Single Donor Research Articles

Evaluation of using local information from donor catchments to improve the performance of selected deterministic and empirical design flood estimation methods in South Africa

There are a number of design flood estimation methods routinely used in South Africa. Flood Frequency Analysis (FFA) remains the preferred technique in instances where adequate records of observed data are available. However, in many parts of South Africa, rivers are not gauged for continuous streamflow monitoring. In the case of ungauged catchments, hydrologists and engineers generally make use of methods based on deterministic and empirical approaches for design flood estimation. Due to the limitations and performance of these methods, improved approaches need to be developed for design flood estimation in ungauged catchments. International practice has shown that making use of local information transfer from nearby gauged catchments, also referred to as donor catchments, can improve flood estimation in ungauged catchments. The main considerations for implementing such methods are the type of information transferred and selection of suitable donor catchments. Approaches for donor catchment selection include physical similarity, spatial proximity and integrated similarity. Some studies have also shown that the use of multiple donor catchments can offer further improvements. Thus, a methodology is proposed and evaluated in this paper for using local information transfer in the form of a method and location-specific adjustment factor from gauged donor catchments to improve the performance of selected deterministic and empirical flood estimation methods widely used in South Africa. The pilot study was undertaken at 48 catchments located in the north-eastern part of South Africa, with river flow data provided by the Department of Water and Sanitation. The results show that the degree of improvement for each of the methods is largely dependent on the approach used for donor catchment selection. Even though the best approach for donor catchment selection varied for the different design flood estimation methods, the integrated similarity approach performed consistently well for all methods considered. Similar to the use of single donor catchments, the results obtained from the use of multiple nearest donor catchments also varied for each of the methods used. Due to the general improvements, and the promising results and success of the simple approach used in this study, it is recommended that further refinements of the proposed methodology and approaches to donor catchment selection be considered for future research projects in order for the method to be used by engineers and hydrologists in practice.

Transfusion Effectiveness of Single Donor Apheresis Platelet over Random Donor Platelet; A Comparative Study

Background: Platelet transfusion performs a key function in treatment for patients with thrombocytopenia. The use of single donor apheresis platelet results in better post-transfusion recovery & survival than random donor platelet. Activation of platelet depends on their preparation and storage and this may be one of the factors responsible for storage related change in platelet membrane proteins. In transfusion medicine laboratory we commonly prepare platelet concentrates from whole blood, platelet rich plasma, buffy coat and single donor plateletpheresis. Objective: The aim of the study was to evaluate the transfusion effectiveness of single donor apheresis platelet over random donor platelet. Methods: This is an observational study. This study was carried out on 125 dengue patients the find out about the population including male and female patients in the Department of Transfusion Medicine, Bangabandhu Sheikh Mujib Medical University, Chittagong Medical College Hospital, Bangladesh and Samorita Hospital & Medical College, Dhaka, Bangladesh. The duration of the period from July 2021 to December 2022. The period from data was entered in MS Excel and Statistical analysis was done using SPSS-24. Results: The total study population was 125 patients aged 10 – 40 years, 17(13.6%) were ≤10 years, 49(39.2%) were 11-20 years, 37(29.6%) were 21-30 years and 22(17.6%) were 31-40 years. Sex distribution of the population where, 85(68.0%) were male and 40(32.0%) were female. Conclusion: Single-donor apheresis platelet transfusions produced higher platelet counts, whereas random donor platelet also effective in preventing hemorrhage.

Optimising platelet usage during the induction therapy of acute myeloid leukaemia: Impact of physician education.

Platelet products are scarce and expensive resources to be used judiciously. However, inappropriate usage is common. Lack of physician awareness is an important issue. We implemented a physician education program (PEP) along with repeated WhatsApp reminders at our centre. We audited the platelet usage practise before and after the intervention. Charts of patients with acute myeloid leukaemia (AML) treated between January 2020 and August 2020 was reviewed, and the mean platelet usage per patient per day was calculated. Physician education was implemented between September 2020 and December 2020 (2 PowerPoint lectures of 20 min each and weekly WhatsApp messages containing the guidelines). Data of patientstreated between Jan 2021 and August 2021 was prospectively audited to understand platelet usage and the indications for transfusions. The British Committee for the Standards in Haematology (BCSH) platelet transfusion guidelines were used as the adjudication tool to evaluate compliance. The mean platelet usage per day per kg body weight of a patient before and after the PEP was compared using the t-test. Group A (before physician education) consisted of 22 patients, and group B (after physician education) consisted of 23 patients. The mean number of platelet transfusions for each patient in a day per kg body weight was 125.7 × 108 in group A whereas, after the PEP, it had reduced to 73.9 × 108 amounting to an absolute reduction of 51 × 108 (58.8%) from the baseline with a statistical significance of P=0.001. After implementing the PEP, the mean number of random donor platelets used reduced by 10.25 units (34% reduction), and the mean single donor platelets used reduced by 0.83 units (19% reduction). The 190 requests for platelet transfusion received during this period were classified as appropriate (157/190), which constituted 82.63% of the requests, or inappropriate (33/190), which accounted for 17.36%. A short-duration education programme supplemented with weekly WhatsApp messages and an active feedback mechanism on the rationale of platelet transfusion by the treating physician and transfusion specialist could significantly reduce platelet consumption during the therapy of acute myeloid leukaemia patients. This is a measure that can be considered by all high-volume haematology centres, which can improve patient safety and reduce costs.

Role of hydrogen bonding on solvent separation using amphiphilic sorbitan ester

Tetrahydrofuran (THF) and water are miscible and interact trough hydrogen (H) bonds. Span 80 (sorbitan ester) is soluble in THF, but not water. Nonetheless, Span 80 H bonds with water, as shown by attenuated total reflectance – Fourier transform infrared spectroscopy. In pure water, species are single (SD) or double (DD) donors, and single (SA) or double (DA) acceptors. In pure water, SD-SA and DD-DA are dominant and have similar abundance. Span 80 and THF alter the distribution of water species. When THF and Span 80 compete for the same water species, THF separation from water is most effective. Span 80 induces a marked shift of SD-SA to higher wavenumbers, which are close to DD-DA. This species intermediate between DD-DA and SD-SA is dominant, indicating that Span 80 mainly interacts with it. This same species is also dominant in THF-water mixtures containing 50–70% THF. Instead, DD-DA is dominant up to 40% THF, while DD-SA dominate at the highest THF percentages. Bottle tests show that Span 80 separates THF and water into bulk phases with 50–70% THF within 1 hr. In contrast, outside this THF range, emulsions are stable for more than 1 hr, as observed by either light scattering or optical microscopy. In mixtures with 50–70% THF, bulk phase separation occurs within 1 hr, because Span 80 competes with THF for the same water species. Separation is poorer outside of this THF range, where Span 80 and THF interact with different water species.

The Use of the Antigenically Variable Major Surface Protein 2 in the Establishment of Superinfection during Natural Tick Transmission of Anaplasma marginale in Southern Ghana.

Many vector-borne pathogens, including Anaplasma spp., Borrelia spp., Trypanosoma spp., and Plasmodium spp., establish persistent infection in the mammalian host by using antigenic variation. These pathogens are also able to establish strain superinfection, defined as infection of an infected host with additional strains of the same pathogen despite an adaptive immune response. The ability to establish superinfection results in a population of susceptible hosts even with high pathogen prevalence. It is likely that antigenic variation, responsible for persistent infection, also plays a role in the establishment of superinfection. Anaplasma marginale, an antigenically variable, obligate intracellular, tickborne bacterial pathogen of cattle, is well suited for the study of the role of antigenically variant surface proteins in the establishment of superinfection. Anaplasma marginale establishes persistent infection by variation in major surface protein 2 (msp2), which is encoded by approximately six donor alleles that recombine into a single expression site to produce immune escape variants. Nearly all cattle in regions of high prevalence are superinfected. By tracking the acquisition of strains in calves through time, the complement of donor alleles, and how those donor alleles are expressed, we determined that simple variants derived from a single donor allele, rather than multiple donor alleles, were predominant. Additionally, superinfection is associated with the introduction of new donor alleles, but these new donor alleles are not predominantly used to establish superinfection. These findings highlight the potential for competition among multiple strains of a pathogen for resources within the host and the balance between pathogen fitness and antigenic variation.

Bioengineered omental transplant site promotes pancreatic islet allografts survival in non-human primates

The transplanting islets to the liver approach suffers from an immediate posttransplant loss of islets of more than 50%, progressive graft dysfunction over time, and precludes recovery of grafts should there be serious complications such as the development of teratomas with grafts that are stem cell-derived islets (SC-islets). The omentum features an attractive extrahepatic alternative site for clinical islet transplantation. We explore an approach in which allogeneic islets are transplanted onto the omentum, which is bioengineered with a plasma-thrombin biodegradable matrix in three diabetic non-human primates (NHPs). Within 1week posttransplant, each transplanted NHP achieves normoglycemia and insulin independence and remains stable until termination of the experiment. Success was achieved in each case with islets recovered from a single NHP donor. Histology demonstrates robust revascularization and reinnervation of the graft. This preclinical study can inform the development of strategies for β cell replacement including the use of SC-islets or other types of novel cells in clinical settings.

REASONS OF DONOR DEFERRAL FOR A SINGLE DONOR PLATELETPHERESIS IN A PUBLIC SECTOR BLOOD TRANSFUSION CENTRE OF LAHORE: A CROSS-SECTIONAL STUDY

Background and Objective: Plateletpheresis is a process by which platelets are extracted from the donor. Donor selection is critical since donors are the sole supply of blood available to satisfy demand. The goal of this study is to investigate the causes behind plateletpheresis donor deferral in order to ensure safe blood donation. Materials and Methods: The research was carried out at the department of Haematology and Transfusion Medicine University of Child Health Sciences, The Children Hospital Lahore. 50 plateletpheresis donors who voluntarily came for donation were considered for the procedure as per guidelines and departmental standard operating procedure. The details of the procedure of plateletpheresis were explained to each donor. Donor questionnaire was filled including brief history, general physical examination, Haematological parameters such as haemoglobin and the donor blood screening was done to be considered fit for procedure. The reasons for deferral of donors were noted after all work up was done. Informed consent was taken before the procedure. Plateletpheresis was done using COM.TEC Cell Separator instrument. Results: In this study 50 donors were included. Out of 50 donors 34 were approved for procedure and 16 were deferred due to different temporary and permanent reasons. The age of the donors were in between 18 to 50 years. Major reason for temporary deferral was poor venous access (n=7, 14%) followed by the low haemoglobin value (n=4, 8%). Other reasons for temporary deferral were history of medication (n=3, 6%), low platelet count (n=4,8%), history of blood transfusion (n=1, 2%), history of vaccination n=2, 4%), leucocytosis (n=1, 2%), underweight (n=4, 8%), fever (n=1, 2%), refusal after questionnaire (n=1, 2%), seropositive for malaria and VDRL (n=3, 6%), high blood pressure (n=1, 2%), and anxiety (n=1, 2%). Permanent reasons for deferral were seropositive for HbsAg (n=2, 4%), seropositive for HCV (n=4, 8%) and tattoo (n=1, 2%). Conclusion: This study found a pattern of donor deferral in single donor platelet apheresis that was our experience in single centre. In conclusion during the selection of donors, Transfusion services should be very careful related to donor safety measures and these causes of deferral should be kept in mind.

Single-Donor and Pooling Strategies for Fecal Microbiota Transfer Product Preparation in Ulcerative Colitis: A Systematic Review and Meta-analysis.

Patients with ulcerative colitis (UC) have a less diverse microbiome than healthy subjects. Multiple studies have evaluated fecal microbiota transfer (FMT) in these patients using different methods of product preparation, doses, and routes of administration. A systematic review and meta-analysis was performed to compare the efficacy of single-donor (SDN) and multidonor (MDN) strategies for product preparation. Systematic searches were performed in Web of Science, Scopus, PubMed, and Orbit Intelligence for studies comparing FMT products manufactured using SDN or MDN strategies to placebo in patients with UC. Fourteen controlled studies were selected for meta-analysis (10 randomized and 4 nonrandomized). The treatment response was assessed by using fixed- and random-effects models, and the significance of the indirect difference between the interventions was assessed using a network approach. Considering all 14 studies, MDN and SDN were superior to placebo in terms of treatment response (risk ratios [RRs]: 4.41 and 1.57, respectively [P ≤ 0.001 for both]), and MDN was superior to SDN (RR: 2.81, P = 0.005). Meta-analysis of the 10 studies with high quality of evidence showed that MDN was superior to SDN in terms of treatment response (RR: 2.31, P = 0.042). Results were identical for both models. There was a significant clinical benefit (remission) for patients with UC who received FMT with products manufactured by MDN strategies. Reduction of donor effect may lead to a gain in microbial diversity that could improve response to treatment. These results may have implications in the treatment approach of other diseases amenable to microbiome manipulation.JOURNAL/cltg/04.03/01720094-202305000-00002/2FFU1/v/2023-05-23T220055Z/r/image-tiff.

New insights into trait introgression with the look-ahead intercrossing strategy.

Trait introgression (TI) can be a time-consuming and costly task that typically requires multiple generations of backcrossing (BC). Usually, the aim is to introduce one or more alleles (e.g. QTLs) from a single donor into an elite recipient, both of which are fully inbred. This article studies the potential advantages of incorporating intercrossing (IC) into TI programs when compared with relying solely on the traditional BC framework. We simulate a TI breeding pipeline using 3 previously proposed selection strategies for the traditional BC scheme and 3 modified strategies that allow IC. Our proposed look-ahead intercrossing method (LAS-IC) combines look-ahead Monte Carlo simulations, intercrossing, and additional selection criteria to improve computational efficiency. We compared the efficiency of the 6 strategies across 5 levels of resource availability considering the generation when the major QTLs have been successfully introduced into the recipient and a desired background recovery rate reached. Simulations demonstrate that the inclusion of intercrossing in a TI program can substantially increase efficiency and the probability of success. The proposed LAS-IC provides the highest probability of success across the different scenarios using fewer resources compared with BC-only strategies.

Screening costs associated with donor selection for fecal microbiota transplantation for treatment of PD-1 refractory melanoma patients.

The gut microbiome acts as a tumor-extrinsic regulator of responses to immune-checkpoint inhibitors (ICIs) targeting PD-1 and CTLA-4 receptors. Primary resistance to anti-PD-1 ICI can be reversed via responder-derived fecal microbiota transplant (FMT) in patients with refractory melanoma. Efforts to create stool banks for FMT have proved difficult. Therefore, we aimed to establish a novel donor-screening program to generate responder-derived FMT for use in PD-1 refractory melanoma. Candidate PD-1 responder donors and PD-1 refractory recipients were recruited via clinic-based encounters at the University of Pittsburgh Medical Center hospitals. Eligible donors and recipients underwent physician assessment and screening of serum, stool and nasopharynx for transmissible agents, which included SARS-CoV-2 modification. The cost of donor and recipient screening was calculated. Initially, 29 donors were screened with 14 eligible donors identified after exclusion; of the 14 donors, eight were utilized in clinical trials. The overall efficiency of screening was 48%. Seroprevalence rates for cytomegalovirus, Epstein-Barr virus, HSV-2, HHV-6, HTLV-1, HTLV-2, and syphilis were similar to published statistics from healthy blood donors in the USA. Donor stool studies indicated a 3.6% incidence of E. histolytica and norovirus, 3.7% incidence of giardia and 7.1% incidence of C. difficile. A single donor tested positive for SARS-CoV-2 in stool only. The cost for finding a single eligible donor was $2260.24 (pre-COVID) and $2,460.24 (post-COVID). The observed screening efficiency suggests that a well-resourced screening program can generate sufficient responder-derived donor material for clinical trial purposes. Eliminating testing for low-prevalence organisms may improve cost-effectiveness.

Liver splitting during normothermic machine perfusion: a novel method to combine the advantages of both in-situ and ex-vivo techniques

BackgroundSplit liver transplantation permits the transplant of two recipients using a single donor liver. Liver splitting can be performed using the ex-vivo technique (more convenient), or the in-situ technique (shorter cold ischaemic time). We aimed to develop a technique for liver splitting during normothermic machine perfusion which combines the advantages of both techniques and permits graft assessment prior to transplant. MethodsHuman livers declined for transplantation were perfused at 36 °C using a modified-commercial perfusion machine. We developed a six-step method to split whole livers into left lateral segment grafts and extended right grafts. Both partial livers were then perfused on separate machines for individual assessment. ResultsUsing our technique, 10 whole livers were successfully split during normothermic perfusion resulting in 20 partial grafts. Apart from a single graft which failed due to a technical error, all grafts survived for 24-h after splitting. Survival was demonstrated by lactate clearance, bile production and synthesis of coagulation factors. ConclusionsLiver splitting during normothermic machine perfusion has the potential to revolutionise split liver transplantation. We describe a novel technique that reliably achieves two grafts from a single donor liver. This raises the possibility of semi-elective transplantation, and sophisticated graft assessment prior to implant.

Features of cytomegalovirus DNAemia and virus-specific T-cell responses in allogeneic hematopoietic stem-cell transplant recipients during prophylaxis with letermovir.

There is scarce information on the natural kinetics of cytomegalovirus (CMV) DNAemia and dynamics of CMV-specific T-cell reconstitution in allogeneic hematopoietic transplant recipients (allo-HSCT) undergoing letermovir (LMV) prophylaxis. Twelve adult CMV-seropositive high-risk recipients (median age, 53 years; 9 males/3 females) undergoing LMV prophylaxis and 13 non-LMV allo-HSCT controls (median age, 58 years; 7 males/6 females) were included. CMV DNAemia in plasma was monitored by real-time polymerase chain reaction. Preemptive antiviral therapy (PET) was administered upon detection of ≥1500IU/ml. CMV-specific interferon-gamma (IFN-γ)-producing CD8+ and CD4+ T cells were enumerated by flow cytometry around days +30, +60, and +90 after allo-HSCT. Ex vivo experiments assessing of the potential effect of LMV on CMV-specific T-cell expansion in a single CMV-seropositive donor were also conducted. Five LMV patients (41.6%) developed CMV DNAemia that cleared spontaneously. Four patients (33.3%) developed CMV DNAemia after LMV cessation, of which two required PET. Nine non-LMV patients (69.2%) developed CMV DNAemia (five required PET). The percentage of LMV and non-LMV patients exhibiting detectable CMV-specific T-cell responses was comparable (7/10 vs. 10/13; p=.71). Nevertheless, median CMV-specific CD4+ and CD8+ T-cell counts were lower in LMV patients by days +60 (p=.006 and .02, respectively) and +90 (p=.08 and .02). Ex vivo, CMV-specific CD8+ T cells expanded to the same level either in the presence (19.8%) or in the absence of LMV (20.6%). In our series, episodes of CMV DNAemia in LMV patients cleared spontaneously. A diminished degree of CMV-specific T-cell reconstitution in LMV patients compared to non-LMV patients was observed.

Quantification of Age-Related Changes in the Lateral Organization of the Lipid Portion of the Intact Membranes Isolated from the Left and Right Eye Lenses of the Same Human Donor.

The continuous wave EPR spin-labeling method was used to evaluate age-related changes in the amounts of phospholipids (PLs) and cholesterol (Chol) in domains present in intact, cortical, and nuclear fiber cell plasma membranes isolated separately from the left and right eye lenses of the same human donor. The relative amounts of boundary plus trapped PLs were evaluated with the PL analog 12-doxylstearic acid spin label (12-SASL) and the relative amounts of trapped Chol with the Chol analog androstane spin label (ASL). The donors ranged in age from 15 to 70 years. Both the left and right eye lenses from donors aged 60, 65, and 70 years had nuclear cataracts; additionally, the right eye lens only of the 60-year-old donor had a cortical cataract. In transparent lenses, the relative amounts of boundary plus trapped PLs increase monotonously with donor age, and, at all ages, this amount was greater in nuclear compared with cortical membranes. Moreover, in transparent lenses, the relative amount of trapped Chol increases with age in nuclear membranes. However, the EPR spectrum of ASL from cortical membranes of 15- to 60-year-old donors shows only the weakly immobilized component assigned to ASL in the bulk plus Chol bilayer domain. Only the cortical membranes of 61- to 70-year-old donors contain both weakly and strongly immobilized components. The strongly immobilized component is assigned to ASL in trapped lipids. We speculate that the age of 60 years may be considered as a "threshold" for appearance of trapped lipids in cortical membranes. The relative amounts of boundary plus trapped PLs in lenses with nuclear cataracts is lower than that predicted from the tendency of the age-dependent increase observed for transparent lenses. The differences in amounts of lipids in the indicated left and right eye domains of each donor are smaller than the differences in single donors of a similar age.

Mass spectrometry-based analysis on the impact of whole blood donation on the global plasma proteome.

Biomonitoring may provide important insights into the impact of a whole blood donation for individual blood donors. Here, we used unbiased mass spectrometry (MS)-based proteomics to assess longitudinal changes in the global plasma proteome, after a single blood donation for new and regular donors. Subsequently, we compared plasma proteomes of 76 male and female whole blood donors, that were grouped based on their ferritin and hemoglobin (Hb) levels. The longitudinal analysis showed limited changes in the plasma proteomes of new and regular donors after a whole blood donation during a 180-day follow-up period, apart from a significant short-term decrease in fibronectin. No differences were observed in the plasma proteomes of donors with high versus low Hb and/or ferritin levels. Plasma proteins with the highest variation between and within donors included pregnancy zone protein, which was associated with sex, Alfa 1-antitrypsin which was associated with the allelic variation, and Immunoglobulin D. Coexpression analysis revealed clustering of proteins that are associated with platelet, red cell, and neutrophil signatures as well as with the complement system and immune responses, including a prominent correlating cluster of immunoglobulin M (IgM), immunoglobulin J chain (JCHAIN), and CD5 antigen-like (CD5L). Overall, our proteomic approach shows that whole blood donation has a limited impact on the plasma proteins measured. Our findings suggest that plasma profiling can be successfully employed to consistently detect proteins and protein complexes that reflect the functionality and integrity of platelets, red blood cells, and immune cells in blood donors and thus highlights its potential use for donor health monitoring.

Efficacy of lyophilised bacteria-rich faecal sediment and supernatant with reduced bacterial count for treating patients with Clostridioides difficile Infection - A novel method for capsule faecal microbiota transfer.

Faecal microbiota transfer (FMT) has managed to earn its place in the Clostridioides difficile infection (CDI) guidelines by having comparable efficacy and recurrence rate of fidaxomicin. After more than 100 successful FMT administration through nasogastric tube, we started using hard gelatine capsules filled with lyophilised faecal sediment and supernatant. Our main question was whether uncoated capsules (containing faecal sediment or supernatant) are comparable to the widely used nasogastric tubes in CDI. We also investigated the effect of storage and time on the survival rate of bacteria in the samples. We compared the efficacy of our capsules to other treatment options of CDI at the Department of Infectology at the University of Pécs (Hungary). For our study, stool was collected from a single donor. We treated 10 patients with relapsing CDI, 5 of them received supernatant, 5 received sediment. Donor samples were stored on 4 different temperatures and tested to determine the survival rates of bacteria. As pilot projects, we also assessed the changes of bacterial taxa, protein- and lipid compositions. Moreover, we selected 4 patients to compare their samples prior and after FMT by using microbiome (16S amplicon sequencing), protein, and lipid analyses. 4 out of the 5 patients who received supernatant became symptomless within 2 days after FMT. In the sediment group 3 out of 5 patients were cured from CDI. Comparing the supernatant to the sediment, we found significantly lower number of colony-forming units in the supernatant. We found that -80°C is the most suitable temperature to store the samples. The stool lipid profiles of recipients showed a more diverse composition after FMT, and changes in the stool protein profiles were observed as well. In the microbiome analysis, we observed an increase in the alpha diversity after FMT. Our study of 10 patients showed good efficacy of lyophilised faecal supernatant using capsules. The single donor approach proved to be effective in our investigation. A significantly lower CFU number was sufficient for the effect, the separation can be achieved by widely available instruments. For storage temperature, -20°C was sufficient in our clinical practice.

A single, improbable B cell receptor mutation confers potent neutralization against cytomegalovirus.

Cytomegalovirus (CMV) is a leading cause of infant hearing loss and neurodevelopmental delay, but there are no clinically licensed vaccines to prevent infection, in part due to challenges eliciting neutralizing antibodies. One of the most well-studied targets for CMV vaccines is the viral fusogen glycoprotein B (gB), which is required for viral entry into host cells. Within gB, antigenic domain 2 site 1 (AD-2S1) is a target of potently neutralizing antibodies, but gB-based candidate vaccines have yet to elicit robust responses against this region. We mapped the genealogy of B cells encoding potently neutralizing anti-gB AD-2S1 antibodies from their inferred unmutated common ancestor (UCA) and characterized the binding and function of early lineage ancestors. Surprisingly, we found that a single amino acid heavy chain mutation A33N, which was an improbable mutation rarely generated by somatic hypermutation machinery, conferred broad CMV neutralization to the non-neutralizing UCA antibody. Structural studies revealed that this mutation mediated key contacts with the gB AD-2S1 epitope. Collectively, these results provide insight into potently neutralizing gB-directed antibody evolution in a single donor and lay a foundation for using this B cell-lineage directed approach for the design of next-generation CMV vaccines.

Fine analysis of the component effect on the microstructure of LiCl solution

Lithium resources are abundant in Chinese salt lakes, but the high Mg/Li ratio in such aqueous natural sources has brought difficulties to the separation and purification of lithium. Crystallization processes are highly affected by the solution microstructure, which, in turn, depends on its composition. Synchrotron X-ray scattering, Raman spectroscopy, and molecular dynamics simulation methods were used to study the microstructure of aqueous LiCl solutions with different concentrations. In the reduced structure function, F(Q), the double peak around the scattering vector Q = 2.5 Å−1 becomes a single peak, which indicates the addition of LiCl changes the tetrahedral hydrogen bond structure in the aqueous solution. The deconvolution fitting of the Raman spectra show that the DDAA-type (double donor-double acceptor) hydrogen bonds tend to be transformed into DA-type (single donor–single acceptor) hydrogen bonds, confirming that the addition of LiCl breaks the tetrahedral hydrogen bond structure. This hydrogen-bond transformation was confirmed by pair distribution function analysis from molecular dynamics simulations of aqueous KCl solutions. In addition, considering the large number of magnesium ions coexisting with LiCl in the Salt Lake, the microstructure of mixed LiCl-MgCl2 solution was also studied. According to the X-ray scattering results, the peak in the reduced pair distribution function G(r) near r = 3.25 Å shifted from 3.25 Å to 3.10 Å with increased Mg/Li ratio. This change is likely to result from the Cl-O and OO interactions in the mixed aqueous solution. The deconvolution fitting results of Raman spectra show that the DDAA type hydrogen bond increases with the Mg/Li ratio, while the DA + DDA type hydrogen bond decreases. The molecular dynamics results showed that chlorine ions have a higher tendency to form contact ion pairs with Mg2+ than Li+. We propose this to be one of the processes retarding the separation of pure LiCl crystal from mixed LiCl-MgCl2 systems.

Optimization of the Superglue Fuming and Powder Technique for the Enhancement of Latent Fingerprints from Objects Submerged in Water: An Experimental Study in Ghana

Abstract Introduction Criminals’ propensity to precautionary mask their tracks such as disposing of an item of evidence in an aquatic environment (including freshwater and seawater) warrants the ongoing quest for advanced reagents and techniques that are tailored to the substrate characteristics on which the print will be developed. Aim The study aimed to evaluate the synergic efficiency of the superglue fuming technique (using a homemade fuming chamber) and the powder technique in the development and visualization of latent fingerprints (LFPs) from different nonporous substrates submerged in an aquatic environment for up to 120 days. Materials and Methods All selected nonporous substrates were cleaned thoroughly with a 70% alcohol swab. Natural latent prints were obtained from a single donor and the substrates were exposed to an aquatic environment. The superglue fuming (using a homemade fuming chamber) plus the powder technique was employed to develop and visualize the print. Results Our findings disclose that the use of the superglue fuming technique together with the powder technique enhances the recovery rate of LFPs from substrates kept underwater for up to 90 days. The development of fingerprints was challenging from the substrates that were submerged in water for exactly 120 days. Conclusions The resulting efficiency of the combined technique (superglue fuming technique using a homemade fuming chamber + powder technique) is substantially more sensitive, and selective, and performs better than the previously used stand-alone fingerprint enhancement technique. The improvised homemade fuming chamber proves to be a viable alternative to the standardized fuming cabinet in terms of functionality and sensitivity.

Role of Oral versus Intravenous Calcium Supplementation in Plateletpheresis Donors: A Prospective Observational Study

Introduction: Single Donor Platelets (SDP) are in high demand and are the preferred choice for patients requiring recurrent platelet transfusions. Citrate, being the anticoagulant of choice, may result in symptoms of citrate toxicity due to repeated frequent donations or increased procedure time. Aim: The present study aimed to evaluate the role of prophylactic calcium supplementation (oral vs intravenous) on plateletpheresis donors and correlate their effects with adverse donor reactions (citrate toxicity). Materials and Methods: This prospective observational study on plateletpheresis donors was conducted for a period of one year in the Department of Transfusion Medicine at Government Royapettah Hospital, The Tamil Nadu Dr. MGR Medical University, Chennai, India. It included 63 plateletpheresis donors divided into two groups based on random allocation-the Oral calcium supplementation group (n=32 donors) and the intravenous calcium supplementation group (n=31 donors). For both groups, their biochemical parameters (serum calcium, serum ionised calcium, serum magnesium) were measured before and within 30 minutes after the plateletpheresis procedure. The parameters were analysed for symptoms of citrate toxicity. Analysis was carried out using Statistical Package for Social Sciences (SPSS) Software version 20.0, and paired t-test was used for analysing biochemical parameters. Results: A statistically significant decline in serum ionised calcium levels (1.17±0.09 vs 1.10±0.11) (preprocedure level vs postprocedure level) was observed in the oral calcium supplementation group compared to the intravenous calcium supplementation group (1.07±0.25 vs 1.11±0.14). The authors observed a decline in the mean levels of serum calcium in both the oral calcium group (10.33±1.62 vs 9.88±1.00) and the intravenous calcium group (10.31±1.33 vs 10.21±0.88). Furthermore, the authors observed a decline in mean serum magnesium levels in the oral calcium group (2.13±0.30 vs 2.07±0.24) with no difference observed in the intravenous calcium group (2.14±0.22 vs 2.14±0.14). Mild citrate toxicity symptoms in the form of tingling sensation and perioral paraesthesia were observed in 26 out of 32 donors in the oral calcium group, whereas no symptoms were recorded in the intravenous calcium group. Conclusion: Prophylactic intravenous calcium supplementation resulted in better bioavailability of serum ionised calcium levels with no citrate toxicity symptoms compared to oral calcium supplementation. This results in better retention of plateletpheresis donors, enabling smooth and comfortable collection of a high concentration of platelets from a single donor. However, it is imperative to conduct more studies with a larger number of plateletpheresis donors to observe donor adverse reactions specific to the population.

A quantum chemical study: thoughtful exploration for optimal donors in Y-type dual donor-based dye sensitizers.

This research explores the influence of different dual donors on the effectiveness of dye sensitizers. We selected 35 diverse donors to construct Y-type dual donor-based dyes, connecting them with thiophene as the π-spacer and cyanoacrylic acid as the acceptor. Density functional theory calculations indicate that these dual donor-based dyes exhibit superior optoelectronic properties compared to their single donor counterparts. Notably, significant variations in charge distribution among the different dual donors affect their donor capabilities. Our calculations specifically highlight the enhanced thermodynamic parameters, including light harvesting efficiency (LHE), the free energy of dye injection (ΔGinject), and regeneration (ΔGreg), for donor moieties containing nitrogen atoms, such as NS-3 (N,N-dimethylaniline), NS-5 (diphenylamine), NS-6 (triphenylamine), and NS-8 (4-methoxy-N-(4-methoxyphenyl)-N-phenylaniline). These results suggest that nitrogen-containing donor moieties act as promising candidates for donors for efficient dye sensitizers. However, further experimental validation in the near future will be necessary to confirm our findings.