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G. Frank Gerberick - One of the best experts on this subject based on the ideXlab platform.

  • examination of a vehicle for use with water soluble materials in the murine local lymph node assay
    Food and Chemical Toxicology, 2002
    Co-Authors: Cindy A Ryan, Rebecca Jane Dearman, R A Skinner, Lynn W Cruse, Ian Kimber, G. Frank Gerberick
    Abstract:

    The murine local lymph node assay (LLNA) is a validated method for identifying skin sensitization hazard. Vehicle choice can influence the sensitization potential of haptens in both the LLNA and in humans, therefore selection of an appropriate vehicle is important. Suggested vehicles for the LLNA include organic solvents and organic-aqueous mixtures. However, due to its high surface tension and poor wetting qualities, water is not recommended and therefore testing aqueous soluble materials can be problematic. The aims of this investigation were to identify a water-based vehicle that possesses better skin wetting properties than water alone, and to assess its performance relative to other solvents in the LLNA using aqueous soluble haptens. The selected wetting agent was the surfactant Pluronic(R) L92 (L92). Concentrations of L92 of up to 50% did not induce positive responses in the LLNA. 1% aqueous L92 was chosen for further examination. Dose-response analyses were performed with dinitrobenzene sulfonic acid (DNBS) and formaldehyde formulated either in water, 1% L92, dimethyl sulfoxide (DMSO) or dimethyl formamide (DMF). Potassium dichromate (PDC) and Nickel Sulfate were tested in 1% L92, DMSO or DMF. The highest concentration of potassium dichromate was retested in each vehicle and in water to assess the effect of the wetting agent. Estimates of the relative sensitizing potency in each vehicle were determined by calculation of EC3 values (the estimated concentration required to induce a threshold positive response). While DNBS and formaldehyde produced positive responses in all four vehicles, their relative potency varied among the vehicles. The rank ordering of potencies for both materials was, from highest to lowest, DMF > or = DMSO > 1% L92 > water. Compared with water, use of 1% L92 resulted in >2-fold increase in potency for DNBS and >3-fold increase for formaldehyde. PDC was positive in DMF, DMSO and 1% L92. The potency ranking was DMF > or = DMSO > 1% L92. Re-evaluation of 0.5% PDC confirmed that formulations of both DMSO and DMF induced strong proliferative responses, whereas somewhat less proliferation was recorded with the 1% L92 vehicle. PDC in water was without activity. The performance of 1% L92 as a vehicle for Nickel Sulfate was assessed relative to DMSO and DMF. In DMSO, Nickel Sulfate produced a stimulation index (SI) >3 at only the highest level. Testing in DMF induced low levels of proliferation, but failed to produce a SI of 3 at any concentration tested. When formulated in 1% L92, Nickel Sulfate caused a SI of 3 when tested at 2.5%. Based on the results of these experiments, for identification of sensitization hazard of aqueous soluble materials using the LLNA, DMF and DMSO are the preferred vehicles. However, if a test material is not soluble in DMF or DMSO, or if higher test concentrations can be achieved in an aqueous vehicle, then 1% L92 may provide a better alternative to water alone in terms of improved assay performance.

  • examination of a vehicle for use with water soluble materials in the murine local lymph node assay
    Food and Chemical Toxicology, 2002
    Co-Authors: Cindy A Ryan, Rebecca Jane Dearman, R A Skinner, Lynn W Cruse, Ian Kimber, G. Frank Gerberick
    Abstract:

    The murine local lymph node assay (LLNA) is a validated method for identifying skin sensitization hazard. Vehicle choice can influence the sensitization potential of haptens in both the LLNA and in humans, therefore selection of an appropriate vehicle is important. Suggested vehicles for the LLNA include organic solvents and organic-aqueous mixtures. However, due to its high surface tension and poor wetting qualities, water is not recommended and therefore testing aqueous soluble materials can be problematic. The aims of this investigation were to identify a water-based vehicle that possesses better skin wetting properties than water alone, and to assess its performance relative to other solvents in the LLNA using aqueous soluble haptens. The selected wetting agent was the surfactant Pluronic(R) L92 (L92). Concentrations of L92 of up to 50% did not induce positive responses in the LLNA. 1% aqueous L92 was chosen for further examination. Dose-response analyses were performed with dinitrobenzene sulfonic acid (DNBS) and formaldehyde formulated either in water, 1% L92, dimethyl sulfoxide (DMSO) or dimethyl formamide (DMF). Potassium dichromate (PDC) and Nickel Sulfate were tested in 1% L92, DMSO or DMF. The highest concentration of potassium dichromate was retested in each vehicle and in water to assess the effect of the wetting agent. Estimates of the relative sensitizing potency in each vehicle were determined by calculation of EC3 values (the estimated concentration required to induce a threshold positive response). While DNBS and formaldehyde produced positive responses in all four vehicles, their relative potency varied among the vehicles. The rank ordering of potencies for both materials was, from highest to lowest, DMF > or = DMSO > 1% L92 > water. Compared with water, use of 1% L92 resulted in >2-fold increase in potency for DNBS and >3-fold increase for formaldehyde. PDC was positive in DMF, DMSO and 1% L92. The potency ranking was DMF > or = DMSO > 1% L92. Re-evaluation of 0.5% PDC confirmed that formulations of both DMSO and DMF induced strong proliferative responses, whereas somewhat less proliferation was recorded with the 1% L92 vehicle. PDC in water was without activity. The performance of 1% L92 as a vehicle for Nickel Sulfate was assessed relative to DMSO and DMF. In DMSO, Nickel Sulfate produced a stimulation index (SI) >3 at only the highest level. Testing in DMF induced low levels of proliferation, but failed to produce a SI of 3 at any concentration tested. When formulated in 1% L92, Nickel Sulfate caused a SI of 3 when tested at 2.5%. Based on the results of these experiments, for identification of sensitization hazard of aqueous soluble materials using the LLNA, DMF and DMSO are the preferred vehicles. However, if a test material is not soluble in DMF or DMSO, or if higher test concentrations can be achieved in an aqueous vehicle, then 1% L92 may provide a better alternative to water alone in terms of improved assay performance.

Xinxin Zhuang - One of the best experts on this subject based on the ideXlab platform.

  • a new crystal of ammonium cobalt Nickel Sulfate hexahydrate for uv light band pass filter
    Optical Materials, 2008
    Co-Authors: Xinxin Zhuang, Guozong Zheng
    Abstract:

    Abstract A new crystal material for UV light band-pass filter, ACNSH (ammonium cobalt Nickel Sulfate hexahydrate) was composed and its crystal structure was studied by X-ray diffraction method. The empirical composition of the title compound is (NH4)2Co0.17Ni0.83(SO4)2 · 6H2O with formula weight 395.15. ACNSH structure belongs to monoclinic space group P2(1)/c, crystal parameters a = 6.2432(3) A, b = 12.4728(5) A, c = 9.1967(4) A, α = γ = 90°, β = 106.9880(10)°, V = 684.90(5) A3, Z = 2, and Dc = 1.916 g/cm3. Solubility of ACNSH in water was determined and large, dark-green crystals with sizes up to 18 × 19 × 45 mm3 have been grown by cooling solution method. Optical transmission spectra reveals that ACNSH has low band at 450–600 nm. Thermo-gravimetric analysis showed that the dehydration temperature of ACNSH is about 97 °C. The relationship between the structural constituents and optical transmission properties is discussed.

  • growth and characterisation of potassium cobalt Nickel Sulfate hexahydrate for uv light filters
    Crystal Research and Technology, 2006
    Co-Authors: Xinxin Zhuang, Guozong Zheng
    Abstract:

    A new single crystal for ultraviolet light filter, KCNSH (Potassium Cobalt Nickel Sulfate Hexahydrate) was designed and its crystal structure was studied using X-ray diffraction in this paper. The empirical of the title compound is K2Co0.1Ni0.9(SO4)2.6H2O with formula weight 437.15. KCNSH crystal belongs to the monoclinic space group P2(1)/c, a=6.1390(3)A, b=12.1839(6)A, c=9.0095(4)A, α=γ=90°, β=105.060(2)°, V=650.74(5)A3, Z=2, Dc=2.231g/cm3. Using the cooling solution method, we have grown a deep green KCNSH crystal with dimension of 12×12×40mm3. The transmission spectrum of KCNSH in the range from UV to near IR wavelengths, its thermal properties, and the relationship between the structure and optical transmission properties are also studied and further discussed in this paper. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

  • structure and spectra character of cobalt Nickel Sulfate twelvehydrate cnsh single crystal
    Crystal Research and Technology, 2003
    Co-Authors: Xinxin Zhuang, Guofu Wang, Zixiang Huang
    Abstract:

    The title compound CoNi(SO4)2 · 12H2O has been prepared and its crystal structure determined by single crystal X-ray differaction at room temperature. The CNSH crystal structure belongs to the monoclinic space group C2/c,a = 9.966(2) A, b = 7.2265(14) A, c = 24.218(5) A, β = 98.32(3)°, V = 1725.9(6) A3, z = 4, Dc = 2.024 gcm−3. The optical transmission character of CNSH crystal in aqueous solution is discontinuous in the range from ultraviolet to near IR wavelengths. The relationship between the structure and the optical transmission property is further discussed. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

  • Ammonium Nickel Sulfate hexahydrate crystal: a new ultraviolet light filter
    Journal of Physics D: Applied Physics, 2002
    Co-Authors: Xinxin Zhuang, Guofu Wang
    Abstract:

    We propounded and grew a new crystal material of ammonium Nickel Sulfate hexahydrate (ANSH) for an ultraviolet light filter. The crystal structure of ANSH was solved by x-ray diffraction method and the empirical formula of the title compound is (NH4)2Ni(SO4)2⋅6H2O. The ANSH crystal belongs to the monoclinic space group P21/C, a = 6.2351 A, b = 12.451(3) A, c = 9.1798(18) A, β = 106.88(3)°, v = 681.9(2) A3, z = 2 and Dc = 1.924 g cm−3. The deep-green ANSH single crystal with a dimension of 20.5×28×15 mm3 has been grown by the cooling solution method. Thermo-gravimetry analysis showed that the dehydration temperature of the ANSH crystal is above 96.06°C, which is much higher than that of commercially available Nickel Sulfate hexahydrate (NSH) crystals. The optical transmission character of the ANSH crystal is discontinuous in the range from ultraviolet (UV) to near IR wavelengths, and has several transmission peaks at 250 nm, 500 nm, 875 nm and 1425 nm, respectively. The UV transmission peak (250 nm) especially has high transmission efficiency and a narrow spectrum band-width. The relationship between the structure and the optical transmission property is further discussed.

  • Growth of potassium Nickel Sulfate hexahydrate (KNSH) crystal and its characterization
    Journal of Crystal Growth, 2001
    Co-Authors: Jianrong Chen, Xinxin Zhuang, Guohui Lee, Rihong Jiang
    Abstract:

    A large clear crystal of potassium Nickel Sulfate hexahydrate (KNSH) with a dimension of 60 x 35 x 30 mm(3) has been grown by a long stick-shaped seed of 60 x 2 x 2 mm3, in a cooling water solution. The habit and condition of growth were observed. The parameters of crystal structure, transmission spectrometry, and thermal properties are reported. (C) 2001 Elsevier Science B.V. All rights reserved.

Cindy A Ryan - One of the best experts on this subject based on the ideXlab platform.

  • examination of a vehicle for use with water soluble materials in the murine local lymph node assay
    Food and Chemical Toxicology, 2002
    Co-Authors: Cindy A Ryan, Rebecca Jane Dearman, R A Skinner, Lynn W Cruse, Ian Kimber, G. Frank Gerberick
    Abstract:

    The murine local lymph node assay (LLNA) is a validated method for identifying skin sensitization hazard. Vehicle choice can influence the sensitization potential of haptens in both the LLNA and in humans, therefore selection of an appropriate vehicle is important. Suggested vehicles for the LLNA include organic solvents and organic-aqueous mixtures. However, due to its high surface tension and poor wetting qualities, water is not recommended and therefore testing aqueous soluble materials can be problematic. The aims of this investigation were to identify a water-based vehicle that possesses better skin wetting properties than water alone, and to assess its performance relative to other solvents in the LLNA using aqueous soluble haptens. The selected wetting agent was the surfactant Pluronic(R) L92 (L92). Concentrations of L92 of up to 50% did not induce positive responses in the LLNA. 1% aqueous L92 was chosen for further examination. Dose-response analyses were performed with dinitrobenzene sulfonic acid (DNBS) and formaldehyde formulated either in water, 1% L92, dimethyl sulfoxide (DMSO) or dimethyl formamide (DMF). Potassium dichromate (PDC) and Nickel Sulfate were tested in 1% L92, DMSO or DMF. The highest concentration of potassium dichromate was retested in each vehicle and in water to assess the effect of the wetting agent. Estimates of the relative sensitizing potency in each vehicle were determined by calculation of EC3 values (the estimated concentration required to induce a threshold positive response). While DNBS and formaldehyde produced positive responses in all four vehicles, their relative potency varied among the vehicles. The rank ordering of potencies for both materials was, from highest to lowest, DMF > or = DMSO > 1% L92 > water. Compared with water, use of 1% L92 resulted in >2-fold increase in potency for DNBS and >3-fold increase for formaldehyde. PDC was positive in DMF, DMSO and 1% L92. The potency ranking was DMF > or = DMSO > 1% L92. Re-evaluation of 0.5% PDC confirmed that formulations of both DMSO and DMF induced strong proliferative responses, whereas somewhat less proliferation was recorded with the 1% L92 vehicle. PDC in water was without activity. The performance of 1% L92 as a vehicle for Nickel Sulfate was assessed relative to DMSO and DMF. In DMSO, Nickel Sulfate produced a stimulation index (SI) >3 at only the highest level. Testing in DMF induced low levels of proliferation, but failed to produce a SI of 3 at any concentration tested. When formulated in 1% L92, Nickel Sulfate caused a SI of 3 when tested at 2.5%. Based on the results of these experiments, for identification of sensitization hazard of aqueous soluble materials using the LLNA, DMF and DMSO are the preferred vehicles. However, if a test material is not soluble in DMF or DMSO, or if higher test concentrations can be achieved in an aqueous vehicle, then 1% L92 may provide a better alternative to water alone in terms of improved assay performance.

  • examination of a vehicle for use with water soluble materials in the murine local lymph node assay
    Food and Chemical Toxicology, 2002
    Co-Authors: Cindy A Ryan, Rebecca Jane Dearman, R A Skinner, Lynn W Cruse, Ian Kimber, G. Frank Gerberick
    Abstract:

    The murine local lymph node assay (LLNA) is a validated method for identifying skin sensitization hazard. Vehicle choice can influence the sensitization potential of haptens in both the LLNA and in humans, therefore selection of an appropriate vehicle is important. Suggested vehicles for the LLNA include organic solvents and organic-aqueous mixtures. However, due to its high surface tension and poor wetting qualities, water is not recommended and therefore testing aqueous soluble materials can be problematic. The aims of this investigation were to identify a water-based vehicle that possesses better skin wetting properties than water alone, and to assess its performance relative to other solvents in the LLNA using aqueous soluble haptens. The selected wetting agent was the surfactant Pluronic(R) L92 (L92). Concentrations of L92 of up to 50% did not induce positive responses in the LLNA. 1% aqueous L92 was chosen for further examination. Dose-response analyses were performed with dinitrobenzene sulfonic acid (DNBS) and formaldehyde formulated either in water, 1% L92, dimethyl sulfoxide (DMSO) or dimethyl formamide (DMF). Potassium dichromate (PDC) and Nickel Sulfate were tested in 1% L92, DMSO or DMF. The highest concentration of potassium dichromate was retested in each vehicle and in water to assess the effect of the wetting agent. Estimates of the relative sensitizing potency in each vehicle were determined by calculation of EC3 values (the estimated concentration required to induce a threshold positive response). While DNBS and formaldehyde produced positive responses in all four vehicles, their relative potency varied among the vehicles. The rank ordering of potencies for both materials was, from highest to lowest, DMF > or = DMSO > 1% L92 > water. Compared with water, use of 1% L92 resulted in >2-fold increase in potency for DNBS and >3-fold increase for formaldehyde. PDC was positive in DMF, DMSO and 1% L92. The potency ranking was DMF > or = DMSO > 1% L92. Re-evaluation of 0.5% PDC confirmed that formulations of both DMSO and DMF induced strong proliferative responses, whereas somewhat less proliferation was recorded with the 1% L92 vehicle. PDC in water was without activity. The performance of 1% L92 as a vehicle for Nickel Sulfate was assessed relative to DMSO and DMF. In DMSO, Nickel Sulfate produced a stimulation index (SI) >3 at only the highest level. Testing in DMF induced low levels of proliferation, but failed to produce a SI of 3 at any concentration tested. When formulated in 1% L92, Nickel Sulfate caused a SI of 3 when tested at 2.5%. Based on the results of these experiments, for identification of sensitization hazard of aqueous soluble materials using the LLNA, DMF and DMSO are the preferred vehicles. However, if a test material is not soluble in DMF or DMSO, or if higher test concentrations can be achieved in an aqueous vehicle, then 1% L92 may provide a better alternative to water alone in terms of improved assay performance.

Guozong Zheng - One of the best experts on this subject based on the ideXlab platform.

  • a new crystal of ammonium cobalt Nickel Sulfate hexahydrate for uv light band pass filter
    Optical Materials, 2008
    Co-Authors: Xinxin Zhuang, Guozong Zheng
    Abstract:

    Abstract A new crystal material for UV light band-pass filter, ACNSH (ammonium cobalt Nickel Sulfate hexahydrate) was composed and its crystal structure was studied by X-ray diffraction method. The empirical composition of the title compound is (NH4)2Co0.17Ni0.83(SO4)2 · 6H2O with formula weight 395.15. ACNSH structure belongs to monoclinic space group P2(1)/c, crystal parameters a = 6.2432(3) A, b = 12.4728(5) A, c = 9.1967(4) A, α = γ = 90°, β = 106.9880(10)°, V = 684.90(5) A3, Z = 2, and Dc = 1.916 g/cm3. Solubility of ACNSH in water was determined and large, dark-green crystals with sizes up to 18 × 19 × 45 mm3 have been grown by cooling solution method. Optical transmission spectra reveals that ACNSH has low band at 450–600 nm. Thermo-gravimetric analysis showed that the dehydration temperature of ACNSH is about 97 °C. The relationship between the structural constituents and optical transmission properties is discussed.

  • growth and characterisation of potassium cobalt Nickel Sulfate hexahydrate for uv light filters
    Crystal Research and Technology, 2006
    Co-Authors: Xinxin Zhuang, Guozong Zheng
    Abstract:

    A new single crystal for ultraviolet light filter, KCNSH (Potassium Cobalt Nickel Sulfate Hexahydrate) was designed and its crystal structure was studied using X-ray diffraction in this paper. The empirical of the title compound is K2Co0.1Ni0.9(SO4)2.6H2O with formula weight 437.15. KCNSH crystal belongs to the monoclinic space group P2(1)/c, a=6.1390(3)A, b=12.1839(6)A, c=9.0095(4)A, α=γ=90°, β=105.060(2)°, V=650.74(5)A3, Z=2, Dc=2.231g/cm3. Using the cooling solution method, we have grown a deep green KCNSH crystal with dimension of 12×12×40mm3. The transmission spectrum of KCNSH in the range from UV to near IR wavelengths, its thermal properties, and the relationship between the structure and optical transmission properties are also studied and further discussed in this paper. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Ian Kimber - One of the best experts on this subject based on the ideXlab platform.

  • examination of a vehicle for use with water soluble materials in the murine local lymph node assay
    Food and Chemical Toxicology, 2002
    Co-Authors: Cindy A Ryan, Rebecca Jane Dearman, R A Skinner, Lynn W Cruse, Ian Kimber, G. Frank Gerberick
    Abstract:

    The murine local lymph node assay (LLNA) is a validated method for identifying skin sensitization hazard. Vehicle choice can influence the sensitization potential of haptens in both the LLNA and in humans, therefore selection of an appropriate vehicle is important. Suggested vehicles for the LLNA include organic solvents and organic-aqueous mixtures. However, due to its high surface tension and poor wetting qualities, water is not recommended and therefore testing aqueous soluble materials can be problematic. The aims of this investigation were to identify a water-based vehicle that possesses better skin wetting properties than water alone, and to assess its performance relative to other solvents in the LLNA using aqueous soluble haptens. The selected wetting agent was the surfactant Pluronic(R) L92 (L92). Concentrations of L92 of up to 50% did not induce positive responses in the LLNA. 1% aqueous L92 was chosen for further examination. Dose-response analyses were performed with dinitrobenzene sulfonic acid (DNBS) and formaldehyde formulated either in water, 1% L92, dimethyl sulfoxide (DMSO) or dimethyl formamide (DMF). Potassium dichromate (PDC) and Nickel Sulfate were tested in 1% L92, DMSO or DMF. The highest concentration of potassium dichromate was retested in each vehicle and in water to assess the effect of the wetting agent. Estimates of the relative sensitizing potency in each vehicle were determined by calculation of EC3 values (the estimated concentration required to induce a threshold positive response). While DNBS and formaldehyde produced positive responses in all four vehicles, their relative potency varied among the vehicles. The rank ordering of potencies for both materials was, from highest to lowest, DMF > or = DMSO > 1% L92 > water. Compared with water, use of 1% L92 resulted in >2-fold increase in potency for DNBS and >3-fold increase for formaldehyde. PDC was positive in DMF, DMSO and 1% L92. The potency ranking was DMF > or = DMSO > 1% L92. Re-evaluation of 0.5% PDC confirmed that formulations of both DMSO and DMF induced strong proliferative responses, whereas somewhat less proliferation was recorded with the 1% L92 vehicle. PDC in water was without activity. The performance of 1% L92 as a vehicle for Nickel Sulfate was assessed relative to DMSO and DMF. In DMSO, Nickel Sulfate produced a stimulation index (SI) >3 at only the highest level. Testing in DMF induced low levels of proliferation, but failed to produce a SI of 3 at any concentration tested. When formulated in 1% L92, Nickel Sulfate caused a SI of 3 when tested at 2.5%. Based on the results of these experiments, for identification of sensitization hazard of aqueous soluble materials using the LLNA, DMF and DMSO are the preferred vehicles. However, if a test material is not soluble in DMF or DMSO, or if higher test concentrations can be achieved in an aqueous vehicle, then 1% L92 may provide a better alternative to water alone in terms of improved assay performance.

  • examination of a vehicle for use with water soluble materials in the murine local lymph node assay
    Food and Chemical Toxicology, 2002
    Co-Authors: Cindy A Ryan, Rebecca Jane Dearman, R A Skinner, Lynn W Cruse, Ian Kimber, G. Frank Gerberick
    Abstract:

    The murine local lymph node assay (LLNA) is a validated method for identifying skin sensitization hazard. Vehicle choice can influence the sensitization potential of haptens in both the LLNA and in humans, therefore selection of an appropriate vehicle is important. Suggested vehicles for the LLNA include organic solvents and organic-aqueous mixtures. However, due to its high surface tension and poor wetting qualities, water is not recommended and therefore testing aqueous soluble materials can be problematic. The aims of this investigation were to identify a water-based vehicle that possesses better skin wetting properties than water alone, and to assess its performance relative to other solvents in the LLNA using aqueous soluble haptens. The selected wetting agent was the surfactant Pluronic(R) L92 (L92). Concentrations of L92 of up to 50% did not induce positive responses in the LLNA. 1% aqueous L92 was chosen for further examination. Dose-response analyses were performed with dinitrobenzene sulfonic acid (DNBS) and formaldehyde formulated either in water, 1% L92, dimethyl sulfoxide (DMSO) or dimethyl formamide (DMF). Potassium dichromate (PDC) and Nickel Sulfate were tested in 1% L92, DMSO or DMF. The highest concentration of potassium dichromate was retested in each vehicle and in water to assess the effect of the wetting agent. Estimates of the relative sensitizing potency in each vehicle were determined by calculation of EC3 values (the estimated concentration required to induce a threshold positive response). While DNBS and formaldehyde produced positive responses in all four vehicles, their relative potency varied among the vehicles. The rank ordering of potencies for both materials was, from highest to lowest, DMF > or = DMSO > 1% L92 > water. Compared with water, use of 1% L92 resulted in >2-fold increase in potency for DNBS and >3-fold increase for formaldehyde. PDC was positive in DMF, DMSO and 1% L92. The potency ranking was DMF > or = DMSO > 1% L92. Re-evaluation of 0.5% PDC confirmed that formulations of both DMSO and DMF induced strong proliferative responses, whereas somewhat less proliferation was recorded with the 1% L92 vehicle. PDC in water was without activity. The performance of 1% L92 as a vehicle for Nickel Sulfate was assessed relative to DMSO and DMF. In DMSO, Nickel Sulfate produced a stimulation index (SI) >3 at only the highest level. Testing in DMF induced low levels of proliferation, but failed to produce a SI of 3 at any concentration tested. When formulated in 1% L92, Nickel Sulfate caused a SI of 3 when tested at 2.5%. Based on the results of these experiments, for identification of sensitization hazard of aqueous soluble materials using the LLNA, DMF and DMSO are the preferred vehicles. However, if a test material is not soluble in DMF or DMSO, or if higher test concentrations can be achieved in an aqueous vehicle, then 1% L92 may provide a better alternative to water alone in terms of improved assay performance.