Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Opt Lett ; 49(12): 3476-3479, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38875649

RESUMEN

A high average power re-frequency operation Fe:ZnSe laser using laser diode side-pumped free-running Er:YAG lasers as activating sources is presented. Two pieces of subsurface layer doped Fe:ZnSe polycrystal are adoptive in a reflective resonator configuration and face-cooled by liquid nitrogen. A maximal Fe:ZnSe laser power of 105 W at a wavelength of 4.1 µm is achieved upon pumping by ten home-made Er:YAG lasers with fiber coupled output working at a frequency of 250 Hz and a pulse duration of ∼420 µs. Corresponding to the maximum Fe:ZnSe laser power, the optical-optical efficiency and slope efficiency with respect to the absorbed pump power are 43% and 44% respectively. The beam quality factor M2 is measured to be 3.4. To the best of our knowledge, it is the highest output average power of an Fe:ZnSe laser reported.

2.
Hum Genet ; 142(1): 103-123, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36129575

RESUMEN

Mutations in myelin regulatory factor (MYRF), a gene mapped to 11q12-q13.3, are responsible for autosomal dominant high hyperopia and seem to be associated with angle closure glaucoma, which is one of the leading causes of irreversible blindness worldwide. Whether there is a causal link from the MYRF mutations to the pathogenesis of primary angle-closure glaucoma (PACG) remains unclear at this time. Six truncation mutations, including five novel and one previously reported, in MYRF are identified in seven new probands with hyperopia, of whom all six adults have glaucoma, further confirming the association of MYRF mutations with PACG. Immunofluorescence microscopy demonstrates enriched expression of MYRF in the ciliary body and ganglion cell layer in humans and mice. Myrfmut/+ mice have elevated IOP and fewer ganglion cells along with thinner retinal nerve fiber layer with ganglion cell layer than wild-type. Transcriptome sequencing of Myrfmut/+ retinas shows downregulation of Dnmt3a, a gene previously associated with PACG. Co-immunoprecipitation demonstrates a physical association of DNMT3A with MYRF. DNA methylation sequencing identifies several glaucoma-related cell events in Myrfmut/+ retinas. The interaction between MYRF and DNMT3A underlies MYRF-associated PACG and provides clues for pursuing further investigation into the pathogenesis of PACG and therapeutic target.


Asunto(s)
Enfermedades Hereditarias del Ojo , Glaucoma de Ángulo Cerrado , Hiperopía , Humanos , Adulto , Ratones , Animales , Hiperopía/genética , Glaucoma de Ángulo Cerrado/genética , Glaucoma de Ángulo Cerrado/complicaciones , Mutación , Enfermedades Hereditarias del Ojo/genética , Factores de Transcripción/genética , Presión Intraocular/genética
3.
Appl Opt ; 62(30): 7966-7969, 2023 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-38038089

RESUMEN

A high beam quality diode-pumped Nd:YAG master oscillator power-amplifier (MOPA) laser with three end-pumped slab amplifiers is developed. The Q-swtiched side-pumped rod oscillator presented a pulse energy 3.1 mJ with beam quality factors of M x2=1.17 and M y2=1.15 at a repetition of 1 kHz. The MOPA system delivered a pulse energy of 1.36 J with a pulse width of 48.2 ns and an extraction efficiency of 44.8%. The beam quality factors of M x2=1.72 and M y2=3.85 are measured without any phase-conjugators or adaptive optics.

4.
Gynecol Endocrinol ; 39(1): 2269235, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37859610

RESUMEN

OBJECTIVE: An increasing number of research have emerged to compare the pregnancy outcomes between the natural cycle and the hormone replacement therapy (HRT) cycle in preparing the endometrium for frozen-thawed embryo transfer (FET), but the results are controversial. This prospective randomized controlled study was hence designed to obtain more solid evidence. MATERIALS AND METHODS: In this study, patients with regular menstrual cycle length (21-35 days) who underwent FET between January 2010 to December 2017 were recruited for this study. Upon further filtering with the selection criteria of patients being, a total of 405 patients were recruited and randomized. Finally, analysis was performed on 384 patients: 178 belonged to the natural cycle group whereas the remaining 206 were in the HRT group. The primary outcome was live birth rate, while the secondary outcomes were implantation rate, clinical pregnancy rate, early miscarriage rate, late miscarriage rate, multiple birth rate and low birth weight rate. RESULTS: The live birth rate (37.6% vs 30.1%, p = 0.119) of natural cycle group were higher than those of the hormone replacement therapy group, although the difference was not significant. The secondary outcomes were not found to differ significantly between the two groups. Nonetheless, the endometrium was found to be thicker in the natural cycle group (10.75 mm) than the HRT group (9.00 mm) (p < 0.001). CONCLUSION: No significant differences were observed between the pregnancy outcomes of the natural cycle group and the HRT group which comprised of patients with regular menstrual cycle length.


Asunto(s)
Aborto Espontáneo , Resultado del Embarazo , Embarazo , Femenino , Humanos , Estudios Prospectivos , Criopreservación , Endometrio , Índice de Embarazo , Transferencia de Embrión/métodos , Estudios Retrospectivos , Nacimiento Vivo
5.
Reprod Biomed Online ; 44(2): 380-388, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34895827

RESUMEN

RESEARCH QUESTION: Do frozen embryo transfer (FET) cycles following long-term gonadotrophin-releasing hormone agonist (GnRHa) pretreatment have better pregnancy outcomes than fresh embryo transfer cycles with long or ultra-long GnRHa protocol in these patients? DESIGN: This study included 537 women with adenomyosis divided into three groups: (Group A) FET cycles following long-term GnRHa pretreatment (192 patients); (Group B) fresh embryo transfer cycles with the ultra-long GnRHa protocol (241 patients); (Group C) fresh embryo transfer cycles with the long GnRHa protocol (104 patients). RESULTS: The total gonadotrophin dose and stimulation duration were significantly lower in Group A than in Groups B and C. The implantation and live birth rates were significantly higher in Group A than in Groups B and C. In the long-term GnRHa pretreatment and FET treatment of Group A, implantation (odds ratio [OR] 1.729, 95% confidence interval [CI] 1.073-2.788, P = 0.025), clinical pregnancy (OR 1.665, 95% CI 1.032-2.686, P = 0.037) and live birth rates (OR 1.694, 95% CI 1.045-2.746, P = 0.033) increased and miscarriage rate (OR 0.203, 95% CI 0.078-0.530, P = 0.001) decreased when compared with Group C. Comparison of Groups A and B showed that with the long-term GnRHa pretreatment, FET was a protective factor for live birth rate (OR 1.350, 95% CI 1.017-1.792, P = 0.038). CONCLUSION: FET following long-term GnRHa pretreatment has a better IVF/intracytoplasmic sperm injection outcome, and a potential benefit in terms of a lower gonadotrophin dose, and a shorter stimulation duration than fresh embryo transfer combined with a long or ultra-long GnRHa protocol.


Asunto(s)
Adenomiosis , Resultado del Embarazo , Adenomiosis/complicaciones , Transferencia de Embrión/métodos , Femenino , Fertilización In Vitro/métodos , Hormona Liberadora de Gonadotropina , Humanos , Inducción de la Ovulación/métodos , Embarazo , Índice de Embarazo , Estudios Retrospectivos
6.
Opt Express ; 26(11): 14592-14600, 2018 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-29877493

RESUMEN

We demonstrate a master oscillator power amplifier (MOPA) architecture based on Yb:YAG amplifiers and adaptive optics (AO) systems with a high power and high beam quality laser output. With two conduction cooled, dual-end-pumped Yb:YAG zigzag-slab amplifiers at room temperature, the fiber laser of 300 W was scaled to 11.9 kW. Moreover, AO system positioned downstream was utilized to correct wavefront of amplified laser. The beam quality ß at maximum output power was 2.8 times diffraction limited with closed-loop AO system.

7.
Opt Lett ; 43(16): 3838-3841, 2018 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-30106896

RESUMEN

A continuous-wave-operation laser amplifier chain consisting of three multi-concentration-doped Yb:YAG slab gain modules (GMs) at room temperature is presented. The output power of 22.3 kW with the beam quality of 3.3 times the diffraction limit is achieved from this chain. To the best of our knowledge, based on a Yb:YAG slab at room temperature, the highest power to date while maintaining excellent beam quality laser output. An extraction efficiency of 36% from the single slab GM is obtained and can be further enhanced to 46% by optimizing the parameters of GM. These results have confirmed that the Yb:YAG slab has an excellent scaling performance and is suitable for the development of high-average-power lasers.

8.
Arch Microbiol ; 200(2): 219-225, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28975374

RESUMEN

In this study, six swine-derived multiple-antimicrobial-resistant (MAR) strains of Salmonella Choleraesuis (S. Choleraesuis) were demonstrated to possess higher efflux pump activity than the wild-type (WT). L-Arabinose, a common inducer for gene expression, modulated S. Choleraesuis efflux pump activity in a dose-dependent manner. At low L-arabinose concentrations, increasing L-arabinose led to a corresponding increase in fluorophore efflux, while at higher L-arabinose concentrations, increasing L-arabinose decreased fluorophore efflux activity. The WT S. Choleraesuis that lacks TolC (ΔtolC), an efflux protein associated with bacterial antibiotic resistance and virulence, was demonstrated to possess a significantly reduced ability to extrude L-arabinose. Further, due to the rapid export of L-arabinose, an efficient method for recombination-mediated gene knockout, the L-arabinose-inducible bacteriophage λ Red recombinase system, has a reduced recombination frequency (~ 12.5%) in clinically isolated MAR Salmonella strains. An increased recombination frequency (up to 60%) can be achieved using a higher concentration of L-arabinose (fivefold) for genetic manipulation and functional analysis for MAR Salmonella using the λ Red system. The study suggests that L-arabinose serves not only as an inducer of the TolC-dependent efflux system but also acts as a competitive substrate of the efflux system. In addition, understanding the TolC-dependent efflux of L-arabinose should facilitate the optimization of L-arabinose induction in strains with high efflux activity.


Asunto(s)
Arabinosa/metabolismo , Farmacorresistencia Bacteriana/genética , Proteínas de Transporte de Membrana/genética , Recombinasas/metabolismo , Salmonella enterica/metabolismo , Animales , Antibacterianos/farmacología , Bacteriófago lambda/enzimología , Transporte Biológico/genética , Técnicas de Inactivación de Genes , Recombinasas/genética , Recombinación Genética , Salmonella enterica/efectos de los fármacos , Salmonella enterica/genética , Serogrupo , Porcinos , Virulencia/efectos de los fármacos
9.
Hum Reprod ; 32(4): 937-943, 2017 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-28333243

RESUMEN

Study question: Is the presence of polycystic ovary syndrome (PCOS) associated with anogenital distance (AGD), a biomarker for the prenatal hormonal environment? Summary answer: The presence of PCOS is associated with longer AGD. What is known already: Although the aetiology of PCOS is unclear, emerging data suggest that the natural history of PCOS may originate from intrauterine life. Prenatal exposure to androgen hormones is considered an important factor of PCOS. AGD is the distance measured from the anus to the genital tubercle and there is considerable evidence in humans and animals to support AGD as a sensitive biomarker of prenatal androgen activity. Study design, size, duration: This case-control study of 156 PCOS patients and 180 reproductively healthy women (control subjects) was performed from October 2015 to July 2016. Participants/materials, setting, methods: The patients and controls were recruited from the out-patient Department of Gynecology of Sun Yat-sen Memorial Hospital. Participants completed health questionnaires and provided a blood sample for evaluation of serum reproductive hormone profiles. Anthropometric indices of AGDAF (anus-fourchette) and AGDAC (anus-clitoris) were measured in all subjects. We used logistic regression to estimate the association between the presence of PCOS and AGD measurements while accounting for important confounders, including age and BMI. Multiple linear regression was used to analyse the relationships between PCOS characteristics (e.g. polycystic ovaries and total testosterone (T)) and two measurements of AGD in the PCOS group and controls. Main results and the role of chance: Overall, logistic regression showed that women with AGDAF in the highest tertile were 18.8 times (95% CI 9.6-36.6; P < 0.001) more likely to have PCOS compared with those in the lowest tertile. Women with AGDAC in the highest tertile were 6.7 times (95% CI 3.7-12.1; P < 0.001) more likely to have PCOS than those in the lowest tertile. In the PCOS group, multiple linear regression analyses revealed that both AGD measurements were positively associated with T levels (ß = 0.246 for AGDAC, ß = 0.368 for AGDAF; P = 0.003 and P < 0.001, respectively), and AGDAF was positively associated with the presence of polycystic ovaries (ß = 0.279; P < 0.001). In the controls, a positive association was found only between T levels with AGDAF (ß = 0.177, P = 0.020), whereas no associations were found between the remaining covariates and AGD measurements. Limitations, reasons for caution: As this was an observational study, causal inference cannot be obtained. Wider implications of the findings: This study suggests that PCOS may originate in intrauterine life, and be affected by prenatal exposure to androgens. Study funding/competing interest(s): This study was supported by funds obtained from the Science Technology Research Project of Guangdong Province (2010B031600058 and 2015A030310083) and the Major Science Technology Research Project of Guangdong Province (ZKM05602S). The authors have no competing interests to declare. Trial registration number: Not applicable.


Asunto(s)
Canal Anal/anatomía & histología , Andrógenos/toxicidad , Genitales Femeninos/anatomía & histología , Síndrome del Ovario Poliquístico/diagnóstico , Efectos Tardíos de la Exposición Prenatal , Antropometría , Biomarcadores , Estudios de Casos y Controles , Femenino , Humanos , Modelos Lineales , Embarazo , Factores de Riesgo
10.
Int J Med Microbiol ; 306(2): 115-22, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26915500

RESUMEN

Clostridium difficile is a human and animal pathogen. Recently, the incidence of community-acquired C. difficile infection has increased, and many studies have indicated that C. difficile might be food-borne. The correlation between C. difficile infection in humans and in animals has been a topic of debate. The objective of this study was to determine the genetic relatedness of C. difficile from human and pigs in Taiwan. We investigated the molecular epidemiology of C. difficile in healthy humans and pigs from 2011 to 2015. The isolation rate of C. difficile from pigs in 13 commercial farms was 49% (100/204), and a high proportion of hypervirulent (C. difficile carrying tcdA, tcdB, and cdtA/B genes and a 39-bp deletion in the tcdC gene) ribotype 078 lineage isolates (90%, 90/100; including 078, 126, 127, and 066-like isolates) were identified. In addition, the C. difficile ribotype 127 isolates from pigs typically exhibited moxifloxacin resistance (37/43; 86%). In healthy humans, the isolation rate was 4.3% (3/69), and all healthy human isolates were non-toxigenic. In particular, we compared the porcine isolates with two patient strains (ribotype 127) obtained from two hospitals in central Taiwan. The multilocus variable number tandem repeat analysis revealed a high genetic relatedness between ribotype 127 from patients and pigs. This study indicated that isolates of the ribotype 078 lineage, and especially ribotype 127, were widely distributed in pig farms and showed a high frequency of moxifloxacin resistance. The closely related ribotype 127 from patients and pigs may have had a common origin or low diversity. In conclusion, C. difficile ribotype 127 is a noteworthy pathogen in pigs and poses a potential public health threat.


Asunto(s)
Clostridioides difficile/aislamiento & purificación , Clostridioides difficile/patogenicidad , Enterocolitis Seudomembranosa/microbiología , Enfermedades de los Porcinos/microbiología , Animales , Clostridioides difficile/efectos de los fármacos , Clostridioides difficile/genética , Análisis por Conglomerados , Enterocolitis Seudomembranosa/epidemiología , Heces/microbiología , Variación Genética , Humanos , Tipificación de Secuencias Multilocus , Reacción en Cadena de la Polimerasa Multiplex , Ribotipificación , Organismos Libres de Patógenos Específicos , Porcinos , Enfermedades de los Porcinos/epidemiología , Taiwán/epidemiología , Virulencia/genética
11.
Opt Express ; 24(12): 12507-14, 2016 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-27410271

RESUMEN

We theoretically analyzed and experimentally demonstrated an injection-locking based all-optical flip-flop memory using a simple and compact tunable V-cavity laser (VCL). A bistable region in the tuning characteristics of the VCL is employed for the flip-flop operation. The state of the VCL can be set and reset by injecting signal pulses at two different wavelengths. The pulse power for both set and reset signal is only about 1 pJ. Short response times of about 150 ps are measured for storing and erasing.

12.
Opt Express ; 24(18): 20318-23, 2016 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-27607638

RESUMEN

We demonstrate all-optical wavelength conversion (AOWC) of non-return-to-zero (NRZ) signal based on cross-gain modulation in a single heterogeneously integrated III-V-on-silicon semiconductor optical amplifier (SOA) with an optical bandpass filter. The SOA is 500 µm long and consumes less than 250 mW electrical power. We experimentally demonstrate 12.5 Gb/s and 40 Gb/s AOWC for both wavelength up and down conversion.

13.
Opt Express ; 24(21): 24517-24523, 2016 Oct 17.
Artículo en Inglés | MEDLINE | ID: mdl-27828179

RESUMEN

We demonstrate a high-efficiency, high-average-power, CW master oscillator power amplifier based on a conduction-cooled, end-pumped Yb:YAG slab architecture at room temperature (RT). Firstly, the CW amplification property is theoretically analyzed based on the kinetics model for Yb:YAG. To realize high-efficiency laser amplification extraction for RT Yb:YAG, not only intense pump but also a high-power seed laser is of great importance. Experimentally, a composite Yb:YAG crystal slab with three doped and two un-doped segments symmetrically is employed as the gain medium, which is end-pumped by two high-power, 940-nm diode lasers. A high-power, narrow-spectral-width, 1030-nm fiber seed laser then double passes the composite slab to realize efficient power amplification. For 0.8-kW seed input, maximum output power of 3.54 kW is obtained at 6.7 kW of pump power, with the optical conversion efficiency of 41% and the highest slope efficiency of 59%. To the best of our knowledge, this is the highest power and efficiency reported for Yb:YAG lasing at RT except thin-disk lasers.

14.
Anaerobe ; 41: 125-130, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27292030

RESUMEN

Clostridium difficile is the major cause of nosocomial diarrhea. We have previously demonstrated that in southern Taiwan, severe C. difficile-associated diarrhea (CDAD) cases were due to the C. difficile RT 126 strain infection, indicating the arrival of an epidemic C. difficile clone in southern Taiwan. RT126 has a close genetic relationship with RT078. However, the RT078 family is the predominant strain of C. difficile in animals worldwide, particularly in swine. In this study, we surveyed C. difficile strains isolated from swine at several farms in Taiwan from August 2011 to March 2015. We found that all swine strains, namely RT078 (32.5%, 37 of 114), RT126 (28.9%, 33 of 114) and RT127 (37.7%, 43 of 114), belonged to the toxigenic RT078 family. All strains had high gyrA mutation rate (57.9%, 66/114), which was linked to quinolone resistance. Notably, Rep-PCR revealed that 3 RT078 animal strains had the same fingerprint as human RT078 clinical isolates; their phylogenic relationship was closely related to the whole gene sequences of tcdB, thus suggesting zoonotic potential for C. difficile infection in Taiwan.


Asunto(s)
Clostridioides difficile/genética , Enterocolitis Seudomembranosa/veterinaria , Enfermedades de los Porcinos/microbiología , Animales , Clostridioides difficile/aislamiento & purificación , Enterocolitis Seudomembranosa/epidemiología , Enterocolitis Seudomembranosa/microbiología , Enterocolitis Seudomembranosa/transmisión , Humanos , Tipificación de Secuencias Multilocus , Filogenia , Sus scrofa , Porcinos , Enfermedades de los Porcinos/epidemiología , Enfermedades de los Porcinos/transmisión , Taiwán/epidemiología , Zoonosis
15.
Zhonghua Fu Chan Ke Za Zhi ; 50(5): 356-60, 2015 May.
Artículo en Zh | MEDLINE | ID: mdl-26311455

RESUMEN

OBJECTIVE: To investigate the change of adiponectin level with menopause status in women aged 40 to 65, and its relationship with androgen. METHODS: A cross-sectional study included woman (aged from 40 to 65) who were in hospital for routine check-up at the Sun Yat-sen Memorial Hospital from August to October in 2013. All subjects underwent laboratory examinations of adiponectin, sex hormone binding globulin (SHBG), dehydroepiandrosterone-sulfate (DHEA-S), total testosterone (TT), collected anthropometric measurements and then calculated free androgen index (FAI) and body mass index (BMI). According to their menstrual status, the subjects were divided into 4 groups: premenopausal group with 119 subjects, perimenopausal group with 60 subjects, early postmenopausal group with 62 subjects, late postmenopausal group with 64 subjects. RESULTS: (1) Adiponectin levels declined to its lowest level in menopausal transition and gradually becoming higher after menopause, which showed a U-shaped trajectory. When compared adiponectin levels in late postmenopausal group [(13 ± 5) mg/L] with those in perimenopausal [(8 ± 6) mg/L] or early postmenopausal group [(9 ± 6) mg/L], it all showed significantly difference (P < 0.05). (2) Both the adiponectin levels were negatively correlated with waistline in the 4 groups (premenopausal group, r = -0.276; perimenopausal group, r = -0.334; early postmenopausal group, r = -0.211; late postmenopausal group, r = -0.218; all P < 0.05). Levels of adiponectin were positively correlated with SHBG (r = 0.536, P < 0.05) and negatively with FAI (r = -0.363, P < 0.05) in menopausal transition, while in late postmenopausal group, negatively correlated with level of DHEA-S (r = -0.450, P < 0.05). When adjusted for age, BMI and waistline, the above correlations still exist. CONCLUSIONS: Adiponectin levels declined to its lowest level in menopausal transition and gradually becoming higher after menopause, which showed a U-shaped trajectory during the sequential menopause status transition in middle aged women. Low level of adiponectin in menopausal transition is closely associated with the relative excess androgen occurred during this stage.


Asunto(s)
Adiponectina/sangre , Andrógenos/sangre , Sulfato de Deshidroepiandrosterona/sangre , Menopausia/sangre , Índice de Masa Corporal , Estudios Transversales , Femenino , Humanos , Persona de Mediana Edad , Premenopausia , Globulina de Unión a Hormona Sexual/análisis , Testosterona/sangre
16.
J Minim Invasive Gynecol ; 25(1): 12-13, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-28373125
17.
Free Radic Biol Med ; 196: 37-52, 2023 02 20.
Artículo en Inglés | MEDLINE | ID: mdl-36638901

RESUMEN

Iron is essential for the health of reproductive system, and women with iron overload suffer from ovarian dysfunction and lack effective treatment in fertility preservation. However, the underlying mechanism of the detrimental effects of iron overload on ovarian function remains ambiguous. Here, we confirmed the excess iron in the circumjacent follicle near endometriomas, which negatively impacted the oocyte development in the affected ovaries. Further, by integrating cell line and chronic iron overload mice model, we demonstrated that iron overload can function as a ROS inducer to amplify mitochondria damage, which significantly elevated the release of cytochrome C and ultimately induced the apoptosis of granular cells. Besides, for the first time, our findings revealed that disruption of HIF-1α/FSHR/CYP19A1 signaling was critical for decreased estrogen synthesis of granular cells in response to iron overload, which can lead to apparent oocyte maldevelopment and subfertility. Overall. this study uncovered that iron overload modulated the follicular microenvironment and generated a deleterious effect on female infertility via ROS/HIF-1α/FSHR signaling. These results might provide potential implications for future clinical risk management of patients with endometrioma and hemopathy.


Asunto(s)
Endometriosis , Sobrecarga de Hierro , Humanos , Animales , Ratones , Femenino , Especies Reactivas de Oxígeno/metabolismo , Sobrecarga de Hierro/metabolismo , Hierro/metabolismo , Folículo Ovárico/metabolismo , Transducción de Señal , Endometriosis/metabolismo
18.
Carbohydr Polym ; 305: 120573, 2023 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-36737209

RESUMEN

Herein, an activated wood surface rich in CHO groups was constructed by spraying a sodium periodate aqueous solution on a natural wood surface. Besides, microcrystalline cellulose was functionalized to obtain aminated cellulose, which was dissolved in an aqueous solution and used as a specific adhesive. Subsequently, an ultrastrong wood bonding interface was co-constructed with the activated wood surface and aminated cellulose, which was formed by a chemical covalent reaction between aldehyde groups at the activated wood interface and amino groups on aminated cellulose. The dry, hot-water, and boiling-water lap shear strengths of the plywood specimens were 1.47, 1.07, and 1.08 MPa, respectively. The boiling-water strength of the plywood made from the activated wood surface achieved increased to 1.08 MPa from 0 MPa of the plywood constructed on the nonactivated wood surface. The chemical crosslinking reaction and bonding mechanism between the adhesive and activated wood surface were clarified by density functional theory calculations, attenuated total reflectance-Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results showed that chemical bonding (aminal NCN and imine CN) at the bonding interface played an important part in improving the water resistance and bonding strength. This work provides new concepts for designing durable and moisture-resistant wood products.

19.
Microorganisms ; 11(10)2023 Sep 22.
Artículo en Inglés | MEDLINE | ID: mdl-37894032

RESUMEN

Hemoprotozoa are microorganisms that parasitize the blood and possess intricate life cycles. Despite the complexity of their nature, little is known about the biology of hemoprotozoa in reptilian hosts. In this study, we conducted disease surveillance on blood samples collected from six black spiny-tailed iguanas (Ctenosaura similis) exhibiting clinical signs. We found two different types of hemoparasites in the blood films and further confirmed they belong to the genera Lakesterella and Hepatozoon through molecular methods. In the tissue section from a dead iguana infected only with Lakesterella sp., parasites were also found in melanomacrophages of the liver and kidney. Since Lakesterella sp. infection has not been reported in C. similis, we propose this hemococcidian as a new species, Lankesterella desseri n. sp. The Hepatozoon parasites discovered in this study were classified as Hepatozoon gamezi based on their morphological characteristics, particularly the notable deformation of all infected erythrocytes, and this classification was further corroborated through molecular biological and phylogenetic analyses. This is the first hemoprotozoa investigation in C. similis with pathological and molecular characterization of these pathogens. We suggest that more studies are needed to understand the epidemiology, transmission, and impact of these parasites on their hosts and ecosystems.

20.
Materials (Basel) ; 16(11)2023 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-37297155

RESUMEN

The performance of urea-formaldehyde (UF) resin and its formaldehyde emission is a natural contradiction. High molar ratio UF resin performance is very good, but its formaldehyde release is high; low molar ratio UF resin formaldehyde release is reduced, but the resin itself performance becomes very bad. In order to solve this traditional problem, an excellent strategy of UF resin modified by hyperbranched polyurea is proposed. In this work, hyperbranched polyurea (UPA6N) is first synthesized by a simple method without any solvent. UPA6N is then added into industrial UF resin in different proportions as additives to manufacture particleboard and test its related properties. UF resin with a low molar ratio has a crystalline lamellar structure, and UF-UPA6N resin has an amorphous structure and rough surface. The results show that internal bonding strength increased by 58.5%, modulus of rupture increased by 24.4%, 24 h thickness swelling rate (%) decreased by 54.4%, and formaldehyde emission decreased by 34.6% compared with the unmodified UF particleboard. This may be ascribed to the polycondensation between UF and UPA6N, while UF-UPA6N resin forms more dense three-dimensional network structures. Finally, the application of UF-UPA6N resin adhesives to bond particleboard significantly improves the adhesive strength and water resistance and reduces formaldehyde emission, suggesting that the adhesive can be used as a green and eco-friendly adhesive resource for the wood industry.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA