Erratum: Debons et al. Magnetic Field Alignment, a Perspective in the Engineering of Collagen-Silica Composite Biomaterials. Biomolecules 2021, 11, 749.

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Magnetic Field Alignment, a Perspective in the Engineering of Collagen-Silica Composite Biomaterials.

Major progress in the field of regenerative medicine is expected from the design of artificial scaffolds that mimic both the structural and functional properties of the ECM. The bionanocomposites approach is particularly well fitted to meet this challenge as it can combine ECM-based matrices and colloidal carriers of biological cues that regulate cell behavior. Here we have prepared bionanocomposites under high magnetic field from tilapia fish scale collagen and multifunctional silica nanoparticles (SiNPs). We show that scaffolding cues (collagen), multiple display of signaling peptides (SiNPs) and control over the global structuration (magnetic field) can be combined into a unique bionanocomposite for the engineering of biomaterials with improved cell performances.

In-situ and real-time growth observation of high-quality protein crystals under quasi-microgravity on earth.

Precise protein structure determination provides significant information on life science research, although high-quality crystals are not easily obtained. We developed a system for producing high-quality protein crystals with high throughput. Using this system, gravity-controlled crystallization are made possible by a magnetic microgravity environment. In addition, in-situ and real-time observation and time-lapse imaging of crystal growth are feasible for over 200 solution samples independently. In this paper, we also report results of crystallization experiments for two protein samples. Crystals grown in the system exhibited magnetic orientation and showed higher and more homogeneous quality compared with the control crystals. The structural analysis reveals that making use of the magnetic microgravity during the crystallization process helps us to build a well-refined protein structure model, which has no significant structural differences with a control structure. Therefore, the system contributes to improvement in efficiency of structural analysis for "difficult" proteins, such as membrane proteins and supermolecular complexes.

Evaluation of mutagenicity and co-mutagenicity of strong static magnetic fields up to 13 Tesla in Escherichia coli deficient in superoxide dismutase.

PURPOSE: To evaluate the biological effects of static magnetic fields (SMFs) up to 13 Tesla (T), with respect to superoxide behavior, by determining the effect on mutagenicity in superoxide dismutase (SOD)-deficient Escherichia coli strain QC774, and its parental strain GC4468. MATERIALS AND METHODS: Experimental strains were exposed to a 5, 10, or 13T SMF for 24 h at 37°C in Luria-Bertani medium. To evaluate mutagenicity after SMF exposure, the mutation frequency in thymine synthesis genes was determined. The effect of exposure to a 5 or 13T SMF on mutagenicity induced by plumbagin was also investigated. RESULTS: No statistically significant differences in the mutation frequency in thymine synthesis genes were observed between SMF-exposed cells and unexposed cells at any of the applied magnetic flux densities. Furthermore, exposure to SMFs up to 13T did not affect mutagenicity induced by plumbagin. CONCLUSION: Exposure to SMFs up to 13T caused neither mutagenicity nor co-mutagenicity in the SOD-deficient E. coli strain QC774 or in its parental strain GC4468, suggesting that exposure to strong SMFs does not affect the behavior of superoxides in these microorganisms.

Control of lattice spacing in a triangular lattice of feeble magnetic particles formed by induced magnetic dipole interactions.

We studied methods of controlling the spacing between particles in the triangular lattice formed by feeble magnetic particles through induced magnetic dipole interaction. Formation of a triangular lattice is described by the balance between the magnetic force and the interaction of induced magnetic dipoles. The intensity of the magnetic force is proportional to the volume of particles V and the difference in the magnetic susceptibilities between the particles and the surrounding medium Δχ. On the other hand, the intensity of the induced magnetic dipole interaction depends on the square of V and Δχ. Therefore, altering the magnetic susceptibility difference by changing the susceptibility of the surrounding medium, volume of the particles, and intensity and spatial distribution of the applied magnetic field effectively controls the distance between the particles. In this study, these three methods were evaluated through experiment and molecular dynamics simulations. The distance between the particles, i.e. the lattice constant of the triangular lattice, was varied from 1.7 to 4.0 in units of the particle diameter. Formation of self-organized triangular lattice through the induced magnetic dipole interaction is based on magnetism, a physical property that all materials have. Therefore, this phenomenon is applicable to any materials of any size. Consequently, structure formation through induced magnetic dipole interaction is a potential way of fabricating materials with ordered structures.

Numerical simulation of chainlike cluster movement of feeble magnetic particles by induced magnetic dipole moment under high magnetic fields.

In this paper, the motion of a chainlike cluster of feeble magnetic particles induced by high magnetic field is discussed on the basis of the results of numerical simulations. The simulations were performed on glass particles with a diameter of 0.8 mm; and the viscosity, applied magnetic field and magnetic properties of the surrounding medium were changed. In addition to the magnetic field and the difference in magnetic susceptibility between the particles and the surrounding medium, the obtained results indicate that the viscosity is an essential factor for the formation of the chainlike alignment of feeble magnetic particles. We also carried out simulations using glass particles with a smaller diameter of 0.1 mm. Chainlike clusters were produced similar to those of ferromagnetic particles formed in a ferromagnetic fluid.

On-chip diamagnetic repulsion in continuous flow.

We explore the potential of a microfluidic continuous flow particle separation system based on the repulsion of diamagnetic materials from a high magnetic field. Diamagnetic polystyrene particles in paramagnetic manganese (II) chloride solution were pumped into a microfluidic chamber and their deflection behaviour in a high magnetic field applied by a superconducting magnet was investigated. Two particle sizes (5 and 10 µm) were examined in two concentrations of MnCl2 (6 and 10%). The larger particles were repelled to a greater extent than the smaller ones, and the effect was greatly enhanced when the particles were suspended in a higher concentration of MnCl2. These findings indicate that the system could be viable for the separation of materials of differing size and/or diamagnetic susceptibility, and as such could be suitable for the separation and sorting of small biological species for subsequent studies.

In situ observation of magnetic orientation process of feeble magnetic materials under high magnetic fields.

An in situ microscopic observation of the magnetic orientation process of feeble magnetic fibers was carried out under high magnetic fields of up to 10 T using a scanning laser microscope. In the experiment, carbon fibers and needle-like titania fibers with a length of 1 to 20 µm were used. The fibers were observed to gradually orient their axes parallel to the direction of the magnetic field. The orientation behavior of the sample fibers was evaluated on the basis of the measured duration required for a certain angular variation. As predicted from the theoretical consideration, it was confirmed that the duration required for a certain angular variation normalized by the viscosity of the fluid is described as a function of the fiber length. The results obtained here appear useful for the consideration of the magnetic orientation of materials suspended in a static fluid.

Magnetically induced orientation of mesochannels in mesoporous silica films at 30 tesla.

We demonstrate the magnetically induced orientation of mesochannels in mesoporous silica films prepared with low-molecular-weight surfactants under an extremely high magnetic field of 30 T. This process is principally applicable to any type of surfactant that has magnetic anisotropy because such a high magnetic field provides sufficient magnetic energy for smooth magnetic orientation. Hexadecyltrimethylammonium bromide (CTAB) and polyoxyethylene-10-cetyl ether (Brij 56) were used as cationic and nonionic surfactants, respectively. According to XRD and cross-sectional TEM, mesochannels aligned perpendicular to the substrates were observed in films prepared with low-molecular-weight surfactants, although the effect was incomplete. The evolution of these types of films should lead to future applications such as highly sensitive chemical sensors and selective separation.

Anti-albuminuric effect of losartan versus amlodipine in hypertensive Japanese patients with type 2 diabetes mellitus: A prospective, open-label, randomized, comparative study.

UNLABELLED: Abstract. BACKGROUND: The antiproteinuric effect of the angiotensin II receptor-antagonist losartan has been observed in patients with type 2 diabetes mellitus (T2DM). Proteinuria is considered to be a predictor of the progression of kidney disease. OBJECTIVE: The aims of the present study were to compare and examine the ability of losartan and amlodipine to ameliorate albuminuria in hypertensive Japanese patients (systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg) with T2DM and whether the change in albuminuria was associated with a change in glomerular filtration rate (GFR). METHODS: This prospective, open-label, randomized, comparative study was conducted over 3 months at the Kinki University School of Medicine, Osaka-Sayama, Japan. Hypertensive patients with T2DM were enrolled and randomly assigned to 1 of 2 study groups receiving either losartan (25-100 mg/d) or the calcium channel-blocker amlodipine (2.5-5 mg/d). Urinary albumin excretion (UAE), creatinine clearance, and GFR were recorded at study initiation (baseline) and study end (month 3). The GFR was measured from the fractional renal accumulation of (99m)Tc-diethylenetriaminepentaacetic acid. Adverse events (AEs) were monitored by a clinical research nurse during the examination. RESULTS: Fifty patients were asked to enroll and 38 returned the informed written consent. Thirty-five Japanese patients were included in the final study analysis. Seventeen patients were assigned to the losartan group (male sex, 10 [58.8%]; mean [SD] age, 58.1 [8.2] years) and 18 were assigned to the amlodipine group (male sex, 10 [55.6%]; mean [SD] age, 57.4 [8.9] years); no significant between-group difference in demographics was observed. A significant decrease from baseline to month 3 of mean (SD) UAE was observed in the losartan group (352.5 [556.6] mg/d vs 275.7 [466.1] mg/d; P = 0.048). No significant difference in mean (SD) UAE was observed in the amlodipine group for the same time period (298.2 [416.6] mg/d vs 322.7 [415.4] mg/d). There was a statistically significant difference found in the mean (SD) percent change of UAE from baseline to month 3 in the losartan group compared with the amlodipine group (-23.52 [28.42] vs +27.90 [63.51]; P = 0.004). Neither group was associated with a significant change in GFR during the course of the study. No patient discontinued the study due to AEs that were considered, by the investigator, to be possibly or probably associated with study treatment. CONCLUSIONS: Treatment with losartan, but not amlodipine, was associated with a reduction in albuminuria in these hypertensive Japanese patients with T2DM within a period as short as 3 months. Neither drug was associated with a significant change in GFR. Therefore, the reduction of UAE was independent of a change in the GFR.

Type 1 diabetes associated with asymptomatic acromegaly successfully treated with surgery after pregnancy: a case report.

We report a rare case of type 1 diabetes in a woman associated with acromegaly who was treated with surgery after pregnancy. An 18-year-old woman came to our hospital in April, 1998, complaining of thirst, polydipsia, polyuria, appetite loss, body weight loss of 8 kg in a month, and amenorrhea beginning 2 months earlier. Based on laboratory data, she was diagnosed as having type 1 diabetes mellitus. Although we suspected her of having acromegaly because of high growth hormone (GH) levels (6.9 or 8.5 ng/ml), blood levels of insulin-like growth factor 1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) were within normal range and the circadian rhythm of her blood GH levels was normally maintained. Her blood GH level was elevated to 12.6 ng/ml 15 minutes after a TRH administration. Blood GH levels were suppressed from 49 ng/ml to 1.5 ng/ml 4 hours after an oral administration of 2.5 mg of bromocriptine. A magnetic resonance images (MRIs) showed pituitary swelling, but no nodules were found in the pituitary. Therefore, we diagnosed her as having acromegaly and observed her without surgery, while prescribing diet therapy and intensive insulin therapy for diabetes. We started a treatment of oral administration of 7.5 mg of bromocriptine per day for the acromegaly from April 28, 2000, because her elevated GH was suspected of causing her diabetes to be poorly controlled. During a pregnancy from October, 2000 to September, 2001, diabetic control was improved with increased administration of insulin under a constant dose of bromocriptine. She delivered a normal full-term infant. After the bromocriptine therapy was stopped as she hoped to breastfeed, blood levels of GH and IGF-1 became elevated and her diabetic control deteriorated. As her pituitary tumor observed in pituitary MRIs became larger during the course, a transsphenoidal surgery was performed on March 8, 2002. After the surgery, blood levels of GH and IGF-1 lowered and diabetic control improved again. We concluded as follows: to rule out acromegaly in patients with poorly controlled diabetes, 1) measurements of serum GH and IGF-1 should be performed, and 2) pituitary MRIs should be performed if blood levels of GH or IGF-1 are high.