Proving or Improving: On Health Care Research as a Form of Self-Reflection

As it is, clinical trials are the gold standard of health care research, employed to prove that the care practices they study are good. Here, the author suggests that we would do better to develop research methods that work toward another goal: to improve care practices. This requires that we no longer foreground the effectiveness but, instead, investigate the various effects of interventions. If undesirable, they might then be tinkered with. As a part of this, the effects on bodily parameters and on the intricacies of daily lives should not be separated out but studied in connection. With examples drawn from studies into care practices for patients with diabetes or atherosclerosis, the author argues that instead of trying to turn the clinic into a laboratory, we should strive to support and strengthen clinical ways of working

Equilibrium constant determination for bisulfite addition to aromatic aldehydes

Equilibrium constants for bisulfite addition to benzaldehyde and its derivatives were determined by a spectrophotometric method developed by Kokesh and Hall. The concentration of the benzaldehyde derivative was monitored by UV as aliquots of a bisulfite solution are added to a buffered solution of the aldehyde. Additional data on ΔH° and ΔS° for the reactions were derived from the temperature variation of the equilibrium constants. For benzaldehyde, the reaction had an equilibrium constant at 25°C of 6.2 x 103 M-1, a ΔH° of -54.3 kJ/mol, and a ΔS° of -111 J/Mol·K. o-Tolualdehyde exhibited a lower Keq of 2.4 x 103 M-1, ΔH° of -39.5 kJ/mol and ΔS° of -67.3 J/Mol·K. Similarly, the reaction with o-anisaldehyde had a Keq of 2.6 x 103 M-1, ΔH° of -38.2 kJ/mol and ΔS° of -62.9 J/Mol·K. The reaction involving salicyladehyde exhibited a much lower Keq of 6.9 x 102 M-1, and ΔH° of -38.5 kJ/Mol and ΔS° of -76.1 J/Mol·K

Two-dimensional magnetism in the pnictide superconductor parent material SrFeAsF probed by muon-spin relaxation

We report muon-spin relaxation measurements on SrFeAsF, which is the parent compound of a newly discovered iron-arsenic-fluoride based series of superconducting materials. We find that this material has very similar magnetic properties to LaFeAsO, such as separated magnetic and structural transitions (TN = 120 K, Ts = 175 K), contrasting with SrFe2As2 where they are coincident. The muon oscillation frequencies fall away very sharply at TN, which suggests that the magnetic exchange between the layers is weaker than in comparable oxypnictide compounds. This is consistent with our specific heat measurements, which find that the entropy change S = 0.05 J/mol/K largely occurs at the structural transition and there is no anomaly at TN.Comment: 4 pages, 3 figure

Potassium silicate-zinc oxide solution for metal finishes

Examples of zinc dust formulations, which are not subject to cracking or crazing, are fire retardant, and have high adhesive qualities, are listed. The potassium silicate in these formulations has mol ratios of dissolved silica potassium oxide in the range 4.8 to 1 - 5.3 to 1

ADSORPSI ISOPROPIL ALKOHOL (IPA) DALAM AIR MENGGUNAKAN KARBON AKTIF DAN BENTONIT TERAKTIVASI ASAM

Metode sederhana untuk memisahkan isopropil alkohol (IPA) telah dikembangkan menggunakan karbon aktif dan bentonit teraktivasi asam sebagai adsorben. Karbon aktif diaktivasi menggunakan asam fosfat dan bentonit di aktivasi menggunakan asam sulfat. Karbon aktif dan bentonit teraktivasi asam dikarakterisasi menggunakan Brunauer-Emmet-Teller (BET). Adsorpsi dilakukan dalam sistem batch menggunakan variasi waktu, massa adsorben, pH dan suhu. Analit yang teradsorpsi ditentukan menggunakan piknometer. Parameter adsorpsi yang ditentukan antara lain kinetika adsorpsi, isoterm adsorpsi dan termodinamika adsorpsi. Jenis adsorpsi isotherm IPA pada karbon aktif adalah mengikuti kinetika orde dua dengan koefisien korelasi (R2) sebesar 0,8141. Model isoterm mengikuti model Langmuir dengan = -0,0886 mg/g, KL = -597,3716 L/mg, R2 = 0,9254. Nilai , dan berturut-turut adalah -32169,79 kJ/mol, 44,5139 kJ/mol dan 99,7347 J/mol.K, Bentonit teraktivasi asam mengikuti kinetika orde dua dengan koefisien korelasi (R2) sebesar 0,6336. Model isoterm mengikuti model Langmuir dengan = -0,1001 mg/g, KL = -561,7977 L/mg, R2 = 0,923. Nilai , dan berturut-turut adalah -7143,01 kJ/mol, 7,0026 kJ/mol, dan - 22,8435 J/mol.K. Campuran karobon aktif dan bentonit teraktivasi asam mengikuti orde dua dengan koefisien korelasi (R2) sebesar 0,6923. Model isoterm mengikuti model Langmuir dengan = -0,0831 mg/g, KL = -641,0256 L/mg, R2 = 0,9212. Nilai , dan berturut-turut adalah -11073,92 kJ/mol, 2,6749 kJ/mol, -35,3885 J/mol.K. Kata kunci : adsorpsi, isopropil alkohol (IPA), karbon aktif, bentonit teraktivasi asa

Kinetic of the thermal decomposition of disubstituted tetroxanes

The thermal decomposition of diphenyl diperoxide (DFT) and dibutanal diperoxide (DPG) were investigated over the temperature range 130 to 166°C. They were found to be first order with a high degree of conversion (60%). Arrhenius parameters were calculated: activation energy, 108 kJ mol-1 and pre-exponential factor, 6.5 109 s -1 for DFT and 80.8 kJ mol-1 and pre-exponential factor, 1.8 109 s - 1 for DPG. The principle decomposition products were aldehyde (about 1.9 mole per mole DFT and 2.0 mole per mole DPG) and oxygen molecule. All observations were interpreted in terms of decomposition pathways initiated by O-O homolysis. The corresponding activation parameters for the reaction of DFT in methanol (ΔH0# = 103.8 ± 3.3 kJ mol-1 ; ΔS0# = -69.9 ± 7.5 J mol-1 K -1 ; ΔG0# = 133.1 ± 3.3 kJ mol-1) were compared with values obtained for PDG thermolysis in the same solvents (ΔH0# = 75.4 ± 2.9 kJ mol-1 ; ΔS0# = -189.2 ± 2.5 J mol-1 K -1 ; ΔG0# = 157.4 ± 2.9 kJ mol-1). Furthermore, the pertinent substituent effect on the peroxidic bond strength of those molecules in solution was evaluated.Fil: Bordón, Alexander Germán. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; ArgentinaFil: Pila, Andrea Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; ArgentinaFil: Jorge, María Cristina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; ArgentinaFil: Jorge, Lilian Cristina. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Profeta, Mariela Inés. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; ArgentinaFil: Romero, Jorge Marcelo. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; ArgentinaFil: Jorge, Nelly Lidia. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura; Argentin