Depositing Fe Species Inside ZSM-5 to Oxidize Cyclohexane to Cyclohexanone (Chemistry)

The directly catalytic oxidation of alkanes has high atomic economy and application value to form corresponding chemical organic products such as alcohols, aldehydes, ketones and carboxylic acid. It is challenging to achieve efficient and selective oxidation of alkane under mild conditions due to the inert C-H bonds of alkanes.

Many researchers have developed a series of supported iron based catalysts to simulate the alkane biological monooxygenase with iron center atoms. However, traditional methods, such as impregnation method, ion exchange method, etc., are difficult to control the dispersion and the deposition position of iron species on the catalyst support.

Generally, iron species can easily replace the H+ of Brønsted acid sites to reduce the number of Brønsted acid sites, and many types of iron species will be formed on other different potential sites of ZSM-5 (Lewis acid sites and defect sites, etc.). The coexistence of multiple active centers on the catalyst is one of the main reasons for the low selectivity.

Atomic layer deposition (ALD) is an advanced thin film technology by single-layer chemisorption and reaction of vapor precursors on the surface of substrates with atomic and molecular control precision.

Recently, Dr. Bin Zhang and colleagues in the Institute of Coal Chemistry, Chinese Academy of Sciences, report a general strategy to selectively deposit high-dispersed Fe species into the micropores of ZSM-5 to prepare FeOx/ZSM-5 catalysts.

The obtained FeOx/ZSM-5 catalysts perform high selectivity of cyclohexanone (92%-97%), and the catalyst activity is significantly higher than those of the iron-based catalysts reported in the literature. Ferrocene (Fe(Cp)2) is used as a precursor for the deposition since its kinetic diameter is smaller than the pore size of ZSM-5. The framework of ZSM-5 and the Brønsted acid sites are intact during ALD, and the Fe species are selectively deposited onto the defect and Lewis acid sites of ZSM-5. The loading, size and surface electronic state of FeOx species can be precisely controlled by merely changing ALD cycles. The Fe content in the FeOx/ZSM-5 catalyst increases linearly with the increase of ALD cycles. Fe-O-Si bonds are dominantly formed over FeOx/ZSM-5 with a low loading of Fe, while FeOx nanoparticles are generated at a high Fe loading. Compared with the FeOx nanoparticles, the Fe-O-Si species performs higher turnover frequency and stability in the oxidation reaction.

Featured image: XPS spectra from ZSM-5, 10FeOx/ZSM-5 and 40FeOx/ZSM-5 of (a) Fe 2p, (b) O 1s. (b) Catalyst studies of Fe-contain for the oxidation of cyclohexane; 1. 10FeOx/ZSM-5(ALD); 2. 40FeOx/ZSM-5(ALD); 3. 0.27 wt.%Fe-ZSM-5 prepared by impregnation method; 4. Fe-ZSM-5 (Impregnation, literature); 5. Fe-ZSM-5([emim]BF4); 6. Fe-MCM-41; 7. FeAPO-5; 8. FeCl2(Tpm) [Tpm=hydrotris(pyrazol-1-yl)methane]. 9. Fe(III)(BPMP)Cl(μ-O)Fe(III)Cl3; K: cyclohexanone; A: cyclohexanol. (c) Catalytic performances of FeOx/ZSM-5 catalysts for selective oxidation of cyclohexane to cyclohexanone. (d) Raman spectra of after sequential addition of H2O2 and cyclohexane onto the surface of 10FeOx/ZSM-5. ©Science China Press


See the article: Zhai, L., Zhang, B., Liang, H. et al. The selective deposition of Fe species inside ZSM-5 for the oxidation of cyclohexane to cyclohexanone. Sci. China Chem. (2021). https://doi.org/10.1007/s11426-020-9968-x https://link.springer.com/article/10.1007/s11426-020-9968-x


Provided by Science China Press

Kirigami-style Fabrication May Enable New 3D Nanostructures (Engineering)

A new technique that mimics the ancient Japanese art of kirigami may offer an easier way to fabricate complex 3D nanostructures for use in electronics, manufacturing and health care.

Kirigami enhances the Japanese artform of origami, which involves folding paper to create 3D structural designs, by strategically incorporating cuts to the paper prior to folding. The method enables artists to create sophisticated three-dimensional structures more easily.

“We used kirigami at the nanoscale to create complex 3D nanostructures,” said Daniel Lopez, Penn State Liang Professor of Electrical Engineering and Computer Science, and leader of the team that published this research in Advanced Materials. “These 3D structures are difficult to fabricate because current nanofabrication processes are based on the technology used to fabricate microelectronics which only use planar, or flat, films. Without kirigami techniques, complex three-dimensional structures would be much more complicated to fabricate or simply impossible to make.”

Lopez said that if force is applied to a uniform structural film, nothing really happens other than stretching it a bit, like what happens when a piece of paper is stretched. But when cuts are introduced to the film, and forces are applied in a certain direction, a structure pops up, similar to when a kirigami artist applies force to a cut paper. The geometry of the planar pattern of cuts determines the shape of the 3D architecture.

“We demonstrated that it is possible to use conventional planar fabrication methods to create different 3D nanostructures from the same 2D cut geometry,” Lopez said. “By introducing minimum changes to the dimensions of the cuts in the film, we can drastically change the three-dimensional shape of the pop-up architectures. We demonstrated nanoscale devices that can tilt or change their curvature just by changing the width of the cuts a few nanometers.”

This new field of kirigami-style nanoengineering enables the development of machines and structures that can change from one shape to another, or morph, in response to changes in the environment. One example is an electronic component that changes shape in elevated temperatures to enable more air flow within a device to keep it from overheating.

“This kirigami technique will allow the development of adaptive flexible electronics that can be incorporated onto surfaces with complicated topography, such as a sensor resting on the human brain,” Lopez said. “We could use these concepts to design sensors and actuators that can change shape and configuration to perform a task more efficiently. Imagine the potential of structures that can change shape with minuscule changes in temperature, illumination or chemical conditions.”

Lopez will focus his future research on applying these kirigami techniques to materials that are one atom thick, and thin actuators made of piezoelectrics. These 2D materials open new possibilities for applications of kirigami-induced structures. Lopez said his goal is to work with other researchers at Penn State’s Materials Research Institute (MRI) to develop a new generation of miniature machines that are atomically flat and are more responsive to changes in the environment.

“MRI is a world leader in the synthesis and characterization of 2D materials, which are the ultimate thin-films that can be used for kirigami engineering,” Lopez said. “Moreover, by incorporating ultra-thin piezo and ferroelectric materials onto kirigami structures, we will develop agile and shape-morphing structures. These shape-morphing micro-machines would be very useful for applications in harsh environments and for drug delivery and health monitoring. I am working at making Penn State and MRI the place where we develop these super-small machines for a specific variety of applications.”

Other authors on the study include Xu Zhang from Carnegie Mellon University and Haogang Cai from New York University, both former postdoctoral fellows with Lopez. Lior Medina and H. Espinosa from Northwestern University and Vladimir Askyuk from the National Institute of Standards and Technology also are part of the team. The research was supported by the U.S. Department of Energy.

Featured image: Strategically placed cuts to structural films can create 3D nanostructures when force is applied to the films, similar to how kirigami cuts made to paper can create pop-up structures. © Jennifer M. McCann/Penn State MRI


Reference: Zhang, X., Medina, L., Cai, H., Aksyuk, V., Espinosa, H. D., Lopez, D., Kirigami Engineering—Nanoscale Structures Exhibiting a Range of Controllable 3D Configurations. Adv. Mater. 2021, 33, 2005275. https://doi.org/10.1002/adma.202005275


Provided by Penn State

GlyNAC Improves Strength And Cognition in Older Humans (Medicine)

A pilot human clinical trial conducted by researchers at Baylor College of Medicine reveals that supplementation with GlyNAC – a combination of glycine and N-acetylcysteine as precursors of the natural antioxidant glutathione – could improve many age-associated defects in older humans to improve muscle strength and cognition, and promote healthy aging.
 
Published in the journal Clinical and Translational Medicine, the results of this study show that older humans taking GlyNAC for 24 weeks saw improvements in many characteristic defects of aging, including glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, insulin resistance, endothelial dysfunction, body fat, genomic toxicity, muscle strength, gait speed, exercise capacity and cognitive function. The benefits declined after stopping supplementation for 12 weeks. GlyNAC supplementation was well tolerated during the study period.
 
“There is limited understanding as to why these defects occur in older humans, and effective interventions to reverse these defects are currently limited or lacking,” said corresponding author endocrinologist Dr. Rajagopal Sekhar, associate professor of medicine in the Section of Endocrinology, Diabetes and Metabolism at Baylor.
 
For the last 20 years, Sekhar and his team have been studying natural aging in older humans and aged mice. Their work brings mitochondria, known as the batteries of the cell, as well as free radicals and glutathione to the table in discussions about why we age.
 
Mitochondrial dysfunction and aging
 
Mitochondria generate energy needed for supporting cellular functions by burning fat and sugar from foods, therefore mitochondrial health is critically important for life. Sekhar believes that improving the health of malfunctioning mitochondria in aging is the key.
 
As mitochondria generate energy, they produce waste products such as free radicals. These highly reactive molecules can damage cells, membranes, lipids, proteins and DNA. Cells depend on antioxidants, such as glutathione, the most abundant antioxidant in our cells, to neutralize these toxic free radicals. Failing to neutralize free radicals leads to harmful and damaging oxidative stress that can affect mitochondrial function.
 
Interestingly, glutathione levels in older people are much lower than those in younger people, and the levels of oxidative stress are much higher.
 
Animal studies conducted in the Sekhar lab have shown that restoring glutathione levels by providing GlyNAC reverses glutathione deficiency, reduces oxidative stress and fully restores mitochondrial function in aged mice.
 
“In previous work we showed that supplementing HIV patients with GlyNAC improved multiple deficits associated with premature aging observed in those patients,” Sekhar said. “In this study, we wanted to understand the effects of GlyNAC supplementation on many age-associated defects in older adults.”
 
GlyNAC improves several hallmark defects in aging
 
The world population of older humans is rapidly increasing and with it comes an increase in many age-related illnesses. To understand what causes unhealthy aging, scientific research has identified nine hallmark defects which are believed to contribute to the aging process.
 
“It is believed that correcting these aging hallmarks could improve or reverse many age-related disorders and help people age in a healthier way,” Sekhar said. “However, we do not fully understand why these hallmark defects happen, and there are currently no solutions to fix even a single hallmark defect in aging.”

This is where Sekhar’s trial results become encouraging, because GlyNAC supplementation for 24 weeks appears to improve four of the nine aging hallmark defects.
 
To further understand whether GlyNAC holds the keys to mitochondrial recovery and more, Sekhar and his team conducted this pilot clinical trial.
 
“We worked with eight older adults 70 to 80 years of age, comparing them with gender-matched younger adults between 21 and 30 years old,” Sekhar said. “We measured glutathione in red-blood cells, mitochondrial fuel-oxidation, plasma biomarkers of oxidative stress and oxidant damage, inflammation, endothelial function, glucose and insulin, gait-speed, muscle strength, exercise capacity, cognitive tests, gene-damage, glucose-production and muscle-protein breakdown rates and body composition. Before taking GlyNAC, all these measurements were abnormal in older adults when compared with those in younger people.”
 
The older participants took GlyNAC for 24 weeks, and then stopped it for 12 weeks. Sekhar and his colleagues repeated the above measurements at the halfway point at 12 weeks, after 24 weeks of taking GlyNAC, and again after stopping GlyNAC for 12 weeks.
 
“We are very excited by the results,” Sekhar said. “After taking GlyNAC for 24 weeks, all these defects in older adults improved and some reversed to the levels found in young adults.” The researchers also determined that older adults tolerated GlyNAC well for 24 weeks. The benefits, however, declined after stopping GlyNAC supplementation for 12 weeks.
 
“I am particularly encouraged by the improvements in cognition and muscle strength,” Sekhar said. “Alzheimer’s disease and mild cognitive impairment (MCI) are serious medical conditions affecting memory in older people and leading to dementia, and there are no effective solutions for these disorders. We are exploring the possibility that GlyNAC could help with these conditions by conducting two pilot randomized clinical trials to test whether GlyNAC supplementation could improve defects linked to cognitive decline in Alzheimer’s disease and in MCI, and possibly improve cognitive function.”
 
“The overall findings of the current study are highly encouraging,” Sekhar said. “They suggest that GlyNAC supplementation could be a simple and viable method to promote and improve healthy aging in older adults. We call this the ‘Power of 3’ because we believe that it takes the combined benefits of glycine, NAC and glutathione to reach this far reaching and widespread improvement. We also have completed a randomized clinical trial on supplementing GlyNAC vs. placebo in older adults and those results will be forthcoming soon.”
 
Premranjan Kumar, Chun Liu, Jean Hsu, Shaji Chacko, Charles Minard and Farook Jahoor, all at Baylor College of Medicine, contributed to this work. This work was supported by a philanthropic gift from the McNair Medical Institute at the Robert and Janice McNair Foundation in Houston, TX.
 
Baylor College of Medicine holds a patent on GlyNAC, which has been licensed to Nestlé Health Science. GlyNAC is marketed in the United States by Nestlé Health Science under the name CelltrientTM Cellular Protect. Nestlé has not provided any funding or financial support for this research work.


Reference: Kumar, P, Liu, C, Hsu, JW, et al. Glycine and N‐acetylcysteine (GlyNAC) supplementation in older adults improves glutathione deficiency, oxidative stress, mitochondrial dysfunction, inflammation, insulin resistance, endothelial dysfunction, genotoxicity, muscle strength, and cognition: Results of a pilot clinical trial. Clin Transl Med. 2021; 11:e372 https://onlinelibrary.wiley.com/doi/full/10.1002/ctm2.372


Provided by Baylor College of Medicine

Exposure to Harmful Chemicals in Plastic May Contribute to Postpartum Depression (Medicine)

Endocrine-disrupting chemicals may influence hormonal shifts during pregnancy as well as contribute to postpartum depression, according to a small study published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism.

Postpartum depression is a serious and common psychiatric disorder that affects up to 1 in 5 childbearing women. The cause of postpartum depression is not well understood, but hormonal changes during pregnancy have been found to be an important factor. Harmful chemicals such as bisphenols and phthalates that are found in plastics and personal care products are known to affect sex hormones.

“We found that phthalate exposure was associated with lower progesterone levels during pregnancy and a greater likelihood of developing postpartum depression,” said study author Melanie Jacobson, Ph.D., M.P.H. of the NYU Langone Medical Center in New York, N.Y. “This research is important because phthalates are so prevalent in the environment that they are detectable in nearly all pregnant women in the United States. If these chemicals can affect prenatal hormone levels and subsequently postpartum depression, reducing exposure to these types of chemicals could be a plausible avenue for preventing postpartum depression.”

The researchers measured the levels of bisphenols and phthalates in urine samples and sex hormones in blood samples from 139 pregnant women. They assessed these women at four months postpartum using the Edinburgh Postnatal Depression Scale (EPDS) and found women with higher levels of phthalates in their urine were more likely to develop postpartum depression. The women also had lower levels of progesterone, a hormone that plays an important role in the menstrual cycle, in maintaining the early stages of pregnancy and in modulating mood.

“These results need to be interpreted with caution as this is the first study to examine these chemicals in relation to postpartum depression and our sample size was small,” Jacobson said.

Other authors of the study include: Cheryl Stein of the Hassenfeld Children’s Hospital at NYU Langone in New York, N.Y.; Mengling Liu, Marra Ackerman, Jennifer Blakemore, Sara Long, Kurunthachalam Kannan and Hongkai Zhu of the NYU Langone Medical Center; Graziano Pinna and Raquel Romay-Tallon of the University of Illinois at Chicago in Chicago, Ill.; and Leonardo Trasande of the NYU Langone Medical Center, the NYU Wagner School of Public Service and the NYU College of Global Public Health in New York, N.Y.

The manuscript received funding from the National Institute of Environmental Health Sciences and the National Institutes of Health Office of the Director.

The manuscript, “Prenatal Exposure to Bisphenols and Phthalates and Postpartum Depression: The Role of Neurosteroid Hormone Disruption,” was published online, ahead of print.


Provided by Endocrine Society

Commercially Available Ultralong Organic Room-temperature Phosphorescence (Chemistry)

Purely organic room-temperature phosphorescence (RTP) materials have been a hot research topic. Currently, the pure RTP materials have been realized by the introduction of heavy halogen atoms, carbonyls groups or some heteroatoms, hydrogen bonding, H-aggregation, strong intermolecular electronic coupling, molecular packing, host-guest interaction, etc. However, the complicated synthesis and high expenditure are still inevitable in these systems. In addition, their performances in air are not satisfactory and the introduction of halogen atoms is generally necessary. Therefore, a new facile and robust host-guest strategy utilizing only electron-rich materials is a promising alternative for constructing RTP systems.

Very recently, Zheng and Qin et al. developed a series of novel host-guest organic phosphorescence systems, in which N,N,N’,N’-tetraphenylbenzidine (TPB) acted as a guest, triphenylphosphine (TPP) or triphenylamine (TPA) served as a host. The maximum phosphorescence efficiency and the longest lifetime could reach 23.6% and 362 ms, respectively. Experimental results and theoretical calculation revealed that the host molecules not only play a vital role in providing a rigid environment and suppressing non-radiative decay of the guest, but also show a synergistic effect to the guest in the photo-physical process through Förster resonance energy transfer (FRET). These new host-guest RTP systems enjoy the integrated merits of commercially available compounds with electron-rich features and low cost, absence of halogen atoms, facile preparation and excellent performances, etc., which shows great potentials in practical applications. Therefore, this work broadens the way for the fabrication of purely organic RTP materials and offers a novel platform for the development of diverse applications.

Featured image : The chemical structures of TPB, TPP and TPA, the phosphorescence of TPB/TPP and TPB/TPA crystalline powders, the advantages of these new host-guest RTP systems. ©Science China Press


Reference: Ning, Y., Yang, J., Si, H. et al. Ultralong organic room-temperature phosphorescence of electron-donating and commercially available host and guest molecules through efficient Förster resonance energy transfer. Sci. China Chem. (2021). https://link.springer.com/article/10.1007/s11426-020-9980-4 https://doi.org/10.1007/s11426-020-9980-4


Provided by Science China Press

CERN Proposes “Space Elevator” Accelerator (Physics)

“Do antimatter apples fall up?” is a question that is certain to aggravate physicists working on a new vertical accelerator proposed for CERN. The true question, they say, is whether antimatter apples fall down differently. If a difference were spotted, it would spell the end of “CPT invariance” – a principle that has underpinned every theory of physics since the invention of quantum mechanics.

“The Standard Model of particle physics has been very successful, but it can’t explain the 95% of the universe which is ‘dark’, and neither Einstein nor any physicist since has been able to cook up a working theory of quantum gravity,” says theorist Flora Oilp. “It’s time to challenge its most fundamental principle head-on.”

The way forward, according to Oilp and her colleagues, is to build a vertical accelerator that will put gravity to the test directly. Every previous particle accelerator has been horizontal. A combination of high speeds and frequent course corrections using focusing magnets has always meant that the effect of gravity can be neglected. But by utilising a range of new, revolutionary techniques, including accelerating particles upwards inside a vacuum vessel, and timing how long they take to fall back down to Earth, physicists can study the elusive fourth force directly. Furthermore, by comparing results with protons and antiprotons, they can watch for signs of “CPT violation”. Such behaviour cannot be explained using conventional theories, which rely on this principle to ensure the conservation of probability.

The accelerator would be built in two stages. Stage one proposes a 500 m vertical accelerator, starting from the base of the LHC shafts. An exciting collaboration with NASA may come to fruition by utilising detectors on the International Space Station (ISS) to detect beams of particles fired by the accelerator every time the ISS is overhead. This “reverse cosmic-ray” experiment would allow the measurement of Earth’s gravity on particle trajectories at unprecedented levels. Stage one will seek to match the roughly 1% precision on measurements of the gravitational constant “g”, which is currently being targeted in parallel by experiments with antihydrogen at the Laboratory’s Antimatter Factory. This moderate build will also allow engineers and physicists to understand the intricacies of running a vertical accelerator in preparation for stage two – the space elevator.

The height of stage one of EIFFEL when compared to buildings of a similar height. With the accelerator starting 175 m deep in the LHC shafts, EIFFEL will actually be very comparable in height to its namesake, the Eiffel Tower. (Image: D. Dominguez/CERN)

First proposed by Russian scientist Konstantin Tsiolkovsky in 1895, a true space elevator would rise from the equator to a height of 35 786 km – the altitude of a geostationary orbit. CERN’s proposed structure is far more modest, rising a mere 2.5 km above the Swiss countryside. If built, however, this advanced particle accelerator would nevertheless be three times taller than the Burj Khalifa in Dubai, which has been the tallest structure in the world since 2009. Each bunch of protons and antiprotons would need to be sent into a so-called “radial elliptic orbit” so that they return to the same point from which they were launched, calling for minute transverse focusing along the way.

Though the technological challenges are formidable, links to industrial and medical applications are promising, and the physics reach of such a machine is compelling. While appearing somewhat outlandish at first sight, the key advantage of the design is that its sensitivity would scale rapidly with its height. With the project eventually being ramped up to 2.5 km – the maximum height thought to be structurally sound, the CPT invariance could be tested with exquisite precision, approaching 0.005%.

“The sky’s the limit!” says CERN’s Pilar Olof, who was recently elected spokesperson of the new Elevator-Inspired Fast-Fermion Endwise Linac collaboration (EIFFEL). “Recent years have seen debates over whether the next accelerator should be linear or circular, but a consensus is now building that it should be vertical. We can’t wait for the world to see the EIFFEL.”

Featured image: An artistic rendering of stage one of EIFFEL, alongside the Esplanade des Particles (Image: D. Dominguez/CERN)


This science news is confirmed by us from CERN


Provided by CERN

ATLAS Searches For Pairs of Higgs Bosons in a Rare Particle Decay (Particle Physics)

A fraction of a second after the Big Bang, the Universe experienced a phase transition into a state of minimum energy, where matter particles interacted with the Higgs field to acquire mass. We have been living in this energy state ever since.

In the post-Higgs discovery era, scientists at the Large Hadron Collider (LHC) have been hard at work studying the Higgs boson’s properties. One property that remains to be experimentally verified is whether the Higgs boson can couple to itself (self-coupling). Such an interaction would contribute to the production of a pair of Higgs bosons, and would define the shape of the Higgs potential. If the Higgs boson’s self-coupling differs significantly from the Standard Model prediction, the Universe might be able to transition into a lower energy state where the laws that govern the interactions of matter could take on a very different shape.

Figure 1: Sketch of the HH invariant mass with the two leading contributions from the triangle (left) and box (right) Feynman diagrams. (Image: F. Cairo/ATLAS Collaboration)

The ATLAS Collaboration has released a new result which aims to address this question by searching for pairs of Higgs bosons (HH). This process is incredibly rare in the Standard Model – more than 1000 times rarer than the production of one Higgs boson! Physicists looked for the most common HH production processes that should be present in LHC collisions, both illustrated in the Feynman diagrams in Figure 1. Only the triangle diagram includes the Higgs self-coupling, and it contributes mainly to the production of Higgs pairs at low mass (shown in pink in Figure 1). If new physics is at play, it could change the Higgs self-coupling and ATLAS would see many more pairs of Higgs bosons than expected (i.e. a higher cross section).

The most powerful HH decay channel in the important low-mass region is the two bottom quark plus two photon channel, HH → bbɣɣ. ATLAS physicists developed new analysis techniques to search for this rare process. First, they divided events into low and high mass regions to better target the Higgs self-coupling. Then, they used a multivariate discriminant (Boosted Decision Tree) to separate the events that look like the HH → bbɣɣ process from those that don’t.


The ATLAS Collaboration’s latest result is more than twice as powerful as their previous result in the same channel!


Due to the development of these new analysis techniques, ATLAS’ latest result is more than twice as powerful as the previous ATLAS result in the same channel! Figure 2 shows limits on the HH production cross section (σ) as a function of the ratio of the Higgs self-coupling to its Standard Model value (κλ). The allowed range for the Higgs self-coupling is shown by the intersection of the observed limit with the theoretical prediction, between -1.5 and 6.7 times the Standard Model prediction. Physicists were able to set a limit on the HH production cross section of 4.1 times the Standard Model prediction. Limits are also set on HH production via the decay of a hypothetical new scalar particle.

Figure 2: Limits on the HH production cross section as a function of κλ. The dashed line shows the expected limits, and the solid line shows the observed limits. The theoretical predictions are shown in dark pink, and the Standard Model point is indicated by a star. The allowed range for κλ is given by the intersection between the observed limits and the theory curve. (Image: ATLAS Collaboration/CERN)

Although this result sets the world’s best limits on the size of the Higgs self-coupling, the work is not done. Much more data is needed to precisely measure the Higgs self-coupling and to see whether it agrees with the Standard Model prediction. The High-Luminosity upgrade of the LHC plans to deliver a dataset 20 times larger than the one used here. If HH production behaves as predicted by the Standard Model, it will be observed in this huge dataset – allowing LHC researchers to make a more quantitative statement on the size of the Higgs self-coupling and the nature of the Higgs potential.

Reference: Search for Higgs boson pair production in the two bottom quarks plus two photons final state in pppp collisions at s√=13s=13 TeV with the ATLAS detector


Featured image: Candidate HH → ɣɣbb event in ATLAS data taken in 2017. Charged-particle tracks are shown in green, the two photons are shown as cyan towers and the two b-jets are shown as red cones. (Image: CERN)


Provided by ATLAS

Cynanchum hubeiense, Rare Plant Endemic to Hubei Province, Discovered (Botany)

Recently, Cynanchum hubeiense Wen, B. Xu, B. S. Xia & J. y. Shen, a rare plant endemic to Hubei Province, was named by researchers from the Wuhan Botanical Garden and the Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences. The paper was published in Taiwania entitled “Cynanchum hubeiense (Apocynaceae), a new species from Hubei, China“. 

During a field investigation in Luotian County, Hubei Province, researchers found an unknown species, of which the flowers have a bowl-shaped corona and five internal appendages.    

This species is similar to C. callialatum Buch.-Ham. ex Wight, C. decipiens Schneid., C. brevipedunculatum J.Y.Shen and C. longipedunculatum M.G.Gilbert & P.T.Li, but distinguished with several morphological features: slightly angulate follicles, shorter peduncle, corolla white to reddish, corolla lobes ovate, planar, stems without two leaf like stipules per node, and stems sparsely puberulent.  

After literature review and comprehensive morphological character analysis, the researchers confirmed that it is a new species and named it as “Cynanchum hubeiense Wen, B. Xu, B. S. Xia & J. y. Shen”. Since it is currently only known from the Hubei Province, China, the specific epithet “hubeiense” is chosen. The Chinese name is “湖北豹藥藤” (hú běi bào yào téng), which means the vine is poisonous.  

The researchers surveyed the surrounding forests carefully, only one population with less than 10 individuals was found in Bodaofeng Mountain, Luotian County, Hubei. Due to the limited population size and restricted distribution of C. hubeiense, it is proposed that the species should be designated as Critically Endangered (CR; criteria B1ab (i, v) + 2ab (i, v), D), according to IUCN (2012). 

The discovery of C. hubeiense is of great significance to the systematics and taxonomy of Cynanchum and it has theoretical guidance for the protection of this rare plant. 

This study was supported by the Conservation and Application of National Strategic Tropical Plant Resources: Theory and Practice Fund, and the Science & Technology Basic Resources Investigation Program of China: Survey and Germplasm Conservation of Plant Species with Extremely Small Population in South-west China.

Featured image: Cynanchum hubeiense. A. Trailing plant in habit; B. Phyllotaxy: opposite leaves; C. Root tuber; D. Inflorescence in ventral view; E. Sciadioidal (pseudo-umbellate) inflorescence in lateral view showing pedicels; F. Flower in dorsal view; G. Flower in lateral view; H. Anthers on gynostegial column showing two corpuscles of the pollinaria; I. Leaf, abaxial surface; J. Young follicle. (Image by XU Wenbin, CHEN Yuxing and SHEN Jianyong)


Reference: Wen-Bin Xu, Bo-Shun Xia, Jin-Qing Wu, Yu-Xing Chen, Jian-Yong Shen, “Cynanchum hubeiense (Apocynaceae), a new species from Hubei, China”, International Journal of Biodiversity, pp. 53-56, DOI: 10.6165/tai.2021.66.53


Provided by Chinese Academy of Sciences

Novel Nanocomposite Developed for Magnetic Resonance Tumor Imaging (Physics)

A research team led by Prof. LIANG Changhao from the Institute of solid State Physics of the Hefei Institutes of Physical Science (HFIPS) successfully obtained Mn3O4/PtOx nanocomposites (NCs) which paved the way for the practical clinical applications for Mn3O4 nanosturctures in magnetic resonance (MR) imaging.

Manganese oxide (Mn3O4) nanoparticles have received widespread attention as Contrast agents (CA) of MR imaging. However, for better bio-safety, Mn3O4 nanoparticles must have small hydrodynamic particle size and compatible surface modification, which possibly make it difficult for Mn2+ ions on the particle surface to chemically exchange with water molecules under the magnetic field. Thus, the contrast performance of Mn3O4 nanoparticles in MR imaging is often not qualified for clinic use.

In this research, the researchers used laser fabrication technology to obtain defect-rich Mn3O4 nanoparticles as precursors to obtain Mn2+-based porous nanostructure with payload of the platinum oxide (PtOx) nanoparticles via the ion exchange reaction.

Schematic of the MR contrast affected by q and τr before and after ion etching. (Image by CAI Yunyu)

They called it Mn3O4/PtOx NCs whose longitudinal relaxivity (r1) and transverse relaxivity (r2) ratio (1.46) was proved much lower than the value 2.61 for the commercial Gd-DTPA.

“It indicates that Mn3O4/PtOx NCs show obvious superior contrast performance than commercial product in MR imaging experiment.” said LIANG Changhao, who led the team.

The team further analyzed the reason behind the phenomenon based on the structure-relaxivity relationship for inorganic nanostructure. They found that surface morphology could increase coordinated number of water molecules and surface payload could prolong the tumbling time. Both could benefit to increase the T1 relaxivity.

As the higher porosity of the NCs indicated more PtOx payload, the surface morphology and the payload synergistically increased the T1 imaging contrast potency of the Mn3O4/PtOx NCs.

These novel findings showcase a brand-new strategy for fabricating excellent manganese-based CAs on the basis of the surface structure.

The research was supported by the National Natural Science Foundation of China.

Featured image: Schematic of formation for Mn3O4/PtOx NCs by laser fabrication in liquids technology. (Image by CAI Yunyu)


Reference

Surface morphology and payload synergistically caused an enhancement of the longitudinal relaxivity of a Mn3O4/PtOx nanocomposite for magnetic resonance tumor imaging


Provided by Chinese Academy of Sciences