Observation of D^{0}→K_{1}(1270)^{-}e^{+}ν_{e}

Using 2.93  fb^{-1} of e^{+}e^{-} collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} semileptonic decay is presented. The statistical significance of the decay D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is greater than 10σ. The branching fraction of D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is measured to be (1.09±0.13_{-0.16}^{+0.09}±0.12)×10^{-3}. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K_{1}(1270)^{-}→K^{-}π^{+}π^{-}. The fraction of longitudinal polarization in D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is determined for the first time to be 0.50±0.19_{stat}±0.08_{syst}.

First Measurement of the Absolute Branching Fraction of Λ→pμ^{-}ν[over ¯]_{μ}

The absolute branching fraction of Λ→pμ^{-}ν[over ¯]_{μ} is reported for the first time based on an e^{+}e^{-} annihilation sample of 10×10^{9}  J/ψ events collected with the BESIII detector at sqrt[s]=3.097  GeV. The branching fraction is determined to be B(Λ→pμ^{-}ν[over ¯]_{μ})=[1.48±0.21(stat)±0.08(syst)]×10^{-4}, which is improved by about 30% in precision over the previous indirect measurements. Combining this result with the world average of B(Λ→pe^{-}ν[over ¯]_{e}), we obtain the ratio {[Γ(Λ→pμ^{-}ν[over ¯]_{μ})]/[Γ(Λ→pe^{-}ν[over ¯]_{e})]} to be 0.178±0.028, which agrees with the standard model prediction assuming lepton flavor universality. The asymmetry of the branching fractions of Λ→pμ^{-}ν[over ¯]_{μ} and Λ[over ¯]→p[over ¯]μ^{+}ν_{μ} is also determined, and no evidence for CP violation is found.

Gamma-Ray Observation of the Cygnus Region in the 100-TeV Energy Region

We report observations of gamma-ray emissions with energies in the 100-TeV energy region from the Cygnus region in our Galaxy. Two sources are significantly detected in the directions of the Cygnus OB1 and OB2 associations. Based on their positional coincidences, we associate one with a pulsar PSR J2032+4127 and the other mainly with a pulsar wind nebula PWN G75.2+0.1, with the pulsar moving away from its original birthplace situated around the centroid of the observed gamma-ray emission. This work would stimulate further studies of particle acceleration mechanisms at these gamma-ray sources.

Hyperglyceridaemia-induced acute pancreatitis in pregnancy: Experience from a tertiary hospital in Singapore

Acute pancreatitis (AP) is a serious condition that can occur suddenly in pregnancy. We present a case of sudden onset of epigastric pain with severely deranged serum triglyceride levels in a 32-year-old Vietnamese primigravida with no significant past medical history in the Singapore General Hospital. The patient was managed in the intensive care unit, with plasmapheres and intravenous insulin and was eventually a healthy term foetus was delievered via ceasarian section. This case showcased multidisciplinary co operation between the obstetrics, anaesthetic, endocrinology and intensive care team and serves as a reminder to consider this rare condition for future similar presentations.

First Detection of sub-PeV Diffuse Gamma Rays from the Galactic Disk: Evidence for Ubiquitous Galactic Cosmic Rays beyond PeV Energies

We report, for the first time, the long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in the Galactic disk. Particularly, all gamma rays above 398 TeV are observed apart from known TeV gamma-ray sources and compatible with expectations from the hadronic emission scenario in which gamma rays originate from the decay of π^{0}'s produced through the interaction of protons with the interstellar medium in the Galaxy. This is strong evidence that cosmic rays are accelerated beyond PeV energies in our Galaxy and spread over the Galactic disk.

Observation of a Near-Threshold Structure in the K^{+} Recoil-Mass Spectra in e^{+}e^{-}→K^{+}(D_{s}^{-}D^{*0}+D_{s}^{*-}D^{0})

We report a study of the processes of e^{+}e^{-}→K^{+}D_{s}^{-}D^{*0} and K^{+}D_{s}^{*-}D^{0} based on e^{+}e^{-} annihilation samples collected with the BESIII detector operating at BEPCII at five center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7  fb^{-1}. An excess of events over the known contributions of the conventional charmed mesons is observed near the D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0} mass thresholds in the K^{+} recoil-mass spectrum for events collected at sqrt[s]=4.681  GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5_{-2.6}^{+1.8}±2.1)  MeV/c^{2} and (12.8_{-4.4}^{+5.3}±3.0)  MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3  σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0}. However, the properties of the excess need further exploration with more statistics.

Model-Independent Determination of the Spin of the Ω^{-} and Its Polarization Alignment in ψ(3686)→Ω^{-}Ω[over ¯]^{+}

We present an analysis of the process ψ(3686)→Ω^{-}Ω[over ¯]^{+} (Ω^{-}→K^{-}Λ, Ω[over ¯]^{+}→K^{+}Λ[over ¯], Λ→pπ^{-}, Λ[over ¯]→p[over ¯]π^{+}) based on a dataset of 448×10^{6}  ψ(3686) decays collected with the BESIII detector at the BEPCII electron-positron collider. The helicity amplitudes for the process ψ(3686)→Ω^{-}Ω[over ¯]^{+} and the decay parameters of the subsequent decay Ω^{-}→K^{-}Λ (Ω[over ¯]^{+}→K^{+}Λ[over ¯]) are measured for the first time by a fit to the angular distribution of the complete decay chain, and the spin of the Ω^{-} is determined to be 3/2 for the first time since its discovery more than 50 years ago.

Observation of the Doubly Cabibbo-Suppressed Decay D^{+}→K^{+}π^{+}π^{-}π^{0} and Evidence for D^{+}→K^{+}ω

Using 2.93  fb^{-1} of e^{+}e^{-} collision data collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, the first observation of the doubly Cabibbo-suppressed decay D^{+}→K^{+}π^{+}π^{-}π^{0} is reported. After removing decays that contain narrow intermediate resonances, including D^{+}→K^{+}η, D^{+}→K^{+}ω, and D^{+}→K^{+}ϕ, the branching fraction of the decay D^{+}→K^{+}π^{+}π^{-}π^{0} is measured to be (1.13±0.08_{stat}±0.03_{syst})×10^{-3}. The ratio of branching fractions of D^{+}→K^{+}π^{+}π^{-}π^{0} over D^{+}→K^{-}π^{+}π^{+}π^{0} is found to be (1.81±0.15)%, which corresponds to (6.28±0.52)tan^{4}θ_{C}, where θ_{C} is the Cabibbo mixing angle. This ratio is significantly larger than the corresponding ratios for other doubly Cabibbo-suppressed decays. The asymmetry of the branching fractions of charge-conjugated decays D^{±}→K^{±}π^{±}π^{∓}π^{0} is also determined, and no evidence for CP violation is found. In addition, the first evidence for the D^{+}→K^{+}ω decay, with a statistical significance of 3.3σ, is presented and the branching fraction is measured to be B(D^{+}→K^{+}ω)=(5.7_{-2.1}^{+2.5}_{stat}±0.2_{syst})×10^{-5}.

Expression of cytosolic and thiolated proteome of Musca domestica larvae under oxidative challenge

The study was aimed to investigate the expression of cytosolic and thiolated proteins of Musca domestica larvae under oxidative stress. Proteins from acute treatment of hydrogen peroxide (LC₅₀ = 21.52% (v/v)) on 3rd stage larvae of housefly were extracted and purified using an activated Thiol Sepharose® for thiolated protein purification. Two dimensional gel electrophoresis was used for visualizing and analyzing expression of cytosolic and thiolated proteins. Protein spots with more than 5 fold of expression change were identified using liquid chromatography- tandem mass spectrometry (LC-MS/MS). The cytosolic proteins were actin, tropomyosin, ubiquitin, arginine kinase, pheromone binding protein/general odorant binding protein, and ATP: guanidino phosphotransferase. The thiolated proteins with more than 5 fold change in expression as an effect to the acute treatment were fructose bisphosphate aldolase, short chain dehydrogenase and lactate/malate dehydrogenase. The proteins identified in the study should provide vital information for future reference in oxidative stress defence and response occurring in houseflies.

Σ^{+} and Σ[over ¯]^{-} Polarization in the J/ψ and ψ(3686) Decays

From 1310.6×10^{6}  J/ψ and 448.1×10^{6}  ψ(3686) events collected with the BESIII experiment, we report the first observation of Σ^{+} and Σ[over ¯]^{-} spin polarization in e^{+}e^{-}→J/ψ[ψ(3686)]→Σ^{+}Σ[over ¯]^{-} decays. The relative phases of the form factors ΔΦ have been measured to be (-15.5±0.7±0.5)° and (21.7±4.0±0.8)° with J/ψ and ψ(3686) data, respectively. The nonzero value of ΔΦ allows for a direct and simultaneous measurement of the decay asymmetry parameters of Σ^{+}→pπ^{0}(α_{0}=-0.998±0.037±0.009) and Σ[over ¯]^{-}→p[over ¯]π^{0}(α[over ¯]_{0}=0.990±0.037±0.011), the latter value being determined for the first time. The average decay asymmetry, (α_{0}-α[over ¯]_{0})/2, is calculated to be -0.994±0.004±0.002. The CP asymmetry A_{CP,Σ}=(α_{0}+α[over ¯]_{0})/(α_{0}-α[over ¯]_{0})=-0.004±0.037±0.010 is extracted for the first time, and is found to be consistent with CP conservation.

Measurements of Absolute Branching Fractions of Fourteen Exclusive Hadronic D Decays to η

Using 2.93  fb^{-1} of e^{+}e^{-} collision data taken at a center-of-mass energy of 3.773 GeV with the BESIII detector, we report the first measurements of the absolute branching fractions of 14 hadronic D^{0(+)} decays to exclusive final states with an η, e.g., D^{0}→K^{-}π^{+}η, K_{S}^{0}π^{0}η, K^{+}K^{-}η, K_{S}^{0}K_{S}^{0}η, K^{-}π^{+}π^{0}η, K_{S}^{0}π^{+}π^{-}η, K_{S}^{0}π^{0}π^{0}η, and π^{+}π^{-}π^{0}η; D^{+}→K_{S}^{0}π^{+}η, K_{S}^{0}K^{+}η, K^{-}π^{+}π^{+}η, K_{S}^{0}π^{+}π^{0}η, π^{+}π^{+}π^{-}η, and π^{+}π^{0}π^{0}η. Among these decays, the D^{0}→K^{-}π^{+}η and D^{+}→K_{S}^{0}π^{+}η decays have the largest branching fractions, which are B(D^{0}→K^{-}π^{+}η)=(1.853±0.025_{stat}±0.031_{syst})% and B(D^{+}→K_{S}^{0}π^{+}η)=(1.309±0.037_{stat}±0.031_{syst})%, respectively. The charge-parity asymmetries for the six decays with highest event yields are determined, and no statistically significant charge-parity violation is found.

First Observation of D^{+}→ημ^{+}ν_{μ} and Measurement of Its Decay Dynamics

By analyzing a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we measure for the first time the absolute branching fraction of the D^{+}→ημ^{+}ν_{μ} decay to be B_{D^{+}→ημ^{+}ν_{μ}}=(10.4±1.0_{stat}±0.5_{syst})×10^{-4}. Using the world averaged value of B_{D^{+}→ηe^{+}ν_{e}}, the ratio of the two branching fractions is determined to be B_{D^{+}→ημ^{+}ν_{μ}}/B_{D^{+}→ηe^{+}ν_{e}}=0.91±0.13_{(stat+syst)}, which agrees with the theoretical expectation of lepton flavor universality within uncertainty. By studying the differential decay rates in five four-momentum transfer intervals, we obtain the product of the hadronic form factor f_{+}^{η}(0) and the c→d Cabibbo-Kobayashi-Maskawa matrix element |V_{cd}| to be f_{+}^{η}(0)|V_{cd}|=0.087±0.008_{stat}±0.002_{syst}. Taking the input of |V_{cd}| from the global fit in the standard model, we determine f_{+}^{η}(0)=0.39±0.04_{stat}±0.01_{syst}. On the other hand, using the value of f_{+}^{η}(0) calculated in theory, we find |V_{cd}|=0.242±0.022_{stat}±0.006_{syst}±0.033_{theory}.

First Observation of D^{+}→ημ^{+}ν_{μ} and Measurement of Its Decay Dynamics

By analyzing a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} collected at a center-of-mass energy of 3.773 GeV with the BESIII detector, we measure for the first time the absolute branching fraction of the D^{+}→ημ^{+}ν_{μ} decay to be B_{D^{+}→ημ^{+}ν_{μ}}=(10.4±1.0_{stat}±0.5_{syst})×10^{-4}. Using the world averaged value of B_{D^{+}→ηe^{+}ν_{e}}, the ratio of the two branching fractions is determined to be B_{D^{+}→ημ^{+}ν_{μ}}/B_{D^{+}→ηe^{+}ν_{e}}=0.91±0.13_{(stat+syst)}, which agrees with the theoretical expectation of lepton flavor universality within uncertainty. By studying the differential decay rates in five four-momentum transfer intervals, we obtain the product of the hadronic form factor f_{+}^{η}(0) and the c→d Cabibbo-Kobayashi-Maskawa matrix element |V_{cd}| to be f_{+}^{η}(0)|V_{cd}|=0.087±0.008_{stat}±0.002_{syst}. Taking the input of |V_{cd}| from the global fit in the standard model, we determine f_{+}^{η}(0)=0.39±0.04_{stat}±0.01_{syst}. On the other hand, using the value of f_{+}^{η}(0) calculated in theory, we find |V_{cd}|=0.242±0.022_{stat}±0.006_{syst}±0.033_{theory}.

[The derivation and vulidafion of a prediction rule for hypoxemia in infants with Pierre Robin sequence after weaning]

Objective: To set up a prediction scoring system for the hypoxemia in infants with Pierre Robin sequence after weaning and evaluate its clinical value. Methods: Data of consecutive patients from November 2016 to June 2019, who underwent mandibular distraction osteogenesis in Guangzhou Women and Children's Medical Center, were retrospectively analyzed (n=148). All the cases were divided into two groups according to the appearance of hypoxemia after weaning. They were randomly divided into the derivation cohorc (2/3,n=100) and the validation cohort (1/3,n=48). Single factor and multiple logistic regression analysis were used to select the independent risk factors related to hypoxemia and establish a prediction model. A prediction scoring system was developed in accordance with assigning of the value of each variable β in the model. Internal verification of scoring system by validation population. Data of consecutive patients from July 2019 to November 2019, who underwent mandibular distraction osteogenesis, were prospectively analyzed (n=26). The diagnostic accuracy were conducted to evaluate the clinical value of the scoring system. Results: The logistic regression demonstrated that age at operation, pulmonary infection and the length of distraction less than 5 mm at weaning were the independent risk factors for hypoxemia. The P value of logistic regression model in Hosmer and Lemeshow goodness of fit test was 0.848, and a prediction scoring system was established accordingly. The area under the ROC curve of the scoring system was 0.890, and the optimum critical value was 53. The sensitivity, specificity, accuracy of the model were 78.6%(11/14),86.1%(74/86), 85.0%(85/100) respectively. The predictive effectiveness of the scoring system in the retrospective validation population was similar to that in the modeling population. 26 patients were included in the prospective analysis. The area under ROC curve of the scoring system was 0.870. The sensitivity, specificity and accuracy were 80.0%(5/6),95.0%(20/21), 96.1%(25/26) respectively. Conclusion: The prediction scoring system established in the study are efficacious for the hypoxemia in infants with Pierre Robin sequence after weaning.

First Detection of Photons with Energy beyond 100 TeV from an Astrophysical Source

We report on the highest energy photons from the Crab Nebula observed by the Tibet air shower array with the underground water-Cherenkov-type muon detector array. Based on the criterion of a muon number measured in an air shower, we successfully suppress 99.92% of the cosmic-ray background events with energies E>100  TeV. As a result, we observed 24 photonlike events with E>100  TeV against 5.5 background events, which corresponds to a 5.6σ statistical significance. This is the first detection of photons with E>100  TeV from an astrophysical source.

[Impact of KIT D816 mutation on salvage therapy in relapsed acute myeloid leukemia with t(8;21) translocation]

Objective: To evaluate the impact of KIT D816 mutation on the salvage therapy in relapsed acute myeloid leukemia (AML) with t(8;21) translocation. Method: The characteristics of the first relapsed AML with t(8;21) translocation from 10 hospitals were retrospectively collected, complete remission (CR(2)) rate after one course salvage chemotherapy and the relationship between KIT mutation and CR(2) rate was analyzed. Results: 68 cases were enrolled in this study, and 30 cases (44.1%) achieved CR(2). All patients received KIT mutation detection, and KIT D816 mutation was identified in 26 cases. The KIT D816 positive group had significantly lower CR(2) compared with non-KIT D816 group (23.1% vs 57.1%, χ(2)=7.559, P=0.006), and patients with longer CR(1) duration achieved significantly higher CR(2) than those with CR(1) duration less than 12 months (74.1% vs 31.9%, χ(2)=9.192, P=0.002). KIT D816 mutation was tightly related to shorter CR(1) duration. No significant difference of 2 years post relapse survival was observed between KIT D816 mutation and non-KIT D816 mutation group. Conclusion: KIT D816 mutation at diagnosis was an adverse factor on the salvage therapy in relapsed AML with t(8;21) translocation, significantly related to shorter CR1 duration, and can be used for prediction of salvage therapy response. KIT D816 mutation could guide the decision-making of salvage therapy in relapsed AML with t(8;21) translocation.

Evaluation of the Interplanetary Magnetic Field Strength Using the Cosmic-Ray Shadow of the Sun

We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disk center in the "away" ("toward") interplanetary magnetic field (IMF) sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the away (toward) sector is 1.54±0.21_{stat}±0.20_{syst} (1.62±0.15_{stat}±0.22_{syst}) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field.

Psychological Morbidity among Emergency Department Doctors and Nurses after the SARS Outbreak

Objective

To determine the psychological morbidity among emergency department (ED) doctors and nurses six months after the 2003 Severe Acute Respiratory Syndrome (SARS) outbreak.

Methods

During the SARS outbreak from 13 March to 31 May 2003, the study ED was designated as Singapore's only screening centre for SARS and was closed to all other patients. A self-administered questionnaire survey was conducted in November 2003. Doctors and nurses of the study ED who had patient contact during the outbreak were included. Data collected were demographics and responses to (a) Impact of Event Scale (IES) and (b) General Health Questionnaire 28 (GHQ 28). Scores were assigned to the responses whereby an IES score ≥26/75 or a GHQ 28 score ≥5/28 was indicative of post-event and psychiatric morbidity respectively.

Results

Thirty-eight out of 41 (92.7%) doctors and 58 out of 83 (69.9%) nurses responded. Fewer doctors reported post-event and psychiatric morbidity compared to nurses, with 5 (13.2%) doctors and 12 (20.7%) nurses scoring ≥26 on IES, 6 (15.8%) doctors and 12 (20.7%) nurses scoring ≥5 on GHQ 28. The doctors reported a median of 9.5 (range 0–47) on IES and 0 (range 0–11) on GHQ 28. The nurses reported a median of 15 (range 0–61) on IES and 1 (range 0–25) on GHQ 28.

Conclusions

Six months after SARS, the rates of post-event and psychiatric morbidity were relatively low among the study ED doctors and nurses. The results might have underestimated actual morbidity as the study was conducted six months after the outbreak.

Decitabine treatment for acute myeloid leukemia relapse after allogeneic hematopoietic stem cell transplantation

Therapeutic options for patients with relapse of acute myeloid leukemia (AML) after allo-SCT are limited. Here, we present a case of a 49-year female with AML who underwent myeloablative allo-SCT from a matched sibling donor. Seven months after transplantation she developed cGVHD and suffered from extramedullary plus concurrent medullary relapse. The presence of CNS extramedullary disease is unique. Our patient was treated with decetabine. After one cycle the patient achieved complete remission and full donor chimerism without severe side effects or the occurrence of GVHD. Our case report, together with previous studies, provides strong evidence that decitabine may be a suitable treatment option for AML relapse after allogeneic transplantation, especially in patients who developed GVHD.

Hypoxia enhances periodontal ligament stem cell proliferation via the MAPK signaling pathway

There is high incidence of periodontal disease in high-altitude environments; hypoxia may influence the proliferation and clone-forming ability of periodontal ligament stem cells (PDLSCs). The MAPK signaling pathway is closely correlated with cell proliferation, differentiation, and apoptosis. Thus, we isolated and cultured PDLSCs under hypoxic conditions to clarify the impact of hypoxia on PDLSC proliferation and the underlying mechanism. PDLSCs were separated and purified by the limiting dilution method and identified by flow cytometry. PDLSCs were cultured under hypoxic or normoxic conditions to observe their cloning efficiency. PDLSC proliferation at different oxygen concentrations was evaluated by MTT assay. Expression of p38/MAPK and MAPK/ERK signaling pathway members was detected by western blotting. Inhibitors for p38/MAPK or ERK were applied to PDLSCs to observe their impacts on clone formation and proliferation. Isolated PDLSCs exhibited typical stem cell morphological characteristics, strong abilities of globular clone formation and proliferation, and upregulated expression of mesenchymal stem cell markers. Stem cell marker expression was not statistically different between PDLSCs cultured under hypoxia and normoxia (P > 0.05). The clone number in the hypoxia group was significantly higher than that in the control (P < 0.05). PDLSC proliferation under hypoxia was higher than that of the control (P < 0.001). p38 and ERK1/2 phosphorylation in hypoxic PDLSCs was markedly enhanced compared to that in the control (P < 0.05). Either P38/MAPK inhibitor or ERK inhibitor treatment reduced clone formation and proliferation. Therefore, hypoxia enhanced PDLSC clone formation and proliferation by activating the p38/MAPK and ERK/MAPK signaling pathways.

[Frequency and clinical features of ASXL2 gene mutation in acute myeloid leukemia patients with AML1- ETO fusion gene positive]

目的

探讨伴AML1-ETO融合基因的急性髓系白血病（AML）患者ASXL2基因突变情况、突变阳性患者临床特征及ASXL2基因突变与c-kit基因突变的关系。

方法

采用PCR扩增产物片段直接测序分析法，检测59例伴AML1-ETO融合基因初发AML患者ASXL2基因第11、12外显子编码区突变情况，比较ASXL2基因突变阳性和阴性组患者的临床特征、生存及c-kit基因突变情况。

结果

59例患者中7例存在ASXL2突变，突变率为11.9%。ASXL2基因突变阳性组患者初诊时外周血红蛋白浓度中位数为56.2（38.0~72.0）g/L，显著低于ASXL2突变阴性组患者的69.0（37.2~154.0）g/L，差异有统计学意义（P=0.038）；外周血WBC、PLT、嗜酸粒细胞比例、骨髓原始细胞比例与ASXL2突变阴性组相比，差异均无统计学意义（P值均>0.05）。两组均未见肝、脾、中枢神经系统浸润；淋巴结不同程度肿大，但ASXL2基因突变阳性、阴性两组间差异无统计学意义（P=0.859）。免疫表型分析显示：ASXL2基因突变阳性组CD33表达显著低于阴性组（P=0.033）；两组患者均未表达cCD3，CD117、cMPO、HLA-DR、CD34、CD38、CD13、CD44、CD15、CD64、CD11b、CD56、CD19、cCD79a、CD7两组表达差异均无统计学意义（P值均>0.05）。ASXL2基因突变阳性与阴性组患者总缓解率、总生存时间差异均无统计学意义（P值分别为0.577、0.631）。两组c-kit基因突变检出率分别为14.3％和29.4%，差异无统计学意义（P=0.697）。

结论

该组伴AML1-ETO融合基因AML患者ASXL2基因突变率为11.9%。ASXL2突变阳性患者外周血红蛋白浓度、CD33表达方面呈现一定的临床特征。ASXL2基因突变与c-kit基因变突可能没有特定的关联性。

[Biomechanics analysis of the impact of maxillofacial injury on skull base damage]

OBJECTIVE

To analyze the impact of maxillofacial injury on skull base.

METHODS

A three-dimensional(3D)finite-element model of cranio-maxillofacial bone was established by CT scan data. A lead cylinder in base diameter of 3 cm was designed as an impactor. There regions(upper right maxilla, left infraorbital margin and left zygomatic body)subjected to an impact at the speed of 8.6 m/s(about 30 km/h)was simulated. Thirteen landmarks at the skull base were selected. The values of stress at the end of 0.5, 1.0, 1.5, 2.0 ms were obtained, and the results were analyzed.

RESULTS

The dynamic process of the fracture of the jaw and the stress distribution and conduction of the skull base were successfully simulated in three parts of the face. When the impact was on the right maxillary bone region, the stress values of the three points(medial foramen rotundum, medial foramen rotundum, anterior clivus reached the peak at each time point, 26.2, 22.4, 21.5 MPa(t=0.5 ms)and 70.0, 55.0, 45.0 MPa(t=1.0 ms)and 38.0, 26.5, 39.5 MPa(t=1.5 ms)and 26.0, 19.0, 23.0 MPa(t=2.0 ms), respectively. When the impact was on the left margo infraorbitalis orbitaeta region, the stress values of the two points(medial left foramen rotundum, posterior clivus)reached the peak at each time point, 8.8, 16.0 MPa(t=0.5 ms)and 10.0, 18.0 MPa(t=1.0 ms)and 5.5, 6.0 MPa(t=1.5 ms)and 11.5, 12.5 MPa(t=2.0 ms), respectively. When the impact was on the body of left zygomatic bone, the stress values of posterior clivus were 45.0 MPa(t=0.5 ms), 40.0 MPa(t=1.0 ms), 12.0 MPa(t=1.5 ms), 42.5 MPa(t= 2.0 ms), respectively.

CONCLUSIONS

According to the difference of stress distribution and conduction of maxillofacial and skull base bone, the speed and the path of force transfer to the skull base were different. Finite-element dynamic simulation can be used for the biomechanics research on maxillofacial trauma.