[Clinical epidemiological characteristics of pertussis in children and the status of infection in their close contacts].

Objective: To investigate the clinical epidemiological characteristics of children with pertussis and the infection of their close contacts. Methods: The clinical data of children with pertussis and the etiological detection results of close contacts in Shenzhen Children's Hospital from 2015 to 2018 were collected and descriptive epidemiological analysis was carried out. Results: The cases of pertussis from 2015 to 2018 were reported as 504, 425, 796 and 991 respectively, with a total of 2 716 cases. The most cases was in May in 2015 (72 cases), in August in 2016 and 2018 (68 cases and 144 cases), and in July in 2017 (115 cases). A total of 1 517 male and 1 199 female children were reported from 2015 to 2018, the ratio of male-to-female was 1.3∶1. The proportion of children under 1 year old was 79.7% (2 165/2 716), of which 74.4% (1 610/2 165) was less than 6 months old. Among the reported cases, 1 605 (59.1%) were treated as outpatients, aged M(Q1,Q3) 5 (3, 11) months, and 1 111 (40.9%) were hospitalized, aged 4 (2, 7) months. There were 876 outpatients (54.4%) and 734 inpatients (45.6%) under 6 months of age, 575 outpatients (63.5%) and 331 inpatients (36.5%) between 6 months and 2 years of age, and 154 outpatients (77.0%) and 46 inpatients (23.0%) with above 2 years old, respectively. There were statistically significant differences between the two treatment methods in different age groups (P<0.001). The average hospitalization time of inpatients under 6 months of age was (8.5±3.9) days, that of inpatients between 6 months and 2 years of age was (7.1±3.7) days, and that of inpatients above 2 years old was (6.8±3.3) days. The difference was statistically significant (P<0.001). The etiological test results of pertussis were collected from 617 close contacts of 270 reported cases, the positive detection rate of mothers was the highest (34.9%). Conclusions: From 2015 to 2018, the number of reported cases of pertussis in our hospital fluctuated and increased year by year, with high incidence in summer, mainly in children under 1 year old, and more males than females. Outpatient treatment was more than inpatient treatment, its age was obviously older than the latter. The younger the children, the higher the proportion of hospitalization, and with the increase of the age, the hospitalization time was obviously shortened. Among the close family contacts, the mother might be the main source of pertussis infection in children.

Reflection high-energy electron diffraction measurements of reciprocal space structure of 2D materials.

Knowledge on the symmetry and perfection of a 2D material deposited or transferred to a surface is very important and valuable. We demonstrate a method to map the reciprocal space structure of 2D materials using reflection high energy diffraction (RHEED). RHEED from a 2D material gives rise to 'streaks' patterns. It is shown that from these streaks patterns at different azimuthal rotation angles that the reciprocal space intensity distribution can be constructed as a function of momentum transfer parallel to the surface. To illustrate the principle, we experimentally constructed the reciprocal space structure of a commercial graphene/SiO2/Si sample in which the graphene layer was transferred to the SiO2/Si substrate after it was deposited on a Cu foil by chemical vapor deposition. The result reveals a 12-fold symmetry of the graphene layer which is a result of two dominant orientation domains with 30° rotation relative to each other. We show that the graphene can serve as a template to grow other materials such as a SnS film that follows the symmetry of graphene.