Evaluating the Feasibility of a Novel Firearm Injury Prevention Program for Pre-adolescent Children Through Health Care and Community-Based Partnerships: The Future Healers Program Pilot Study

BACKGROUND

Firearm violence is an American public health crisis that negatively impacts children and disproportionately affects Black youth. Few firearm injury prevention programs have been described in pre-adolescent children. The Future Healers Program is a novel collaboration constructed via partnership between the medical school, trauma center, academic surgery department, and local non-profit community organization. Our study sought to evaluate if (1) partnering with community organizations facilitated recruitment of children with prior exposure to firearm violence and (2) the health care community was a potential trusted partner appropriate for program delivery.

METHODS

Children aged 4-13 were recruited to join the program via news outlets and social media and in partnership with a local non-profit organization. Of the children and parents participating in the program, 48% (44/92) and 59% (38/64), respectively, completed an IRB-approved survey study. Pearson's chi-square, percentages, and 95% confidence intervals evaluated differences between children and caregivers on sociodemographic characteristics, firearm exposure (FE), firearm violence exposure (FVE), and perception of health care. Participant's residence was geocoded in relationship to incidents of firearm injury (2008-2021) in the same region.

RESULTS

Caregivers (95%) and children (84%) reported substantial exposure to firearm violence and resided in areas with frequent firearm injury incidents. Notably, 82% of caregivers and 66% of children reported having a family member injured by gunfire. A high percentage of caregivers (79%) and children (91%) self-reported trust in the health care system.

CONCLUSION

Partnerships between community organizations and health care systems can develop prevention programs that effectively recruit and engage pre-adolescent children impacted by firearm violence.

A taxonomically representative strain collection to explore xenobiotic and secondary metabolism in bacteria

Bacteria employ secondary metabolism to combat competitors, and xenobiotic metabolism to survive their chemical environment. This project has aimed to introduce a bacterial collection enabling comprehensive comparative investigations of those functions. The collection comprises 120 strains (Proteobacteria, Actinobacteria and Firmicutes), and was compiled on the basis of the broad taxonomic range of isolates and their postulated biosynthetic and/or xenobiotic detoxification capabilities. The utility of the collection was demonstrated in two ways: first, by performing 5144 co-cultures, recording inhibition between isolates and employing bioinformatics to predict biosynthetic gene clusters in sequenced genomes of species; second, by screening for xenobiotic sensitivity of isolates against 2-benzoxazolinone and 2-aminophenol. The co-culture medium of Bacillus siamensis D9 and Lysinibacillus sphaericus DSM 28^T was further analysed for possible antimicrobial compounds, using liquid chromatography-mass spectrometry (LC-MS), and guided by computational predictions and the literature. Finally, LC-MS analysis demonstrated N-acetylation of 3,4-dichloroaniline (a toxic pesticide residue of concern) by the actinobacterium Tsukamurella paurometabola DSM 20162^T which is highly tolerant of the xenobiotic. Microbial collections enable "pipeline" comparative screening of strains: on the one hand, bacterial co-culture is a promising approach for antibiotic discovery; on the other hand, bioremediation is effective in combating pollution, but requires knowledge of microbial xenobiotic metabolism. The presented outcomes are anticipated to pave the way for studies that may identify bacterial strains and/or metabolites of merit in biotechnological applications.

MAS-NMR spectroscopy studies in the setting reaction of glass ionomer cements

OBJECTIVES

The main objective is the characterisation of the setting reaction in glass ionomer cements based on experimental ionomer glasses with different fluorine content and a commercial glass ionomer cement liquid by using 13C CP/MAS-NMR, 29Si, 27Al and 31P MAS-NMR spectroscopy in order to receive information specifically about the cross-linking process.

METHODS

Different fluorine containing glass compositions based on 4.5SiO2-3Al2O3-1.5P2O5-(5-z)CaO-zCaF(2) where z=0-3, were mixed with a commercially available polymer liquid to form glass ionomer cements. The cements were subjected to 27Al, 13C CP/MAS, 29Si, and 31P MAS-NMR analysis.

RESULTS

The 27Al spectra showed clearly the formation of six-fold coordinate Al(VI), that may crosslink the carboxyl groups in the poly-acid molecules. A shift towards to more positive values of the carboxyl peak in the 13C CP/MAS-NMR spectra showed clearly the proton dissociation of the carboxyl groups. A shift towards more negative values was observed in the 29Si MAS-NMR spectra, suggesting formation of hydrated silica gel and consequently formation of additional Si-O-Si bonds. 31P MAS-NMR spectra also reflected changes in the coordination state around a PO4(3-) tetrahedron. Increasing the fluorine content of the glasses resulted generally in increased reactivity during setting, due to promoting cross-linking and repolymerisation of the silicate phase, followed by clear changes in the MAS-NMR spectra.

CONCLUSIONS

The cross-linking process during the setting reaction of glass ionomer cements can be followed by MAS-NMR spectroscopy observing the conversion of Al(IV) to Al(VI). The acid base setting reaction is completed in 1 day and no further significant changes in the MAS-NMR spectra can be observed. Further study is required in order to understand the role of phosphorus.

Effects of hydrothermal treatment with CaCl(2) solution on surface property and cell response of titanium implants

In order to obtain early and good osteointegration after implantation of a titanium implant in the human body, the surface modified treatments using NaOH or H(2)O(2) etc. were reported. In this study, titanium was hydrothermally treated with CaCl(2) solutions at 200 degrees C for 24hr (CaCl(2)-HT). Scanning electron microscope (SEM) observation clearly showed apatite deposition on the surface of CaCl(2) HT treated titanium faster than other chemical treated titanium immersion in simulated body fluid. X-ray photoelectron spectroscopy (XPS) analysis demonstrated that Ti--O--Ca bonding was formed on titanium surface by hydrothermal treatment with CaCl(2) solution. And it was revealed that thickness of TiO(2), which was known to play important roles for the formation of bone-like apatite, became approximately three times thicker than as-polished titanium. The amount of initial attached MC3T3-E1 cells on as-polished and NaOH, H(2)O(2) and this CaCl(2) HT treated titanium were almost the same values. After 5 days incubation, the growth rate of MC3T3-E1 cells on CaCl(2)-HT treated titanium was significantly higher than that on other chemical treated titanium. The hydrothermal treatment with 10-20 mmol/L CaCl(2) solution at 200 degrees C was an effective method for the fabrication of titanium implant with good bioactivity and osteoconductivity.

The effect of Pt and Pd alloying additions on the corrosion behavior of titanium in fluoride-containing environments

In this study, we examined the corrosion behaviors of pure titanium, the alloys Ti-6Al-4V and Ti-6Al-7Nb, and the new experimental alloys Ti-Pt and Ti-Pd using anodic polarization and corrosion potential measurements in an environment containing fluoride. Before and after immersion in the test solutions, we made observations using a scanning electron microscope. The test solutions included an artificial saliva containing 0.2% NaF (corresponding to 905 ppm F) and an artificial saliva with a low concentration of oxygen. Although the surfaces of the Ti-Pt and Ti-Pd alloys were not affected by an acidic environment containing fluoride, the surfaces of the pure titanium, the Ti-6Al-4V alloy, and the Ti-6Al-7Nb alloy were markedly roughened by corrosion. The surfaces of the pure titanium, the Ti-6Al-4V alloy, and the Ti-6Al-7Nb alloy were microscopically damaged by corrosion when they were immersed in the solution containing a low concentration of dissolved oxygen, even with a fluoride concentration included in the commercial dentifrices. In this situation, however, the surfaces of the new Ti-Pt and Ti-Pd alloys were not affected. These alloys are expected to be of use in dental work as new titanium alloys with high corrosion resistances.

Basic properties of apatite cement containing spherical tetracalcium phosphate made with plasma melting method

Apatite cement (AC) can be injected through syringe and forms apatite mass. Therefore, AC is very useful for a minimally invasive surgical operation aimed for the reconstruction of bone defects. However, injectability of current AC is not satisfactory for its clinical use. In this investigation, therefore, spherical tetracalcium phosphate (s-TTCP) was prepared with plasma melting method and its effect on injectability were evaluated as well as other basic properties of AC. We found much better handling property and injectability when we used s-TTCP as a component of AC (s-AC). For example, cement spread area used as an index of consistency of the s-AC paste was 512 mm2 whereas that of ordinary AC with irregular TTCP (i-AC) was 158 mm2 when powder to liquid mixing ratio was 2.5. However, diametral tensile strength of set s-AC (1.4 MPa) was significantly lower than that of set i-AC (10.7 MPa) when the powder to liquid ratio was 4.0. X-ray powder diffraction analysis revealed limited formation of apatite in the case of s-AC. Although there are some drawbacks, we feel the use of spherical particle is very useful to improve the injectability of AC. Therefore, it is important to find suitable method to prepare spherical powder as the component of AC.

Corrosion behavior of pure titanium and titanium alloys in fluoride-containing solutions

The effects of fluoride concentrations and pH on the corrosion behavior of pure titanium, Ti-6Al-4V, Ti-6Al-7Nb alloys and a new Ti alloy adding palladium, which is expected to promote a repassivation of Ti were examined by anodic polarization and corrosion potential measurements. The amount of dissolved Ti was analyzed by inductively coupled plasma mass spectroscopy. The surface of the specimen was analyzed by X-ray photoelectron spectroscopy before and after the measurement. Pure Ti, Ti-6Al-4V and Ti-6Al-7Nb alloys were easily corroded even in a low fluoride concentration in an acidic environment. The corrosion resistance of Ti-0.2Pd alloy was greater than those of pure Ti, Ti-6Al-4V and Ti-6Al-7Nb alloys in the wide range of pH and fluoride concentrations. The high corrosion resistance of Ti-0.2Pd alloy was caused by the surface enrichment of Pd promoting a repassivation of Ti. The Ti-0.2Pd alloy is expected to be useful as a new Ti alloy with high corrosion resistance in dental use.

Phase transformation mechanisms in (AuCu)1-xPdx pseudobinary alloys by direct aging method

Phase transformation mechanisms in the AuCu-Pd pseudobinary system were studied by means of electrical resistivity measurements, hardness tests, X-ray diffraction and transmission electron microscopy. A direct aging method was employed to eliminate the otherwise unavoidable ordering that takes place rapidly during quenching into ice brine, hence it is important to distinguish the ordering processes with and without an incubation period. Three phase transformation modes occurred, namely; ordering at grain boundaries and in the grain interior with nucleation and growth mechanism after incubation, and spinodal ordering without any incubation period. The age-hardening of the alloys examined was attributed to AuCu I ordering. Nucleation and growth mechanism followed by twinning occurred in the specimens aged at higher temperatures, while spinodal ordering was seen in specimens aged in lower temperature. The spinodal ordering temperature of AuCu-Pd alloys increased according to Pd content.

Phase transformations and age-hardening behaviors related to Au3Cu in Au-Cu-Pd alloys

Phase transformation behaviors in Au-Cu-Pd alloys were investigated by means of electrical resistivity measurements, hardness tests, X-ray diffraction and transmission electron microscopy. Anisothermal and isothermal annealing were performed. Two types of phase transformations were found, namely related to the single phase of Au3Cu and the coexistent phase of Au3Cu and AuCu I. The latter produced more remarkable hardening than the former. Hardening was brought about by the antiphase domain size effect of Au3Cu ordered phase in the single phase and by the formation of AuCu I ordered phase in the Au3Cu ordered matrix. There are three modes of phase transformation in the coexistent region depending on the composition. Each sequence is discussed.

Ageing behaviour in a dental low-gold alloy with high copper content

Phase transformation behaviour in a dental low-gold alloy with high copper content during continuous heating was investigated by hardness tests, electrical resistivity measurements, X-ray diffraction, scanning and transmission electron microscopies. Two kinds of solution treatment conditions (at 873 K and 1073 K) followed by iced-brine quench, represented different ageing behaviours. Although subsequent anisothermal annealing produced same phase separation of face-centred cubic disordered and ordered (Cu3Au) phases in both specimens, the specimen quenched from 1073 K had already been hardened by a spinodal decomposition.

A coherent phase diagram of the [(AuCu)0.86Ag0.14]1-XPtX pseudobinary section in Au-Cu-Ag-Pt quaternary system

In order to determine a coherent phase diagram of the [(AuCu)0.86Ag0.14]1-XPtX pseudobinary system, phase identifications and analyses of the microstructural configurations were performed by means of transmission electron microscopy. Various phase regions were detected in the coherent phase diagram as follows; (1) alpha 0 (fcc) single phase region, (2) two-phase region (alpha 1 + alpha 2), (3) AuCu I (L10) + alpha 0, (4) AuCu I + alpha 2, (5) AuCu II (L10-S) + alpha 2, (6) AuCu I + AuCu II + alpha 2, (7) AuCu I single phase region. Microstructural features of these regions relating to the phase transformations were described.

Ageing reactions in a high carat gold alloy for dental porcelain bonding

The phase transformation during continuous heating of a high carat gold alloy used for porcelain bonding was investigated by electrical resistivity measurements, hardness tests, X-ray diffraction and scanning and transmission electron microscopy. Four reaction stages (I, II, III and IV) were found. Stage I corresponded to the formation of a short-range order. A discontinuous precipitation took place in stage II, which contributed to remarkable hardening. Stages III and IV were reactions to the stable phases at each temperature region, and resulted in softening. The activation energies for stages I, II and III are 27.1, 33.8 and 58.2 kcal/mol, respectively.

Abnormal behavior in adiabatic calorimetry of set dental stone

Dehydration in set dental stone was studied by employing specific heat measurements. Dehydration proceeds in two steps in air. In the case of bulk samples, especially those made with a lower water-powder ratio, three endothermic reaction stages are observed; a reaction of the dihydrate to the hemihydrate is apparently separated in two, one of which is not inherent. It is thought that the occurrence of a new peak is due to the difficulty for the dehydrated water to escape, depending on the porosity of the set stone.

Effects of the current used on determining a critical temperature by electrical resistivity measurements in dental alloys

The electrical resistivity measurement to determine a critical temperature (Tc) in a stoichiometric CuAu alloy is discussed on the dependence of the current used. The temperature was measured on two ways: With the thermocouple connected to the specimen by spot-welding, and with them separated. In the latter case, the greater the current, the lower the apparent Tc because of the generation of Joule heat. To obtain a more precise Tc, the current should be as small as possible or the thermocouple should be located as close as possible to the specimen. It is highly desirable for the thermocouple and the specimen to be welded together, if the effects of some contamination can be ignored in measuring system.

Age-hardening mechanisms in a commercial dental gold alloy containing platinum and palladium

The age-hardening mechanism of a commercial dental gold alloy containing platinum and palladium (in wt.%, 15 Cu, 6 Ag, 5 Pt, 3 Pd, 3 Zn, with the balance as gold) was elucidated by means of electrical resistivity, hardness tests, x-ray and electron diffraction and electron microscopy, as well as high-resolution electron microscopy. The sequence of phase transformations during isothermal aging below the critical temperature, Tc = 825 K, was described as follows: disordered solid solution alpha 0 (FCC)----metastable AuCu I' ordered phase (FCT)----metastable alpha 2 disordered phase (FCC) equilibrium AuCu I ordered phase (FCT) + equilibrium alpha 2 disordered phase (FCC). The hardening was due to the introduction of coherency strain at the interface between the AuCu I' platelet and the matrix. These ordered platelets had mutually perpendicular c-axes to compensate for the strain introduced by their tetragonality. A loss of coherency at the interface brought about softening of the alloy, i.e., over-aging.