Quantum computers promise to perform certain tasks that are believed to be intractable to classical computers. Boson sampling is such a task and is considered a strong candidate to demonstrate the ...quantum computational advantage. We performed Gaussian boson sampling by sending 50 indistinguishable single-mode squeezed states into a 100-mode ultralow-loss interferometer with full connectivity and random matrix-the whole optical setup is phase-locked-and sampling the output using 100 high-efficiency single-photon detectors. The obtained samples were validated against plausible hypotheses exploiting thermal states, distinguishable photons, and uniform distribution. The photonic quantum computer,
, generates up to 76 output photon clicks, which yields an output state-space dimension of 10
and a sampling rate that is faster than using the state-of-the-art simulation strategy and supercomputers by a factor of ~10
.
We report phase-programmable Gaussian boson sampling (GBS) which produces up to 113 photon detection events out of a 144-mode photonic circuit. A new high-brightness and scalable quantum light source ...is developed, exploring the idea of stimulated emission of squeezed photons, which has simultaneously near-unity purity and efficiency. This GBS is programmable by tuning the phase of the input squeezed states. The obtained samples are efficiently validated by inferring from computationally friendly subsystems, which rules out hypotheses including distinguishable photons and thermal states. We show that our GBS experiment passes a nonclassicality test based on inequality constraints, and we reveal nontrivial genuine high-order correlations in the GBS samples, which are evidence of robustness against possible classical simulation schemes. This photonic quantum computer, Jiuzhang 2.0, yields a Hilbert space dimension up to ∼ 1043, and a sampling rate ∼ 1024 faster than using brute-force simulation on classical supercomputers.
The basic principle of quantum mechanics1 guarantees the unconditional security of quantum key distribution (QKD)2–6 at the cost of forbidding the amplification of a quantum state. As a result, and ...despite remarkable progress in worldwide metropolitan QKD networks7,8 over the past decades, a long-haul fibre QKD network without a trusted relay has not yet been achieved. Here, through the sending-or-not-sending protocol9, we achieve twin-field QKD10 and distribute secure keys without any trusted repeater over a 511 km long-haul fibre trunk that links two distant metropolitan areas. The fibre trunk contains 12 fibres in the cable, three of which are used for the quantum channel, optical synchronization and frequency locking, respectively. The remaining nine are used for classical fibre communication. Our secure key rate is around three orders of magnitude greater than that expected if the previous QKD field-test system was applied over the same length. Efficient quantum-state transmission and stable single-photon interference over such a long-haul deployed fibre pave the way to large-scale fibre quantum networks.A field test of twin-field quantum key distribution was implemented through a 511 km optical fibre. To this end, precise wavelength control of remote independent laser sources and fast time- and phase-compensation systems are developed.
In this report, we demonstrate that sodium hydrosulfide （NariS）, a hydrogen sulfide （H2S） donor, promoted adventitious root formation mediated by auxin and nitric oxide （NO）. Application of the HzS ...donor to seedling cuttings of sweet potato （Ipomoea batatas L.） promoted the number and length of adventitious roots in a dose-dependent manner. It was also verified that H2S or HS- rather than other sulfur-containing components derived from NariS could be attributed to the stimulation of adventitious root formation. A rapid increase in endogenous H2S, indole acetic acid （IAA） and NO were sequentially observed in shoot tips of sweet potato seedlings treated with HallS. Further investigation showed that H2S-mediated root formation was alleviated by N-1-naphthylphthalamic acid （NPA）, an IAA transport inhibitor, and 2-（4-carboxyphenyl）. 4,4,5,5-tetramethylimidazoline-1-oxyl-3-0xide （cPTIO）, an NO scavenger. Similar phenomena in H2S donor-dependent root organogenesis were observed in both excised willow （Salix matsudana var. tortuosa Vilm） shoots and soybean （Glycine max L.） seedlings. These results indicated that the process of H2S-induced adventitious root formation was likely mediated by IAA and NO, and that H2S acts upstream of IAA and NO signal transduction pathways.
Though essential oils exhibit antibacterial activity against food pathogens, their underlying mechanism is understudied. We extracted ginger essential oil (GEO) using supercritical CO
and steam ...distillation. A chemical composition comparison by GC-MS showed that the main components of the extracted GEOs were zingiberene and α-curcumene. Their antibacterial activity and associated mechanism against
and
were investigated. The diameter of inhibition zone (DIZ) of GEO against
was 17.1 mm, with a minimum inhibition concentration (MIC) of 1.0 mg/mL, and minimum bactericide concentration (MBC) of 2.0 mg/mL. For
the DIZ was 12.3 mm with MIC and MBC values of 2.0 mg/mL and 4.0 mg/mL, respectively. The SDS-PAGE analysis revealed that some of the electrophoretic bacterial cell proteins bands disappeared with the increase in GEO concentration. Consequently, the nucleic acids content of bacterial suspension was raised significantly and the metabolic activity of bacteria was markedly decreased. GEO could thus inhibit the expression of some genes linked to bacterial energy metabolism, tricarboxylic acid cycle, cell membrane-related proteins, and DNA metabolism. Our findings speculate the bactericidal effects of GEO primarily through disruption of the bacterial cell membrane indicating its suitability in food perseveration.
It has been speculated that the partial pressure of carbon dioxide (pCO
) in shelf waters may lag the rise in atmospheric CO
. Here, we show that this is the case across many shelf regions, implying ...a tendency for enhanced shelf uptake of atmospheric CO
. This result is based on analysis of long-term trends in the air-sea pCO
gradient (ΔpCO
) using a global surface ocean pCO
database spanning a period of up to 35 years. Using wintertime data only, we find that ΔpCO
increased in 653 of the 825 0.5° cells for which a trend could be calculated, with 325 of these cells showing a significant increase in excess of +0.5 μatm yr
(p < 0.05). Although noisier, the deseasonalized annual data suggest similar results. If this were a global trend, it would support the idea that shelves might have switched from a source to a sink of CO
during the last century.
The SARS-CoV-2-infected disease (COVID-19) outbreak is a major threat to human beings. Previous studies mainly focused on Wuhan and typical symptoms. We analysed 74 confirmed COVID-19 cases with GI ...symptoms in the Zhejiang province to determine epidemiological, clinical and virological characteristics.
COVID-19 hospital patients were admitted in the Zhejiang province from 17 January 2020 to 8 February 2020. Epidemiological, demographic, clinical, laboratory, management and outcome data of patients with GI symptoms were analysed using multivariate analysis for risk of severe/critical type. Bioinformatics were used to analyse features of SARS-CoV-2 from Zhejiang province.
Among enrolled 651 patients, 74 (11.4%) presented with at least one GI symptom (nausea, vomiting or diarrhoea), average age of 46.14 years, 4-day incubation period and 10.8% had pre-existing liver disease. Of patients with COVID-19 with GI symptoms, 17 (22.97%) and 23 (31.08%) had severe/critical types and family clustering, respectively, significantly higher than those without GI symptoms, 47 (8.14%) and 118 (20.45%). Of patients with COVID-19 with GI symptoms, 29 (39.19%), 23 (31.08%), 8 (10.81%) and 16 (21.62%) had significantly higher rates of fever >38.5°C, fatigue, shortness of breath and headache, respectively. Low-dose glucocorticoids and antibiotics were administered to 14.86% and 41.89% of patients, respectively. Sputum production and increased lactate dehydrogenase/glucose levels were risk factors for severe/critical type. Bioinformatics showed sequence mutation of SARS-CoV-2 with m
A methylation and changed binding capacity with ACE2.
We report COVID-19 cases with GI symptoms with novel features outside Wuhan. Attention to patients with COVID-19 with non-classic symptoms should increase to protect health providers.
The clove essential oil (CEO) loaded nano and pickering emulsions prepared with Tween 80 and whey protein isolate/inulin mixture, respectively were incorporated into pullulan-gelatin film base fluid ...at three levels (0.2%, 0.4%, and 0.6%). The droplet sizes of NE and PE loaded with CEO were 15.93 nm and 266.9 nm, respectively. The PDI of CEOs with stable NE and PE were 0.262 and 0.259, respectively. Our results showed the improved compatibility between pullulan-gelatin and essential oil-loaded nanocarriers. The active film composed of PE carrier had the structural characteristics of high density, low water content, and low permeability, thus exhibiting excellent mechanical properties, water barrier properties, and appreciable antioxidant activities. Compared with NE, it was found that the CEO-loaded PE showed slow-release profile in the film sample. The prepared active film containing PE possessed a great potential to be used as effective and natural alternatives for active food packaging.
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•The clove essential oil (CEO) nano and pickering emulsions were incorporated into pullulan-gelatin film.•CEO loaded emulsions and active films exhibited strong antimicrobial and antioxidant activity, respectively.•The fabricated films particularly with PE showed higher mechanical and water barrier properties.•The encapsulation of CEO with PE provided slower release profile in the films compared to NE.
This study uses a simulation method to explore how estuarine pH is affected by mixing between river water, anthropogenic CO2 enriched seawater, and by respiration. Three rivers with different levels ...of weathering products (Amazon, Mississippi, and St. Johns) are selected for this simulation. The results indicate that estuaries that receive low to moderate levels of weathering products (Amazon and St. Johns) exhibit a maximum pH decrease in the midsalinity region as a result of anthropogenic CO2 intrusion. This maximum pH decrease coincides with a previously unrecognized mid‐salinity minimum buffer zone (MBZ). In addition, water column oxygen consumption can further depress pH for all simulated estuaries. We suggest that recognition of the estuarine MBZs may be important for studying estuarine calcifying organisms and pH‐sensitive biogeochemical processes.
Key Points
Ocean acidification and O2 consumption can both lead to estuarine acidification
An previously undefined estuarine minimum buffer zone (MBZ) is demonstrated
Both estuarine carbonate chemistry and temperature affect the MBZ
The locus for familial cortical myoclonic tremor with epilepsy (FCMTE) has long been mapped to 8q24 in linkage studies, but the causative mutations remain unclear. Recently, expansions of intronic ...TTTCA and TTTTA repeat motifs within
were found to be involved in the pathogenesis of FCMTE in Japanese pedigrees. We aim to identify the causative mutations of FCMTE in Chinese pedigrees.
We performed genetic linkage analysis by microsatellite markers in a five-generation Chinese pedigree with 55 members. We also used array-comparative genomic hybridisation (CGH) and next-generation sequencing (NGS) technologies (whole-exome sequencing, capture region deep sequencing and whole-genome sequencing) to identify the causative mutations in the disease locus. Recently, we used low-coverage (~10×) long-read genome sequencing (LRS) on the PacBio Sequel and Oxford Nanopore platforms to identify the causative mutations, and used repeat-primed PCR for validation of the repeat expansions.
Linkage analysis mapped the disease locus to 8q23.3-24.23. Array-CGH and NGS failed to identify causative mutations in this locus. LRS identified the intronic TTTCA and TTTTA repeat expansions in
as the causative mutations, thus corroborating the recently published results in Japanese pedigrees.
We identified the pentanucleotide repeat expansion in
as the causative mutation in Chinese FCMTE pedigrees. Our study also suggested that LRS is an effective tool for molecular diagnosis of genetic disorders, especially for neurological diseases that cannot be positively diagnosed by conventional clinical microarray and NGS technologies.
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