Hydrocyclones for single-use perfusion application

Hydrocyclones (HC) are very compact devices that promote solid-liquid separation under the action of a centrifugal field. Despite the small size, HCs have a large processing capacity and do not suffer from clogging. Therefore, several publications explored HCs as a potential cell retention device in perfusion applications in the last 20 years, but limited to non-disposable lab-scale bioreactors and to relatively low cell densities (up to ~10 million cells/mL). Even though the absence of moving parts may streamline the HC manufacturing, the performance of solid-liquid separation is highly dependent on the HC internal geometry. Said that, hydrocyclones can be produced by 3D printing, making them a promising alternative for the integration of cell retention devices in single-use bioreactor bags. The performance of hydrocyclones also depends on the attachment configuration to the bioreactor and cell concentration of the feed suspension. In this work, at first rapid batch tests were carried out to evaluate the impact of: (i) cell concentration; (ii) diameter of connector installed in the recirculation loop; and (iii) controlled harvest flow rate enabled by a peristaltic pump (520U model, Watson Marlow). The main response considered was their effect on HC separation efficiency. The stainless-steel HC2015 designed for mammalian cell separation (Pinto et al., 2008) was selected for the preliminary batch tests, and also used as a benchmark for plastic prototypes produced by 3D-printing techniques. Afterwards, the same HC2015 was installed in a 50-L single-use bag (XDR50 Xcellerex, GE Healthcare) specially customized for a perfusion cultivation with a mAb producer CHO cell line. The stainless-steel HC2015 when operating at 2.3 bar provided a total separation efficiency (Et) up to 96%, and a centrifugal separation efficiency (E´) of 82% for a CHO cell suspension at 24E6 viable cells per mL Concentrated cells recovered by the underflow port did not show decrease in viability compared to the feed suspension. The reduction of a TC connector size from 19.7 to 12.7 mm resulted in the total filling of the recirculation loop with liquid, disrupting the formation of the desirable umbrella-pattern discharge of the underflow and reducing cell retention. The use of a peristaltic pump to control the overflow flow rate equivalent to perfusion rates of 1 and 2 RV (reactor volume) per day in 40-L bioreactor working volume resulted in a reduction of the E´ values and a consequent increase of cell concentration in the harvest stream. The reduction in the separation efficiency was probably due to a disturbance of the liquid flow pattern inside the HC, since it was observed that the typical gas core coming out from the overflow was absent. These features were taken into account in the HC operation in the single-use 50-L perfusion bioreactor, and a cell concentration of 50E6 cells per mL was successfully achieved with a cell-specific perfusion rate (CSPR) as low as 20 pL per cell per day. The harvest stream consisted of a natural cell bleeding leaving the overflow outlet. Moreover, the lower cell viability and average diameter in the overflow evidenced the preferential retention of viable cells returning into the bioreactor, thus providing a healthier culture environment. A 3D-printed hydrocyclone with equivalent geometry to the stainless-steel HC2015 was made and presented slightly lower separation efficiencies. Further studies proposing materials with a smoother surface and investigating further 3D-printing techniques are currently ongoing. Pinto, R. C.V., Medronho, R. A., Castilho, L. R. (2008). Separation of CHO cells using hydrocyclones. Cytotechnology, 56(1), 57–67. doi:10.1007/s10616-007-9108-

Signatures of the Self-Similar Regime of Strongly Coupled Stimulated Brillouin Scattering for Efficient Short Laser Pulse Amplification

Plasma-based laser amplification is considered as a possible way to overcome the technological limits of present day laser systems and achieve exawatt laser pulses. Efficient amplification of a picosecond laser pulse by stimulated Brillouin scattering (SBS) of a pump pulse in a plasma requires to reach the self-similar regime of the strongly coupled (SC) SBS. In this Letter, we report on the first observation of the signatures of the transition from linear to self-similar regimes of SC-SBS, so far only predicted by theory and simulations. With a new fully head-on collision geometry, subpicosecond pulses are amplified by a factor of 5 with energy transfers of few tens of mJ. We observe pulse shortening, frequency spectrum broadening, and down-shifting for increasing gain, signatures of SC-SBS amplification entering the self-similar regime. This is also confirmed by the power law dependence of the gain on the amplification length: doubling the interaction length increases the gain by a factor 1.4. Pump backward Raman scattering (BRS) on SC-SBS amplification has been measured for the first time, showing a strong decrease of the BRS amplitude and frequency bandwidth when SBS seed amplification occurs

ANALISIS YURIDIS SOSIOLOGIS PROSEDUR PENYELAMATAN KREDIT BERMASALAH BANK DANAMON BERDASARKAN PERATURAN BANK INDONESIA NOMOR 14/15/PBI/2012 TENTANG PENILAIAN KUALITAS ASET BANK UMUM (Studi Pada Kasus Konflik Bank Danamon Tanjung Balai Karimun Provinsi Kepualauan Riau Dengan Nasabah Bank Danamon)

Kasus mengenai penanganan kredit bermasalah di Bank Danamon sering mengalami permasalahan terutama dalam hal pelelangan. Kejadian tersebut dikarenakan bahwa Bank Danamon sering melakukan tindakan pelelangan tanpa pemberitahuan oleh nasabah serta tidak melakukan proses penyelamatan kredit bermasalah terlebih dahulu terhadap nasabah yang mengalami kredit bermasalah. Penelitian ini mengambil rumusan masalah Bagaimana prosedur penyelamatan kredit bermasalah yang dilakukan oleh PT.Bank Danamon dikaitkan dengan Peraturan Bank Indonesia Nomor 14/15/PBI/2012 Tentang Penilaian Kualitas Aset Bank Umum dan Apa faktor yang mendasari PT.Bank Danamon melakukan pelelangan terhadap jaminan nasabah. Penelitian ini menggunakan pendekatan Yuridis Sosiologis. Berdasarkan hasil penelitian tersebut ada beberapa peraturan dari Bank Danamon yang tidak mengikuti prosedur dari BI serta terjadi ketidaksesuain dengan peraturan yang dikeluarkan oleh Bank Danamon pusat dengan tindakan yang dilakukan oleh Bank Danamon Tanjung Balai Karimun. Proses penyelamatan kredit bermasalah yang dilakukan oleh bank adalah dengan mengeluarkan surat penggilan yang berisi mengenai pelunasan pembayaran, Bank Danamon tidak melakukan restrukturisasi sebelum nasabah sendiri yang membuat permohonan untuk dapat restrukturisasi. Mengenai pelelangan Bank Danmon kurang melengkapi salah satu persyaratan untuk melakukan lelng yaitu tidak adanya surat pemberitahuan lelang kepada debitur sehingga pelelangan yang dilakukan oleh bank danamon kurang sempurna. Kesimpulannya bahwa Bank Danamon Tanjung Balai Karimun kurang menerapkan peraturan yang telah dikeluarkan oleh Bank Danamon Pusat. Saran, Bank Danamon Tanjung Balai Karimun dapat memperbaiki kinerja bank dan melakukan perbuatan sesuai dengan perturan yang telah dikeluarkan

Development and clinical validation of the Genedrive point-of-care test for qualitative detection of hepatitis C virus

Objective: Recently approved direct acting antivirals provide transformative therapies for chronic hepatitis C virus (HCV) infection. The major clinical challenge remains to identify the undiagnosed patients worldwide, many of whom live in low-income and middle-income countries, where access to nucleic acid testing remains limited. The aim of this study was to develop and validate a point-of-care (PoC) assay for the qualitative detection of HCV RNA. Design: We developed a PoC assay for the qualitative detection of HCV RNA on the PCR Genedrive instrument. We validated the Genedrive HCV assay through a case–control study comparing results with those obtained with the Abbott RealTime HCV test. Results: The PoC assay identified all major HCV genotypes, with a limit of detection of 2362 IU/mL (95% CI 1966 to 2788). Using 422 patients chronically infected with HCV and 503 controls negative for anti-HCV and HCV RNA, the Genedrive HCV assay showed 98.6% sensitivity (95% CI 96.9% to 99.5%) and 100% specificity (95% CI 99.3% to 100%) to detect HCV. In addition, melting peak ratiometric analysis demonstrated proof-of-principle for semiquantification of HCV. The test was further validated in a real clinical setting in a resource-limited country. Conclusion: We report a rapid, simple, portable and accurate PoC molecular test for HCV, with sensitivity and specificity that fulfils the recent FIND/WHO Target Product Profile for HCV decentralised testing in low-income and middle-income countries. This Genedrive HCV assay may positively impact the continuum of HCV care from screening to cure by supporting real-time treatment decisions

Dynamics of nanosecond laser pulse propagation and of associated instabilities in a magnetized underdense plasma

The propagation and energy coupling of intense laser beams in plasmas are critical issues in laser-driven inertial confinement fusion. Applying magnetic fields to such a setup has been evoked to enhance fuel confinement and heating, and mitigate laser energy losses. Here we report on experimental measurements demonstrating improved transmission and increased smoothing of a high-power laser beam propagating in an underdense magnetized plasma. We also measure enhanced backscattering, which our simulations show is due to hot electrons confinement, thus leading to reduced target preheating

The efficacy of suppressive antibiotic treatment in patients managed non-operatively for periprosthetic joint infection and a draining sinus

Objectives: Patients with prosthetic joint infections (PJIs) not suitable for curative surgery may benefit from suppressive antibiotic therapy (SAT). However, the usefulness of SAT in cases with a draining sinus has never been investigated. Methods: A multicentre, retrospective observational cohort study was performed in which patients with a PJI and a sinus tract were eligible for inclusion if managed conservatively and if sufficient follow-up data were available (i.e. at least 2 years). SAT was defined as a period of > 6 months of oral antibiotic therapy. Results: SAT was initiated in 63 of 72 (87.5 %) included patients. Implant retention during follow-up was the same in patients receiving SAT vs. no SAT (79.4 % vs. 88.9 %; pCombining double low line0.68). In total, 27 % of patients using SAT experienced side effects. In addition, the occurrence of prosthetic loosening in initially fixed implants, the need for surgical debridement, or the occurrence of bacteremia during follow-up could not be fully prevented with the use of SAT, which still occurred in 42 %, 6.3 %, and 3.2 % of cases, respectively. However, the sinus tract tended to close more often (42 % vs. 13 %; pCombining double low line0.14), and a higher resolution of pain was observed (35 % vs. 14 %; pCombining double low line0.22) in patients receiving SAT. Conclusions: SAT is not able to fully prevent complications in patients with a draining sinus. However, it may be beneficial in a subset of patients, particularly in those with pain or the hindrance of a draining sinus. A future prospective study, including a higher number of patients not receiving SAT, is needed

Factors associated with return of spontaneous circulation after out-of-hospital cardiac arrest in Poland : a one-year retrospective study

Background: Out-of-hospital cardiac arrest (OHCA) is a common reason for calls for intervention by emergency medical teams (EMTs) in Poland. Regardless of the mechanism, OHCA is a state in which the chance of survival is dependent on rapid action from bystanders and responding health professionals in emergency medical services (EMS). We aimed to identify factors associated with return of spontaneous circulation (ROSC). Methods: The medical records of 2137 EMS responses to OHCA in the city of Wroclaw, Poland between July 2017 and June 2018 were analyzed. Results: The OHCA incidence rate for the year studied was 102 cases per 100,000 inhabitants. EMS were called to 2317 OHCA events of which 1167 (50.4%) did not have resuscitation attempted on EMS arrival. The difference between the number of successful and failed cardiopulmonary resuscitations (CPRs) was statistically significant (p < 0.001). Of 1150 patients in whom resuscitation was attempted, ROSC was achieved in 250 (27.8%). Rate of ROSC was significantly higher when CPR was initiated by bystanders (p < 0.001). Patients presenting with asystole or pulseless electrical activity (PEA) had a higher risk of CPR failure (86%) than those with ventricular fibrillation/ventricular tachycardia (VF/VT). Patients with VF/VT had a higher chance of ROSC (OR 2.68, 1.86–3.85) than those with asystole (p < 0.001). The chance of ROSC was 1.78 times higher when the event occurred in a public place (p < 0.001). Conclusions: The factors associated with ROSC were occurrence in a public place, CPR initiation by witnesses, and presence of a shockable rhythm. Gender, age, and the type of EMT did not influence ROSC. Low bystander CPR rates reinforce the need for further efforts to train the public in CPR