Jicama (Pachyrhizus spp.) a nonconventional starch: A review on isolation, composition, structure, properties, modifications and its application.

Starch attracts food industries due to their availability in nature, cheapness, biodegradability and possibilities of endless applications. The starch properties and their modification affect food quality. Compared to other cereals, tuber and root starches, more systematic information is needed on the jicama starches (JS). This review article summarizes the isolation, composition, morphology, rheological, thermal and digestibility properties of JS. The modifications and its current and potential applications are also discussed. The chemical composition and structure of JS are different from other starches, influencing its properties. JS has been modified by physical and chemical methods to improve the properties of starch. However, there are very few studies on the modification of JS as compared with other commercial starch although it has been used in food formulation as a stabilizer and to improve the texture of food products. It is also applied as an edible coating to preserve the quality of food products and use as a raw material for making edible and bioplastic packaging. However, large-scale utilization of JS is unexplored compared to commercial starches. Therefore, this review would provide useful information and suggestions for more research on Jicama starch and its industrial applications.

Effectiveness of take ACTION online naloxone training for law enforcement officers.

BACKGROUND: Training law enforcement officers (LEOs) to administer naloxone is a recommended strategy to reduce overdose deaths in the United States. To achieve this, an evidence-based and scalable naloxone training curriculum that is easy to use and readily scalable is needed. Convenient web-based training is a flexible method for delivering educational interventions particularly for LEOs who have irregular or shifting schedules. This study examined the effectiveness of a comprehensive web-based naloxone training that was created in partnership with LEOs on their knowledge, confidence, and attitudes regarding naloxone. METHODS: From May 2019 to September 2020, five law enforcement departments from Michigan participated in web-based naloxone training. A total of 182 LEOs (77% male) were in the final sample based on matching pre-and post-test surveys. LEOs were assessed on knowledge, confidence, and attitudes towards naloxone. Negative binomial and Poisson regression was conducted to assess associations between knowledge, confidence, and attitudes towards naloxone before and after training. RESULTS: Significant improvements in overdose knowledge and confidence were revealed across all departments with median (IQR) total composite scores for knowledge increasing from 35 (32, 37) to 40 (39, 42) (p < 0.01) and confidence increasing from 18.5 (15, 20) to 20 (20, 25) (p < 0.01). Median (IQR) attitude scores did not change. CONCLUSION: Our web-based naloxone training was effective in improving knowledge and confidence for LEOs but did not significantly improve LEOs attitudes towards naloxone across most departments. The web-based format is readily scalable and quickly disseminated and meets the immediate need for LEO overdose training. Additional intervention is needed to address the negative attitudes of LEOs regarding naloxone.

Developmental Mouse Brain Common Coordinate Framework.

3D standard reference brains serve as key resources to understand the spatial organization of the brain and promote interoperability across different studies. However, unlike the adult mouse brain, the lack of standard 3D reference atlases for developing mouse brains has hindered advancement of our understanding of brain development. Here, we present a multimodal 3D developmental common coordinate framework (DevCCF) spanning mouse embryonic day (E) 11.5, E13.5, E15.5, E18.5, and postnatal day (P) 4, P14, and P56 with anatomical segmentations defined by a developmental ontology. At each age, the DevCCF features undistorted morphologically averaged atlas templates created from Magnetic Resonance Imaging and co-registered high-resolution templates from light sheet fluorescence microscopy. Expert-curated 3D anatomical segmentations at each age adhere to an updated prosomeric model and can be explored via an interactive 3D web-visualizer. As a use case, we employed the DevCCF to unveil the emergence of GABAergic neurons in embryonic brains. Moreover, we integrated the Allen CCFv3 into the P56 template with stereotaxic coordinates and mapped spatial transcriptome cell-type data with the developmental ontology. In summary, the DevCCF is an openly accessible resource that can be used for large-scale data integration to gain a comprehensive understanding of brain development.

Training undergraduate students in HIPAA compliance.

The Health Insurance Portability and Accountability Act (HIPAA) has radically changed the way healthcare is conducted, and its relevance continues to expand as healthcare technology evolves. This article describes a method for training inexperienced undergraduate students to become HIPAA-compliant clinical research volunteers in a pediatric traumatic brain injury (TBI) study. Volunteers are trained to use the hospital's electronic health records (EHR) system to identify potential study candidates for approach, and they develop this skill set through google classroom modules/quizzes along with routine zoom calls to solidify their consenting approach. Since the inception of this study in 2018, there have been over one hundred different undergraduate research volunteers involved, and there has not been a single HIPAA violation to date. This compliance success rate is indicative of the efficacy of this training protocol. This paper serves as a guide to implementing HIPAA compliance training and ensuring accountability in new and existing clinical research studies.

Evolution of anterior cruciate ligament reconstruction & graft choice: a review.

The surgical treatment of anterior cruciate ligament (ACL) injuries dates back over 100 years from the present day [2022]. While open repair of the torn ACL was popularized in the early 1900s, the first ACL reconstructions utilized the fascia lata as a graft and other extra-articular stabilizing techniques. The first free tendon graft reported for ACL reconstructions was the quadriceps tendon (QT) in the 1930s, followed by the hamstrings tendon (HT), and then the patellar tendon. With improved understanding of the ACL anatomy and biomechanics and the invention of the arthroscope, ACL reconstruction evolved from open procedures to arthroscopic. Similarly, with the help of many surgeon-scientists who reported patient outcomes following ACL reconstruction with various techniques, graft choice evolved with the hamstrings and patellar tendon grafts becoming the dominant and preferred choice of both surgeons and patients. In present day, we see a resurgence of one of the original grafts reported, the QT, as well as primary ACL repair. Future research will result in continued advancements of ACL surgical techniques and graft harvesting, which will allow the orthopedic community (including patients and surgeons) to benefit from such innovations and advanced technologies.

Genomic Medicine Guidance: A Point-of-Care App for Heritable Thoracic Aortic Diseases.

Genetic testing can determine familial and personal risks for heritable thoracic aortic aneurysms and dissections (TAD). The 2022 ACC/AHA guidelines for TAD recommend management decisions based on the specific gene mutation. However, many clinicians lack sufficient comfort or insight to integrate genetic information into clinical practice. We therefore developed the Genomic Medicine Guidance (GMG) app, an interactive point-of care tool to inform clinicians and patients about TAD diagnosis, treatment, and surveillance. GMG is a REDCap-based app that combines publicly available genetic data and clinical recommendations based on the TAD guidelines into one translational education tool. TAD genetic information in GMG was sourced from the Montalcino Aortic Consortium, a worldwide collaboration of TAD centers of excellence, and the NIH genetic repositories ClinVar and ClinGen. The app streamlines data on the 13 most frequently mutated TAD genes with 2,286 unique pathogenic mutations that cause TAD so that users receive comprehensive recommendations for diagnostic testing, imaging, surveillance, medical therapy, preventative surgical repair, as well as guidance for exercise safety and management during pregnancy. The app output can be displayed in a clinician view or exported as an informative pamphlet in a patient-friendly format. The overall goal of the GMG app is to make genomic medicine more accessible to clinicians and patients, while serving as a unifying platform for research. We anticipate that these features will be catalysts for collaborative projects that aim to understand the spectrum of genetic variants that contribute to TAD.

Circulating microRNAs from early childhood and adolescence are associated with pre-diabetes at 18 years of age in women from the PMNS cohort.

With type 2 diabetes presenting at younger ages, there is a growing need to identify biomarkers of future glucose intolerance. A high (20%) prevalence of glucose intolerance at 18 years was seen in women from the Pune Maternal Nutrition Study (PMNS) birth cohort. We investigated the potential of circulating microRNAs in risk stratification for future pre-diabetes in these women. Here, we provide preliminary longitudinal analyses of circulating microRNAs in normal glucose tolerant (NGT@18y, N = 10) and glucose intolerant (N = 8) women (ADA criteria) at 6, 12 and 17 years of their age using discovery analysis (OpenArray™ platform). Machine-learning workflows involving Lasso with bootstrapping/leave-one-out cross-validation identified microRNAs associated with glucose intolerance at 18 years of age. Several microRNAs, including miR-212-3p, miR-30e-3p and miR-638, stratified glucose-intolerant women from NGT at childhood. Our results suggest that circulating microRNAs, longitudinally assessed over 17 years of life, are dynamic biomarkers associated with and predictive of pre-diabetes at 18 years of age. Validation of these findings in males and remaining participants from the PMNS birth cohort will provide a unique opportunity to study novel epigenetic mechanisms in the life-course progression of glucose intolerance and enhance current clinical risk prediction of pre-diabetes and progression to type 2 diabetes.

White paper on high-throughput process development for integrated continuous biomanufacturing.

Continuous manufacturing is an indicator of a maturing industry, as can be seen by the example of the petrochemical industry. Patent expiry promotes a price competition between manufacturing companies, and more efficient and cheaper processes are needed to achieve lower production costs. Over the last decade, continuous biomanufacturing has had significant breakthroughs, with regulatory agencies encouraging the industry to implement this processing mode. Process development is resource and time consuming and, although it is increasingly becoming less expensive and faster through high-throughput process development (HTPD) implementation, reliable HTPD technology for integrated and continuous biomanufacturing is still lacking and is considered to be an emerging field. Therefore, this paper aims to illustrate the major gaps in HTPD and to discuss the major needs and possible solutions to achieve an end-to-end Integrated Continuous Biomanufacturing, as discussed in the context of the 2019 Integrated Continuous Biomanufacturing conference. The current HTPD state-of-the-art for several unit operations is discussed, as well as the emerging technologies which will expedite a shift to continuous biomanufacturing.

Highly Stable Cycling of Silicon-Nanographite Aerogel-Based Anode for Lithium-Ion Batteries.

Silicon anodes are considered as promising electrode materials for next-generation high capacity lithium-ion batteries (LIBs). However, the capacity fading due to the large volume changes (∼300%) of silicon particles during the charge-discharge cycles is still a bottleneck. The volume changes of silicon lead to a fracture of the silicon particles, resulting in recurrent formation of a solid electrolyte interface (SEI) layer, leading to poor capacity retention and short cycle life. Nanometer-scaled silicon particles are the favorable anode material to reduce some of the problems related to the volume changes, but problems related to SEI layer formation still need to be addressed. Herein, we address these issues by developing a composite anode material comprising silicon nanoparticles and nanographite. The method developed is simple, cost-efficient, and based on an aerogel process. The electrodes produced by this aerogel fabrication route formed a stable SEI layer and showed high specific capacity and improved cyclability even at high current rates. The capacity retentions were 92 and 72% of the initial specific capacity at the 171st and the 500th cycle, respectively.

Promoting Pro-Endocrine Differentiation and Graft Maturation Following Surgical Resection of the Mouse Pancreas.

Type 1 diabetes (T1D) is an autoimmune disease, where insulin-producing ß-cells in the pancreas are inappropriately recognized and destroyed by immune cells. Islet transplantation is the most successful cell-based therapy for T1D individuals who experience frequent and severe life-threatening hypoglycemia. However, this therapy is extremely restricted owing to the limited availability of donor pancreas. In recent years, significant progress has been made in generating ß-cells from stem/progenitor cells using different approaches of in vitro differentiation. The insulin production from such in vitro generated ß-cells is still far less than that observed in islet ß-cells. We employed a novel strategy to improve the efficiency of progenitor cell differentiation by performing partial mouse pancreas resection after transplanting in vitro generated insulin-producing cells under the kidney capsule of these mice. Pancreas resection (pancreatectomy) has been shown to induce regenerative pathways, leading to regeneration of almost the entire resected pancreas over 3-5 weeks in mice. We found that in our method, regenerating mouse pancreas promotes better graft differentiation/maturation and insulin production from transplanted cells. In this chapter, we detail the protocols used for transplantation of in vitro differentiated cells in immunocompromised mice, partial pancreatectomy in host (NOD scid) mice, and assessment of graft function. We believe that our protocols provide a solid platform for further studies aimed at understanding growth/differentiation molecules secreted from regenerating pancreas that promote graft maturation.

Assessing the interplay between travel patterns and SARS-CoV-2 outbreak in realistic urban setting.

BACKGROUND: The dense social contact networks and high mobility in congested urban areas facilitate the rapid transmission of infectious diseases. Typical mechanistic epidemiological models are either based on uniform mixing with ad-hoc contact processes or need real-time or archived population mobility data to simulate the social networks. However, the rapid and global transmission of the novel coronavirus (SARS-CoV-2) has led to unprecedented lockdowns at global and regional scales, leaving the archived datasets to limited use. FINDINGS: While it is often hypothesized that population density is a significant driver in disease propagation, the disparate disease trajectories and infection rates exhibited by the different cities with comparable densities require a high-resolution description of the disease and its drivers. In this study, we explore the impact of creation of containment zones on travel patterns within the city. Further, we use a dynamical network-based infectious disease model to understand the key drivers of disease spread at sub-kilometer scales demonstrated in the city of Ahmedabad, India, which has been classified as a SARS-CoV-2 hotspot. We find that in addition to the contact network and population density, road connectivity patterns and ease of transit are strongly correlated with the rate of transmission of the disease. Given the limited access to real-time traffic data during lockdowns, we generate road connectivity networks using open-source imageries and travel patterns from open-source surveys and government reports. Within the proposed framework, we then analyze the relative merits of social distancing, enforced lockdowns, and enhanced testing and quarantining mitigating the disease spread. SCOPE: Our results suggest that the declaration of micro-containment zones within the city with high road network density combined with enhanced testing can help in containing the outbreaks until clinical interventions become available.

Pilot-scale demonstration of an end-to-end integrated and continuous biomanufacturing process.

There has been increasing momentum recently in the biopharmaceutical industry to transition from traditional batch processes to next-generation integrated and continuous biomanufacturing. This transition from batch to continuous is expected to offer several advantages which, taken together, could significantly improve access to biologics drugs for patients. Despite this recent momentum, there has not been a commercial implementation of a continuous bioprocess reported in the literature. In this study, we describe a successful pilot-scale proof-of-concept demonstration of an end-to-end integrated and continuous bioprocess for the production of a monoclonal antibody (mAb). This process incorporated all of the key unit operations found in a typical mAb production process, including the final steps of virus removal filtration, ultrafiltration, diafiltration, and formulation. The end-to-end integrated process was operated for a total of 25 days and produced a total of 4.9 kg (200 g/day or 2 g/L BRX/day) of the drug substance from a 100-L perfusion bioreactor (BRX) with acceptable product quality and minimal operator intervention. This successful proof-of-concept demonstrates that end-to-end integrated continuous bioprocessing is achievable with current technologies and represents an important step toward the realization of a commercial integrated and continuous bioprocessing process.

Gamma irradiating chromatography columns enables bioburden-free integrated continuous biomanufacturing.

An important consideration for integrated continuous biomanufacturing is that the downstream chromatography steps integrated with the bioreactor should maintain a low bioburden state throughout the entire duration of the operation. One potential strategy to achieve this is to start bioburden-free and functionally close the chromatography system. While chromatography skids themselves can be rendered bioburden-free, limitations exist in applying these methods to chromatography columns. The small column sizes used in continuous multicolumn chromatography enable gamma irradiation of disposable columns to render them bioburden-free. However, this approach has not been widely implemented, likely because gamma irradiation can negatively impact resin performance. Here, several protective mobile-phase modifiers were screened and shown to help chromatography resins retain naïve-like performance. Gamma irradiated columns were then integrated into perfusion bioreactors for continuous capture. Successful integrated continuous capture downstream of perfusion bioreactors for greater than 40 days using protein A, custom affinity, and non-affinity capture resins for multiple biologic modalities is demonstrated in development and commercial settings. No indications of time-based performance decline or bioburden growth have been observed. This strategy enables bioburden-free integrated continuous biomanufacturing operations and could allow full process closure and decreased environmental control requirements for facilities; thus, permitting simultaneous multi-product operations in a ballroom arrangement.

Cost analysis of treatment strategies for the control of HSV-2 infection in the U.S.: A mathematical modeling-based case study.

Infection of Herpes Simplex Virus type 2 (HSV-2) is a lifelong sexually transmitted disease. According to the Center for Disease Control and Prevention (CDC), 11.9% of the United States (U.S.) population was infected with HSV-2 in 2015-2016. The HSV-2 pathogen establishes latent infections in neural cells and can reactivate causing lesions later in life, a strategy that increases pathogenicity and allows the virus to evade the immune system. HSV-2 infections are currently treated by Acyclovir only in the non-constitutional stage, marked by genital skin lesions and ulcers. However, patients in the constitutional stage expressing mild and common (with other diseases) symptoms, such as fever, itching and painful urination, remain difficult to detect and are untreated. In this study, we develop and analyze a mathematical model to study the transmission and control of HSV-2 among the U.S. population between the ages of 15-49 when there are options to treat individuals in different stages of their pathogenicity. In particular, the goals of this work are to study the effect on HSV-2 transmission dynamics and to evaluate and compare the cost-effectiveness of treating HSV-2 infections in both constitutional and non-constitutional stages (new strategy) against the current conventional treatment protocol for treating patients in the non-constitutional stage (current strategy). Our results distinguish model parameter regimes where each of the two treatment strategies can optimize the available resources and consequently gives the long-term reduced cost associated with each treatment and incidence. Moreover, we estimated that the public health cost of HSV-2 with the proposed most cost-effective treatment strategy would increase by approximately 1.63% in 4 years of implementation. However, in the same duration, early treatment via the new strategy will reduce HSV-2 incidence by 42.76% yearly and the reproduction number will decrease to 0.84 from its current estimate of 2.5. Thus, the proposed new strategy will be significantly cost-effective in controlling the transmission of HSV-2 if the strategy is properly implemented.

Silicon-Nanographite Aerogel-Based Anodes for High Performance Lithium Ion Batteries.

To increase the energy storage density of lithium-ion batteries, silicon anodes have been explored due to their high capacity. One of the main challenges for silicon anodes are large volume variations during the lithiation processes. Recently, several high-performance schemes have been demonstrated with increased life cycles utilizing nanomaterials such as nanoparticles, nanowires, and thin films. However, a method that allows the large-scale production of silicon anodes remains to be demonstrated. Herein, we address this question by suggesting new scalable nanomaterial-based anodes. Si nanoparticles were grown on nanographite flakes by aerogel fabrication route from Si powder and nanographite mixture using polyvinyl alcohol (PVA). This silicon-nanographite aerogel electrode has stable specific capacity even at high current rates and exhibit good cyclic stability. The specific capacity is 455 mAh g-1 for 200th cycles with a coulombic efficiency of 97% at a current density 100 mA g-1.

Biochemical Recurrence in Prostate Cancer and Temporal Association to Bone Metastasis.

BACKGROUND Prostate cancer is a common cancer in men. Radical prostatectomy, i.e., the surgical removal of the entire prostate, is a frequently used option. Biochemical recurrence (BCR), i.e., detectable prostate specific antigen (PSA), is common in some men following such treatment. The timing of BCR to metastatic spread of disease in bones is usually a few years. If the biochemical failure occurs after a longer duration from the time of curative intent, it is generally believed to lead to local recurrence. CASE REPORT We report on two cases. A 78-year-old male was diagnosed with Gleason 7, prostate cancer in 2001. He subsequently underwent an open radical prostatectomy. Serial post-operative PSA's were undetectable (<0.01 ng/mL) up to 2016. He was diagnosed with a detectable PSA for the first time with a value of 0.3 ng/mL, that year. The PSA continued to rise to a level of 1.1 ng/mL. This rise in the PSA was within a 12-month interval. Subsequent bone scan and bone biopsy detected prostate cancer metastasis in multiple bones. Our second case was a 65-year-old male who underwent a laparoscopic radical prostatectomy in the year 2006 for a biopsy proven prostate cancer with Gleason 3+4=7. Serial post-operative PSA's were undetectable up to 2017. Within a span of 8 months, the PSA rose from 0.3 ng/mL to 1.52 ng/mL. A positron emission tomography scan demonstrated pubic bone lesion indicative of prostate cancer metastasis. CONCLUSIONS BCR can occur a decade after curative intent treatment of prostate cancer. The duration from BCR to detectable metastasis can be shorter. We demonstrated here that the site of recurrence, in such scenarios, can be distant metastasis and not local recurrence alone. Better imaging modalities are needed to identify the spread of prostate cancer at low levels of PSA.

Alterations in Skin Microbiomes of Patients With Cirrhosis.

BACKGROUND & AIMS: Patients with cirrhosis have intestinal dysbiosis and are prone to itching and skin or soft-tissue infections. The skin microbiome, and its relationship with intestinal microbiome, have not been characterized. We investigated alterations in skin microbiota of patients with cirrhosis and their association with intestinal microbiota and modulators of itch. METHODS: We collected skin swabs at 7 sites and blood and stool samples from 20 healthy individuals (control subjects; mean age, 59 years) and 50 patients with cirrhosis (mean age, 61 years; mean model for end-stage disease score, 12; 20 with decompensation). Skin and stool samples were analyzed by 16s rRNA sequencing and serum samples were analyzed by liquid chromatography and mass spectrometry for levels of bile acids (BAs) and by an ELISA for autotaxin (an itch modulator). Participants were analyzed by the visual analog itch scale (VAS, 0-10,10 = maximum intensity). Data were compared between groups (cirrhosis vs control subjects, with vs without decompensation, VAS 5 or higher vs less than 5). Correlation networks between serum levels of BAs and skin microbiomes were compared between patients with cirrhosis with vs without itching. RESULTS: The composition of microbiomes at all skin sites differed between control subjects and patients with cirrhosis and between patients with compensated vs decompensated cirrhosis. Skin microbiomes of patients with cirrhosis (especially those with decompensation) contained a higher relative abundance of Gammaproteobacteria, Streptococaceae, and Staphylococcaceae, and fecal microbiomes contained a higher relative abundance of Gammaproteobacteria, than control subjects. These bacterial taxa were associated with serum levels of autotaxin and BAs, which were higher in patients with VAS scores ≥5. Based on network statistics, microbial and BA interactions at all sites were more complex in patients with greater levels of itching in the shin, the most common site of itch. CONCLUSIONS: We identified alterations in skin microbiome of patients with cirrhosis (in Gammaproteobacteria, Streptococcaceae, and Staphylococcaceae)-especially in patients with decompensation; fecal microbiomes of patients with cirrhosis had a higher relative abundance of Gammaproteobacteria than control subjects. These specific microbial taxa are associated with itching intensity and itch modulators, such as serum levels of BAs and autotaxin.

Association Between Intestinal Microbiota Collected at Hospital Admission and Outcomes of Patients With Cirrhosis.

BACKGROUND & AIMS: Inpatients with cirrhosis are prone to develop acute-on-chronic liver failure (ACLF). ACLF is associated with dysbiosis of the intestinal microbiota, which might serve as a prognostic factor. We investigated whether features of the intestinal microbiota associate organ failure, transfer to intensive care, and mortality within 30 days in patients admitted to the hospital with cirrhosis. METHODS: Stool samples were collected from 181 patients with cirrhosis (age 56 years; mean model for end-stage liver disease score, 21; 43% with infections) at time of admission, from multiple hospitals in North America. Patients were followed for 30 days for development of ACLF, extra-hepatic organ failures, and death or hospice care. Microbiota were analyzed by 16s rRNA sequencing for alpha diversity (within groups), beta diversity (between groups), cirrhosis dysbiosis ratio (CDR), and taxa that differed between groups with vs without negative outcomes (individual organ failures, transfer to intensive care, ACLF, death, or hospice). Regression analyses were performed using microbial and clinical variables for each outcome. RESULTS: ACLF developed in 8% of study subjects; 16% were transferred to intensive care and 21% died. Beta diversity of the intestinal microbiome was significantly different, whereas alpha diversity was similar, between subjects with vs without outcomes. The CDR was lower in subjects who developed ACLF, especially among those with renal failure. Taxa belonging to phylum Proteobacteria (Enterobacteriaceae, Campylobacteriaceae, and Pasteurellaceae) and Firmicutes (Enterococcaceae and Streptococcaceae) were associated with development of negative outcomes, whereas other Firmicutes members (Lachnospiraceae and Clostridiales) reduced risk of negative outcomes. Changes in the microbiota associated with extra-hepatic organ failure, transfer to intensive care, ACLF, and death, independently on logistic regression analyses. CONCLUSION: In hospitalized patients with cirrhosis, dysbiosis of the intestinal microbiota on admission (particularly changes in Protebacteria constituents) associates with increased risk of extra-hepatic organ failure, ACLF, and death, independent of clinical factors. Strategies to reduce gut dysbiosis might improve outcomes of patients with cirrhosis.

Continuous Manufacturing of Recombinant Therapeutic Proteins: Upstream and Downstream Technologies.

Continuous biomanufacturing of recombinant therapeutic proteins offers several potential advantages over conventional batch processing, including reduced cost of goods, more flexible and responsive manufacturing facilities, and improved and consistent product quality. Although continuous approaches to various upstream and downstream unit operations have been considered and studied for decades, in recent years interest and application have accelerated. Researchers have achieved increasingly higher levels of process intensification, and have also begun to integrate different continuous unit operations into larger, holistically continuous processes. This review first discusses approaches for continuous cell culture, with a focus on perfusion-enabling cell separation technologies including gravitational, centrifugal, and acoustic settling, as well as filtration-based techniques. We follow with a review of various continuous downstream unit operations, covering categories such as clarification, chromatography, formulation, and viral inactivation and filtration. The review ends by summarizing case studies of integrated and continuous processing as reported in the literature.

Design and Fabrication of Wettability Gradients with Tunable Profiles through Degrafting Organosilane Layers from Silica Surfaces by Tetrabutylammonium Fluoride.

Surface-bound wettability gradients allow for a high-throughput approach to evaluate surface interactions for many biological and chemical processes. Here we describe the fabrication of surface wettability gradients on flat surfaces by a simple, two-step procedure that permits precise tuning of the gradient profile. This process involves the deposition of homogeneous silane SAMs followed by the formation of a surface coverage gradient through the selective removal of silanes from the substrate. Removal of silanes from the surface is achieved by using tetrabutylammonium fluoride which selectively cleaves the Si-O bonds at the headgroup of the silane. The kinetics of degrafting has been modeled by using a series of first order rate equations, based on the number of attachment points broken to remove a silane from the surface. Degrafting of monofunctional silanes exhibits a single exponential decay in surface coverage; however, there is a delay in degrafting of trifunctional silanes due to the presence of multiple attachment points. The effects of degrafting temperature and time are examined in detail and demonstrate the ability to reliably and precisely control the gradient profile on the surface. We observe a relatively homogeneous coverage of silane (i.e., without the presence of islands or holes) throughout the degrafting process, providing a much more uniform surface when compared to additive approaches of gradient formation. Linear gradients were formed on the substrates to demonstrate the reproducibility and tuneability of this subtractive approach.