Comparison of Blue and Infrared Light Transmission Through Dental Tissues and Restorative Materials.

OBJECTIVES: The depth of cure using blue-light photocuring units (BL) is limited by tooth structure and qualities of the restorative material through which the activating wavelength must pass. Recent developments incorporate an infrared (IR) activated upconversion (UC) fluorescence of a lining agent filled with nanocrystals of NaYF4 and doped with YB+3 and Tm+3 that emit both blue and violet light locally at the interface of the liner and restorative resin. The purpose of this study was to evaluate the BL and 975 nm infrared (IR) light power transmission through dental tissues and restorative materials. METHODS AND MATERIALS: Power transmissions of the IR laser (975 nm) and a monowave blue-only light-curing unit (Bluephase 16i) through dental tissues (enamel, dentin, and enamel/dentin junction, or DEJ), eight (8) various dental resin composites, and eight (8) dental ceramics, each at four thicknesses (1, 2, 3 and 4 mm) were evaluated (n=5) using a thermopile sensor (PM10, Coherent Inc) connected to a laser power meter (Fieldmate, Coherent Inc). Power transmission values of each light source and restorative material were subjected to analysis of variance and Tukey test at a pre-set alpha of 0.05. RESULTS: A linear correlation (r=0.9884) between the supplied current and emitted IR power of the laser diode was found, showing no statistical power reduction with increased distances (collimated beam). For tooth tissues, the highest power transmissions for both light sources were observed using 1.0 mm enamel while the lowest values were found for 2.0 mm dentin and an association of 2.0 mm DEJ and 1.0 mm dentin. The only group where IR demonstrated significantly higher transmission when compared to BL was 1.0 mm enamel. For all resin composites and dental ceramics, increased thickness resulted in a reduction of IR power transmission (except for EverX Posterior fiber-reinforced composite and e.max HT ceramic). IR resulted in higher transmission through all resin composites, except for Tetric EvoCeram White. The highest BL transmission was observed for SDR Flow, at all thicknesses. Higher IR/BL ratios were observed for EverX Posterior, Herculite Ultra, and Lava Ultimate, while the lowest ratio was observed for Tetric EvoCeram White. Reduced translucency shades within the same material resulted in lower power ratio values, especially for BL transmission. Higher IR/BL ratios were observed for e.Max LT, VitaVM7 Base Dentin, and e.max CAD HT, while the lowest values were found for VitaVM7 Enamel and Paradigm C. CONCLUSION: IR power transmission through enamel was higher when compared to blue light, while no difference was observed for dentin. The power transmission of IR was higher than BL for resin composites, except for a high value and low chroma shade. Fiber-reinforced resin composite demonstrated the highest IR/BL power transmission ratio. A greater IR/BL ratio was observed for lower translucency ceramics when compared to high translucency.

Getting from here to there: future planning as reported by adult siblings of individuals with disabilities.

BACKGROUND: Although they will often serve as caregivers for their brothers-sisters with intellectual and developmental disabilities (IDD), adult siblings are rarely included in future planning. METHOD: This study examined 495 American siblings who completed a web-based questionnaire about themselves, their brother-sister with IDD, parents and whether their families completed 11 future planning activities. RESULTS: Although virtually all families completed some future planning, on average, families completed slightly over half of the 11 activities (75% completed eight or fewer). Families more frequently identified a successor to current caregivers and engaged in planning discussions with one another and with the brother-sister; least often, families completed a letter of intent or began securing residential placements. Future planning activities comprised three domains: (1) legal activities, (2) residential activities and (3) family discussions about the future. Variables relating to one or more domains included whether the brother-sister lived in or outside of family home; brother-sister independent living abilities; presence of an intellectual disability; parent caregiving ability; and current sibling caregiving and involvement with the brother-sister with IDD. CONCLUSIONS: Although most families engage in some future planning, performance varies widely within and across future planning domains. Future planning involves different considerations and interventions depending on whether one is considering legal, residential or family discussions.

Crystalline electric field study in a putative topologically trivial rare-earth doped YPdBi compound.

Topological states of matter have attracted a lot of attention recently due to their intriguing physical properties and potential applications. In particular, the family of half-Heusler compounds [Formula: see text] (R = rare earth, M = Pt, Pd or Au, and T = Bi, Sb, Pb or Sn) has been predicted to display tunable topological properties via their cubic unit cell volume and/or the charges of the M and T atoms. In this work, we report electron spin resonance (ESR), along with complementary macroscopic experiments, in the putative topologically trivial rare-earth doped (Gd, Nd and Er) YPdBi. From magnetic susceptibility data analysis constrained by ESR results, we were able to extract the fourth (A 4) and sixth (A 6) order crystal field parameters (CFP) for YPdBi and compared them with those already reported to YPtBi, which is known as a topologically non-trivial compound. We observed that the sign of the CFP changes systematically from YPdBi to YPtBi, possibly due to the inversion of the valence and conduction bands at the Fermi level. The enhanced spin-orbit coupling in YPtBi, when compared to YPdBi, induces the band inversion that drives the system to a non-trivial topological state. This band inversion likely has an effect on the effective charges surrounding the magnetic dopants that are probed by the CFP.

Evidence of precursor orthorhombic domains well above the electronic nematic transition temperature in Sr(Fe1-x Co x )2As2.

Raman scattering, synchrotron x-ray diffraction, specific heat, resistivity and magnetic susceptibility measurements were performed in Sr(Fe1-x Co x )2As2 [[Formula: see text]] single crystals with superconducting critical temperature [Formula: see text] K and two additional transitions at 132 and 152 K observed in both specific heat and resistivity data. A quasielastic Raman signal with B 2g symmetry (tetragonal cell) associated with electronic nematic fluctuations is observed. Crucially, this signal shows maximum intensity at [Formula: see text] K, marking the nematic transition temperature. X-ray diffraction shows evidence of coexisting orthorhombic and tetragonal domains between [Formula: see text] and [Formula: see text] ∼ 152 K, implying that precursor orthorhombic domains emerge over an extended temperature range above [Formula: see text]. While the height of the quasielastic Raman peak is insensitive to [Formula: see text], the temperature-dependence of the average nematic fluctuation rate indicates a slowing down of the nematic fluctuations inside the precursor orthorhombic domains. These results are analogous to those previously reported for the LaFeAsO parent oxypnictide (Kaneko et al 2017 Phys. Rev. B 96 014506). We propose a scenario where the precursor orthorhombic phase may be generated within the electronically disordered regime ([Formula: see text]) as long as the nematic fluctuation rate is sufficiently small in comparison to the optical phonon frequency range. In this regime, the local atomic structure responds adiabatically to the electronic nematic fluctuations, creating a net of orthorhombic clusters that, albeit dynamical for [Formula: see text], may be sufficiently dense to sustain long-range phase coherence in a diffraction process up to [Formula: see text].

Getting by with a little help from my friends: siblings report on the amount of informal support received by adults with disabilities.

BACKGROUND: Given decreased formal supports for adults with intellectual and developmental disabilities (IDDs) in many industrialised countries, we need to know more about informal, or natural, supports. METHOD: Adult siblings (N = 632) responded to a web-based survey about the informal supports received by their brothers/sisters with IDDs. RESULTS: Informal support was organised by the life domains of recreation, employment and housing. Adults with IDDs received the most extensive informal support in recreation and the least extensive in housing; low levels characterised all domains. Individuals with greater numbers of supporters in a domain experienced higher levels of support, as did those residing with family and who received more state-supported, formal benefits. CONCLUSIONS: Unpaid, informal supports supplement the support needs of adults with IDDs. Connections between formal and informal supports for adults with IDDs need to be examined further.

High-pressure studies on heavy-fermion antiferromagnet CeCuBi2.

We report in-plane electrical resistivity studies of CeCuBi2 and LaCuBi2 single crystals under applied pressure. At ambient pressure, CeCuBi2 is a c-axis Ising antiferromagnet with a transition temperature [Formula: see text] K. In a magnetic field applied along the c-axis at [Formula: see text] K a spin-flop transition takes place [Formula: see text] T. Applying pressure on CeCuBi2 suppresses T N at a slow rate. [Formula: see text] extrapolates to zero temperature at [Formula: see text] GPa. The critical field of the spin-flop transition [Formula: see text] displays a maximum of 6.8 T at [Formula: see text] GPa. At low temperatures, a zero-resistance superconducting state emerges upon the application of external pressure having a maximum T c of 7 K at 2.6 GPa in CeCuBi2. High-pressure electrical-resistivity experiments on the non-magnetic reference compound LaCuBi2 reveal also a zero resistance state with similar critical temperatures in the same pressure range as CeCuBi2. The great similarity between the superconducting properties of both materials and elemental Bi suggests a common origin of the superconductivity. We discuss that the appearance of this zero resistance state superconductivity may be related to the Bi layers present in the crystalline structure of both compounds and, therefore, could be intrinsic to CeCuBi2 and LaCuBi2, however further experiments under pressure are necessary to clarify this issue.

Linfoma difuso de celulas b grandes de origen yeyunal: reporte de caso y revisión de la literatura / Diffuse large b-cell lymphoma, jejunal origin: case report and literature review

El linfoma difuso de células B grandes, es una neoplasia maligna linfoproliferativa caracterizada por la reproducción monoclonal de linfocitos de la estirpe B en diferentes órganos y tejidos. Se describe el caso de un paciente femenino de 63 años de edad, quien ingresa al servicio de urgencias por cuadro de dolor abdominal, asociado a pérdida de peso y presencia de melenas. Durante la hospitalización presenta cuadro de obstrucción intestinal y agravamiento del cuadro clínico, por lo que se indica realizar laparotomía exploratoria en donde se encuentra una gran masa con múltiples ganglios en meso de yeyuno de aspecto tumoral. El estudio de patología con inmunohistoquímica de la muestra reporta reactividad difusa para CD20 y para vimentina, además de CD3 y BCL2, hallazgos compatibles con Linfoma de células B grandes, un linfoma no Hodgkin gastrointestinal de presentación infrecuente en yeyuno.

Diffuse large B-cell lymphoma is a malignancy lymphoproliferative characterized by monoclonal lymphocytes B strain reproduction in different organs and tissues. This article is a case report of a female 63-year-old, who admitted to the emergency room with abdominal pain associated with weight loss and presence of manes. During hospitalization, she presents intestinal obstruction associated with clinical worsening and indicating completion of Laparotomy Diagnostics where it's found a large malignant tumor mass with multiple nodes in meso aspect jejunal tumor. The study of pathology with immunohistochemistry of the sample reports diffuse reactivity for CD20 and for vimentin in addition to CD3 and BCL2, compatible findings with large B cell lymphoma, gastrointestinal Non-Hodgking lymphoma of jejunum uncommon presentation.

Trombocitopenia inducida por tamoxifeno y letrozol / Thrombocytopenia induced by tamoxifen and letrozole

El tamoxifeno y el letrozol son fármacos muy utilizados en el tratamiento del cáncer de mama. Está descrito que la trombocitopenia (recuento plaquetario inferior a 100.000/mm3) es un efecto secundario raro tras el tratamiento con tamoxifeno. Sin embargo, no es un efecto adverso conocido del letrozol. Presentamos dos casos clínicos en los que tras tratamientos prolongados con estos fármacos nos encontramos con que las pacientes desarrollan trombocitopenia. En ambos casos, este efecto adverso desaparece en pocas semanas tras la retirada del fármaco.

Letrozole and tamoxifen are drugs used in the treatment of breast cancer. It is reported that thrombocytopenia (less than 100,000 / mm3 platelet count) is a rare side effect of tamoxifen. However, it is not a known side effect of letrozole. We present two cases in which after prolonged treatment with these drugs we found that the patients develop thrombocytopenia. In both cases, this adverse effect disappears a few weeks after drugs were stopped.

The tobacco paradox in acute coronary syndrome. The prior cessation of smoking as a marker of a better short-term prognosis. / La paradoja del tabaco en el síndrome coronario agudo. El abandono previo del hábito tabáquico como marcador de mejor pronóstico a corto plazo.

OBJECTIVE: The tobacco paradox is a phenomenon insufficiently explained by previous studies. This study analyses the prognostic role of prior or active smoking in patients with acute coronary syndrome. METHODS: We obtained data from the ARIAM registry, between 2001 and 2012. The study included 42,827 patients with acute coronary syndrome (mean age, 65±13 years; 26.4% women). The influence of smoking and that of being an ex-smoker on mortality was analysed using a multivariate analysis. RESULTS: The smokers were younger, were more often men, had less diabetes, hypertension and prior history of heart failure, stroke, arrhythmia and renal failure and more frequently had ST-elevation and a family history of smoking. The ex-smokers had more dyslipidaemia and history of angina, myocardial infarction, ischemic heart disease, peripheral vasculopathy and chronic bronchial disease. Smokers and ex-smokers less frequently developed cardiogenic shock (smokers 4.2%, ex-smokers 4.7% and nonsmokers 6.9%, P<.001). Hospital mortality was 7.8% for the nonsmokers, 4.9% for the ex-smokers and 3.1% for the smokers (P<.001). In the multivariate analysis, the smoker factor lost its influence in the prognosis (-0.26%, p=.52 using an inverse probability calculation; and+0.26%, P=.691 using a propensity analysis). However, the exsmoker factor showed a significant reduction in mortality in both tests (-2.4% in the inverse probability analysis, P<.001; and -1.5% in the propensity analysis, P=.005). CONCLUSIONS: The tobacco paradox is a finding that could be explained by other prognostic factors. Smoking cessation prior to hospitalization for acute coronary syndrome is associated with a better prognosis.

Unusual diffusive effects on the ESR of Nd³âº ions in the tunable topologically nontrivial semimetal YBiPt.

Electron spin resonance (ESR) of diluted Nd(3+) ions in the topologically nontrivial semimetallic (TNSM) YBiPt compound is reported. The cubic YBiPt compound is a non-centrosymmetric half Heusler material which crystallizes in the F43m space group. The low temperature Nd(3+) ESR spectra showed a g-value of 2.66(4) corresponding to a Γ6 cubic crystal field Kramers' doublet ground state. Remarkably, the observed metallic and diffusive (Dysonian) Nd(3+) lineshape presented an unusual dependence with grain size, microwave power, Nd(3+) concentration and temperature. Moreover, the spin dynamic of the localized Nd(3+) ions in YBiPt was found to be characteristic of a phonon-bottleneck regime. It is claimed that, in this regime for YBiPt, phonons are responsible for mediating the diffusion of the microwave energy absorbed at resonance by the Nd(3+) ions to the thermal bath throughout the skin depth (δ ≃ µm). We argue that this is only possible because of the existence of highly mobile conduction electrons inside the skin depth of YBiPt that are strongly coupled to the phonons by spin-orbit coupling. Therefore, our unexpected ESR results point to a coexistence of metallic and insulating behaviors within the skin depth of YBiPt. This scenario is discussed in the light of the TNSM properties of this compound.

Conduction electron spin resonance in the α-Yb1-xFexAlB4 (0 ⩽ x ⩽ 0.50) and α-LuAlB4 compounds.

ß-YbAlB4 has become one of the most studied heavy fermion systems since its discovery due to its remarkable physical properties. This system is the first reported Yb-based heavy-fermion superconductor (HFS) for which the low-T superconducting state emerges from a non-fermi-liquid (NFL) normal state associated with quantum criticality Nakatsuji et al 2008 Nature 4 603. Additionally, it presents a striking and unprecedented electron spin resonance (ESR) signal which behaves as a conduction electron spin resonance (CESR) at high temperatures and acquires features of the Yb(3+) local moment ESR at low temperatures. The latter, also named Kondo quasiparticles spin resonance (KQSR), has been defined as a 4f-ce strongly coupled ESR mode that behaves as a local probe of the Kondo quasiparticles in a quantum critical regime, Holanda et al 2011 Phys. Rev. Lett. 107 026402. Interestingly, ß-YbAlB4 possesses a previously known structural variant, namely the α-YbAlB4, phase which is a paramagnetic Fermi liquid (FL) at low temperatures Macaluso et al 2007 Chem. Mater. 19 1918. However, it has been recently suggested that the α-YbAlB4 phase may be tuned to NFL behavior and/or magnetic ordering as the compound is doped with Fe. Here we report ESR studies on the α-Yb1-xFexAlB4 (0 â©½ x â©½ 0.50) series as well as on the reference compound α-LuAlB4. For all measured samples, the observed ESR signal behaves as a CESR in the entire temperature range (10 K â‰² T â‰² 300 K) in clear contrast with what has been observed for ß-YbAlB4. This striking result indicates that the proximity to a quantum critical point is crucial to the occurrence of a KQSR signal.

Combined external pressure and Cu-substitution studies on BaFe2As2 single crystals.

We report a combined study of external pressure and Cu-substitution on BaFe2As2 single crystals grown by the in-flux technique. At ambient pressure, the Cu-substitution is known to suppress the spin density wave (SDW) phase in pure BaFe2As2(T(SDW) ≈ 140 K) and to induce a superconducting (SC) dome with a maximum transition temperature T(c)(max) ≃ 4.2 K. This T(c)(max) is much lower than the T(c) ∼ 15-28 K achieved in the case of Ru, Ni and Co substitutions. Such a lower T(c) is attributed to a Cu(2+) magnetic pair-breaking effect. The latter is strongly suppressed by applied pressure, as shown herein, Tc can be significantly enhanced by applying high pressures. In this work, we investigated the pressure effects on Cu(2+) magnetic pair-breaking in the BaFe(2-x)Cu(x)As2 series. Around the optimal concentration (x(opd) = 0.11), all samples showed a substantial increase of T(c) as a function of pressure. Yet for those samples with a slightly higher doping level (over-doped regime), T(c) presented a dome-like shape with maximum T(c) ≃ 8 K. Remarkably interesting, the under-doped samples, e.g. x = 0.02 display a maximum pressure induced T(c) ≃ 30 K which is comparable to the maximum T(c)'s found for the pure compound under external pressures. Furthermore, the magnetoresistance effect as a function of pressure in the normal state of the x = 0.02 sample also presented an evolution consistent with the screening of the Cu(2+) local moments. These findings demonstrate that the Cu(2+) magnetic pair-breaking effect is completely suppressed by applying pressure in the low concentration regime of Cu(2+) substituted BaFe2As2.

Site specific spin dynamics in BaFe2As2: tuning the ground state by orbital differentiation.

The role of orbital differentiation on the emergence of superconductivity in the Fe-based superconductors remains an open question to the scientific community. In this investigation, we employ a suitable microscopic spin probe technique, namely Electron Spin Resonance (ESR), to investigate this issue on selected chemically substituted BaFe2As2 single crystals. As the spin-density wave (SDW) phase is suppressed, we observe a clear increase of the Fe 3d bands anisotropy along with their localization at the FeAs plane. Such an increase of the planar orbital content is interestingly independent of the chemical substitution responsible for suppressing the SDW phase. As a consequence, the magnetic fluctuations in combination with this particular symmetry of the Fe 3d bands are propitious ingredients for the emergence of superconductivity in this class of materials.

Possible unconventional superconductivity in substituted BaFe2As2 revealed by magnetic pair-breaking studies.

The possible existence of a sign-changing gap symmetry in BaFe2As2-derived superconductors (SC) has been an exciting topic of research in the last few years. To further investigate this subject we combine Electron Spin Resonance (ESR) and pressure-dependent transport measurements to investigate magnetic pair-breaking effects on BaFe1.9M0.1As2 (M = Mn, Co, Cu, and Ni) single crystals. An ESR signal, indicative of the presence of localized magnetic moments, is observed only for M = Cu and Mn compounds, which display very low SC transition temperature (Tc) and no SC, respectively. From the ESR analysis assuming the absence of bottleneck effects, the microscopic parameters are extracted to show that this reduction of Tc cannot be accounted by the Abrikosov-Gorkov pair-breaking expression for a sign-preserving gap function. Our results reveal an unconventional spin- and pressure-dependent pair-breaking effect and impose strong constraints on the pairing symmetry of these materials.

Emergent antiferromagnetism out of the "hidden-order" state in URu2Si2: high magnetic field nuclear magnetic resonance to 40 T.

Very high field (29)Si-NMR measurements using a fully (29)Si-enriched URu(2)Si(2) single crystal were carried out in order to microscopically investigate the "hidden order" (HO) state and adjacent magnetic phases in the high field limit. At the lowest measured temperature of 0.4 K, a clear anomaly reflecting a Fermi surface instability near 22 T inside the HO state is detected by the (29)Si shift, (29)K(c). Moreover, a strong enhancement of (29)K(c) develops near a critical field H(c) ≃ 35.6 T, and the ^{29}Si-NMR signal disappears suddenly at H(c), indicating the total suppression of the HO state. Nevertheless, a weak and shifted (29)Si-NMR signal reappears for fields higher than H(c) at 4.2 K, providing evidence for a magnetic structure within the magnetic phase caused by the Ising-type anisotropy of the uranium ordered moments.

Conduction electron spin resonance in AlB2.

This work reports on electron spin resonance experiments in oriented single crystals of the hexagonal AlB2 diboride compound (P6/mmm, D16h structure) which display conduction electron spin resonance. The X-band electron spin resonance spectra showed a metallic Dysonian resonance with g-value and intensity independent of temperature. The thermal broadening of the anisotropic electron spin resonance linewidth ΔH tracks the T-dependence of the electrical resistivity below T is approximately equal to 100 K. These results confirm the observation of a conduction electron spin resonance in AlB2 and are discussed in comparison with other boride compounds. Based on our main findings for AlB2 and the calculated electronic structure of similar layered honeycomb-like structures, we conclude that any array of covalent B-B layers potentially results in a conduction electron spin resonance signal. This observation may shed new light on the nature of the non-trivial conduction electron spin resonance-like signals of complex f-electron systems such as ß-YbAlB4.

Determining the amount, timing and causes of mortality among infants with Down syndrome.

OBJECTIVE: To examine the amount, timing and causes/correlates of infant mortality among newborns with Down syndrome. METHODS: Using the Tennessee Department of Health Birth, Hospital Discharge and Death records, infants were identified who were born with Down syndrome from 1990 to 2006. Those who died during the first year were separated into three groups (first day death, neonatal mortality, post-neonatal mortality) and data from the Birth and Death records were used to compare the three death groups and the survival group on correlates of mortality. RESULTS: Of 1305 infants born in Tennessee with Down syndrome from 1990 to 2006, 97 died within the first year, for a mortality rate of 74 per 1000. Most Down syndrome infant deaths occurred during the post-neonatal period (56%), although many occurred during the first day (27%). Newborns who died during the first day had significantly lower birthweight, 5-min Apgar scores and gestational lengths, whereas those who died in the post-neonatal period had significantly more heart-related causes of death (all Ps < 0.001). No associations were found in this sample between increased infant mortality and maternal age, education, race, marital status or familial urban residence. CONCLUSIONS: Infants with Down syndrome experience high rates of mortality occurring at three distinct times during the first year. These groupings are tied to specific, different causes of death.

Distinct high-T transitions in underdoped Ba(1-x)KxFe2As2.

In contrast with the simultaneous structural and magnetic first order phase transition T0 previously reported, our detailed investigation on an underdoped Ba(0.84)K(0.16)Fe2As2 single crystal unambiguously revealed that the transitions are not concomitant. The tetragonal (τ: I4/mmm)-orthorhombic (ϑ: Fmmm) structural transition occurs at T(S)≃110 K, followed by an adjacent long-range antiferromagnetic (AFM) transition at T(N)≃102 K. Hysteresis and coexistence of the τ and ϑ phases over a finite temperature range observed by NMR experiments confirm the first order character of the τ-ϑ transition and provide evidence that both T(S) and T(N) are strongly correlated. Our data also show that superconductivity develops in the ϑ phase below T(c)=20 K and coexists with AFM. This new observation, T(S)≠T(N), firmly establishes another similarity between the hole-doped BaFe2As2 and the electron-doped iron-arsenide superconductors.

The effect of donepezil treatment on cardiovascular mortality.

The acetylcholinesterase inhibitor donepezil hydrochloride improves cognitive function in patients with Alzheimer's disease and vascular dementia. Given acetylcholine's important actions on the heart, we undertook a retrospective cohort investigation to assess whether donepezil usage affects cardiovascular mortality. In patients treated with donepezil, hazard ratios for total and cardiovascular mortality were 0.68 (P = 0.045, 95% confidence interval 0.46-0.99) and 0.54 (P = 0.042, 95% confidence interval 0.30-0.98), respectively. The apparent survival benefit in donepezil-treated patients should not be overinterpreted. Prospective clinical trials are warranted.

Chemical pressure induced spin freezing phase transition in kagome pr langasites.

The 2D kagome system Pr3Ga5SiO14 has been previously identified as a spin-liquid candidate in zero field, displaying no magnetic long-ranged order down to at least 35 mK. Perturbations upon such systems, either under applied fields or applied pressure, should induce a spin freezing phase transition, but there are very few experimental realizations of this phenomena other than the well-studied 3D pyrochlore Tb2Ti2O7. In this Letter, we report the observation of a spin freezing phase transition in Pr3Ga5SiO14 through the application of chemical pressure--that is, through a systematic substitution on the Si site with larger ions and an elongation of the nearest-neighbor Pr-Pr distance in the kagome lattice. This results in a suppression of the T2 component of the heat capacity, and the reduction of the exchange constant eventually leads to dipolar-driven spin freezing.