Phase Transformation after Heat Treatment of Cr-Ni Stainless Steel Powder for 3D Printing

Today, Ni-Cr steel is used for advanced applications in the high-temperature and electrical industries, medical equipment, food industry, agriculture and is applied in food and beverage packaging and kitchenware, automotive or mesh. A study of input steel powder from various stages of the recycling process intended for 3D printing was conducted. In addition to the precise evaluation of the morphology, particle size and composition of the powders used for laser 3D printing, special testing and evaluation of the heat-treated powders were carried out. Heat treatment up to 950 °C in an air atmosphere revealed the properties of powders that can appear during laser sintering. The powders in the oxidizing atmosphere change the phase composition and the original FeNiCr stainless steel changes to a two-phase system of Fe₃Ni and Cr₂O₃, as evaluated by X-ray diffraction analysis. Observation of the morphology showed the separation of the oxidic phase in the sense of a brittle shell. The inner part of the powder particle is a porous compact core. The particle size is generally reduced due to the peeling of the oxide shell. This effect can be critical to 3D printing processing, causing defects on the printed parts, as well as reducing the usability of the precursor powder and can also change the properties of the printed part.     

ADAM12s in maternal serum as a potential marker of pre-eclampsia

OBJECTIVE: To examine whether maternal serum ADAM12s, a potential first- and second-trimester marker of fetal aneuploidy and fetal growth, had altered concentrations in the first or second trimester of pregnancies subsequently developing pre-eclampsia. METHODS: ADAM12s was measured by a time-resolved fluoroimmunoassay developed by PerkinElmer Life Science. Maternal serum samples from women taking part in early first-trimester aneuploidy screening in whom the pregnancy resulted in pre-eclampsia (64) were identified from a cohort of 4,390 singleton pregnancies in which uterine artery Doppler mean Pulsatility Index (PI) had been measured at 22-24 weeks. From amongst those cases delivering a normal term infant with birth weight greater than the 10th centile for gestational age 240 cases were selected as gestational age-matched controls. A second study group consisting of maternal serum taken at 22-24 weeks at the time of uterine artery Doppler in a group of 12 women developing pre-eclampsia were compared with 86 matched controls from a previously studied cohort of 24 cases and 144 controls. Serum ADAM12s concentrations were converted to multiple of the median (MoM) to take account of gestational age variation. RESULTS: First-trimester maternal serum ADAM12s levels in women who developed pre-eclampsia were reduced with a median MoM of 0.71 which was further reduced in those delivering prior to 35 weeks (0.50). At the 5th centile of normal (0.48 MoM) ADAM12s identified 27% of cases with pre-eclampsia and 47% of those with early pre-eclampsia. Combining ADAM12s with PAPP-A from a previous study only resulted in a further 1% increase in detection of all women developing pre-eclampsia. However combining ADAM12s with mean PI increased the detection rate to 66%. In the second trimester at 22-24 weeks the maternal serum ADAM12s levels were increased in those women developing pre-eclampsia compared to controls (709 vs 486 ug/L, p = 0.045). CONCLUSION: ADAM12s in addition to being a potential marker of aneuploidy may also be a marker of pre-eclampsia. Further studies are required to see if this can improve on the clinical discrimination already provided by PAPP-A in the early first trimester.     

Amorphous FeCoCrSiB Ribbons with Tailored Anisotropy for the Development of Magnetic Elements for High Frequency Applications

The ferromagnetic resonance (FMR) in the frequency range of 0.5 to 12.5 GHz has been investigated as a function of external magnetic field for rapidly quenched Fe₃Co₆₇Cr₃Si₁₅B₁₂ amorphous ribbons with different features of the effective magnetic anisotropy. Three states of the ribbons were considered: as-quenched without any treatment; after relaxation annealing without stress at the temperature of 350 °C during 1 h; and after annealing under specific stress of 230 MPa at the temperature of 350 °C during 1 h. For FMR measurements, we adapted a technique previously proposed and tested for the case of microwires. Here, amorphous ribbons were studied using the sample holder based on a commercial SMA connector. On the basis of the measurements of the reflection coefficient S_11, the total impedance including its real and imaginary components was determined to be in the frequency range of 0.5 to 12.5 GHz. In order to confirm the validity of the proposed technique, FMR was also measured by the certified cavity perturbation technique using a commercial Bruker spectrometer operating at X-band frequency of 9.39 GHz. As part of the characterization of the ribbons used for microwave measurements, comparative analysis was performed of X-ray diffraction, optical microscopy, transmission electron microscopy, inductive magnetic hysteresis loops, vibrating sample magnetometry, magneto-optical Kerr effect (including magnetic domains) and magnetoimpedance data for of all samples.     

Impact of natural selection on global patterns of genetic variation and association with clinical phenotypes at genes involved in SARS-CoV-2 infection

Human genomic diversity has been shaped by both ancient and ongoing challenges from viruses. The current coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a devastating impact on population health. However, genetic diversity and evolutionary forces impacting host genes related to SARS-CoV-2 infection are not well understood. We investigated global patterns of genetic variation and signatures of natural selection at host genes relevant to SARS-CoV-2 infection (angiotensin converting enzyme 2 [ACE2], transmembrane protease serine 2 [TMPRSS2], dipeptidyl peptidase 4 [DPP4], and lymphocyte antigen 6 complex locus E [LY6E]). We analyzed data from 2,012 ethnically diverse Africans and 15,977 individuals of European and African ancestry with electronic health records and integrated with global data from the 1000 Genomes Project. At ACE2, we identified 41 nonsynonymous variants that were rare in most populations, several of which impact protein function. However, three nonsynonymous variants (rs138390800, rs147311723, and rs145437639) were common among central African hunter-gatherers from Cameroon (minor allele frequency 0.083 to 0.164) and are on haplotypes that exhibit signatures of positive selection. We identify signatures of selection impacting variation at regulatory regions influencing ACE2 expression in multiple African populations. At TMPRSS2, we identified 13 amino acid changes that are adaptive and specific to the human lineage compared with the chimpanzee genome. Genetic variants that are targets of natural selection are associated with clinical phenotypes common in patients with COVID-19. Our study provides insights into global variation at host genes related to SARS-CoV-2 infection, which have been shaped by natural selection in some populations, possibly due to prior viral infections.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Coronaviruses are enveloped, positive-sense, and single-stranded RNA viruses, many of which are zoonotic pathogens that crossed over into humans. Seven coronavirus species, including SARS-CoV-2, have been discovered that, depending on the virus and host physiological condition, may cause mild or lethal respiratory disease. There is considerable variation in disease prevalence and severity across populations and communities. Importantly, minority populations in the United States appear to have been disproportionally affected by COVID-19 (1, 2). For example, in Chicago, more than 50% of COVID-19 cases and nearly 70% of COVID-19 deaths are in African Americans (who make up 30% of the population of Chicago) (1). While social and economic factors are largely responsible for driving COVID-19 health disparities, investigating genetic diversity at host genes related to SARS-CoV-2 infection could help identify functionally important variation, which may play a role in individual risk for severe COVID-19 infection.In this study, we focused on four key genes playing a role in SARS-CoV-2 infection (3). The ACE2 gene, encoding the angiotensin-converting enzyme-2 protein, was reported to be a main binding site for severe acute respiratory syndrome coronavirus (SARS-CoV) during an outbreak in 2003, and evidence showed stronger binding affinity to SARS-CoV-2, which enters the target cells via ACE2 receptors (3, 4). The ACE2 gene is located on the X chromosome (chrX); its expression level varies among populations (5); and it is ubiquitously expressed in the lung, blood vessels, gut, kidney, testis, and brain, all organs that appear to be affected as part of the COVID-19 clinical spectrum (6). SARS-CoV-2 infects cells through a membrane fusion mechanism, which in the case of SARS-CoV, is known to induce down-regulation of ACE2 (7). Such down-regulation has been shown to cause inefficient counteraction of angiotensin II effects, leading to enhanced pulmonary inflammation and intravascular coagulation (7). Additionally, altered expression of ACE2 has been associated with cardiovascular and cerebrovascular disease, which is highly relevant to COVID-19 as several cardiovascular conditions are associated with severe disease. TMPRSS2, located on the outer membrane of host target cells, binds to and cleaves ACE2, resulting in activation of spike proteins on the viral envelope and facilitating membrane fusion and endocytosis (8). Two additional genes, DPP4 and LY6E, have been shown to play an important role in the entry of SARS-CoV-2 virus into host cells. DPP4 is a known functional receptor for the Middle East respiratory syndrome coronavirus (MERS-CoV), causing a severe respiratory illness with high mortality (9, 10). LY6E encodes a glycosylphosphatidylinositol-anchored cell surface protein, which is a critical antiviral immune effector that controls coronavirus infection and pathogenesis (11). Mice lacking LY6E in hematopoietic cells were susceptible to murine coronavirus infection (11).Previous studies of genetic diversity at ACE2 and TMPRSS2 in global human populations did not include an extensive set of African populations (5, 12–14). No common coding variants (defined here as minor allele frequency [MAF] > 0.05) at ACE2 were identified in any prior population studies. However, few studies included diverse indigenous African populations whose genomes harbor the greatest diversity among humans. This leads to a substantial disparity in the representation of African ancestries in human genetic studies of COVID-19, impeding health equity as the transferability of findings based on non-African ancestries to African populations can be low (15). Including more African populations in studying the genetic diversity of genes involved in SARS-CoV-2 infection is extremely necessary. Additionally, the evolutionary forces underlying global patterns of genetic diversity at host genes related to SARS-CoV-2 infection are not well understood. Using methods to detect natural selection signatures at host genes related to viral infections helps identify putatively functional variants that could play a role in disease risk.We characterized genetic variation and studied natural selection signatures at ACE2, TMPRSS2, DPP4, and LY6E in ethnically diverse human populations by analyzing 2,012 genomes from ethnically diverse Africans (referred to as the “African diversity” dataset), 2,504 genomes from the 1000 Genomes Project (1KG), and whole-exome sequencing of 15,977 individuals of European ancestry (EA) and African ancestry from the Penn Medicine BioBank (PMBB) dataset (SI Appendix, Fig. S1). The African diversity dataset includes populations with diverse subsistence patterns (hunter-gatherers, pastoralists, agriculturalists) and speaking languages belonging to the four major language families in Africa (Khoesan; Niger–Congo, of which Bantu is the largest subfamily; Afroasiatic; and Nilo-Saharan). We identify functionally relevant variation, compare the patterns of variation across global populations, and provide insight into the evolutionary forces underlying these patterns of genetic variation. In addition, we perform an association study using the variants identified from whole-exome sequencing at the four genes and clinical traits derived from electronic health record (EHR) data linked to the subjects enrolled in the PMBB. The EHR data include diseases related to organ dysfunctions associated with severe COVID-19, such as respiratory, cardiovascular, liver, and renal complications. Our study of genetic variation in genes involved in SARS-CoV-2 infection provides data to investigate infection susceptibility within and between populations and indicates that variants in these genes may play a role in comorbidities relevant to COVID-19 severity.     

Cavotricuspid isthmus ablation guided by force‐time integral – A randomized study

BackgroundForce‐time integral (FTI) is an ablation marker of lesion quality and transmurality. A target FTI of 400 gram‐seconds (gs) has been shown to improve durability of pulmonary vein isolation, following atrial fibrillation ablation. However, relevant targets for cavotricuspid isthmus (CTI) ablation are lacking.HypothesisWe sought to investigate whether CTI ablation with 600 gs FTI lesions is associated with reduced rate of transisthmus conduction recovery compared to 400 gs lesions.MethodsFifty patients with CTI‐dependent flutter were randomized to ablation using 400 gs (FTI400 group, n = 26) or 600 gs FTI lesions (FTI600 group, n = 24). The study endpoint was spontaneous or adenosine‐mediated recovery of transisthmus conduction, after a 20‐min waiting period.ResultsThe study endpoint occurred in five patients (19.2%) in group FTI400 and in four patients (16.7%) in group FTI600, p = .81. First‐pass CTI block was similar in both groups (50% in FTI400 vs. 54.2% in FTI600, p = .77). There were no differences in the total number of lesions, total ablation time, procedure time and fluoroscopy duration between the two groups. There were no major complications in any group. In the total population, patients not achieving first‐pass CTI block had significantly higher rate of acute CTI conduction recovery, compared to those with first‐pass block (29.2% vs. 7.7% respectively, p = .048).ConclusionsCTI ablation using 600 gs FTI lesions is not associated with reduced spontaneous or adenosine‐mediated recurrence of transisthmus conduction, compared to 400 gs lesions.     

A phase I evaluation of the effect of curcumin on dose‐limiting toxicity and pharmacokinetics of irinotecan in participants with solid tumors

Curcumin inhibits UDP‐glucuronyltransferases, a primary metabolic pathway for cancer chemotherapeutic agents like irinotecan. Concurrent administration of both agents may exacerbate irinotecan toxicity. We conducted this phase I study to determine the safety of concurrent curcumin and irinotecan administration. Ten participants with advanced solid tumors received one of four doses (1, 2, 3, and 4 g) of a curcumin phosphatidylcholine complex (PC) orally daily, and 200 mg/m² of i.v. infusion irinotecan on days 1 and 15 of a 28‐day cycle, to determine the maximum tolerated dose (MTD) of PC. Thirteen participants received 4 g of PC (MTD) to assess the effect on the pharmacokinetic (PK) properties of irinotecan and its metabolites, SN‐38 and SN‐38G. Irinotecan, SN‐38, and SN‐38G exposure equivalence with and without curcumin was assessed using area under the plasma concentration‐time curves from 0 to 6 h (AUC_0‐6h). Safety assessments and disease responses were also evaluated. The combination of irinotecan and PC was well‐tolerated. Because there was no dose limiting toxicity, the maximum dose administered (4 g) was defined as the recommended phase II dose of PC. PC did not significantly alter the plasma exposure and other PK properties of irinotecan and its metabolites. There was no apparent increase in the incidence of irinotecan‐associated toxicities. The objective response rate was 3/19 (22%, 95% confidence interval [CI]: 5–39%), median progression free survival and overall survival (n = 23) were 4 months (95% CI: 2.9–8.9 months) and 8.4 months (95% CI: 3.7 – not evaluable [NE]), respectively. Future studies are required to evaluate the efficacy of this combination.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Curcumin can be safely administered with some standard chemotherapy agents like gemcitabine, taxanes, and 5‐fluorouracil.

• WHAT QUESTION DID THIS STUDY ADDRESS?

Both curcumin and irinotecan are metabolized by UGT enzymes and concurrent administration may affect the pharmacokinetics (PKs) and clinical effect of irinotecan. This study sought to assess the effect of curcumin on the PK properties and adverse effect profile of irinotecan.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Up to 4 g of a phosphatidylcholine curcumin (PC) formulation can be safely administered with irinotecan without an impact on the PK and adverse event profile of irinotecan.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Curcumin’s anticancer properties have been documented. Higher doses of PC can be investigated to determine a dose that acts synergistically with irinotecan to improve clinical outcomes.     

Phantom-based assessment of motion and needle targeting accuracy of robotic devices for magnetic resonance imaging-guided needle biopsy

Background

The current study proposes simple methods for assessing the performance of robotic devices intended for Magnetic Resonance Imaging (MRI)-guided needle biopsy.

Methods

In-house made agar-based breast phantoms containing biopsy targets served as the main tool in the evaluation process of an MRI compatible positioning device comprising a needle navigator. The motion accuracy of mechanical stages was assessed by calliper measurements. Laboratory evaluation of needle targeting included a repeatability phantom test and a laser-based method. The accuracy and repeatability of needle targeting was also assessed by MRI.

Results

The maximum error of linear motion for steps up to 10 mm was 0.1 mm. Needle navigation relative to the phantom and alignment with the various biopsy targets were performed successfully in both the laboratory and MRI settings. The proposed biopsy phantoms offered tissue-like signal in MRI and good haptic feedback during needle insertion.

Conclusions

The proposed methods could be valuable in the process of validating the accuracy of MRI-guided biopsy robotic devices in both laboratory and real environments.     

The relationship between activity and ions in patients with metal-on-metal bearing hip prostheses

BACKGROUND: Total hip replacements with metal-on-metal bearings are frequently implanted in young, active patients. The relationship between patient activity and cobalt and chromium ion levels has not been investigated, to our knowledge. METHODS: Seven patients with well-functioning metal-on-metal bearing hip prostheses and one control subject (no implants), all with normal renal function, were monitored during a two-week-long activity protocol. Lower-extremity activity was continuously assessed with use of a computerized, two-dimensional accelerometer. During the first week, the subjects were requested to limit physical activity. The subjects then completed an hour-long treadmill test followed by a week in which they were encouraged to be as physically active as practically possible. Serum levels of cobalt and chromium ions and urine levels of chromium were assessed at ten time-points during these two weeks. RESULTS: Regardless of activity, the serum ion levels for a given patient were essentially constant and no correlation was found between patient activity and serum levels of cobalt or chromium, or urine levels of chromium. A mean increase in activity of 28% during the week of high-intensity activity was associated with a mean decrease of 2.7% in the serum cobalt level and a mean increase of 2.0% in the serum chromium level. During the treadmill test, a mean increase in activity of 1621% was associated with a mean increase of 3.0% in the serum cobalt level and a mean increase of 0.8% in the serum chromium level. These results fall within the variability for the measurement accuracy of these tests. CONCLUSIONS: For these patients, serum cobalt and chromium ion levels were not acutely affected by patient activity. Periodic measurements of serum ion levels could be used to monitor the tribologic (lubrication, friction, and wear) performance of a metal-on-metal bearing without adjusting for patient activity. Additional research is needed into the kinetics of ion production, transport, and excretion.