One of the common problems in strawberry (
Fragaria
×
ananassa
) micropropagation is the vitrification phenomenon (succulent plantlets, brittle stems, yellow leaves, etc.) leading to the reduction ...of plantlets quality and low survival rate in the greenhouse. In this study, the effects of silver nanoparticles (AgNPs) on explant disinfection
,
in vitro growth (shoot multiplication, and root formation), runner formation as well as ethylene accumulation during micropropagation of strawberry were investigated. The results showed that leaf explants treated with 200 mg/L AgNPs solution for 20 min was more effective in explant disinfection and shoot regeneration than using 1 g/L HgCl
2
. In addition, AgNPs stimulated the growth of shoot and plantlet and as well shortened the duration of root formation (4 days) as compared to those in control without AgNPs during micropropagation. Besides, AgNPs reduced the ethylene gas accumulation in the culture’s vessels of shoots (0.66 ppm) and plants (0.06 ppm) compared to controls (1.77 ppm; 0.15 ppm; respectively). Moreover, AgNPs combination with culture period (5; 10 or 15 days) effect root formation stage and acclimatization in the greenhouse. The plantlets that cultured on MS medium supplemethed with 0.5 mg/L AgNPs during 10 days showed higher survival rate (93.33%) after 15 days as well as runner formation per plant (8.00 runners) after 60 days in greenhouse than those in control.
Key message
AgNPs improved explant disinfection and in vitro growth. AgNPs improved runner formation in the greenhouse. AgNPs limited ethylene accumulation during micropropagation.
The weak emission intensity of rare-earth element-doped dual-mode materials leads to low-sensor sensitivity, which is a challenge in optical sensor applications. The present work achieved high-sensor ...sensitivity and high green color purity based on the intense green dual-mode emission of Er/Yb/Mo-doped CaZrO3 perovskite phosphors. Their structure, morphology, luminescent properties, and optical temperature sensing properties have been investigated in detail. Phosphor shows a uniform cubic morphology with an average size of approximately 1 μm. Rietveld refinement confirms the formation of single-phase orthorhombic CaZrO3. Under the excitation of 975 and 379 nm, the phosphor emits pure green up and down-conversion (UC and DC) emission at 525/546 nm corresponding to 2H11/2/4S3/2–4I15/2 transitions of Er3+ ions, respectively. Intense green UC emissions were achieved because of energy transfer (ET) from the high-energy excited state of Yb3+–MoO42− dimer to the 4F7/2 level of Er3+ ion. Furthermore, the decay kinetics of all obtained phosphors confirmed ET efficiency from Yb3+–MoO42− dimer to Er3+ ions, leading to strong green DC emission. Moreover, the DC of the obtained phosphor shows that a sensor sensitivity value of 0.697% K−1 at 303 K is higher than the UC (0.667% K−1 at 313 K) because the thermal effect generated by the DC excitation source light is ignored compared with UC luminescence. CaZrO3:Er–Yb–Mo phosphor shows intense green dual-mode emission with high green color purity, 96.50% of DC and 98% of UC emissions, and high sensitivity, making it suitable for optoelectronic devices and thermal sensor applications.
In this work, low-temperature hydrothermal synthesis of a series of
x
Mo-1%Er-10%Yb (
x
:mol%) doped hydroxyapatite (HA) phosphors was studied. The single phase of hexagonal structure HA nanorods ...obtained with high crystallinity was verified using characterization techniques such as XRD and HRTEM + SAED. It was found that the presence of the orientation associated with near to the {210} planes of the HA phase was favored with the increase of the Mo
6+
doping content and different hydrothermal reaction times. The Mo
6+
doped HA:Er-Yb phosphor showed an energetic green UC emission band (520/550 nm) and weak red UC emission band (655 nm) attributed to (
2
H
11/2
,
4
S
3/2
)-
4
I
15/2
,
4
F
9/2
-
4
I
15/2
transition of the Er
3+
ion, respectively, under 975 nm laser excitation. Notably, the green emission intensity of the Mo
6+
doped phosphor is 70 times higher than that of the samples without doped Mo
6+
content. The high efficiency of the green UC can be attributed to the novel energy transfer process from the |
2
F
7/2
,
3
T
2
〉 state of the Yb
3+
-MoO
4
2−
dimer to the
4
F
7/2
of the Er
3+
ions. The results from fitting the theoretical model to the experimental luminescence decay curves of the undoped and doped samples showed that the decay time of green emission of the sample doped with Mo
6+
ions (329 μs) is longer than that of the undoped sample (299 μs), which confirms the presence of the Yb
3+
-MoO
4
2−
dimer in the system. Moreover, the grain orientations due to the effect of Mo
6+
ions doped in the HA phosphor could favor the enhancement of the UC emission intensity. The UC mechanism of Mo
6+
doped HA:Er-Yb was determined to be three (green band) and two photon (red band) absorption processes. The results suggest that the HA:Er-Yb-Mo phosphor could have potential in solar cell and biomedical applications.
In this work, low-temperature hydrothermal synthesis of a series of
x
Mo-1%Er-10%Yb (
x
:mol%) doped hydroxyapatite (HA) phosphors was studied.
The use of robust ecological data to make evidence‐based management decisions is frequently prevented by limited data quantity or quality, and local ecological knowledge (LEK) is increasingly seen as ...an important source of information for conservation. However, there has been little assessment of LEK's usefulness for informing prioritization and management of landscapes for threatened species, or assessing comparative species status across landscapes. A large‐scale interview survey in the Annamite Mountains (Vietnam and Lao PDR) compiled the first systematic LEK data set for saola Pseudoryx nghetinhensis, one of the world's rarest mammals, and eight other ungulates. Saola conservation is hindered by uncertainty over continued presence across much of its proposed distribution. We analysed comparative LEK‐based last‐sighting data across three landscapes to determine whether regional sighting histories support previous suggestions of landscape importance for saola conservation (Hue‐Quang Nam: top‐priority Vietnamese landscape; Pu Mat: lower priority Vietnamese landscape; Viengthong: high‐priority Lao landscape) and whether they constitute an effective spatial prioritization tool for cryptic species management. Wild pig and red muntjac may be the only Annamite ungulates with stable populations; the regional status of all other species appears to be worse. Saola have declined more severely and/or are significantly rarer than most other ungulates and have been seen by relatively few respondents. Saola were also frequently considered locally rarest or declining, and never as species that had not declined. In contrast to other species, there are no regional differences in saola sighting histories, with continued persistence in all landscapes challenging suggestions that regional status differs greatly. Remnant populations persist in Vietnam despite heavy hunting, but even remote landscapes in Lao may be under intense pressure. Synthesis and applications. Our local ecological knowledge data suggest that intact saola populations probably no longer exist, but individuals persist in all three landscapes, making management activities to reduce hunting pressure on ungulates in each landscape a conservation priority. Analysis of last‐sighting histories can constitute an important conservation tool when robust data are otherwise unavailable, and collection of last‐sighting records should be incorporated more widely into field studies and management of other highly threatened, cryptic species.
In this study, copper selenide (Cu2Se) compounds were synthesized using a solid-state reaction technique and post-sintering processes (573 K–973 K). The mass density of the Cu2Se compounds ...decreased with increasing sintering temperatures due to changes in grain morphology and an increase in the number and size of pores in the samples. The sintering temperature also affected carrier generation mechanisms, which directly impacted the electrical transport characteristics and thermal properties. The α→β phase transition at around 400 K was observed in all samples. The low thermal conductivity was mainly attributed to the low lattice thermal conductivity (κlattice). As the result, the sample sintered at 773 K showed an outstanding ZT value of 1.44 at 773 K, with a power factor of 12.1 μWm−1K−2 and the thermal conductivity of 0.65 Wm−1K−1. The sintering temperature dependence of thermal conductivity was elucidated in terms of the growth of microstructural pores.
Copper selenide (Cu2Se) compounds synthesized using the solid-state reaction technique and post-sintering processes have achieved outstanding ZT values of up to 1.44 at 773 K. Display omitted
•Successful synthesis of Cu2Se compounds using solid-state reaction and sintering processes.•Mass density decreased with increasing sintering temperature due to changes in grain morphology and pore size.•Carrier generation mechanisms played a crucial role in determining electrical and thermal transport characteristics.•Sintered samples at 773 K showed exceptional thermoelectric performance with a ZT value of 1.44.•Thermal conductivity depended on sintering temperature and was correlated with the growth of microstructural pores.
In this study, hydroxyapaptite (HAp) has been successfully coated on acid-etched titanium substrate by hydrothermal method. The phase composition and surface morphology of HAp have been analyzed by ...X-ray diffraction, digital microscopy images, and scanning electron microcopy analysis. Biocompability of the HAp coating has been evaluated by SBF immersion test and in vitro baby hamster kidney (BHK) cell attachment. The optimal parameters such as temperature, time, and pH of the hydrothermal process have been established. The HAp coating has a single-phase HAp structure with hexagonal symmetry as hydrothermal process at temperature of 240°C, pH value of 10 and coating time of 24 h. The HAp coating has great applicability in biomedical materials because of its high biocompatibility.
Micropropagation has proven to be an effective method for large-scale plant production in a short time and a useful tool for plant breeding. Microbial contamination is one of the most difficult ...micropropagation challenges, resulting in reduced plant quality and loss of valuable stocks. Therefore, sterilization of culture media is a critical step in plant micropropagation. However, sterilized media might reduce the activity of plant growth regulators and nutritional components of culture media. The sterilization effects of silver nanoparticles (AgNP) on the growth of explants and culture media were examined. The treatment with 250 ppm AgNP for 15 to 20 min of 4-wk-old
ex vitro
leaves proved optimal for controlling the contamination. Furthermore, the Murashige and Skoog medium containing 4 ppm AgNP resulted in 100% medium disinfection (no contamination) after 4 wk of culture. The plantlets obtained from non-sterilized MS medium (NoM) containing 4 ppm AgNP and 4 g L
−1
agar gave similar results as the control medium with 8 g L
−1
agar and the absence of AgNP. Large scale culture systems using NoM in large plastic containers of two different sizes (NoM1 and NoM2) could produce quality plantlets. Chrysanthemum plantlets in the NoM1 system showed higher antioxidant enzyme activities of ascorbate peroxidase and superoxide dismutase than plantlets in the autoclaved medium. Furthermore, the plantlets from NoM were better acclimatized under greenhouse conditions than those from the autoclaved medium (AuM) system. The developmental stages (flower buds and blooming time) of NoM1 and NoM2 plantlets, were 1 wk earlier than those from the AuM system. The successful use of AgNP as a sterilizer and as a component of culture media would reduce the cost of micropropagation and improve plants' quality.
Nontyphoidal
(NTS), particularly
serovar Typhimurium, is among the leading etiologic agents of bacterial enterocolitis globally and a well-characterized cause of invasive disease (iNTS) in ...sub-Saharan Africa. In contrast,
Typhimurium is poorly defined in Southeast Asia, a known hot spot for zoonotic disease with a recently described burden of iNTS disease. Here, we aimed to add insight into the epidemiology and potential impact of zoonotic transfer and antimicrobial resistance (AMR) in
Typhimurium associated with iNTS and enterocolitis in Vietnam. We performed whole-genome sequencing and phylogenetic reconstruction on 85 human (enterocolitis, carriage, and iNTS) and 113 animal
Typhimurium isolates isolated in Vietnam. We found limited evidence for the zoonotic transmission of
Typhimurium. However, we describe a chain of events where a pandemic monophasic variant of
Typhimurium (serovar I:4,5,12:i:- sequence type 34 ST34) has been introduced into Vietnam, reacquired a phase 2 flagellum, and acquired an IncHI2 multidrug-resistant plasmid. Notably, these novel biphasic ST34
Typhimurium variants were significantly associated with iNTS in Vietnamese HIV-infected patients. Our study represents the first characterization of novel iNTS organisms isolated outside sub-Saharan Africa and outlines a new pathway for the emergence of alternative
variants into susceptible human populations.
Typhimurium is a major diarrheal pathogen and associated with invasive nontyphoid
(iNTS) disease in vulnerable populations. We present the first characterization of iNTS organisms in Southeast Asia and describe a different evolutionary trajectory from that of organisms causing iNTS in sub-Saharan Africa. In Vietnam, the globally distributed monophasic variant of
Typhimurium, the serovar I:4,5,12:i:- ST34 clone, has reacquired a phase 2 flagellum and gained a multidrug-resistant plasmid to become associated with iNTS disease in HIV-infected patients. We document distinct communities of
Typhimurium and I:4,5,12:i:- in animals and humans in Vietnam, despite the greater mixing of these host populations here. These data highlight the importance of whole-genome sequencing surveillance in a One Health context in understanding the evolution and spread of resistant bacterial infections.
•Dual-mode intense green emission of HA/β-TCP: Er-Yb-Mo composite synthesized by hydrothermal method.•Mo6+ doped system enhances strongly both UC and DC green emissions.•Dual-mode mechanism of ...HA/β-TCP:Er-Yb-Mo phosphor has explained.•Good temperature sensing property was obtained.
Display omitted
This work presents a novel multifunctional material synthesized by hydroxyapatite/ β-tricalcium phosphate (HA/β-TCP) doped with Er-Yb-Mo ions (using hydrothermal method) and its characterization, showing a peculiar property of green dual-mode emissions (up and down-conversions). It was found that the obtained material exhibits an intense green emission (510–560 nm) both via up-conversion (excited by 975 nm) and down-conversion (excited by 379 nm), which depend on the Mo6+ contents. Particularly, compared with the free-Mo6+ sample, the green emission intensities of the samples doped with 5% Mo6+ mol are 50 and 35 times higher for UC and DC emissions, respectively. Furthermore, the temperature sensing property of the HA/β-TCP: Er-Yb-Mo composite is investigated by fluorescence intensity ratio (FIR) technique, showing a high and competitive sensitivity with a maximum value of 0.0064 K−1 at 403 K. The results indicated that the HA/β-TCP: Er-Yb-Mo phosphor can be useful for high-temperature-sensing applications.
In this paper, a novel material based on Er-Yb-Mo tri-doped HA/β-TCP phosphor for intense green up-conversion (UC) emission was successfully synthesized by solid-state reaction method. X-ray ...diffraction (XRD) measurements verified that the materials including a trace amount of HA phase has a hexagonal structure and main β-TCP phase has a rhombohedral structure, which is controlled by the doped ions. Under excitation wavelength of 976 nm laser diode, the HA/β-TCP:Er-Yb-Mo phosphor showed strong green UC emission band at 520/556 nm and weak red emission band at 656 nm which are attributed to (2H11/2, 4S3/2) - 4I15/2, 4F9/2 - 4I15/2 transition of the Er3+ ion, respectively. Remarkably, compared with the sample without Mo6+, the green emission intensities increased ∼650 times was achieved by using Er3+-Yb3+-Mo6+ doped phosphor. The high efficiency of the UC can be attributed to novel energy transfer process from |2F7/2, 3T2> state of Yb3+ - MoO42− dimer to the 4F7/2 of Er3+ ions. Moreover, the grain orientations due to the effect of Mo6+ ions doped in β-TCP phosphor could play an important role in the enhancement of UC emission intensity. These results indicate that the HA/β-TCP: Er-Yb-Mo phosphor has potential application in biological imaging and medicine.
Display omitted
•Novel upconversion material (Er-Yb-Mo tri-doped HA/β-TCP phosphor) was facilely synthesized by solid-state reaction method.•The crystalline single – phase of β-TCP was achieved by doping with Mo6+ ions.•The green emission intensity of the sample doped with Mo was 650 times higher compared with the sample without Mo.•The selective green upconversion emission can be controlled by controlling the doping Mo6+ concentration in HA/β-TCP: Er3+-Yb3+.
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