Accurate diagnosis of colorectal cancer based on histopathology images using artificial intelligence

BACKGROUND

Accurate and robust pathological image analysis for colorectal cancer (CRC) diagnosis is time-consuming and knowledge-intensive, but is essential for CRC patients' treatment. The current heavy workload of pathologists in clinics/hospitals may easily lead to unconscious misdiagnosis of CRC based on daily image analyses.

METHODS

Based on a state-of-the-art transfer-learned deep convolutional neural network in artificial intelligence (AI), we proposed a novel patch aggregation strategy for clinic CRC diagnosis using weakly labeled pathological whole-slide image (WSI) patches. This approach was trained and validated using an unprecedented and enormously large number of 170,099 patches, > 14,680 WSIs, from > 9631 subjects that covered diverse and representative clinical cases from multi-independent-sources across China, the USA, and Germany.

RESULTS

Our innovative AI tool consistently and nearly perfectly agreed with (average Kappa statistic 0.896) and even often better than most of the experienced expert pathologists when tested in diagnosing CRC WSIs from multicenters. The average area under the receiver operating characteristics curve (AUC) of AI was greater than that of the pathologists (0.988 vs 0.970) and achieved the best performance among the application of other AI methods to CRC diagnosis. Our AI-generated heatmap highlights the image regions of cancer tissue/cells.

CONCLUSIONS

This first-ever generalizable AI system can handle large amounts of WSIs consistently and robustly without potential bias due to fatigue commonly experienced by clinical pathologists. It will drastically alleviate the heavy clinical burden of daily pathology diagnosis and improve the treatment for CRC patients. This tool is generalizable to other cancer diagnosis based on image recognition.

Quantum Phase Transition in a Quantum Ising Chain at Nonzero Temperatures

We study the response of a thermal state of an Ising chain to a nonlocal non-Hermitian perturbation, which coalesces the topological Kramer-like degeneracy in the ferromagnetic phase. The dynamic responses for initial thermal states in different quantum phases are distinct. The final state always approaches its half component with a fixed parity in the ferromagnetic phase but remains almost unchanged in the paramagnetic phase. This indicates that the phase diagram at zero temperature is completely preserved at finite temperatures. Numerical simulations for Loschmidt echoes demonstrate such dynamical behaviors in finite-size systems. In addition, it provides a clear manifestation of the bulk-boundary correspondence at nonzero temperatures. This work presents an alternative approach to understanding the quantum phase transitions of quantum spin systems at nonzero temperatures.

The gene NtMYC2a acts as a 'master switch' in the regulation of JA-induced nicotine accumulation in tobacco

The biosynthesis and transport of nicotine has been shown to be coordinately upregulated by jasmonate (JA). MYC2, a member of basic helix-loop-helix (bHLH) transcription factor family, is well-documented as the core player in the JA signalling pathway to regulate diverse plant development processes. Four MYC2 genes were found in the tobacco genome, NtMYC2a/2b and 1a/1b. In this study, we tested whether one of them, NtMYC2a, acts as a 'master switch' in the regulation of nicotine biosynthesis and transport in tobacco. We generated NtMYC2a knockout tobacco plants using the CRISPR-Cas9 technique and analysed the effect of NtMYC2a knockout on expression of the nicotine biosynthesis genes (NtAO, NtQS, NtPMT1a, NtQPT2, NtODC2, NtMPO1, NtA622 and NtBBLa) and transport genes (NtMATE2 and NtJAT1), as well as leaf accumulation of nicotine in the NtMYC2a knockout plants. We found that all the nicotine biosynthesis and transport genes tested in this study were significantly downregulated (>50% reduction compared with wild-type control) in the NtMYC2a knockout plants. Moreover, the leaf nicotine content in knockout plants was dramatically reduced by ca 80% compared with the wild-type control. These results clearly show that NtMYC2a acts as a 'master switch' to coordinate JA-induced nicotine accumulation in tobacco and suggests that NtMYC2a might play an important role in tobacco nicotine-mediated defence against herbivory.

A Tale of Transition: Trends of Catastrophic Health Expenditure and Impoverishment in Urban China, 1986-2009

From 1986 to 2009, China's health system reform first adopted a market-oriented approach and later reemphasized the role of the government starting from 2002. China's oscillating health care financing policies present us a unique opportunity to examine the consequences of government-led financing and market-oriented financing measures. This study uses the Urban Household Survey, a diary data in China that covers the period of 1986 to 2009, to examine the long-run trends in the incidence and intensity of catastrophic health expenditure and medical impoverishment. Four major findings emerge. First, the incidence and intensity of catastrophic health expenditure in urban Chinese households increased rapidly between 1986 and 2002, whereas they stabilized after 2002. Second, the incidence of medical impoverishment and its depth in the poverty gap remained stable before 2002 and decreased rapidly after 2002. Third, income and regional inequality in measures of catastrophic health expenditure widened from 1986 to 2002. They narrowed in the 2000s but remain wide. Fourth, income and regional inequality in medical impoverishment remained unchanged between 1986 and 2002 and narrowed substantially after 2002. All these results suggest that China's two cycles of health care reform generated significantly different outcomes in financial protection, holding lessons for the ongoing health care reform in China and other countries.

Patterns of left ventricular longitudinal myocardial dysfunction in mitral valve prolapse and effects of valve repair

Background

Regional longitudinal left ventricular (LV) dysfunction in patients with mitral regurgitation (MR) due to valve prolapse (MVP) with normal ejection fraction has been recently described, with data pointing at dysfunction of the LV base related to dilatation of the mitral annulus.

Purpose

To investigate degree and extent of regional LV dysfunction and its mechanisms in patients with MVP and severe acute (MRa, n=27) or chronic (MRc, n=41) MR and no coronary disease, undergoing surgical valve repair with 3 months follow-up (FU); 20 normal subjects were used as controls (N).

Methods

Speckle-tracking echocardiography was performed pre- (Bas), 1 week (1w) and 4 months (4mo) post-operatively to measure longitudinal global (GLPSS, %), regional (RPSS, %) and segmental (SPSS) peak systolic strain. Maximum and minimum mitral annulus (MA) diameters were measured with 3D echo at Bas. We also evaluated: LV end-diastolic volume index (EDVi, ml/m2); ejection fraction (EF, %); left atrial end-systolic volume index (LAVi, ml/m2); non-invasive pulmonary systolic pressure (PSP, mmHg).

Results

Risk factors (hypertension, diabetes, atrial fibrillation, smoke and previous stroke) were similar in MRc and MRa. At Bas EDVi was larger by definition in MRc (MRc: 102±21, MRa: 67±10 ml/m2, p<0.001) as LAVi (101±46 vs 76±31 ml/m2, p=0.035). Both EF (65±8 vs 64±8 ml/m2) and GLPSS (−20±4 vs −21±5%) were normal, but RPSS was reduced, only at the base (−13±6 vs −13±6%, p= ns; N: −18±2, p<0.03 vs MRc and MRa) in MRc and MRa, with reduced SPSS localized at anterior, lateral and posterior – but not septal – segments. At 1w, EF decreased in both MRc (47±14%, p<0.001 vs Bas) and MRa (56±10%, p=0.014 vs Bas), together with GLPSS (MRc: −11±4%, p<0.001 vs Bas; MRa; −13±4, p<0.001 vs Bas) driven by a prevalent marked decrease in RPSS (MRc: −7±4%, p<0.001 vs Bas; MRa; −8±5, p<0.001 vs Bas) of the LV base. All patients were alive at 3 months with no MACEs, similar reduction of mean MR grade (MRc: 4±0 to 1.9±0.7, p<0.001; MRa: 3.9±0.3 to 0.9±0.9, p<0.001) and PSP (MRc: 50±23 to 29±5 mmHg, p<0.001; MRa: 42±22 to 32±6 mmHg, p=0.039), normal EDVi (MRc: 70±27, MRa: 49±10 ml/m2), dilated LAVi (MRc: 101±46, MRa: 54±13 ml/m2), and reduced GLPSS (MRc: −12±5%, p<0.001 vs Bas; MRa; −15±3, p=0.001 vs Bas) and base RPSS (MRc: −7±6%, p=0.004 vs Bas; MRa; −10±4, p= ns vs Bas). At multivariate analysis, regional dysfunction was not related to the prolapsing scallop, presence of flail, commissure involvement, dimension and geometry of the MA, EF or pulmonary pressures.

Conclusions

In patients with MVP and severe MR, there is a specific regional longitudinal dysfunction pattern prevalent at the LV base which may be related to the duration of MR but not to annular dilatation or morphology of the prolapsing leaflets. The dysfunction worsens greatly following acute reduction of preload after surgical repair and is still significant at 4mo FU.

Funding Acknowledgement

Type of funding source: None

[Net ecosystem carbon exchange and its affecting factors in a deciduous broad-leaved forest in Songshan, Beijing, China]

Forests play an important role in terrestrial carbon cycles. The mechanism underlying carbon balance in temperate deciduous broad-leaved forests is not clear. In this study, net ecosystem exchange (NEE) and environmental factors, including air temperature (T_a), soil temperature (T_s), photosynthetically active radiation (PAR), vapor pressure deficit (VPD), soil water content (SWC) and precipitation (P) were continually measured using eddy covariance techniques in 2019 in a deciduous broad-leaved forest in Songshan, Beijing. We analyzed the characteristics of NEE and its response to environmental factors. The results showed that, at diurnal scale, the monthly averaged NEE exhibited a "U" shape curve (i.e., being a carbon sink over daytime while being a carbon source during nighttime) over the growing season. During the non-growing season, NEE was positive (i.e., carbon source) at diurnal scale. At the seasonal scale, NEE exhibited a unimodal curve. The annual cumulative NEE was -111 g C·m^-2·a^-1. Annual ecosystem respiration was 555 g C·m^-2·a^-1, while gross ecosystem productivity was 666 g C·m^-2·a^-1. Carbon sequestration peaked in June, while emission peaked in November. PAR was the dominant factor affecting daytime NEE (NEE_d). VPD was the main factor that indirectly affected daytime NEE_d, with an optimal VPD value that maximizes daytime NEE around 1-1.5 kPa. Soil temperature was the main factor affecting nighttime NEE (NEE_n). SWC was a limiting factor for NEE_n. Too high or too low SWC would inhibit NEE_n, with an optimal SWC value of 0.28 m³·m^-3.

Transcatheter arterial infusion of anti-programmed cell death 1 antibody pembrolizumab combined with temozolomide or nab-paclitaxel in patient with primary anorectal malignant melanoma: Four case reports

Primary anorectal malignant melanoma (ARMM) is an extremely rare but aggressive tumor. We assessed the efficacy and safety of transcatheter arterial infusion (TAI) with anti-PD-1 antibody pembrolizumab at a dosage of 100 mg with 0.9% NaCl at a volume of 100 mL administered over a 30-min period every 3 weeks, combined with temozolomide or albumin-bound paclitaxel (nab-paclitaxel) in four patients with ARMM. Temozolomide was administered orally once per day at a dosage of 200 mg/m2/d for five consecutive days about every 4 weeks. Nab-paclitaxel was administered at a dosage of 200mg/m2/d once about every 3 weeks. Among four patients with a median follow-up of 8.9 months, two cases showed Murine Double Minute 2 (MDM2) amplification. Case 1 with Stage II ARMM showed pathological complete response after four cycles of TAI with pembrolizumab combined with nab-paclitaxel. Case 4 was at Stage II and showed stable disease consistently throughout the treatment. Case 2 was at stage II and Case 3 was at stage III, and they showed partial response after four or three cycles, respectively, of TAI with pembrolizumab combined with temozolomide. No Grades 3-4 adverse reactions were observed. Therefore, a combination of TAI with pembrolizumab and temozolomide or with nab-paclitaxel appears to be a promising option for treating ARMM. However, multicenter clinical trials are required to confirm the efficacy and safety of this procedure.

Cryoablation combined with transarterial infusion of pembrolizumab (CATAP) for liver metastases of melanoma: an ambispective, proof-of-concept cohort study

BACKGROUND

The presence of liver metastasis correlates with poor therapeutic response of PD-1 blockade therapy in melanoma. A novel treatment protocol by combining cryoablation with transarterial infusion of pembrolizumab (CATAP) was proposed, and its feasibility and safety was assessed among this group of patients.

METHODS

This registered ambispective cohort study enrolled fifteen melanoma patients with multiple hepatic metastases who received planned two-stage CATAP therapy: in the combined stage, subtotal cryoablation on day 1, in which one to two intrahepatic lesions were ablated completely with other lesions left untreated, sequentially combined transarterial infusion of pembrolizumab on day 3, every three weeks, for at least one cycle; in the infusion stage, arterial infusion of pembrolizumab was recommended at three-week interval until disease progression. The primary endpoint was objective response rate by RECIST (version 1.1); secondary end points included progression-free survival (PFS) and safety; exploratory endpoints were changes of cytokines and immune cell compositions in peripheral blood samples.

RESULTS

Of the 15 patients enrolled, no grade 3-4 adverse events or major complications were observed. One patient (6.7%) achieved complete response, and 3 (20.0%) achieved partial response. The overall response rates of CATAP for the entire cohort and patients with cutaneous melanoma were 26.7% (95% confidence interval (CI) 4.3-49.0%) and 33.3% (95% CI 2.5-64.1%), respectively. Clinical response was observed in a proportion of patients (2/6; 33.3%) who failed first-line intravenous pembrolizumab treatment. The median overall PFS time and hepatic PFS time were 4.0 (95% CI 2.5-5.5) and 5.73 (95% CI 1.1-10.4) months, respectively. A significant increase in CD3-CD16 + CD56 + cells (natural killer cells; P = 0.0124) and a marginally significant decrease in CD4 + CD25 + cells (regulatory T cells; P = 0.0546) were observed three weeks after the first cycle of treatment in the combined stage.

CONCLUSIONS

The CATAP therapy demonstrated positive clinical activity and a favorable safety profile for melanoma patients with liver metastasis.

Emergency management of 2019 novel coronavirus: implications for the dermatology department

Since cases first emerged in December 2019, COVID‐19 (a type of coronavirus) has rapidly become pandemic. This fast‐tracked paper (published quickly) from China on COVID‐19 is written by dermatologists at the epicentre of the outbreak in Wuhan.

Dermatology clinic staff may be at risk because protective equipment is not routinely available, and skin lesions might possibly transmit the virus indirectly. These authors suggest preventive measures based on experience in this and previous coronavirus outbreaks.

Online consultation for non‐urgent patients reduces the numbers of patients attending clinics. Nurse‐led triage, to identify patients with possible COVID‐19, at the entrances of hospital and skin clinics directs patients with a cough or fever to a specific COVID‐19 area and a dermatologist is consulted if the fever might be related to skin disease.

Clinic staff wear N95 masks and observe hand hygiene during consultations. Patients are admitted to a ward only if routine blood tests and chest CT scans exclude COVID‐19. Triage will not detect patients who are showing no symptoms but who are developing the disease, so the hospital should provide an on‐call expert team to discuss inpatients suspected or diagnosed with COVID‐19 and refer them to radiology, respiratory or intensive care colleagues as required.

Confirmed cases are managed following local policies. Skin disorders in COVID‐19 inpatients can usually be managed remotely using photographs, email and teleconferencing. If necessary a multidisciplinary team (a team of medical staff from different specialties) can meet in the clean area of the isolation ward. If the dermatologist must see the patient, all records should be provided in advance to minimise exposure time.

With these precautions, as of 20th February 2020 no infected patients were detected in the Wuhan Dermatology Department.

This is a summary of the study: Emergency management for preventing and controlling nosocomial infection of 2019 novel coronavirus: implications for the dermatology department

Linked Article: Tao et al. Br J Dermatol 2020; 182:1477–1478

TACE-Sorafenib With Thermal Ablation Has Survival Benefits in Patients With Huge Unresectable Hepatocellular Carcinoma

Purpose

To investigate the effectiveness and safety of transarterial chemoembolization (TACE) combined with sorafenib and thermal ablation in patients with huge hepatocellular carcinoma (HCC).

Materials and Methods

This retrospective study examined 50 patients with huge unresectable HCC treated from January 2009 to December 2015. Among them, 28 cases received TACE-sorafenib treatment (TACE-sorafenib group), and 22 cases received TACE-sorafenib plus thermal ablation treatment (TACE-sorafenib-thermal ablation group). The Overall survival (OS), progression-free survival (PFS), and adverse events (AEs) were compared.

Results

The median follow-up was 13.5 months (ranges 4.2 to 96.7 months). The median OS was significantly longer in the TACE-sorafenib-thermal ablation group than that in the TACE-sorafenib group (20.8 vs. 10.4 months, P=0.003). The median PFS of the ablation and no ablation groups were 4.3 vs. 7.1 months (P=0.546). The treatment modality was an independent predictor of OS (P=0.004). There were no notable drug-related high grade adverse events or permanent adverse sequelae.

Conclusion

TACE-sorafenib-thermal ablation provided extended OS to patients with huge unresectable HCC and could be a better choice than TACE-sorafenib.

The PPRD score stratifies patients with hepatocellular carcinoma and portal vein tumor thrombus treated with sorafenib plus transarterial chemoembolization

OBJECTIVES

To identify clinical prognostic and predictive factors in patients with hepatocellular carcinoma (HCC) and portal vein tumor thrombus (PVTT) undergoing sorafenib plus transarterial chemoembolization (TACE) and establish a prognostic score for these patients.

METHODS

Between January 2012 and December 2017, 184 consecutive patients with HCC and PVTT were concurrently treated with sorafenib and TACE. Univariate and multivariate analyses were performed to explore the clinical factors independently correlated with overall survival (OS). A prognostic score was then developed to identify different prognoses in an initial cohort and validated in an external cohort (n = 72).

RESULTS

In the multivariate analysis, performance status, extension of PVTT, initial radiological response, and sorafenib-related dermatologic toxicity were identified as predictors associated with OS. These factors were used to develop a prognostic score (PPRD score, range from 0 to 11). The median survival was found to decrease as the PPRD score increased, and patients were stratified into a favorable group (0 points), intermediate group (1-4 points), and dismal group (> 4 points). The median survival of patients in the three groups was 34.0 months, 20.0 months, and 7.0 months, respectively (p < 0.001). Additionally, the time to progression (TTP) (p < 0.001) was stratified along the same prognostic groups. The external validation cohort confirmed the prognostic scores.

CONCLUSIONS

The proposed score system can accurately stratify the outcomes of patients with HCC and PVTT treated with sorafenib plus TACE to help identify which group of patients may benefit from treatment.

KEY POINTS

• The survival benefits of patients with advanced HCC treated with sorafenib plus TACE remains controversial. • The independent factors associated with survival were identified to develop a prognostic score, called the PPRD score (standing for performance status, PVTT grade, radiological response, and sorafenib-related dermatologic toxicity); the median survival decreases as the score increases. • The scoring system can accurately stratify the survival benefits of patients with HCC and PVTT treated with combination therapy and help to identify which group of patients may benefit from the treatment. Graphical abstract.

Apatinib treatment may improve survival outcomes of patients with hepatitis B virus-related sorafenib-resistant hepatocellular carcinoma

AIMS

This study aimed to (a) assess the effectiveness and safety of apatinib as a subsequent treatment for patients with sorafenib-resistant hepatocellular carcinoma (HCC), and (b) identify the clinical factors influencing their treatment outcomes.

METHODS

The electronic medical records of consecutive patients with newly diagnosed advanced HCC treated with first-line sorafenib from 2015 to 2017 were retrospectively reviewed. Patients who were confirmed to have primary resistance to sorafenib were enrolled in this study. The outcomes of patients treated with apatinib were compared with those of patients who received supportive care. The primary endpoint was overall survival (OS).

RESULTS

A total of 92 patients with sorafenib-resistant advanced HCC (84 men and 8 women; mean age, 51.9 years) were included. All patients had an etiology of hepatitis B. The median OS in the overall cohort was 5.0 months [95% confidence interval (CI): 3.9, 6.0]. Of 92 patients, 58 (63.0%) were treated with apatinib, and 34 (37.0%) received supportive care. Apatinib treatment was associated with longer survival times than supportive care for patients with sorafenib-resistant advanced HCC (median OS: 7.0 versus 4.0 months, p < 0.001). The results of the multivariate analysis demonstrated that liver tumor load [hazard ratio (HR): 3.653, 95% CI: 2.047, 5.965, p < 0.001] and extrahepatic spread (HR: 0.303, 95% CI: 0.231, 0.778, p = 0.003) were independent predictors of OS after apatinib treatment.

CONCLUSION

This study showed that subsequent apatinib treatment may improve survival outcomes compared with supportive care for patients with sorafenib-resistant, advanced hepatitis B virus (HBV)-related HCC, especially for patients who have a lower liver tumor load and extrahepatic spread.

HIF-1α Mediates Osteoclast-Induced Mandibular Condyle Growth via AMPK Signaling

During the mandibular condylar growth, the absorption of calcified cartilage matrix induced by osteoclasts is crucial for the continuous endochondral osteogenesis. Meanwhile, recent studies showed that subchondral bone resided within the low-oxygen microenvironment, and our previous study revealed that hypoxia-inducible transcription factor 1α (HIF-1α) promoted osteoclastogenesis under hypoxia. However, whether HIF-1α regulates the function of osteoclasts in the mandibular condyle cartilage remains elusive. Our study indicated that severe deformity of the mandibular condyle was displayed in 10-wk-old osteoclast-specific HIF-1α conditional knockout (CKO) mice, accompanied by shortened length of condylar process and disorganized fibrocartilage. In 1-, 2-, and 4-wk-old CKO mice, the size of the hypertrophic layer and chondrocytic layer was significantly thickened. In the chondrocytic layer, chondrocytes were atrophied, showing a form of apoptosis in 4-wk-old CKO mice. Furthermore, an increase in the thickness of the fibrous and proliferating layer was observed in 10-wk-old CKO mice, as well as a significant decrease in that of the chondrocytic and hypertrophic chondrocyte layers. Interestingly, the articular surface of the condylar process abnormally presented a horizontal concave shape, and a disk-like acellular connective tissue appeared. In addition, genetic ablation of HIF-1α blunted cartilage matrix loss by subchondral osteoclast deficiency, resulting in a high subchondral bone mass phenotype, accompanied with a decreased number of blood vessels, alkaline phosphatase staining, and vascular endothelial growth factor (VEGF) expression. Mechanistically, the number of osteoclasts in the center of the condyle in CKO mice was significantly reduced by attenuated expression of adenosine 5′-monophosphate-activated protein kinase (AMPK) signaling. These findings reveal a novel influence of HIF-1α function in osteoclasts on maintenance of osteoclast-induced resorption of calcified cartilage matrix via AMPK signaling, as well as subchondral bone formation through VEGF-dependent angiogenesis in bone marrow.

AB0834 CLINICAL CHARACTERISTICS OF PSORIATIC ARTHRITIS IN CHINESE PATIENTS: A CROSS‑SECTIONAL OBSERVATIONAL STUDY

Background:

The clnical features of psoriatic arthritis(PsA)greatly varied in reports fomr different countries.There was no exact data in China.

Objectives:

To disclose the characteristics of PsA in China, we initiated an investigation it in our cohort of PsA patients.

Methods:

A cross-sectional observational study was conducted in our PsA cohort of Peking University First Hospital. All the clinical and imaging data at the patient’s first visit were collected, including the age, gender, disease course, skin lesion, arthritis, dactylitis, enthesis, laboratory tests, concomitant diseases and so on.

Results:

Two hundred and seventy-nine patients with PsA were enrolled in this study. Their mean age was 41 year-old with 132 (47.3%) female. Median disease duration was 3 years. Among these patients, 196(73.4%)patients had the skin lesion first, 47 (17.6%)patients had the arthritis first, and the other 24(9.0%) patients had the psoriasis and the arthritis at the same time. Arthritis was the most common manifestation. Polyarthritis was the most common arthritic manifestation with proximal interphalangeal (PIP) joint as the most frequently involved joint. Dactylitis was observed in 89 (31.9%) patients, mostly at the second, third and fourth toe. Enthesis was found in 18 (6.5%) patients by physical examination, however, in 158 (56.5%) patients with the aid of ultrasound and MRI.

Conclusion:

Polyarthritis was the most common arthritis type in Chinese PsA patients, and PIP joint was the most involved joint, and the second, the middle and the fourth toe were the most frequently digits. The imaging techniques, especially ultrasound dramatically increased the identification of enthesis.

References:

[1]Ritchlin CT, Colbert RA, Gladman DD. Psoriatic arthritis. N Engl J Med 2017;376: 957–70.

[2]Qing Yu Zeng, Ren Chen, John Darmawan et al. Rheumatic Diseases in China. Arthritis Research & Therapy Vol 10 No 1.

Disclosure of Interests:

None declared

Evaluation of Pantoea eucalypti FBS135 for pine (Pinus massoniana) growth promotion and its genome analysis

AIMS

Pinus massoniana is one of the most widely distributed forest plants in China. In this study, we isolated a bacterial endophyte (designated FBS135) from apical buds and needles of P. massoniana. Investigations were performed to understand the effects of the strain on pine growth, its genomic features and the functions of the plasmids it carries.

METHODS AND RESULTS

Based on its morphological features and 16S rRNA sequence, strain FBS135 was primarily identified as Pantoea eucalypti. We found that FBS135 not only promoted the growth of P. massoniana seedlings, but also significantly increased the survival rate of pine seedlings. The whole genome of FBS135 was sequenced, which revealed that the bacterium carries one chromosome and four plasmids. Its chromosome is 4 023 751 bp in size and contains dozens of genes involved in plant symbiosis. Curing one of the four plasmids, pPant1, resulted in a decrease in the size of the FBS135 colonies and the loss of the ability to synthesize yellow pigment, indicating that this plasmid may be very important for FBS135.

CONCLUSIONS

Pantoea eucalypti FBS135 has a genomic basis to be implicated in plant-associated lifestyle and was established to have the capability to promote pine growth.

SIGNIFICANCE AND IMPACT OF THE STUDY

To the best of our knowledge, this is the first report that such a bacterial species, P. eucalypti, was isolated from pine trees and evidenced to have pine beneficial activities. Our results elucidate the ecological effects of endophytes on forest plants as well as endophyte-plant interaction mechanisms.

Coalescing Majorana edge modes in non-Hermitian [Formula: see text]-symmetric Kitaev chain

A single unit cell contains all the information about the bulk system, including the topological feature. The topological invariant can be extracted from a finite system, which consists of several unit cells under certain environment, such as a non-Hermitian external field. We present an exact solvable non-Hermitian finite-size Kitaev chain with [Formula: see text]-symmetric chemical potentials at the symmetric point. The straightforward calculation shows that there are two kinds of Majorana edge modes in this model divided by [Formula: see text] symmetry-broken and unbroken. The one appeared in the [Formula: see text] symmetry-unbroken region can be seen as the finite-size projection of the conventional degenerate zero modes in a Hermitian infinite system with the open boundary condition. It indicates a possible variant of the bulk-edge correspondence: The number of Majorana edge modes in a finite non-Hermitian system can be the topological invariant to identify the topological phase of the corresponding bulk Hermitian system.

Emergency management for preventing and controlling nosocomial infection of the 2019 novel coronavirus: implications for the dermatology department

Plain language summary available online

Ultrafast Control of Excitonic Rashba Fine Structure by Phonon Coherence in the Metal Halide Perovskite CH_{3}NH_{3}PbI_{3}

We discover hidden Rashba fine structure in CH_{3}NH_{3}PbI_{3} and demonstrate its quantum control by vibrational coherence through symmetry-selective vibronic (electron-phonon) coupling. Above a critical threshold of a single-cycle terahertz pump field, a Raman phonon mode distinctly modulates the middle excitonic states with persistent coherence for more than ten times longer than the ones on two sides that predominately couple to infrared phonons. These vibronic quantum beats, together with first-principles modeling of phonon periodically modulated Rashba parameters, identify a threefold excitonic fine structure splitting, i.e., optically forbidden, degenerate dark states in between two bright ones with a narrow, ∼3  nm splitting. Harnessing of vibronic quantum coherence and symmetry inspires light-perovskite quantum control and sub-THz-cycle "Rashba engineering" of spin-split bands for ultimate multifunction device.