A minimally invasive optical trapping system to understand cellular interactions at onset of an immune response

T-cells and antigen presenting cells are an essential part of the adaptive immune response system and how they interact is crucial in how the body effectively fights infection or responds to vaccines. Much of the experimental work studying interaction forces between cells has looked at the average properties of bulk samples of cells or applied microscopy to image the dynamic contact between these cells. In this paper we present a novel optical trapping technique for interrogating the force of this interaction and measuring relative interaction forces at the single-cell level. A triple-spot optical trap is used to directly manipulate the cells of interest without introducing foreign bodies such as beads to the system. The optical trap is used to directly control the initiation of cell-cell contact and, subsequently to terminate the interaction at a defined time point. The laser beam power required to separate immune cell pairs is determined and correlates with the force applied by the optical trap. As proof of concept, the antigen-specific increase in interaction force between a dendritic cell and a specific T-cell is demonstrated. Furthermore, it is demonstrated that this interaction force is completely abrogated when T- cell signalling is blocked. As a result the potential of using optical trapping to interrogate cellular interactions at the single cell level without the need to introduce foreign bodies such as beads is clearly demonstrated

Cryogenic Etching of Silicon: An Alternative Method for Fabrication of Vertical Microcantilever Master Molds

Seiring berkembangnya jaman, kini paguyuban tidak lagi identik dengan karakteristik masyarakat desa. Akan tetapi pada masyarakat kota juga ditemukan kegemaran masyarakat untuk menghimpun diri dalam bentuk paguyuban. Hal ini ditandai dengan munculnya berbagai macam komunitas. Salah satunya yaitu maraknya komunitas penggemar sepeda yang terbentuk atas persamaan hobi. Penelitian ini difokuskan pada komunitas penggemar sepeda gunung yang menyukai aktifitas bersepeda dengan rute offroad. Penelitian ini menggunakan metode kualitatif dengan pendekatan interaksionisme simbolik George Herbert Mead. Perspektif interaksionisme simbolik berusaha mempelajari interaksi sosial individu dengan menggunakan simbol-simbol yang dipahaminya. Hasil penelitian adalah interaksi yang dilakukan antar anggota berbeda-beda, tergantung dengan siapa anggota tersebut berinteraksi. Mind dalam komunitas NCC adalah ketika anggota berpikir mengenai respon apa yang sesuai dengan stimulus yang muncul. Seperti pemikiran anggota pengguna sepeda gunung merek lokal menerima bahasa bullying dari anggota pengguna sepeda gunung merek impor. Anggota akan berpikir mengenai tindakan apa yang tepat untuk menghindari adanya bahasa bullying tersebut. Sehingga anggota mulai berpikir untuk beralih menggunakan sepeda gunung merek impor sebagai bentuk penyesuaian diri terhadap lingkungan sosialnya. Self anggota adalah ketika anggota menempatkan diri mereka sebagai subyek (I) atau obyek (Me). Perilaku “I” ditunjukkan dengan perilaku anggota senior yang lebih bersifat spontanitas ketika berinteraksi dengan anggota junior. Sedangkan perilaku “Me” memuat suatu kesadaran dan tanggung jawab. Sehingga perilaku anggota akan lebih dibatasi oleh norma-norma yang berlaku misalnya sopan santun. Seperti perilaku anggota junior yang lebih menempatkan dirinya sebagai anggota yang selalu menghormati keberadaan anggota senior, bagaimanapun ia diperlakukan. Kata Kunci: Interaksi Simbolik, Komunikasi, Komunita

Clinical features of COVID-19 in Ghana : Symptomatology, illness severity and comorbid non-communicable diseases

Objective: This analysis described the clinical features of COVID-19 in the early phase of the pandemic in Ghana. Methods: Data were extracted from two national COVID-19 treatment centers in Ghana for over 11 weeks(from March to May 2020). Descriptive and inferential statistics were performed. Modified Ordered Logistic and Negative Binomial Regression analysis were applied to establish factors associated with illness severity and Non-communicable Disease (NCDs) counts respectively. All analysis was conducted at the 95% confidence level (p-value ≤ 0.05) using Stata 16. Results: Among the 275 patients, the average age was 40.7±16.4, with a preponderance of males (54.5%). The three commonest symptoms presented were cough (21.3%), headache (15.7%), and sore throat (11.7%). Only 7.6% of the patients had a history of fever. Most patients were asymptomatic (51.65). Approximately 38.9% have an underlying co-morbid NCDs, with Hypertension (32.1%), Diabetes (9.9%), and Asthma (5.2%) being the three commonest. The odds of Moderate/severe (MoS) was significantly higher for those with unknown exposures to similar illness [aOR(95%CI) = 4.27(1.12-10.2)] compared with non-exposure to similar illness. An increased unit of NCD’s count significantly increased the odds of COVID-19 MoS illness by 26%[cOR(95%CI) =1.26(1.09-1.84)] and 67% (adjusting for age) [aOR(95%CI)=1.67(1.13-2.49)]. Conclusion: The presence of cardiovascular co-morbidities dictated the frequency of reported symptoms and severity of COVID-19 infection in this sample of Ghanaians. Physicians should be aware of the presence of co-morbid NCDs and prepare to manage effectively among COVID-19 patients