BackgroundMaternity health care available in Canada is based on the needs of women born in Canada and often lacks the flexibility to meet the needs of immigrant women. The purpose of this study was to explore immigrant Chinese women’s experiences in accessing maternity care, the utilization of maternity health services, and the obstacles they perceived in Canada.MethodsThis descriptive phenomenology study used in-depth semi-structured interviews to examine immigrant Chinese women’s experiences. Fifteen participants were recruited from the Chinese community in Toronto, Canada by using purposive sampling. The interviews were digitally recorded and transcribed verbatim into written Chinese. The transcripts were analyzed using Colaizzi’s (1978) phenomenological method.ResultsSix themes were extracted from the interviews: (1) preference for linguistically and culturally competent healthcare providers, with obstetricians over midwives, (2) strategies to deal with the inconvenience of the Canadian healthcare system (3) multiple resources to obtain pregnancy information, (4) the merits of the Canadian healthcare system, (5) the need for culturally sensitive care, and (6) the emergence of alternative supports and the use of private services.ConclusionsThe findings provide new knowledge and understanding of immigrant Chinese women’s experiences in accessing maternity health services within a large metropolitan Canadian city. Participants described two unique experiences within the themes: preference for linguistically and culturally competent healthcare providers, with obstetricians over midwives, and the emergence of alternative supports and the use of private services. Few studies of immigrant maternity service access have identified these experiences which may be linked to cultural difference. Further investigation with women from different cultural backgrounds is needed to develop a comprehensive understanding of immigrant women’s experiences with maternity care.

In this paper, a matrix‐free strategy based on the analysis of nitrocellulose membranes (NCMs) modified with gold nanoparticles (AuNPs) is described, using pulsed‐laser desorption ionization mass spectrometry (LDI‐MS) for comprehensive quantification of lead ions (Pb) with a sub‐nanomolar sensitivity in complicated biofluids. The strong hydrophobic interactions between the NCM and bovine serum albumin (BSA) lead to trapping of BSA‐modified AuNPs (BSA‐AuNPs), resulting in the formation of a nanocomposite film of BSA‐AuNPs on the membrane (BSA‐AuNP/NCM). When the AuNPs interact with thiosulfate (S2O32−) ions in solution, Au+·S2O32− complexes form on the AuNP surfaces, facilitating the deposition of Pb atoms in the form of PbAu alloys in the presence of Pb2+ ions. The BSA‐AuNP/NCM nanocomposite is a useful LDI‐MS matrix because it allows: i) the soft and enhanced ionization of Pb−Au alloys from the AuNP surfaces; ii) accurate mass measurements (precision: 5 ppm) of Au, Pb, and Au–Pb ions; iii) the extraction of Pb2+ ions from very‐dilute aqueous solutions (1.0 × 10−9 M); and iv) analyses to be performed directly after the introduction of the substrate into the mass‐analysis LDI spectrometer (i.e., without the need for an elution process). In contrast to the noisy spectra typically obtained when using other AuNP‐assisted LDI approaches, our homogeneous BSA‐AuNP/NCM nanocomposite provides clean mass spectra with fewer and weaker signals from AuNP‐associated interfering species. As a result, the BSA‐AuNP/NCM substrates allow sensitive LDI‐MS detection of analytes with low mass‐to‐charge ratios. Under optimal conditions, this LDI‐MS approach provides high sensitivity, a wide dynamic detection range (1.0 × 10−9–5.0 × 10−6 M), and a high selectivity toward Pb2+ ions (with at least a 100‐fold concentration tolerance relative to other metal ions). The BSA‐AuNP/NCM nanocomposite also provides excellent shot‐to‐shot (<5%) and sample‐to‐sample (<5%) reproducibilities of ion production because of its homogeneous substrate surface, thereby enabling LDI‐based measurements to a consistent quantification of Pb2+ ions in real samples (e.g., urine, whole blood).

In this paper, we describe a pulsed-laser desorption/ionization mass spectrometry (LDI-MS) approach for the detection of proteins with femtomolar sensitivity through the analysis of gold (Au) clusters desorbed from aptamer-modified gold nanoparticles (Apt-AuNPs) on a nitrocellulose membrane (NCM). After the target protein (thrombin) was selectively captured by the surface-bound 29-mer thrombin-binding aptamer (TBA(29)), the thrombin/TBA(29)-AuNP complexes were concentrated and deposited onto the NCM to form a highly efficient background-free surface-assisted LDI substrate. Under pulsed laser irradiation (355 nm), the binding of thrombin decreased the desorption and/or ionization efficiencies of the Au atoms from the AuNP surfaces. The resulting decreases in the intensities of the signals for Au clusters in the mass spectra provided a highly amplified target-labeling indicator for the targeted protein. Under optimized conditions, this probe was highly sensitive (limit of detection: ca. 50 fM) and selective (by at least 1000-fold over other proteins) toward thrombin; it also improved reproducibility (<5%) of ion production by presenting a more-homogeneous substrate surface, thereby enabling LDI-based measurements for the accurate and precise quantification of thrombin in human serum. This novel LDI-MS approach allows high-speed analyses of low-abundance thrombin with ultrahigh sensitivity; decorating the AuNP surfaces with other aptamers also allowed amplification of other biological signals.

In this study, we employed laser desorption/ionization mass spectrometry (LDI-MS) to explore the interactions between thiolated DNA (HS-DNA) and gold nanoparticles (Au NPs). Under nanosecond-pulsed laser irradiation (Nd:YAG, 355 nm), the efficiency of Au cluster ion formation from the Au NPs decreased in the presence of HS-DNA. At the optimal laser power density (2.1 × 10(4) W cm(-2)), the intensity of the Au cluster signal was sensitive to the DNA coverage and the length of the DNA strands on the Au NPs (diameter: 13 nm). Using this information, we developed a simple and specific DNA sensor that operates through analysis of the Au cluster ions formed from the fragmentation of Au NPs under LDI conditions. The coverage of the thiolated probe DNA (pDNA) on the Au NPs increased in the presence of its perfectly matched DNA (DNA(pm)). As a result, the intensity of the signal of Au cluster ions decreased upon increasing the concentration of DNA(pm). Coupling these pDNA-Au NPs with LDI-MS allowed the detection of DNA(pm) at concentrations down to the nanomolar regime. Furthermore, we applied this pDNA-Au NP probe to the detection of single-nucleotide polymorphisms (SNPs) of the Arg249Ser unit in the TP53 gene. To the best of our knowledge, this paper provides the first example of the use of LDI to analyze the coverage and structure of DNA strands on metal NPs. This simple, rapid, high-throughput detection system, based on the coupling of biofunctional Au NPs with LDI-MS, appears to hold great practicality for bioanalyses of oligonucleotides and proteins.

To improve the accuracy of bracket placement in vivo, a protocol and device were introduced, which consisted of operative procedures for accurate control, a computer-aided design, and an augmented reality–assisted bracket navigation system. The present study evaluated the accuracy of this protocol. Methods: Thirty-one incisor teeth were tested from four participators. The teeth were bonded by novice and expert orthodontists. Compared with the control group by Boone gauge and the experiment group by augmented reality-assisted bracket navigation system, our study used for brackets measurement. To evaluate the accuracy, deviations of positions for bracket placement were measured. Results: The augmented reality-assisted bracket navigation system and control group were used in the same 31 cases. The priority of bonding brackets between control group or experiment group was decided by tossing coins, and then the teeth were debonded and the other technique was used. The medium vertical (incisogingival) position deviation in the control and AR groups by the novice orthodontist was 0.90 ± 0.06 mm and 0.51 ± 0.24 mm, respectively (p < 0.05), and by the expert orthodontist was 0.40 ± 0.29 mm and 0.29 ± 0.08 mm, respectively (p < 0.05). No significant changes in the horizontal position deviation were noted regardless of the orthodontist experience or use of the augmented reality–assisted bracket navigation system. Conclusion: The augmented reality–assisted bracket navigation system increased the accuracy rate by the expert orthodontist in the incisogingival direction and helped the novice orthodontist guide the bracket position within an acceptable clinical error of approximately 0.5 mm.