In Situ Compensation Method for Precise Integral SQUID Magnetometry of Miniscule Biological, Chemical, and Pow-der Specimens Requiring the Use of Capsules

Steadily growing interest in magnetic characterization of organic compounds for therapeutic purposes or of other irregularly shaped specimens calls for refinements of experimental methodology to satisfy experimental challenges. Encapsulation in capsules remains the method of choice, but its applicability in precise magnetometry is limited. This is particularly true for minute specimens in the single milligram range as they are outweighed by the capsules and are subject to large alignment errors. We present here a completely new experimental methodology that permits 30-fold in situ reduction of the signal of capsules by substantially restoring the symmetry of the sample holder that is otherwise broken by the presence of the capsule. In practical terms it means that the standard 30 mg capsule is seen by the magnetometer as approximately a 1 mg object, effectively opening the window for precise magnetometry of single milligram specimens. The method is shown to work down to 1.8 K and in the whole range of the magnetic fields. The method is demonstrated and validated using the reciprocal space option of MPMS-SQUID magnetometers; however, it can be easily incorporated in any magnetometer that can accommodate straw sample holders (i.e., the VSM-SQUID). Importantly, the improved sensitivity is accomplished relying only on the standard accessories and data reduction method provided by the SQUID manufacturer, eliminating the need for elaborate raw data manipulations.

In Situ Compensation Method for Precise Integral SQUID Magnetometry of Miniscule Biological, Chemical, and Powder Specimens Requiring the Use of Capsules

Steadily growing interest in magnetic characterization of organic compounds for therapeutic purposes or of other irregularly shaped specimens calls for refinements of experimental methodology to satisfy experimental challenges. Encapsulation in capsules remains the method of choice, but its applicability in precise magnetometry is limited. This is particularly true for minute specimens in the single milligram range as they are outweighed by the capsules and are subject to large alignment errors. We present here a completely new experimental methodology that permits 30-fold in situ reduction of the signal of capsules by substantially restoring the symmetry of the sample holder that is otherwise broken by the presence of the capsule. In practical terms it means that the standard 30 mg capsule is seen by the magnetometer as approximately a 1 mg object, effectively opening the window for precise magnetometry of single milligram specimens. The method is shown to work down to 1.8 K and in the whole range of the magnetic fields. The method is demonstrated and validated using the reciprocal space option of MPMS-SQUID magnetometers; however, it can be easily incorporated in any magnetometer that can accommodate straw sample holders (i.e., the VSM-SQUID). Importantly, the improved sensitivity is accomplished relying only on the standard accessories and data reduction method provided by the SQUID manufacturer, eliminating the need for elaborate raw data manipulations.

Type B Uncertainty Analysis of Gravity-Based Determinations of Triaxial-Accelerometer Properties by Simulation of Measurement Errors

We simulated the effects of gimbal-alignment errors and rotational step-size errors on measurements of the sensitivity matrix and intrinsic properties of a triaxial accelerometer. We restricted the study to measurements carried out on a two-axis calibration system using a previously described measurement and analysis protocol. As well as imperfections in the calibration system, we simulated imperfect orthogonality of the accelerometer axes and non-identical sensitivity of the individual accelerometers in an otherwise perfect triaxial accelerometer, but we left characterization of other accelerometer imperfections such as non-linearity for future study. Within this framework, sensitivity-matrix errors are caused by imperfections in the construction and installation of the accelerometer calibration system, but not by the accelerometer imperfections included in the simulations. We use the results of this study to assign type B uncertainties to the components of the sensitivity matrix and related intrinsic properties due to imperfections in the measurement system. For calibrations using a reasonably well manufactured and installed multi-axis rotation stage such as that studied in this paper, we estimated upper bounds to the standard uncertainties of the order of 1 ×10−5 , 2 ×10−5 , 2 ×10−4 , and 5 ×10−5 for the intrinsic sensitivities, diagonal elements of the sensitivity matrix, off-diagonal elements of the sensitivity matrix, and zero-acceleration offsets, relative to a sensitivity-matrix element of 1, respectively, and 5 ×10−3 degrees for the intrinsic angles

In Situ Compensation Method for Precise Integral SQUID Magnetometry of Miniscule Biological, Chemical, and Pow-der Specimens Requiring the Use of Capsules

Steadily growing interest in magnetic characterization of organic compounds aiming at therapeutic purposes, or of other irregular-shaped specimens calls for refinements of experimental methodology to satisfy experimental challenges. Encapsulation in capsules remains the method of choice, but its applicability in precise magnetometry is limited. This is particularly true for minute specimens in single mg range since they are outweighed by the capsules and due to large alignment errors. We present here a complete new experimental methodology which permits 30-fold in situ reduction of the signal of capsules. In practical terms it means that the standard 30 mg capsule is seen by the magnetometer as about 1 mg object, effectively opening the window for precise magnetometry of single mg specimens. The method is shown to work down to 1.8 K and in the whole range of the magnetic fields. The method is demonstrated and validated using the reciprocal space option of MPMS-SQUID magnetometers, however it can be easily incorporated in any magnetometer which can accommodate straw sample holders (i.e. the VSM-SQUID). Importantly, the improved sensitivity is accomplished relying only on the standard accessories and data reduction method provided by the SQUID manufacturer, eliminating needs for an elaborate raw data manipulations.

Post-Alignment Adjustment and Its Automation

Multiple sequence alignment (MSA) is the basis for almost all sequence comparison and molecular phylogenetic inferences. Large-scale genomic analyses are typically associated with automated progressive MSA without subsequent manual adjustment, which itself is often error-prone because of the lack of a consistent and explicit criterion. Here, I outlined several commonly encountered alignment errors that cannot be avoided by progressive MSA for nucleotide, amino acid, and codon sequences. Methods that could be automated to fix such alignment errors were then presented. I emphasized the utility of position weight matrix as a new tool for MSA refinement and illustrated its usage by refining the MSA of nucleotide and amino acid sequences. The main advantages of the position weight matrix approach include (1) its use of information from all sequences, in contrast to other commonly used methods based on pairwise alignment scores and inconsistency measures, and (2) its speedy computation, making it suitable for a large number of long viral genomic sequences.

Effect of limb rotation on radiographic alignment measurement in mal-aligned knees

PurposeLong-leg-radiography (LLR) is commonly used for measurement of lower limb alignment. However, limb rotations during radiography may interfere with the alignment measurement. This study examines the effect of limb rotation on the accuracy of measurements based on the mechanical and anatomical axes of the femur and tibia, with variations in knee flexion and coronal deformity. MethodsForty-five lower limbs of thirty patients were scanned with CT. Virtual LLRs simulating 5 rotational positions (neutral, ±10°, and ±20° internal rotation) were generated from the CT images. Changes in the hip-knee-ankle angle (HKA) and the femorotibial angle (FTA) were measured on each image with respect to neutral values. These changes were related to knee flexion and coronal deformity under both weight- and non-weight-bearing conditions. ResultsThe measurement error of the HKA and FTA derived from limb rotation were up to 4.84±0.66° and 7.35±0.88° respectively, and were correlated with knee flexion (p＜0.001) and severe coronal deformity (p≤0.001). Compared with non-weight-bearing position, coronal deformity measured in weight-bearing condition was 2.62° greater, the correlation coefficients between the coronal deformity and the deviation ranges of HKA and FTA were also greater. ConclusionFlexion and severe coronal deformity have significant influence on the measurement error of lower limb alignment. Errors can be amplified in the weight-bearing condition compared with the non-weight-bearing condition. The error of measurement of the anatomic axis is greater than the mechanical axis. Considering LLR is the gold standard image modality, attention should be paid to the measurement of knee alignment. Especially for the possible errors derives from weight-bearing long leg radiographs of patients with severe knee deformities.

Understanding Jig Alignment Error Occurrences for Substrate 1-Map Strips

Singulation is a process in a semiconductor industry where high dense strips were singulated into single units. Jig saw singulation was the updated technology where strips were seated and vacuumed on a rubber nest jig during singulation. Jig saw singulation is also practical for high volume manufacturing as it demands minimal indirect materials. To cut the strips, jig alignment with the strip was measured by the machine to ensure that the rubber nest jig will not be cut and damaged while the strip is being singulated. However, with the different upstream process that the strip undergone, machine prompt frequent jig alignment errors when the machine detected that the strip saw street has high displacement with the recorded alignment of the saw street of rubber nest jig. Through this study, the authors have driven to understand the jig alignment errors occurrences as well as the assistance that can be made for the strip to be processed. The authors also included the study of the risks that might be imposed on both rubber nest jig and the affected strips, as well as the recommendations when jig alignment errors were encountered.