foil irradiated by a 10-TW femtosecond laser pulse. By characterizing the terahertz and electron emission in combination with particle-in-cell simulations, the physical reasons behind the efficient terahertz generation are discussed. The resulting focused terahertz electric field strength reaches over 2 GV/m, which is justified by experiments on terahertz strong-field-driven nonlinearity in semiconductors.

Video laryngoscope-guided urethral catheterization in female minipigs.

OBJECTIVE: The objective of this work was to anatomically locate the urethral orifice in female minipigs and describe the use of video laryngoscopes in urethral catheterization. METHODS: Urethral catheterization guided by a video laryngoscope was attempted in 16 adult female Bama minipigs. The anatomical location of urethral orifices, operating time and complications (mucosal edema and bleeding in the vaginal vestibule, and the numbers of red blood cells (RBCs) and white blood cells (WBCs) in mid-stream urine samples) were recorded. RESULTS: The anatomical location of the urethral orifice: the depth of the urethral orifice in female Bama minipigs was 4.2 ± 1.2 cm; all the urethral orifices were covered by mucosal folds of the vaginal vestibule. In the supine position, the orifice of the urethra at 9-12 and 1-3 o'clock accounted for 6.25%, 6.25%, 18.75%, 50%, 12.5%, 6.25% and 6.25%, respectively. All animals were successfully catheterized and the operating time was 9.0 (6.0-12.8) min. Complications: no bleeding in the vaginal vestibule was observed; the incidence of mucosal edema was 12.5%, all of which were mild; of urine samples collected 1 h after catheterization, 12.5% were found to contain RBCs and no RBCs were detected 6 h after catheterization; no WBCs were detected 1 h or 6 h after catheterization. CONCLUSIONS: The urethral orifice of female minipigs was located deep in the vagina at variable clock directions and was unexceptionally covered by mucosal folds. Applying a video laryngoscope in urethral catheterization allowed quick and accurate exposure of the urethral orifice and minimal operational injury in female minipigs.

Two-dimensional monitoring of a laser-solid x-ray source spot via penumbral coded aperture imaging technique.

The uncertainties of spot size and position need to be clarified for x-ray sources as they can affect the detecting precision of the x-ray probe beam in applications such as radiography. In particular, for laser-driven x-ray sources, they would be more significant as they influence the inevitable fluctuation of the driving laser pulses. Here, we have employed the penumberal coded aperture imaging technique to diagnose the two-dimensional spatial distribution of an x-ray emission source spot generated from a Cu solid target irradiated by an intense laser pulse. Taking advantage of the high detection efficiency and high spatial resolution of this technique, the x-ray source spot is characterized with a relative error of ∼5% in the full width at half maximum of the intensity profile in a single-shot mode for general laser parameters, which makes it possible to reveal the information of the unfixed spot size and position precisely. Our results show the necessity and feasibility of monitoring the spot of these novel laser-driven x-ray sources via the penumbral coded aperture imaging technique.

How to improve the safety of bicortical pedicle screw insertion in the thoracolumbar vertebrae: analysis base on three-dimensional CT reconstruction of patients in the prone position.

BACKGROUND: Through the comparison of three-dimensional CT reconstruction between the supine position and the prone position, the relative position of thoracolumbar great vessels and vertebral body was studied, and the shortest safe distance between them was measured to improve the safety of bicortical pedicle screw insertion and reduce the risk of vascular injury. METHODS: Forty adults were selected to participate the research. Three-dimensional reconstruction of thoracolumbar (T9-L3) CT was performed in the prone position and the supine position. The relative distance between the Aorta/Inferior Vena Cava (IVC) and vertebral body was obtained as AVD/VVD respectively. The relative angle of the Aorta/ IVC and the vertebral body was calculated as ∠AOY/∠VOY. Self-controlled experiments were carried out in the prone and the supine positions, and the data obtained were analyzed using SPSS 22.0 statistical software. RESULTS: The AVD of the prone position and the supine position was the shortest at T12 (3.18 ± 0.68 mm), but the difference was not statistically significant. The aorta of the T9-L3 segment was shifted from the anterolateral to the anteromedial. The ∠AOY of the other groups differed significantly between the prone and supine positions in all vertebrae except T12 and L1 (P < 0.05), and the aorta in the prone position was more anteromedial than that of supine position. With regard to VVD/∠VOY, there was no significant difference between the prone and supine positions (P ≥ 0.05), and the minimum VVD of L3 segment is greater than 5.4 mm. The IVC has no obvious mobility and is fixed in the range of 20 ° ~ 30 ° near the midline. CONCLUSION: When using bicortical anchoring of pedicle screws, it is safe to ensure that the protruding tips of the screw is less than 3 mm. Due to the mobility of the aorta in different postures and individual differences in anatomy, the prone position CT can help doctors to make better preoperative plans and decisions.

Optical steering of electron beam in laser plasma accelerators.

Using a Dazzler system and tilting a compressor grating, we provide an effective way of using the laser group delay dispersion to continuously steer the electron beam accelerated by an asymmetric laser wakefield. The deviation angle of the electron beam was the same as that of the angularly chirped laser pulse from its initial optical axis, which is determined by the laser pulse-front-tilt (PFT). This method can be utilized to continuously control over the pointing direction of electron bunches to the requisite trajectories, especially for practical applications in highly sensitive alignment devices such as electron-positron colliders or undulators. Additionally, we investigate the effect of PFT on the properties of the electron beam.

[Advances in clinical diagnosis and treatment of chronic osteomyelitis in adults].

OBJECTIVE: To review the progress of clinical diagnosis and treatment of chronic osteomyelitis in adults. METHODS: The literature related to chronic osteomyelitis in recent years was extensively reviewed, and the clinical diagnosis and treatment methods were summarized. RESULTS: Clinical characteristics and laboratory examination can help to diagnose chronic osteomyelitis in adults. Pathogenic identification is the basis for choosing antibiotics. Diagnostic imaging is specific. The treatment includes systemic treatment and local treatment, and the local treatment is the key to radical cure. CONCLUSION: The diagnosis of chronic osteomyelitis in adults should be made as early as possible. According to the anatomical and physiological classification of the patients, the appropriate treatment plan should be made.

Highly efficient generation of 0.2 mJ terahertz pulses in lithium niobate at room temperature with sub-50 fs chirped Ti:sapphire laser pulses.

We demonstrate generation of 0.2 mJ terahertz (THz) pulses in lithium niobate driven by Ti:sapphire laser pulses at room temperature. Employing tilted pulse front technique, the 800 nm-to-THz energy conversion efficiency has been optimized to 0.3% through chirping the sub-50 fs pump laser pulses to overcome multi-photon absorption and to extend effective interaction length for phase matching. Our approach paves the way for mJ-level THz generation via optical rectification using existing Ti:sapphire laser systems which can deliver Joule-level pulse energy with sub-50 fs pulse duration.

Demonstration of Coherent Terahertz Transition Radiation from Relativistic Laser-Solid Interactions.

Coherent transition radiation in the terahertz (THz) region with energies of sub-mJ/pulse has been demonstrated by relativistic laser-driven electron beams crossing the solid-vacuum boundary. Targets including mass-limited foils and layered metal-plastic targets are used to verify the radiation mechanism and characterize the radiation properties. Observations of THz emissions as a function of target parameters agree well with the formation-zone and diffraction model of transition radiation. Particle-in-cell simulations also well reproduce the observed characteristics of THz emissions. The present THz transition radiation enables not only a potential tabletop brilliant THz source, but also a novel noninvasive diagnostic for fast electron generation and transport in laser-plasma interactions.

Backward terahertz radiation from intense laser-solid interactions.

We report a systematic study on backward terahertz (THz) radiation generation from laser-solid interactions by changing a variety of laser/plasma parameters. We demonstrate a high-energy (with an energy flux density reaching 80 µJ/sr), broadband (>10 THz) plasma-based radiation source. The radiation energy is mainly distributed either in the >10 THz or <3 THz regions. A radial surface current formed by the lateral transport of low-energy electrons (LEE) is believed to be responsible for the radiation in the high-THz region (>10 THz), while high-energy surface fast electrons (SFE) accelerated along the target surface mainly contribute to lower frequency (<3 THz) radiation. The unifying explanation could be applied to backward THz radiation generation from solid targets with presence of relative small preplasmas.

Quasi-steady-state air plasma channel produced by a femtosecond laser pulse sequence.

A long air plasma channel can be formed by filamentation of intense femtosecond laser pulses. However, the lifetime of the plasma channel produced by a single femtosecond laser pulse is too short (only a few nanoseconds) for many potential applications based on the conductivity of the plasma channel. Therefore, prolonging the lifetime of the plasma channel is one of the key challenges in the research of femtosecond laser filamentation. In this study, a unique femtosecond laser source was developed to produce a high-quality femtosecond laser pulse sequence with an interval of 2.9 ns and a uniformly distributed single-pulse energy. The metre scale quasi-steady-state plasma channel with a 60-80 ns lifetime was formed by such pulse sequences in air. The simulation study for filamentation of dual femtosecond pulses indicated that the plasma channel left by the previous pulse was weakly affected the filamentation of the next pulse in sequence under our experimental conditions.

Role of resonance absorption in terahertz radiation generation from solid targets.

The interaction of 100-fs laser pulses with solid targets at laser intensities 10(16)-10(18)W/cm(2) has been investigated experimentally by simultaneous measurements of terahertz (THz) and second harmonic signals. THz yield at the front side of the target, which rises from the self-organized transient electron currents along the target surface, is found scaling linearly with the laser intensity basically. Measurements of specularly reflected light spectrum show clear evidence of resonance absorption. The positive effects of resonance absorption on surface current and THz radiation generation have been confirmed by two-dimensional (2D) particle-in-cell (PIC) simulations and angular-dependent experiments, respectively.

Allotransplantation of cryopreserved prepubertal mouse ovaries restored puberty and fertility without affecting methylation profile of Snrpn-DMR.

OBJECTIVE: To evaluate the genetic safety of vitrification on the methylation imprints and the development and fertility potential of prepubertal mouse ovaries. DESIGN: Experimental animal study. SETTING: University-based fertility center. ANIMAL(S): Institute of Cancer Research (ICR) 10-day-old female mice, 10-week-old adult female mice, and 12-week-old adult male mice. INTERVENTION(S): Vitrification of juvenile mouse ovaries was performed using ED20 and EG5.5/30 solutions followed by retrieval of fresh and vitrified-warmed germinal vesicle (GV) oocytes for Snrpn differentially methylated regions (DMR) methylation analyses, collection of mature oocytes from superovulated ovarian grafts, in vitro fertility(IVF), and early embryonic development after heterotopic allotransplantation. MAIN OUTCOME MEASURE(S): Analysis of methylation status of Snrpn-DMR, percentage of fertilization, and blastocysts formation. RESULT(S): Methylation status of Snrpn-DMR from vitrified-warmed GV oocytes did not show significant alteration compared with that of controls, although a significant reduction of viable oocytes was observed. Puberty as well as endocrine function was restored, and no significant difference was shown in number of follicles, percentage of mice retaining fertility, and blastocyst formation among three groups. CONCLUSION(S): Our study proved that vitrification of prepubertal mouse ovaries did not alter the methylation profile of Snrpn-DMR and subsequent allotransplantation; IVF could restore the development and fertility potential.